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• FreeBSD 8.1 unstable network connection

  - by frankcheong

  I have three FreeBSD 8.1 running on three different hardware and therefore consist of different network adapter as well (bce, bge and igb). I found that the network connection is kind of unstable which I have tried to scp some 10MB file and found that I cannot always get the files completed successfully. I have further checked with my network admin and he claim that the problem is being caused by the network driver which cannot support the load whereby he tried to ping using huge packet size (around 15k) and my server will drop packet consistently at a regular interval. I found that this statement may not be valid since the three server is using three different network drive and it would be quite impossible that the same problem is being caused by three different network adapter and thus different network driver. Since then I have tried to tune up the performance by playing around with the /etc/sysctl.conf figures with no luck. kern.ipc.somaxconn=1024 kern.ipc.shmall=3276800 kern.ipc.shmmax=1638400000 # Security net.inet.ip.redirect=0 net.inet.ip.sourceroute=0 net.inet.ip.accept_sourceroute=0 net.inet.icmp.maskrepl=0 net.inet.icmp.log_redirect=0 net.inet.icmp.drop_redirect=1 net.inet.tcp.drop_synfin=1 # Security net.inet.udp.blackhole=1 net.inet.tcp.blackhole=2 # Required by pf net.inet.ip.forwarding=1 #Network Performance Tuning kern.ipc.maxsockbuf=16777216 net.inet.tcp.rfc1323=1 net.inet.tcp.sendbuf_max=16777216 net.inet.tcp.recvbuf_max=16777216 # Setting specifically for 1 or even 10Gbps network net.local.stream.sendspace=262144 net.local.stream.recvspace=262144 net.inet.tcp.local_slowstart_flightsize=10 net.inet.tcp.nolocaltimewait=1 net.inet.tcp.mssdflt=1460 net.inet.tcp.sendbuf_auto=1 net.inet.tcp.sendbuf_inc=16384 net.inet.tcp.recvbuf_auto=1 net.inet.tcp.recvbuf_inc=524288 net.inet.tcp.sendspace=262144 net.inet.tcp.recvspace=262144 net.inet.udp.recvspace=262144 kern.ipc.maxsockbuf=16777216 kern.ipc.nmbclusters=32768 net.inet.tcp.delayed_ack=1 net.inet.tcp.delacktime=100 net.inet.tcp.slowstart_flightsize=179 net.inet.tcp.inflight.enable=1 net.inet.tcp.inflight.min=6144 # Reduce the cache size of slow start connection net.inet.tcp.hostcache.expire=1 Our network admin also claim that they see quite a lot of network up and down from their cisco switch log while I cannot find any up down message inside the dmesg. Have further checked the netstat -s but dont have concrete idea. tcp: 133695291 packets sent 39408539 data packets (3358837321 bytes) 61868 data packets (89472844 bytes) retransmitted 24 data packets unnecessarily retransmitted 0 resends initiated by MTU discovery 50756141 ack-only packets (2148 delayed) 0 URG only packets 0 window probe packets 4372385 window update packets 39781869 control packets 134898031 packets received 72339403 acks (for 3357601899 bytes) 190712 duplicate acks 0 acks for unsent data 59339201 packets (3647021974 bytes) received in-sequence 114 completely duplicate packets (135202 bytes) 27 old duplicate packets 0 packets with some dup. data (0 bytes duped) 42090 out-of-order packets (60817889 bytes) 0 packets (0 bytes) of data after window 0 window probes 3953896 window update packets 64181 packets received after close 0 discarded for bad checksums 0 discarded for bad header offset fields 0 discarded because packet too short 45192 discarded due to memory problems 19945391 connection requests 1323420 connection accepts 0 bad connection attempts 0 listen queue overflows 0 ignored RSTs in the windows 21133581 connections established (including accepts) 21268724 connections closed (including 32737 drops) 207874 connections updated cached RTT on close 207874 connections updated cached RTT variance on close 132439 connections updated cached ssthresh on close 42392 embryonic connections dropped 72339338 segments updated rtt (of 69477829 attempts) 390871 retransmit timeouts 0 connections dropped by rexmit timeout 0 persist timeouts 0 connections dropped by persist timeout 0 Connections (fin_wait_2) dropped because of timeout 13990 keepalive timeouts 2 keepalive probes sent 13988 connections dropped by keepalive 173044 correct ACK header predictions 36947371 correct data packet header predictions 1323420 syncache entries added 0 retransmitted 0 dupsyn 0 dropped 1323420 completed 0 bucket overflow 0 cache overflow 0 reset 0 stale 0 aborted 0 badack 0 unreach 0 zone failures 1323420 cookies sent 0 cookies received 1864 SACK recovery episodes 18005 segment rexmits in SACK recovery episodes 26066896 byte rexmits in SACK recovery episodes 147327 SACK options (SACK blocks) received 87473 SACK options (SACK blocks) sent 0 SACK scoreboard overflow 0 packets with ECN CE bit set 0 packets with ECN ECT(0) bit set 0 packets with ECN ECT(1) bit set 0 successful ECN handshakes 0 times ECN reduced the congestion window udp: 5141258 datagrams received 0 with incomplete header 0 with bad data length field 0 with bad checksum 1 with no checksum 0 dropped due to no socket 129616 broadcast/multicast datagrams undelivered 0 dropped due to full socket buffers 0 not for hashed pcb 5011642 delivered 5016050 datagrams output 0 times multicast source filter matched sctp: 0 input packets 0 datagrams 0 packets that had data 0 input SACK chunks 0 input DATA chunks 0 duplicate DATA chunks 0 input HB chunks 0 HB-ACK chunks 0 input ECNE chunks 0 input AUTH chunks 0 chunks missing AUTH 0 invalid HMAC ids received 0 invalid secret ids received 0 auth failed 0 fast path receives all one chunk 0 fast path multi-part data 0 output packets 0 output SACKs 0 output DATA chunks 0 retransmitted DATA chunks 0 fast retransmitted DATA chunks 0 FR's that happened more than once to same chunk 0 intput HB chunks 0 output ECNE chunks 0 output AUTH chunks 0 ip_output error counter Packet drop statistics: 0 from middle box 0 from end host 0 with data 0 non-data, non-endhost 0 non-endhost, bandwidth rep only 0 not enough for chunk header 0 not enough data to confirm 0 where process_chunk_drop said break 0 failed to find TSN 0 attempt reverse TSN lookup 0 e-host confirms zero-rwnd 0 midbox confirms no space 0 data did not match TSN 0 TSN's marked for Fast Retran Timeouts: 0 iterator timers fired 0 T3 data time outs 0 window probe (T3) timers fired 0 INIT timers fired 0 sack timers fired 0 shutdown timers fired 0 heartbeat timers fired 0 a cookie timeout fired 0 an endpoint changed its cookiesecret 0 PMTU timers fired 0 shutdown ack timers fired 0 shutdown guard timers fired 0 stream reset timers fired 0 early FR timers fired 0 an asconf timer fired 0 auto close timer fired 0 asoc free timers expired 0 inp free timers expired 0 packet shorter than header 0 checksum error 0 no endpoint for port 0 bad v-tag 0 bad SID 0 no memory 0 number of multiple FR in a RTT window 0 RFC813 allowed sending 0 RFC813 does not allow sending 0 times max burst prohibited sending 0 look ahead tells us no memory in interface 0 numbers of window probes sent 0 times an output error to clamp down on next user send 0 times sctp_senderrors were caused from a user 0 number of in data drops due to chunk limit reached 0 number of in data drops due to rwnd limit reached 0 times a ECN reduced the cwnd 0 used express lookup via vtag 0 collision in express lookup 0 times the sender ran dry of user data on primary 0 same for above 0 sacks the slow way 0 window update only sacks sent 0 sends with sinfo_flags !=0 0 unordered sends 0 sends with EOF flag set 0 sends with ABORT flag set 0 times protocol drain called 0 times we did a protocol drain 0 times recv was called with peek 0 cached chunks used 0 cached stream oq's used 0 unread messages abandonded by close 0 send burst avoidance, already max burst inflight to net 0 send cwnd full avoidance, already max burst inflight to net 0 number of map array over-runs via fwd-tsn's ip: 137814085 total packets received 0 bad header checksums 0 with size smaller than minimum 0 with data size < data length 0 with ip length > max ip packet size 0 with header length < data size 0 with data length < header length 0 with bad options 0 with incorrect version number 1200 fragments received 0 fragments dropped (dup or out of space) 0 fragments dropped after timeout 300 packets reassembled ok 137813009 packets for this host 530 packets for unknown/unsupported protocol 0 packets forwarded (0 packets fast forwarded) 61 packets not forwardable 0 packets received for unknown multicast group 0 redirects sent 137234598 packets sent from this host 0 packets sent with fabricated ip header 685307 output packets dropped due to no bufs, etc. 52 output packets discarded due to no route 300 output datagrams fragmented 1200 fragments created 0 datagrams that can't be fragmented 0 tunneling packets that can't find gif 0 datagrams with bad address in header icmp: 0 calls to icmp_error 0 errors not generated in response to an icmp message Output histogram: echo reply: 305 0 messages with bad code fields 0 messages less than the minimum length 0 messages with bad checksum 0 messages with bad length 0 multicast echo requests ignored 0 multicast timestamp requests ignored Input histogram: destination unreachable: 530 echo: 305 305 message responses generated 0 invalid return addresses 0 no return routes ICMP address mask responses are disabled igmp: 0 messages received 0 messages received with too few bytes 0 messages received with wrong TTL 0 messages received with bad checksum 0 V1/V2 membership queries received 0 V3 membership queries received 0 membership queries received with invalid field(s) 0 general queries received 0 group queries received 0 group-source queries received 0 group-source queries dropped 0 membership reports received 0 membership reports received with invalid field(s) 0 membership reports received for groups to which we belong 0 V3 reports received without Router Alert 0 membership reports sent arp: 376748 ARP requests sent 3207 ARP replies sent 245245 ARP requests received 80845 ARP replies received 326090 ARP packets received 267712 total packets dropped due to no ARP entry 108876 ARP entrys timed out 0 Duplicate IPs seen ip6: 2226633 total packets received 0 with size smaller than minimum 0 with data size < data length 0 with bad options 0 with incorrect version number 0 fragments received 0 fragments dropped (dup or out of space) 0 fragments dropped after timeout 0 fragments that exceeded limit 0 packets reassembled ok 2226633 packets for this host 0 packets forwarded 0 packets not forwardable 0 redirects sent 2226633 packets sent from this host 0 packets sent with fabricated ip header 0 output packets dropped due to no bufs, etc. 8 output packets discarded due to no route 0 output datagrams fragmented 0 fragments created 0 datagrams that can't be fragmented 0 packets that violated scope rules 0 multicast packets which we don't join Input histogram: UDP: 2226633 Mbuf statistics: 962679 one mbuf 1263954 one ext mbuf 0 two or more ext mbuf 0 packets whose headers are not continuous 0 tunneling packets that can't find gif 0 packets discarded because of too many headers 0 failures of source address selection Source addresses selection rule applied: icmp6: 0 calls to icmp6_error 0 errors not generated in response to an icmp6 message 0 errors not generated because of rate limitation 0 messages with bad code fields 0 messages < minimum length 0 bad checksums 0 messages with bad length Histogram of error messages to be generated: 0 no route 0 administratively prohibited 0 beyond scope 0 address unreachable 0 port unreachable 0 packet too big 0 time exceed transit 0 time exceed reassembly 0 erroneous header field 0 unrecognized next header 0 unrecognized option 0 redirect 0 unknown 0 message responses generated 0 messages with too many ND options 0 messages with bad ND options 0 bad neighbor solicitation messages 0 bad neighbor advertisement messages 0 bad router solicitation messages 0 bad router advertisement messages 0 bad redirect messages 0 path MTU changes rip6: 0 messages received 0 checksum calculations on inbound 0 messages with bad checksum 0 messages dropped due to no socket 0 multicast messages dropped due to no socket 0 messages dropped due to full socket buffers 0 delivered 0 datagrams output netstat -m 516/5124/5640 mbufs in use (current/cache/total) 512/1634/2146/32768 mbuf clusters in use (current/cache/total/max) 512/1536 mbuf+clusters out of packet secondary zone in use (current/cache) 0/1303/1303/12800 4k (page size) jumbo clusters in use (current/cache/total/max) 0/0/0/6400 9k jumbo clusters in use (current/cache/total/max) 0/0/0/3200 16k jumbo clusters in use (current/cache/total/max) 1153K/9761K/10914K bytes allocated to network (current/cache/total) 0/0/0 requests for mbufs denied (mbufs/clusters/mbuf+clusters) 0/0/0 requests for jumbo clusters denied (4k/9k/16k) 0/8/6656 sfbufs in use (current/peak/max) 0 requests for sfbufs denied 0 requests for sfbufs delayed 0 requests for I/O initiated by sendfile 0 calls to protocol drain routines Anyone got an idea what might be the possible cause?

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• Implementation of ZipCrypto / Zip 2.0 encryption in java

  - by gomesla

  I'm trying o implement the zipcrypto / zip 2.0 encryption algoritm to deal with encrypted zip files as discussed in http://www.pkware.com/documents/casestudies/APPNOTE.TXT I believe I've followed the specs but just can't seem to get it working. I'm fairly sure the issue has to do with my interpretation of the crc algorithm. The documentation states CRC-32: (4 bytes) The CRC-32 algorithm was generously contributed by David Schwaderer and can be found in his excellent book "C Programmers Guide to NetBIOS" published by Howard W. Sams & Co. Inc. The 'magic number' for the CRC is 0xdebb20e3. The proper CRC pre and post conditioning is used, meaning that the CRC register is pre-conditioned with all ones (a starting value of 0xffffffff) and the value is post-conditioned by taking the one's complement of the CRC residual. Here is the snippet that I'm using for the crc32 public class PKZIPCRC32 { private static final int CRC32_POLYNOMIAL = 0xdebb20e3; private int crc = 0xffffffff; private int CRCTable[]; public PKZIPCRC32() { buildCRCTable(); } private void buildCRCTable() { int i, j; CRCTable = new int[256]; for (i = 0; i <= 255; i++) { crc = i; for (j = 8; j > 0; j--) if ((crc & 1) == 1) crc = (crc >>> 1) ^ CRC32_POLYNOMIAL; else crc >>>= 1; CRCTable[i] = crc; } } private int crc32(byte buffer[], int start, int count, int lastcrc) { int temp1, temp2; int i = start; crc = lastcrc; while (count-- != 0) { temp1 = crc >>> 8; temp2 = CRCTable[(crc ^ buffer[i++]) & 0xFF]; crc = temp1 ^ temp2; } return crc; } public int crc32(int crc, byte buffer) { return crc32(new byte[] { buffer }, 0, 1, crc); } } Below is my complete code. Can anyone see what I'm doing wrong. package org.apache.commons.compress.archivers.zip; import java.io.IOException; import java.io.InputStream; public class ZipCryptoInputStream extends InputStream { public class PKZIPCRC32 { private static final int CRC32_POLYNOMIAL = 0xdebb20e3; private int crc = 0xffffffff; private int CRCTable[]; public PKZIPCRC32() { buildCRCTable(); } private void buildCRCTable() { int i, j; CRCTable = new int[256]; for (i = 0; i <= 255; i++) { crc = i; for (j = 8; j > 0; j--) if ((crc & 1) == 1) crc = (crc >>> 1) ^ CRC32_POLYNOMIAL; else crc >>>= 1; CRCTable[i] = crc; } } private int crc32(byte buffer[], int start, int count, int lastcrc) { int temp1, temp2; int i = start; crc = lastcrc; while (count-- != 0) { temp1 = crc >>> 8; temp2 = CRCTable[(crc ^ buffer[i++]) & 0xFF]; crc = temp1 ^ temp2; } return crc; } public int crc32(int crc, byte buffer) { return crc32(new byte[] { buffer }, 0, 1, crc); } } private static final long ENCRYPTION_KEY_1 = 0x12345678; private static final long ENCRYPTION_KEY_2 = 0x23456789; private static final long ENCRYPTION_KEY_3 = 0x34567890; private InputStream baseInputStream = null; private final PKZIPCRC32 checksumEngine = new PKZIPCRC32(); private long[] keys = null; public ZipCryptoInputStream(ZipArchiveEntry zipEntry, InputStream inputStream, String passwd) throws Exception { baseInputStream = inputStream; // Decryption // ---------- // PKZIP encrypts the compressed data stream. Encrypted files must // be decrypted before they can be extracted. // // Each encrypted file has an extra 12 bytes stored at the start of // the data area defining the encryption header for that file. The // encryption header is originally set to random values, and then // itself encrypted, using three, 32-bit keys. The key values are // initialized using the supplied encryption password. After each byte // is encrypted, the keys are then updated using pseudo-random number // generation techniques in combination with the same CRC-32 algorithm // used in PKZIP and described elsewhere in this document. // // The following is the basic steps required to decrypt a file: // // 1) Initialize the three 32-bit keys with the password. // 2) Read and decrypt the 12-byte encryption header, further // initializing the encryption keys. // 3) Read and decrypt the compressed data stream using the // encryption keys. // Step 1 - Initializing the encryption keys // ----------------------------------------- // // Key(0) <- 305419896 // Key(1) <- 591751049 // Key(2) <- 878082192 // // loop for i <- 0 to length(password)-1 // update_keys(password(i)) // end loop // // Where update_keys() is defined as: // // update_keys(char): // Key(0) <- crc32(key(0),char) // Key(1) <- Key(1) + (Key(0) & 000000ffH) // Key(1) <- Key(1) * 134775813 + 1 // Key(2) <- crc32(key(2),key(1) >> 24) // end update_keys // // Where crc32(old_crc,char) is a routine that given a CRC value and a // character, returns an updated CRC value after applying the CRC-32 // algorithm described elsewhere in this document. keys = new long[] { ENCRYPTION_KEY_1, ENCRYPTION_KEY_2, ENCRYPTION_KEY_3 }; for (int i = 0; i < passwd.length(); ++i) { update_keys((byte) passwd.charAt(i)); } // Step 2 - Decrypting the encryption header // ----------------------------------------- // // The purpose of this step is to further initialize the encryption // keys, based on random data, to render a plaintext attack on the // data ineffective. // // Read the 12-byte encryption header into Buffer, in locations // Buffer(0) thru Buffer(11). // // loop for i <- 0 to 11 // C <- buffer(i) ^ decrypt_byte() // update_keys(C) // buffer(i) <- C // end loop // // Where decrypt_byte() is defined as: // // unsigned char decrypt_byte() // local unsigned short temp // temp <- Key(2) | 2 // decrypt_byte <- (temp * (temp ^ 1)) >> 8 // end decrypt_byte // // After the header is decrypted, the last 1 or 2 bytes in Buffer // should be the high-order word/byte of the CRC for the file being // decrypted, stored in Intel low-byte/high-byte order. Versions of // PKZIP prior to 2.0 used a 2 byte CRC check; a 1 byte CRC check is // used on versions after 2.0. This can be used to test if the password // supplied is correct or not. byte[] encryptionHeader = new byte[12]; baseInputStream.read(encryptionHeader); for (int i = 0; i < encryptionHeader.length; i++) { encryptionHeader[i] ^= decrypt_byte(); update_keys(encryptionHeader[i]); } } protected byte decrypt_byte() { byte temp = (byte) (keys[2] | 2); return (byte) ((temp * (temp ^ 1)) >> 8); } @Override public int read() throws IOException { // // Step 3 - Decrypting the compressed data stream // ---------------------------------------------- // // The compressed data stream can be decrypted as follows: // // loop until done // read a character into C // Temp <- C ^ decrypt_byte() // update_keys(temp) // output Temp // end loop int read = baseInputStream.read(); read ^= decrypt_byte(); update_keys((byte) read); return read; } private final void update_keys(byte ch) { keys[0] = checksumEngine.crc32((int) keys[0], ch); keys[1] = keys[1] + (byte) keys[0]; keys[1] = keys[1] * 134775813 + 1; keys[2] = checksumEngine.crc32((int) keys[2], (byte) (keys[1] >> 24)); } }

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• Postgres cannot connect to server

  - by user1408935

  Super stumped by why Postgres isn't working on a new app I just started. I've got it working for one app already. I'm using postgres.app, and it's running. I started a new app with rails new depot -d postgresql and then I went into the database.yml file and changed username to my $USER (which is what it is for the other app, which is working). So now my database.yml file has this development section: development: adapter: postgresql encoding: unicode database: depot_development pool: 5 username: <username> password: But when I run "rake db:create" or "rake db:create:all" I still got this error (in full, cause I don't know what's relevant): Couldn't create database for {"adapter"=>"postgresql", "encoding"=>"unicode", "database"=>"depot_development", "pool"=>5, "username"=>"<username>", "password"=>nil} could not connect to server: Permission denied Is the server running locally and accepting connections on Unix domain socket "/var/pgsql_socket/.s.PGSQL.5432"? /Users/<username>/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.8/lib/active_record/connection_adapters/postgresql_adapter.rb:1213:in `initialize' /Users/<username>/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.8/lib/active_record/connection_adapters/postgresql_adapter.rb:1213:in `new' /Users/<username>/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.8/lib/active_record/connection_adapters/postgresql_adapter.rb:1213:in `connect' /Users/<username>/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.8/lib/active_record/connection_adapters/postgresql_adapter.rb:329:in `initialize' /Users/<username>/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.8/lib/active_record/connection_adapters/postgresql_adapter.rb:28:in `new' /Users/<username>/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.8/lib/active_record/connection_adapters/postgresql_adapter.rb:28:in `postgresql_connection' /Users/<username>/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.8/lib/active_record/connection_adapters/abstract/connection_pool.rb:309:in `new_connection' /Users/<username>/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.8/lib/active_record/connection_adapters/abstract/connection_pool.rb:319:in `checkout_new_connection' /Users/<username>/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.8/lib/active_record/connection_adapters/abstract/connection_pool.rb:241:in `block (2 levels) in checkout' /Users/<username>/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.8/lib/active_record/connection_adapters/abstract/connection_pool.rb:236:in `loop' /Users/<username>/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.8/lib/active_record/connection_adapters/abstract/connection_pool.rb:236:in `block in checkout' /Users/<username>/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/monitor.rb:211:in `mon_synchronize' /Users/<username>/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.8/lib/active_record/connection_adapters/abstract/connection_pool.rb:233:in `checkout' /Users/<username>/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.8/lib/active_record/connection_adapters/abstract/connection_pool.rb:96:in `block in connection' /Users/<username>/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/monitor.rb:211:in `mon_synchronize' /Users/<username>/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.8/lib/active_record/connection_adapters/abstract/connection_pool.rb:95:in `connection' /Users/<username>/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.8/lib/active_record/connection_adapters/abstract/connection_pool.rb:404:in `retrieve_connection' /Users/<username>/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.8/lib/active_record/connection_adapters/abstract/connection_specification.rb:170:in `retrieve_connection' /Users/<username>/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.8/lib/active_record/connection_adapters/abstract/connection_specification.rb:144:in `connection' /Users/<username>/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.8/lib/active_record/railties/databases.rake:107:in `rescue in create_database' /Users/<username>/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.8/lib/active_record/railties/databases.rake:51:in `create_database' /Users/<username>/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.8/lib/active_record/railties/databases.rake:40:in `block (3 levels) in <top (required)>' /Users/<username>/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.8/lib/active_record/railties/databases.rake:40:in `each' /Users/<username>/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.8/lib/active_record/railties/databases.rake:40:in `block (2 levels) in <top (required)>' /Users/<username>/.rvm/gems/ruby-1.9.3-p194@global/gems/rake-0.9.2.2/lib/rake/task.rb:205:in `call' /Users/<username>/.rvm/gems/ruby-1.9.3-p194@global/gems/rake-0.9.2.2/lib/rake/task.rb:205:in `block in execute' /Users/<username>/.rvm/gems/ruby-1.9.3-p194@global/gems/rake-0.9.2.2/lib/rake/task.rb:200:in `each' /Users/<username>/.rvm/gems/ruby-1.9.3-p194@global/gems/rake-0.9.2.2/lib/rake/task.rb:200:in `execute' /Users/<username>/.rvm/gems/ruby-1.9.3-p194@global/gems/rake-0.9.2.2/lib/rake/task.rb:158:in `block in invoke_with_call_chain' /Users/<username>/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/monitor.rb:211:in `mon_synchronize' /Users/<username>/.rvm/gems/ruby-1.9.3-p194@global/gems/rake-0.9.2.2/lib/rake/task.rb:151:in `invoke_with_call_chain' /Users/<username>/.rvm/gems/ruby-1.9.3-p194@global/gems/rake-0.9.2.2/lib/rake/task.rb:144:in `invoke' /Users/<username>/.rvm/gems/ruby-1.9.3-p194@global/gems/rake-0.9.2.2/lib/rake/application.rb:116:in `invoke_task' /Users/<username>/.rvm/gems/ruby-1.9.3-p194@global/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `block (2 levels) in top_level' /Users/<username>/.rvm/gems/ruby-1.9.3-p194@global/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `each' /Users/<username>/.rvm/gems/ruby-1.9.3-p194@global/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `block in top_level' /Users/<username>/.rvm/gems/ruby-1.9.3-p194@global/gems/rake-0.9.2.2/lib/rake/application.rb:133:in `standard_exception_handling' /Users/<username>/.rvm/gems/ruby-1.9.3-p194@global/gems/rake-0.9.2.2/lib/rake/application.rb:88:in `top_level' /Users/<username>/.rvm/gems/ruby-1.9.3-p194@global/gems/rake-0.9.2.2/lib/rake/application.rb:66:in `block in run' /Users/<username>/.rvm/gems/ruby-1.9.3-p194@global/gems/rake-0.9.2.2/lib/rake/application.rb:133:in `standard_exception_handling' /Users/<username>/.rvm/gems/ruby-1.9.3-p194@global/gems/rake-0.9.2.2/lib/rake/application.rb:63:in `run' /Users/<username>/.rvm/gems/ruby-1.9.3-p194@global/gems/rake-0.9.2.2/bin/rake:33:in `<top (required)>' /Users/<username>/.rvm/gems/ruby-1.9.3-p194@global/bin/rake:19:in `load' /Users/<username>/.rvm/gems/ruby-1.9.3-p194@global/bin/rake:19:in `<main>' /Users/<username>/.rvm/gems/ruby-1.9.3-p194/bin/ruby_noexec_wrapper:14:in `eval' /Users/<username>/.rvm/gems/ruby-1.9.3-p194/bin/ruby_noexec_wrapper:14:in `<main>' Couldn't create database for {"adapter"=>"postgresql", "encoding"=>"unicode", "database"=>"depot_test", "pool"=>5, "username"=>"<username>", "password"=>nil} I have tried createdb depot_development I have tried going into the psql environment and listing users (which included my username among them). In the same psql environment, I tried CREATE DATABASE depot; I've made sure that the pg gem is installed with bundle install, I've run "pg_ctl start", to which I got this response: pg_ctl: no database directory specified and environment variable PGDATA unset I ran "ps aux | grep postgres" to make sure postgres was running, to which I got this in return (which looks like it's doing OK, right?): <username> 10390 0.4 0.0 2425480 180 s000 R+ 6:15PM 0:00.00 grep postgres <username> 2907 0.0 0.0 2441604 464 ?? Ss 6:17PM 0:02.31 postgres: stats collector process <username> 2906 0.0 0.0 2445520 1664 ?? Ss 6:17PM 0:02.33 postgres: autovacuum launcher process <username> 2905 0.0 0.0 2445388 600 ?? Ss 6:17PM 0:09.25 postgres: wal writer process <username> 2904 0.0 0.0 2445388 1252 ?? Ss 6:17PM 0:12.08 postgres: writer process <username> 2902 0.0 0.0 2445388 3688 ?? S 6:17PM 0:00.54 /Applications/Postgres.app/Contents/MacOS/bin/postgres -D /Users/<username>/Library/Application Support/Postgres/var -p5432 The short of it, is I've been troubleshooting for a WHILE and have NO idea what's wrong. Any ideas? I'd really appreciate it, cause I'm pretty new to Rails, and this is a pretty disheartening roadblock. Thanks! EDIT -- Per request, posting the successful database.yml . It seems the difference is the inclusion of a password: development: adapter: postgresql encoding: unicode database: *******_development pool: 5 username: ******* password: ******* EDIT2 -- When I add a password to the .yml file, then run rake db:create again, I get this error. rake aborted! No Rakefile found (looking for: rakefile, Rakefile, rakefile.rb, Rakefile.rb)

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• calling and killing a parent function with onmouseover and onmouseout events

  - by Zoolu

  I want to call the function upon the onmouseover="ParentFunction();" then kill it onmouseout="killParent();". Note: in my code the parent function is called initiate(); and the killer function is called reset(); which lies outside the parent function at the bottom of the script. I don't know how to kill the intitiate() function my first guess was: var reset = function(){ return initiate(); }; here's my source code: any suggestions and help appreciated. <!doctype html> <html> <head> <title> function/event prototype </title> <link rel="stylesheet" type="text/css" href="styling.css" /> </head> <body> <h2> <em>Fantastical place<br/>prototype</em> </h2> <div id="button-container"> <div id="button-box"> <button id="activate" onmouseover="initiate()" onmouseout="reset();" width="50px" height="50px" title="Activate"> </button> </div> <div id="text-box"> </div> </div> <div id="container"> <canvas id="playground" width="200px" height="250px"> </canvas> <canvas id="face" width="400px" height="200px"> </canvas> <!-- <div id="clear"> </div> --> </div> <script> alert("Welcome, there are x entries as of" +""+new Date().getHours()); //global scope var i=0; var c1 = []; //c is short for collect var c2 = []; var c3 = []; var c4 = []; var c5 = []; var c6 = []; var initiate = function(){ //the button that triggers the program var timer = setInterval(function(){clock()},90); //copy this block for ref. function clock(){ i+=1; var a = Math.round(Math.random()*200); var b = Math.round(Math.random()*250); var c = Math.round(Math.random()*200); var d = Math.round(Math.random()*250); var e = Math.round(Math.random()*200); var f = Math.round(Math.random()*250); c1.push(a); c2.push(b); c3.push(c); c4.push(d); c5.push(e); c6.push(f); // document.write(i); var c = document.getElementById("playground"); var ctx = c.getContext("2d"); ctx.beginPath(); ctx.moveTo(c3[i-2], c4[i-2]); ctx.bezierCurveTo(c1[i-2],c2[i-2],c5[i-2],c6[i-2],c3[i-1], c4[i-1]); // ctx.lineTo(c3[i-1], c4[i-1]); if(a<200){ ctx.strokeStyle="#FF33CC"; } else if(a<400){ ctx.strokeStyle="#FF33aa"; } else{ ctx.strokeStyle="#FF3388"; } ctx.stroke(); document.getElementById("text-box").innerHTML=i+"<p>Thoughts.</p>"; if(i===20){ //alert("15 reached"); clearInterval(timer);//to clearInterval must be using a global scoped variable. return; } }; //end of clock //setInterval(clock,150); var targetFace = document.getElementById("face"); var face = targetFace.getContext("2d"); var faceTimer = setInterval(function(){faceAnim()},80); //copy this block for ref. global scoped. function faceAnim(){ face.beginPath(); face.strokeStyle="#FF33CC"; face.moveTo(100,104); //eye line face.bezierCurveTo(150,125,250,125,300,104); face.moveTo(200,1); //centre line face.lineTo(200,400); face.moveTo(125,111);//left eye lid face.bezierCurveTo(160,135,170,130,185,120); face.moveTo(150,116);//left eye face.bezierCurveTo(155,125,165,125,170,118); face.moveTo(275,111);//right eye lid face.bezierCurveTo(240,135,230,130,215,120); face.moveTo(250,116);//right eye face.bezierCurveTo(245,125,235,125,230,118); face.moveTo(195, 118); //left nose face.lineTo(190, 160); face.lineTo(200,170); face.moveTo(190,160); //left nostroll face.lineTo(180,160); face.lineTo(191,154); face.moveTo(180,160); //left lower nostrol face.lineTo(200,170); face.moveTo(205, 118); //right nose face.lineTo(210, 160); face.lineTo(200,170); face.moveTo(210,160); //right nostroll face.lineTo(220,160); face.lineTo(209,154); face.moveTo(220,160); //right lower nostrol face.lineTo(200,170); face.moveTo(200,140); //outer triad face.lineTo(170, 100); face.lineTo(230, 100); face.lineTo(200, 140); face.moveTo(200,145); //outer triad drop shadow face.lineTo(170, 100); face.lineTo(230, 100); face.lineTo(200, 145); face.moveTo(200,130); //inner triad face.lineTo(180, 105); face.lineTo(220, 105); face.lineTo(200, 130); //face.lineWidth =0.6; face.moveTo(280,111);//outer right eye lid face.bezierCurveTo(240,140,230,135,210,120); face.moveTo(120,111);//outer left eye lid face.bezierCurveTo(160,140,170,135,190,120); face.moveTo(162,174); //upper mouth line face.bezierCurveTo(170,180,230,180,238,174); face.moveTo(165,175); //mouth line bottom face.bezierCurveTo(190,Math.floor(Math.random()*25+180),210,Math.floor(Math.random()*25+180),235,175); face.moveTo(232,204); //head shape face.lineTo(340, 20); face.moveTo(168,204); //head shape face.lineTo(60, 20); face.stroke(); //exicute all co-ords. }; //end of face anim var clearFace = function(){ document.getElementById('face').getContext('2d').clearRect(0, 0, 700, 750); }; setInterval(clearFace,90); }; //end of parent function var reset = function(){ document.getElementById('playground').getContext('2d').clearRect(0, 0, 700, 750); //clearInterval(faceTimer); //delete initiate(); }; </script> </body> </html>

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• Problem Solving: Algorithm Required Urgently, Plz Help

  - by user616417

  Problem Solving: I've been working on something since last week. I am stuck at a point, where I want to find the minimum number of airplanes required to carry out a flight schedule given below. Plz, try out the brainstorming, i need the algorithm really badly, i'm also short of time. Thank u in advance. The Schedule---- Flight #,From,To,Departure,Arrival,Days,Via 6E 204,Agartala,Delhi,10:15:00,13:55:00,Daily,Kolkata 6E 360,Agartala,Imphal,13:50:00,14:35:00,Mo Th Sa, 6E 204,Agartala,Kolkata,10:15:00,11:00:00,Daily, 6E 360,Agartala,Kolkata,13:50:00,16:15:00,Mo Th Sa,Imphal 6E 362,Agartala,Kolkata,15:25:00,16:15:00,Tu We Fr Su, 6E 153,Ahmedabad,Bangalore,17:00:00,19:00:00,Daily, 6E 212,Ahmedabad,Chennai,9:00:00,12:55:00,Daily,Mumbai 6E 154,Ahmedabad,Delhi,12:30:00,14:00:00,Daily, 6E 211,Ahmedabad,Jaipur,19:10:00,20:20:00,Daily, 6E 410,Ahmedabad,Kolkata,15:00:00,17:30:00,Daily, 6E 212,Ahmedabad,Mumbai,9:00:00,10:10:00,Daily, 6E 409,Ahmedabad,Pune,14:25:00,15:40:00,Ex Sat, 6E 154,Bangalore,Ahmedabad,10:00:00,12:00:00,Daily, 6E 277,Bangalore,Chennai,15:35:00,16:25:00,Daily, 6E 132,Bangalore,Delhi,6:00:00,8:25:00,Daily, 6E 102,Bangalore,Delhi,9:50:00,13:45:00,Ex Sat,Pune 6E 154,Bangalore,Delhi,10:00:00,14:00:00,Daily,Ahmedabad 6E 104,Bangalore,Delhi,11:30:00,14:10:00,Sat, 6E 122,Bangalore,Delhi,17:20:00,20:00:00,Daily, 6E 108,Bangalore,Delhi,19:20:00,23:10:00,Sat,Pune 6E 106,Bangalore,Delhi,19:30:00,22:00:00,Ex Sat, 6E 275,Bangalore,Goa,12:15:00,13:15:00,Daily, 6E 351,Bangalore,Hyderabad,8:25:00,9:25:00,Daily, 6E 152,Bangalore,Hyderabad,19:10:00,20:10:00,Ex Sat, 6E 152,Bangalore,Hyderabad,19:30:00,20:35:00,Sat, 6E 152,Bangalore,Jaipur,19:10:00,22:30:00,Ex Sat,Hyderabad 6E 152,Bangalore,Jaipur,19:30:00,22:30:00,Sat,Hyderabad 6E 351,Bangalore,Kolkata,8:25:00,11:55:00,Daily,Hyderabad 6E 277,Bangalore,Kolkata,15:35:00,19:15:00,Daily,Chennai 6E 402,Bangalore,Mumbai,6:05:00,7:45:00,Daily, 6E 275,Bangalore,Mumbai,12:15:00,14:45:00,Daily,Goa 6E 414,Bangalore,Mumbai,12:45:00,14:20:00,Daily, 6E 412,Bangalore,Mumbai,21:20:00,23:20:00,Daily, 6E 102,Bangalore,Pune,9:50:00,11:10:00,Ex Sat, 6E 108,Bangalore,Pune,19:20:00,20:40:00,Sat, 6E 258,Bhubaneshwar,Delhi,18:55:00,20:55:00,Daily, 6E 257,Bhubaneshwar,Hyderabad,10:40:00,12:05:00,Daily, 6E 257,Bhubaneshwar,Mumbai,10:40:00,13:50:00,Daily,Hyderabad 6E 211,Chennai,Ahmedabad,15:10:00,18:40:00,Daily,Mumbai 6E 275,Chennai,Bangalore,10:50:00,11:40:00,Daily, 6E 302,Chennai,Delhi,11:35:00,15:20:00,Daily,Hyderabad 6E 282,Chennai,Delhi,19:45:00,22:30:00,Daily, 6E 275,Chennai,Goa,10:50:00,13:15:00,Daily,Bangalore 6E 302,Chennai,Hyderabad,11:35:00,12:40:00,Daily, 6E 211,Chennai,Jaipur,15:10:00,20:20:00,Daily,Mumbai/Ahmedabad 6E 523,Chennai,Kolkata,8:20:00,10:30:00,Daily, 6E 277,Chennai,Kolkata,16:55:00,19:15:00,Daily, 6E 211,Chennai,Mumbai,15:10:00,16:50:00,Daily, 6E 524,Chennai,Pune,21:15:00,23:00:00,Daily, 6E 273,Delhi,Agartala,6:15:00,9:45:00,Daily,Kolkata 6E 153,Delhi,Ahmedabad,14:45:00,16:30:00,Daily, 6E 101,Delhi,Bangalore,6:30:00,9:10:00,Ex Sat, 6E 103,Delhi,Bangalore,6:45:00,10:40:00,Sat,Pune 6E 121,Delhi,Bangalore,9:30:00,12:10:00,Daily, 6E 105,Delhi,Bangalore,14:20:00,18:30:00,Ex Sat,Pune 6E 153,Delhi,Bangalore,14:45:00,19:00:00,Daily,Ahmedabad 6E 107,Delhi,Bangalore,15:55:00,18:40:00,Sat, 6E 131,Delhi,Bangalore,20:45:00,23:15:00,Daily, 6E 257,Delhi,Bhubaneshwar,8:10:00,10:10:00,Daily, 6E 301,Delhi,Chennai,7:00:00,11:05:00,Daily,Hyderabad 6E 283,Delhi,Chennai,16:30:00,19:05:00,Daily, 6E 181,Delhi,Goa,9:15:00,13:35:00,Daily,Mumbai 6E 333,Delhi,Goa,11:45:00,14:15:00,Daily, 6E 201,Delhi,Guwahati,5:30:00,7:50:00,Daily, 6E 301,Delhi,Hyderabad,7:00:00,9:00:00,Daily, 6E 257,Delhi,Hyderabad,8:10:00,12:05:00,Daily,Bhubaneshwar 6E 305,Delhi,Hyderabad,14:00:00,15:55:00,Daily, 6E 307,Delhi,Hyderabad,21:00:00,22:55:00,Daily, 6E 201,Delhi,Imphal,5:30:00,9:10:00,Daily,Guwahati 6E 305,Delhi,Kochi,14:00:00,18:25:00,Daily,Hyderabad 6E 273,Delhi,Kolkata,6:15:00,8:20:00,Daily, 6E 203,Delhi,Kolkata,15:00:00,17:05:00,Daily, 6E 209,Delhi,Kolkata,18:30:00,20:45:00,Daily, 6E 183,Delhi,Mumbai,6:45:00,8:35:00,Daily, 6E 181,Delhi,Mumbai,9:15:00,11:35:00,Daily, 6E 481,Delhi,Mumbai,10:50:00,13:50:00,Daily,Vadodara 6E 189,Delhi,Mumbai,14:45:00,16:50:00,Daily, 6E 187,Delhi,Mumbai,17:50:00,19:50:00,Daily, 6E 185,Delhi,Mumbai,20:15:00,22:20:00,Daily, 6E 135,Delhi,Nagpur,8:55:00,10:40:00,Ex Sat, 6E 103,Delhi,Pune,6:45:00,8:45:00,Sat, 6E 135,Delhi,Pune,8:55:00,12:30:00,Ex Sat,Nagpur 6E 105,Delhi,Pune,14:20:00,16:30:00,Ex Sat, 6E 481,Delhi,Vadodara,10:50:00,12:20:00,Daily, 6E 277,Goa,Bangalore,14:05:00,15:00:00,Daily, 6E 277,Goa,Chennai,14:05:00,16:25:00,Daily,Bangalore 6E 334,Goa,Delhi,14:45:00,17:10:00,Daily, 6E 277,Goa,Kolkata,14:05:00,19:15:00,Daily,Bangalore/Chennai 6E 275,Goa,Mumbai,13:45:00,14:45:00,Daily, 6E 202,Guwahati,Delhi,11:00:00,13:25:00,Daily, 6E 201,Guwahati,Imphal,8:25:00,9:10:00,Daily, 6E 208,Guwahati,Jaipur,12:40:00,16:55:00,Daily,Kolkata 6E 208,Guwahati,Kolkata,12:40:00,14:00:00,Daily, 6E 322,Guwahati,Kolkata,15:30:00,16:50:00,Daily, 6E 322,Guwahati,Mumbai,15:30:00,20:20:00,Daily,Kolkata 6E 151,Hyderabad,Bangalore,8:20:00,9:20:00,Daily, 6E 352,Hyderabad,Bangalore,19:40:00,20:40:00,Daily, 6E 258,Hyderabad,Bhubaneshwar,16:40:00,18:20:00,Daily, 6E 301,Hyderabad,Chennai,9:50:00,11:05:00,Daily, 6E 308,Hyderabad,Delhi,6:10:00,8:00:00,Daily, 6E 302,Hyderabad,Delhi,13:10:00,15:20:00,Daily, 6E 258,Hyderabad,Delhi,16:40:00,20:55:00,Daily,Bhubaneshwar 6E 306,Hyderabad,Delhi,21:00:00,23:05:00,Daily, 6E 152,Hyderabad,Jaipur,20:50:00,22:30:00,Ex Sat, 6E 152,Hyderabad,Jaipur,21:10:00,22:30:00,Sat, 6E 305,Hyderabad,Kochi,16:45:00,18:25:00,Daily, 6E 351,Hyderabad,Kolkata,9:55:00,11:55:00,Daily, 6E 257,Hyderabad,Mumbai,12:35:00,13:50:00,Daily, 6E 362,Imphal,Agartala,14:15:00,14:55:00,Tu We Fr Su, 6E 202,Imphal,Delhi,9:40:00,13:25:00,Daily,Guwahati 6E 202,Imphal,Guwahati,9:40:00,10:25:00,Daily, 6E 362,Imphal,Kolkata,14:15:00,16:15:00,Tu We Fr Su,Agartala 6E 360,Imphal,Kolkata,15:05:00,16:15:00,Mo Th Sa, 6E 212,Jaipur,Ahmedabad,7:30:00,8:35:00,Daily, 6E 151,Jaipur,Bangalore,6:00:00,9:20:00,Daily,Hyderabad 6E 212,Jaipur,Chennai,7:30:00,12:55:00,Daily,Mumbai/Ahmedabad 6E 207,Jaipur,Guwahati,8:20:00,12:10:00,Daily,Kolkata 6E 151,Jaipur,Hyderabad,6:00:00,7:40:00,Daily, 6E 207,Jaipur,Kolkata,8:20:00,10:10:00,Daily, 6E 323,Jaipur,Kolkata,17:35:00,23:00:00,Daily,Mumbai 6E 212,Jaipur,Mumbai,7:30:00,10:10:00,Daily,Ahmedabad 6E 323,Jaipur,Mumbai,17:35:00,19:15:00,Daily, 6E 306,Kochi,Delhi,19:00:00,23:05:00,Daily,Hyderabad 6E 306,Kochi,Hyderabad,19:00:00,20:30:00,Daily, 6E 273,Kolkata,Agartala,8:50:00,9:45:00,Daily, 6E 360,Kolkata,Agartala,12:30:00,13:20:00,Mo Th Sa, 6E 362,Kolkata,Agartala,12:30:00,14:55:00,TuWeFrSu,Imphal 6E 409,Kolkata,Ahmedabad,11:10:00,13:50:00,Daily, 6E 275,Kolkata,Bangalore,7:30:00,11:40:00,Daily,Chennai 6E 352,Kolkata,Bangalore,16:50:00,20:40:00,Daily,Hyderabad 6E 275,Kolkata,Chennai,7:30:00,9:50:00,Daily, 6E 524,Kolkata,Chennai,18:15:00,20:25:00,Daily, 6E 210,Kolkata,Delhi,7:45:00,10:05:00,Daily, 6E 204,Kolkata,Delhi,11:40:00,13:55:00,Daily, 6E 274,Kolkata,Delhi,19:45:00,22:10:00,Daily, 6E 275,Kolkata,Goa,7:30:00,13:15:00,Daily,Chennai/Bangalore 6E 207,Kolkata,Guwahati,10:50:00,12:10:00,Daily, 6E 321,Kolkata,Guwahati,13:00:00,14:20:00,Daily, 6E 352,Kolkata,Hyderabad,16:50:00,19:00:00,Daily, 6E 362,Kolkata,Imphal,12:30:00,13:45:00,Tu We Fr Su, 6E 360,Kolkata,Imphal,12:30:00,14:35:00,MoThSa,Agartala 6E 208,Kolkata,Jaipur,14:35:00,16:55:00,Daily, 6E 320,Kolkata,Mumbai,6:00:00,8:30:00,Daily, 6E 322,Kolkata,Mumbai,17:35:00,20:20:00,Daily, 6E 404,Kolkata,Mumbai,18:35:00,21:55:00,Daily,Nagpur 6E 404,Kolkata,Nagpur,18:35:00,20:05:00,Daily, 6E 409,Kolkata,Pune,11:10:00,15:40:00,Ex Sat,Ahmedabad 6E 524,Kolkata,Pune,18:15:00,23:00:00,Daily,Chennai 6E 211,Mumbai,Ahmedabad,17:40:00,18:40:00,Daily, 6E 411,Mumbai,Bangalore,6:20:00,7:50:00,Daily, 6E 413,Mumbai,Bangalore,15:00:00,16:40:00,Daily, 6E 415,Mumbai,Bangalore,21:05:00,22:40:00,Daily, 6E 258,Mumbai,Bhubaneshwar,14:30:00,18:20:00,Daily,Hyderabad 6E 212,Mumbai,Chennai,11:00:00,12:55:00,Daily, 6E 184,Mumbai,Delhi,6:15:00,8:15:00,Daily, 6E 180,Mumbai,Delhi,8:25:00,10:35:00,Daily, 6E 482,Mumbai,Delhi,9:25:00,12:35:00,Daily,Vadodara 6E 188,Mumbai,Delhi,14:25:00,16:35:00,Daily, 6E 186,Mumbai,Delhi,17:50:00,19:55:00,Daily, 6E 182,Mumbai,Delhi,21:15:00,23:20:00,Daily, 6E 181,Mumbai,Goa,12:35:00,13:35:00,Daily, 6E 321,Mumbai,Guwahati,9:20:00,14:20:00,Daily,Kolkata 6E 258,Mumbai,Hyderabad,14:30:00,16:00:00,Daily, 6E 207,Mumbai,Jaipur,5:55:00,7:40:00,Daily, 6E 211,Mumbai,Jaipur,17:40:00,20:20:00,Daily,Ahmedabad 6E 207,Mumbai,Kolkata,5:55:00,10:10:00,Daily,Jaipur 6E 321,Mumbai,Kolkata,9:20:00,12:00:00,Daily, 6E 403,Mumbai,Kolkata,15:35:00,18:50:00,Daily,Nagpur 6E 323,Mumbai,Kolkata,20:05:00,23:00:00,Daily, 6E 403,Mumbai,Nagpur,15:35:00,16:50:00,Daily, 6E 482,Mumbai,Vadodara,9:25:00,10:25:00,Daily, 6E 136,Nagpur,Delhi,18:10:00,19:40:00,Ex Sat, 6E 403,Nagpur,Kolkata,17:20:00,18:50:00,Daily, 6E 404,Nagpur,Mumbai,20:35:00,21:55:00,Daily, 6E 135,Nagpur,Pune,11:20:00,12:30:00,Ex Sat, 6E 410,Pune,Ahmedabad,13:10:00,14:30:00,Ex Sat, 6E 103,Pune,Bangalore,9:15:00,10:40:00,Sat, 6E 105,Pune,Bangalore,17:00:00,18:30:00,Ex Sat, 6E 523,Pune,Chennai,5:55:00,7:40:00,Daily, 6E 102,Pune,Delhi,11:45:00,13:45:00,Ex Sat, 6E 136,Pune,Delhi,16:15:00,19:40:00,Ex Sat,Nagpur 6E 108,Pune,Delhi,21:10:00,23:10:00,Sat, 6E 523,Pune,Kolkata,5:55:00,10:30:00,Daily,Chennai 6E 410,Pune,Kolkata,13:10:00,17:30:00,Ex Sat,Ahmedabad 6E 136,Pune,Nagpur,16:15:00,17:40:00,Ex Sat, 6E 482,Vadodara,Delhi,10:55:00,12:35:00,Daily, 6E 481,Vadodara,Mumbai,12:50:00,13:50:00,Daily,

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• Help with Java Program for Prime numbers

  - by Ben

  Hello everyone, I was wondering if you can help me with this program. I have been struggling with it for hours and have just trashed my code because the TA doesn't like how I executed it. I am completely hopeless and if anyone can help me out step by step, I would greatly appreciate it. In this project you will write a Java program that reads a positive integer n from standard input, then prints out the first n prime numbers. We say that an integer m is divisible by a non-zero integer d if there exists an integer k such that m = k d , i.e. if d divides evenly into m. Equivalently, m is divisible by d if the remainder of m upon (integer) division by d is zero. We would also express this by saying that d is a divisor of m. A positive integer p is called prime if its only positive divisors are 1 and p. The one exception to this rule is the number 1 itself, which is considered to be non-prime. A positive integer that is not prime is called composite. Euclid showed that there are infinitely many prime numbers. The prime and composite sequences begin as follows: Primes: 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, … Composites: 1, 4, 6, 8, 9, 10, 12, 14, 15, 16, 18, 20, 21, 22, 24, 25, 26, 27, 28, … There are many ways to test a number for primality, but perhaps the simplest is to simply do trial divisions. Begin by dividing m by 2, and if it divides evenly, then m is not prime. Otherwise, divide by 3, then 4, then 5, etc. If at any point m is found to be divisible by a number d in the range 2 d m-1, then halt, and conclude that m is composite. Otherwise, conclude that m is prime. A moment’s thought shows that one need not do any trial divisions by numbers d which are themselves composite. For instance, if a trial division by 2 fails (i.e. has non-zero remainder, so m is odd), then a trial division by 4, 6, or 8, or any even number, must also fail. Thus to test a number m for primality, one need only do trial divisions by prime numbers less than m. Furthermore, it is not necessary to go all the way up to m-1. One need only do trial divisions of m by primes p in the range 2 p m . To see this, suppose m 1 is composite. Then there exist positive integers a and b such that 1 < a < m, 1 < b < m, and m = ab . But if both a m and b m , then ab m, contradicting that m = ab . Hence one of a or b must be less than or equal to m . To implement this process in java you will write a function called isPrime() with the following signature: static boolean isPrime(int m, int[] P) This function will return true or false according to whether m is prime or composite. The array argument P will contain a sufficient number of primes to do the testing. Specifically, at the time isPrime() is called, array P must contain (at least) all primes p in the range 2 p m . For instance, to test m = 53 for primality, one must do successive trial divisions by 2, 3, 5, and 7. We go no further since 11 53 . Thus a precondition for the function call isPrime(53, P) is that P[0] = 2 , P[1] = 3 , P[2] = 5, and P[3] = 7 . The return value in this case would be true since all these divisions fail. Similarly to test m =143 , one must do trial divisions by 2, 3, 5, 7, and 11 (since 13 143 ). The precondition for the function call isPrime(143, P) is therefore P[0] = 2 , P[1] = 3 , P[2] = 5, P[3] = 7 , and P[4] =11. The return value in this case would be false since 11 divides 143. Function isPrime() should contain a loop that steps through array P, doing trial divisions. This loop should terminate when 2 either a trial division succeeds, in which case false is returned, or until the next prime in P is greater than m , in which case true is returned. Function main() in this project will read the command line argument n, allocate an int array of length n, fill the array with primes, then print the contents of the array to stdout according to the format described below. In the context of function main(), we will refer to this array as Primes[]. Thus array Primes[] plays a dual role in this project. On the one hand, it is used to collect, store, and print the output data. On the other hand, it is passed to function isPrime() to test new integers for primality. Whenever isPrime() returns true, the newly discovered prime will be placed at the appropriate position in array Primes[]. This process works since, as explained above, the primes needed to test an integer m range only up to m , and all of these primes (and more) will already be stored in array Primes[] when m is tested. Of course it will be necessary to initialize Primes[0] = 2 manually, then proceed to test 3, 4, … for primality using function isPrime(). The following is an outline of the steps to be performed in function main(). • Check that the user supplied exactly one command line argument which can be interpreted as a positive integer n. If the command line argument is not a single positive integer, your program will print a usage message as specified in the examples below, then exit. • Allocate array Primes[] of length n and initialize Primes[0] = 2 . • Enter a loop which will discover subsequent primes and store them as Primes[1] , Primes[2], Primes[3] , ……, Primes[n -1] . This loop should contain an inner loop which walks through successive integers and tests them for primality by calling function isPrime() with appropriate arguments. • Print the contents of array Primes[] to stdout, 10 to a line separated by single spaces. In other words Primes[0] through Primes[9] will go on line 1, Primes[10] though Primes[19] will go on line 2, and so on. Note that if n is not a multiple of 10, then the last line of output will contain fewer than 10 primes. Your program, which will be called Prime.java, will produce output identical to that of the sample runs below. (As usual % signifies the unix prompt.) % java Prime Usage: java Prime [PositiveInteger] % java Prime xyz Usage: java Prime [PositiveInteger] % java Prime 10 20 Usage: java Prime [PositiveInteger] % java Prime 75 2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97 101 103 107 109 113 127 131 137 139 149 151 157 163 167 173 179 181 191 193 197 199 211 223 227 229 233 239 241 251 257 263 269 271 277 281 283 293 307 311 313 317 331 337 347 349 353 359 367 373 379 % 3 As you can see, inappropriate command line argument(s) generate a usage message which is similar to that of many unix commands. (Try doing the more command with no arguments to see such a message.) Your program will include a function called Usage() having signature static void Usage() that prints this message to stderr, then exits. Thus your program will contain three functions in all: main(), isPrime(), and Usage(). Each should be preceded by a comment block giving it’s name, a short description of it’s operation, and any necessary preconditions (such as those for isPrime().) See examples on the webpage.

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• c++ stl priority queue insert bad_alloc exception

  - by bsg

  Hi, I am working on a query processor that reads in long lists of document id's from memory and looks for matching id's. When it finds one, it creates a DOC struct containing the docid (an int) and the document's rank (a double) and pushes it on to a priority queue. My problem is that when the word(s) searched for has a long list, when I try to push the DOC on to the queue, I get the following exception: Unhandled exception at 0x7c812afb in QueryProcessor.exe: Microsoft C++ exception: std::bad_alloc at memory location 0x0012ee88.. When the word has a short list, it works fine. I tried pushing DOC's onto the queue in several places in my code, and they all work until a certain line; after that, I get the above error. I am completely at a loss as to what is wrong because the longest list read in is less than 1 MB and I free all memory that I allocate. Why should there suddenly be a bad_alloc exception when I try to push a DOC onto a queue that has a capacity to hold it (I used a vector with enough space reserved as the underlying data structure for the priority queue)? I know that questions like this are almost impossible to answer without seeing all the code, but it's too long to post here. I'm putting as much as I can and am anxiously hoping that someone can give me an answer, because I am at my wits' end. The NextGEQ function is too long to put here, but it reads a list of compressed blocks of docids block by block. That is, if it sees that the lastdocid in the block (in a separate list) is larger than the docid passed in, it decompresses the block and searches until it finds the right one. If it sees that it was already decompressed, it just searches. Below, when I call the function the first time, it decompresses a block and finds the docid; the push onto the queue after that works. The second time, it doesn't even need to decompress; that is, no new memory is allocated, but after that time, pushing on to the queue gives a bad_alloc error. struct DOC{ long int docid; long double rank; public: DOC() { docid = 0; rank = 0.0; } DOC(int num, double ranking) { docid = num; rank = ranking; } bool operator>( const DOC & d ) const { return rank > d.rank; } bool operator<( const DOC & d ) const { return rank < d.rank; } }; struct listnode{ int* metapointer; int* blockpointer; int docposition; int frequency; int numberdocs; int* iquery; listnode* nextnode; }; void QUERYMANAGER::SubmitQuery(char *query){ vector<DOC> docvec; docvec.reserve(20); DOC doct; //create a priority queue to use as a min-heap to store the documents and rankings; //although the priority queue uses the heap as its underlying data structure, //I found it easier to use the STL priority queue implementation priority_queue<DOC, vector<DOC>,std::greater<DOC>> q(docvec.begin(), docvec.end()); q.push(doct); //do some processing here; startlist is a pointer to a listnode struct that starts the //linked list cout << "Opening lists:" << endl; //point the linked list start pointer to the node returned by the OpenList method startlist = &OpenList(value); listnode* minpointer; q.push(doct); //more processing here; else{ //start by finding the first docid in the shortest list int i = 0; q.push(doct); num = NextGEQ(0, *startlist); q.push(doct); while(num != -1) cout << "finding nextGEQ from shortest list" << endl; q.push(doct); //the is where the problem starts - every previous q.push(doct) works; the one after //NextGEQ(num +1, *startlist) gives the bad_alloc error num = NextGEQ(num + 1, *startlist); q.push(doct); //if you didn't break out of the loop; i.e., all lists contain a matching docid, //calculate the document's rank; if it's one of the top 20, create a struct //containing the docid and the rank and add it to the priority queue if(!loop) { cout << "found match" << endl; if(num < 0) { cout << "reached end of list" << endl; //reached the end of the shortest list; close the list CloseList(startlist); break; } rank = calculateRanking(table, num); try{ //if the heap is not full, create a DOC struct with the docid and //rank and add it to the heap if(q.size() < 20) { doc.docid = num; doc.rank = rank; q.push(doct); q.push(doc); } } catch (exception& e) { cout << e.what() << endl; } } } Thank you very much, bsg.

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• GDI+ crashes when loading PNG from IStream

  - by konforce

  I wrote something to load PNG files from a custom C++ IStream via GDI+. It worked great until I ran it on Vista machines. Crashes every time. When compiled on VS 2008, I found that inserting code into the IStream::AddRef method, such as a cout, made the problem go away. When compiling with VS 2010, it still crashes regardless of that. I stripped the program down to its basics. I copied a FileStream straight from Microsoft's documentation. It can load PNGs when using Bitmap::FromFile. It can load JPEGs, GIFs, and BMPs via FromFile or FromStream. So in short: on Vista, PNG files loaded via Bitmap::FromStream crash. #pragma comment(lib, "gdiplus.lib") #include <iostream> #include <objidl.h> #include <gdiplus.h> class FileStream : public IStream { public: FileStream(HANDLE hFile) { _refcount = 1; _hFile = hFile; } ~FileStream() { if (_hFile != INVALID_HANDLE_VALUE) { ::CloseHandle(_hFile); } } public: HRESULT static OpenFile(LPCWSTR pName, IStream ** ppStream, bool fWrite) { HANDLE hFile = ::CreateFileW(pName, fWrite ? GENERIC_WRITE : GENERIC_READ, FILE_SHARE_READ, NULL, fWrite ? CREATE_ALWAYS : OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL); if (hFile == INVALID_HANDLE_VALUE) return HRESULT_FROM_WIN32(GetLastError()); *ppStream = new FileStream(hFile); if(*ppStream == NULL) CloseHandle(hFile); return S_OK; } virtual HRESULT STDMETHODCALLTYPE QueryInterface(REFIID iid, void ** ppvObject) { if (iid == __uuidof(IUnknown) || iid == __uuidof(IStream) || iid == __uuidof(ISequentialStream)) { *ppvObject = static_cast<IStream*>(this); AddRef(); return S_OK; } else return E_NOINTERFACE; } virtual ULONG STDMETHODCALLTYPE AddRef(void) { return (ULONG)InterlockedIncrement(&_refcount); } virtual ULONG STDMETHODCALLTYPE Release(void) { ULONG res = (ULONG) InterlockedDecrement(&_refcount); if (res == 0) delete this; return res; } // ISequentialStream Interface public: virtual HRESULT STDMETHODCALLTYPE Read(void* pv, ULONG cb, ULONG* pcbRead) { ULONG local_pcbRead; BOOL rc = ReadFile(_hFile, pv, cb, &local_pcbRead, NULL); if (pcbRead) *pcbRead = local_pcbRead; return (rc) ? S_OK : HRESULT_FROM_WIN32(GetLastError()); } virtual HRESULT STDMETHODCALLTYPE Write(void const* pv, ULONG cb, ULONG* pcbWritten) { BOOL rc = WriteFile(_hFile, pv, cb, pcbWritten, NULL); return rc ? S_OK : HRESULT_FROM_WIN32(GetLastError()); } // IStream Interface public: virtual HRESULT STDMETHODCALLTYPE SetSize(ULARGE_INTEGER) { return E_NOTIMPL; } virtual HRESULT STDMETHODCALLTYPE CopyTo(IStream*, ULARGE_INTEGER, ULARGE_INTEGER*, ULARGE_INTEGER*) { return E_NOTIMPL; } virtual HRESULT STDMETHODCALLTYPE Commit(DWORD) { return E_NOTIMPL; } virtual HRESULT STDMETHODCALLTYPE Revert(void) { return E_NOTIMPL; } virtual HRESULT STDMETHODCALLTYPE LockRegion(ULARGE_INTEGER, ULARGE_INTEGER, DWORD) { return E_NOTIMPL; } virtual HRESULT STDMETHODCALLTYPE UnlockRegion(ULARGE_INTEGER, ULARGE_INTEGER, DWORD) { return E_NOTIMPL; } virtual HRESULT STDMETHODCALLTYPE Clone(IStream **) { return E_NOTIMPL; } virtual HRESULT STDMETHODCALLTYPE Seek(LARGE_INTEGER liDistanceToMove, DWORD dwOrigin, ULARGE_INTEGER* lpNewFilePointer) { DWORD dwMoveMethod; switch(dwOrigin) { case STREAM_SEEK_SET: dwMoveMethod = FILE_BEGIN; break; case STREAM_SEEK_CUR: dwMoveMethod = FILE_CURRENT; break; case STREAM_SEEK_END: dwMoveMethod = FILE_END; break; default: return STG_E_INVALIDFUNCTION; break; } if (SetFilePointerEx(_hFile, liDistanceToMove, (PLARGE_INTEGER) lpNewFilePointer, dwMoveMethod) == 0) return HRESULT_FROM_WIN32(GetLastError()); return S_OK; } virtual HRESULT STDMETHODCALLTYPE Stat(STATSTG* pStatstg, DWORD grfStatFlag) { if (GetFileSizeEx(_hFile, (PLARGE_INTEGER) &pStatstg->cbSize) == 0) return HRESULT_FROM_WIN32(GetLastError()); return S_OK; } private: volatile HANDLE _hFile; volatile LONG _refcount; }; #define USE_STREAM int main() { Gdiplus::GdiplusStartupInput gdiplusStartupInput; ULONG_PTR gdiplusToken; Gdiplus::GdiplusStartup(&gdiplusToken, &gdiplusStartupInput, NULL); Gdiplus::Bitmap *bmp; #ifndef USE_STREAM bmp = Gdiplus::Bitmap::FromFile(L"test.png", false); if (!bmp) { std::cerr << " Unable to open image file." << std::endl; return 1; } #else IStream *s; if (FileStream::OpenFile(L"test.png", &s, false) != S_OK) { std::cerr << "Unable to open image file." << std::endl; return 1; } bmp = Gdiplus::Bitmap::FromStream(s, false); #endif std::cout << "Image is " << bmp->GetWidth() << " by " << bmp->GetHeight() << std::endl; Gdiplus::GdiplusShutdown(gdiplusToken); #ifdef USE_STREAM s->Release(); #endif return 0; } Tracing and debugging, shows that it does make some calls to the IStream class. It crashes inside of lastResult = DllExports::GdipCreateBitmapFromStream(stream, &bitmap); from GdiPlusBitmap.h, which is a static inline wrapper over the flat API. Other than the reference counting, the only IStream methods it calls is stat (for file size), read, and seek. Call stack looks like: ntdll.dll!_DbgBreakPoint@0() + 0x1 bytes ntdll.dll!_RtlpBreakPointHeap@4() + 0x28 bytes ntdll.dll!_RtlpValidateHeapEntry@12() + 0x70a3c bytes ntdll.dll!_RtlDebugFreeHeap@12() + 0x9a bytes ntdll.dll!@RtlpFreeHeap@16() + 0x13cdd bytes ntdll.dll!_RtlFreeHeap@12() + 0x2e49 bytes kernel32.dll!_HeapFree@12() + 0x14 bytes ole32.dll!CRetailMalloc_Free() + 0x1c bytes ole32.dll!_CoTaskMemFree@4() + 0x13 bytes GdiPlus.dll!GpPngDecoder::GetImageInfo() + 0x68 bytes GdiPlus.dll!GpDecodedImage::InternalGetImageInfo() + 0x3c bytes GdiPlus.dll!GpDecodedImage::GetImageInfo() + 0x18 bytes GdiPlus.dll!CopyOnWriteBitmap::CopyOnWriteBitmap() + 0x49 bytes GdiPlus.dll!CopyOnWriteBitmap::Create() + 0x1d bytes GdiPlus.dll!GpBitmap::GpBitmap() + 0x2c bytes I was unable to find anybody else with the same problem, so I assume there's something wrong with my implementation...

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• Floats will not align, stay staggered, can't find a solution?

  - by Sarah Proper

  What I am trying to do is build a multi column layout. The main two sections are divided 2/3 to 1/3 and inside the 2/3 column is divided 2/3 1/3 as well. My problem is that my floats will not align nicely with each other, choosing instead to stagger like stairs. I have tried declaring the widths smaller, floating them individually, including in the float sections display:block,inline, or inline-block and nothing seems to be working. I am getting really frustrated and would appreciate any help! Thanks! <div class="wrapper"> <div class="width50" style="float:left;"> <h1>Our Mission:</h1> <p> Bacon ipsum dolor sit amet swine spare ribs pork meatloaf pancetta filet mignon. Rump frankfurter pork belly prosciutto beef boudin andouille pig pork chop meatball ham drumstick filet mignon. Strip steak flank shank pig, tongue tri-tip jowl leberkas sirloin brisket t-bone. Ground round spare ribs salami capicola filet mignon. Capicola turkey t-bone corned beef sausage ham hock. Corned beef capicola leberkas pork chop, swine pastrami drumstick. Frankfurter fatback bacon jowl short loin, jerky pancetta bresaola corned beef shoulder drumstick ball tip tri-tip.</p> <div class="width50 float-left"> <img src="@Url.StaticContent(Links.Content.images.map_homepage_png)" alt="Map" /> </div> <div class="width33 float-right"> <img src="@Url.StaticContent(Links.Content.images.address_line_text_png)" alt="addressline" /> <br /> <h3>address</h3> <b>405 Empire Boulevard<br /> Rochester, NY 14609 </b> </div> </div> <div class="width33" style="float:right;"> <h1>Events</h1> <ul class="events"> <li> <h2>Fall Volunteer Festival</h2> <p> <b>october 6<br /> 10 am to 3pm </b> </p> <p> come to our town location for some fun activities for family and friends! </p> </li> <li> <h2>Fall Volunteer Festival</h2> <p> <b>october 6<br /> 10 am to 3pm </b> </p> <p> come to our town location for some fun activities for family and friends! </p> </li> <li> <h2>Fall Volunteer Festival</h2> <p> <b>october 6<br /> 10 am to 3pm </b> </p> <p> come to our town location for some fun activities for family and friends! </p> </li> </ul> </div> </div> </div> and the css: .clearfix:before, .clearfix:after, .grid-block:before, .grid-block:after, .deepest:before, .deepest:after { content: ""; display: table; } .clearfix:after, .grid-block:after, .deepest:after { clear: both; } .grid-box { float: left; } /* Grid Units */ .width16 { width: 16.666%; } .width20 { width: 20%; } .width25 { width: 25%; } .width33 { width: 39.333%; } .width40 { width: 40%; } .width50 { width: 50%; } .width60 { width: 60%; } .width66 { width: 66.666%; } .width75 { width: 75%; } .width80 { width: 80%; } .width100 { width: 100%; } .width16, .width20, .width25, .width33, .width40, .width50, .width60, .width66, .width75, .width80, .width100 { -moz-box-sizing: border-box; -webkit-box-sizing: border-box; box-sizing: border-box; padding: 5px 10px 5px 10px; } /* Create new Block Formatting Contexts */ .bfc-o { overflow: hidden; } .bfc-f { -moz-box-sizing: border-box; -webkit-box-sizing: border-box; box-sizing: border-box; width: 100%; float: left; } /* Align Boxes */ .float-left { float: left; } .float-right { float: right; } /* Grid Gutter */ .grid-gutter.grid-block { margin: 0 -15px; } .grid-gutter > .grid-box > * { margin: 0 15px; } .grid-gutter > .grid-box > * > :first-child { margin-top: 0; } .grid-gutter > .grid-box > * > :last-child { margin-bottom: 0; } /* Layout Defaults --------------------------------------------------------------------------------------- -------------*/ /* Center Page */ .wrapper { -moz-box-sizing: border-box; -webkit-box-sizing: border-box; box-sizing: border-box; margin: auto; } /* Header */ #header { position: relative; padding-top: 10px; } #toolbar .float-left .module, #toolbar .float-left > time { margin: 0 15px 0 0; float: left; } #toolbar .float-right .module { margin: 0 0 0 15px; float: right; } #headerbar .module { max-width: 300px; margin-right: 0; float: right; } #logo, #logo > img, #menu { float: left; } #search { float: right; } #banner { position: absolute; top: 0; right: -200px; } /* Footer */ #footer { position: relative; text-align: center; } /* Absolute */ #absolute { position: absolute; z-index: 15; width: 100%; }

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• Ajax, Callback, postback and Sys.WebForms.PageRequestManager.getInstance().add_beginRequest

  - by user338262

  Hi, I have a user control which encapsulates a NumericUpDownExtender. This UserControl implements the interface ICallbackEventHandler, because I want that when a user changes the value of the textbox associated a custom event to be raised in the server. By the other hand each time an async postback is done I shoe a message of loading and disable the whole screen. This works perfect when something is changed in for example an UpdatePanel through this lines of code: Sys.WebForms.PageRequestManager.getInstance().add_beginRequest( function (sender, args) { var modalPopupBehavior = $find('programmaticSavingLoadingModalPopupBehavior'); modalPopupBehavior.show(); } ); The UserControl is placed inside a detailsview which is inside an UpdatePanel in an aspx. When the custom event is raised I want another textbox in the aspx to change its value. So far, When I click on the UpDownExtender, it goes correctly to the server and raises the custom event, and the new value of the textbox is assigned in the server. but it is not changed in the browser. I suspect that the problem is the callback, since I have the same architecture for a UserControl with an AutoCompleteExtender which implement IPostbackEventHandler and it works. Any clues how can I solve this here to make the UpDownNumericExtender user control to work like the AutComplete one? This is the code of the user control and the parent: using System; using System.Web.UI; using System.ComponentModel; using System.Text; namespace Corp.UserControls { [Themeable(true)] public partial class CustomNumericUpDown : CorpNumericUpDown, ICallbackEventHandler { protected void Page_PreRender(object sender, EventArgs e) { if (!Page.IsPostBack) { currentInstanceNumber = CorpAjaxControlToolkitUserControl.getNextInstanceNumber(); } registerControl(this.HFNumericUpDown.ClientID, currentInstanceNumber); string strCallServer = "NumericUpDownCallServer" + currentInstanceNumber.ToString(); // If this function is not written the callback to get the disponibilidadCliente doesn't work if (!Page.ClientScript.IsClientScriptBlockRegistered("ReceiveServerDataNumericUpDown")) { StringBuilder str = new StringBuilder(); str.Append("function ReceiveServerDataNumericUpDown(arg, context) {}").AppendLine(); Page.ClientScript.RegisterClientScriptBlock(typeof(CorpNumericUpDown), "ReceiveServerDataNumericUpDown", str.ToString(), true); } nudeNumericUpDownExtender.BehaviorID = "NumericUpDownEx" + currentInstanceNumber.ToString(); ClientScriptManager cm = Page.ClientScript; String cbReference = cm.GetCallbackEventReference(this, "arg", "ReceiveServerDataNumericUpDown", ""); String callbackScript = "function " + strCallServer + "(arg, context)" + Environment.NewLine + "{" + Environment.NewLine + cbReference + ";" + Environment.NewLine + "}" + Environment.NewLine; cm.RegisterClientScriptBlock(typeof(CustomNumericUpDown), strCallServer, callbackScript, true); base.Page_PreRender(sender,e); } [System.ComponentModel.Browsable(true)] [System.ComponentModel.Bindable(true)] public Int64 Value { get { return (string.IsNullOrEmpty(HFNumericUpDown.Value) ? Int64.Parse("1") : Int64.Parse(HFNumericUpDown.Value)); } set { HFNumericUpDown.Value = value.ToString(); //txtAutoCompleteCliente_AutoCompleteExtender.ContextKey = value.ToString(); // TODO: Change the text of the textbox } } [System.ComponentModel.Browsable(true)] [System.ComponentModel.Bindable(true)] [Description("The text of the numeric up down")] public string Text { get { return txtNumericUpDown.Text; } set { txtNumericUpDown.Text = value; } } public delegate void NumericUpDownChangedHandler(object sender, NumericUpDownChangedArgs e); public event NumericUpDownChangedHandler numericUpDownEvent; [System.ComponentModel.Browsable(true)] [System.ComponentModel.Bindable(true)] [System.ComponentModel.Description("Raised after the number has been increased or decreased")] protected virtual void OnNumericUpDownEvent(object sender, NumericUpDownChangedArgs e) { if (numericUpDownEvent != null) //check to see if anyone has attached to the event numericUpDownEvent(this, e); } #region ICallbackEventHandler Members public string GetCallbackResult() { return "";//throw new NotImplementedException(); } public void RaiseCallbackEvent(string eventArgument) { NumericUpDownChangedArgs nudca = new NumericUpDownChangedArgs(long.Parse(eventArgument)); OnNumericUpDownEvent(this, nudca); } #endregion } /// <summary> /// Class that adds the prestamoList to the event /// </summary> public class NumericUpDownChangedArgs : System.EventArgs { /// <summary> /// The current selected value. /// </summary> public long Value { get; private set; } public NumericUpDownChangedArgs(long value) { Value = value; } } } using System; using System.Collections.Generic; using System.Text; namespace Corp { /// <summary> /// Summary description for CorpAjaxControlToolkitUserControl /// </summary> public class CorpNumericUpDown : CorpAjaxControlToolkitUserControl { private Int16 _currentInstanceNumber; // This variable hold the instanceNumber assignated at first place. public short currentInstanceNumber { get { return _currentInstanceNumber; } set { _currentInstanceNumber = value; } } protected void Page_PreRender(object sender, EventArgs e) { const string strOnChange = "OnChange"; const string strCallServer = "NumericUpDownCallServer"; StringBuilder str = new StringBuilder(); foreach (KeyValuePair<String, Int16> control in controlsToRegister) { str.Append("function ").Append(strOnChange + control.Value).Append("(sender, eventArgs) ").AppendLine(); str.Append("{").AppendLine(); str.Append(" if (sender) {").AppendLine(); str.Append(" var hfield = document.getElementById('").Append(control.Key).Append("');").AppendLine(); str.Append(" if (hfield.value != eventArgs) {").AppendLine(); str.Append(" hfield.value = eventArgs;").AppendLine(); str.Append(" ").Append(strCallServer + control.Value).Append("(eventArgs, eventArgs);").AppendLine(); str.Append(" }").AppendLine(); str.Append(" }").AppendLine(); str.Append("}").AppendLine(); Page.ClientScript.RegisterClientScriptBlock(typeof(CorpNumericUpDown), Guid.NewGuid().ToString(), str.ToString(), true); } str = new StringBuilder(); foreach (KeyValuePair<String, Int16> control in controlsToRegister) { str.Append(" funcsPageLoad[funcsPageLoad.length] = function() { $find('NumericUpDownEx" + control.Value + "').add_currentChanged(").Append(strOnChange + control.Value).Append(");};").AppendLine(); str.Append(" funcsPageUnLoad[funcsPageUnLoad.length] = function() { $find('NumericUpDownEx" + control.Value + "').remove_currentChanged(").Append(strOnChange + control.Value).Append(");};").AppendLine(); } Page.ClientScript.RegisterClientScriptBlock(typeof(CorpNumericUpDown), Guid.NewGuid().ToString(), str.ToString(), true); } } } and to create the loading view I use this: //The beginRequest event is raised before the processing of an asynchronous postback starts and the postback is sent to the server. You can use this event to call custom script to set a request header or to start an animation that notifies the user that the postback is being processed. Sys.WebForms.PageRequestManager.getInstance().add_beginRequest( function (sender, args) { var modalPopupBehavior = $find('programmaticSavingLoadingModalPopupBehavior'); modalPopupBehavior.show(); } ); //The endRequest event is raised after an asynchronous postback is finished and control has been returned to the browser. You can use this event to provide a notification to users or to log errors. Sys.WebForms.PageRequestManager.getInstance().add_endRequest( function (sender, arg) { var modalPopupBehavior = $find('programmaticSavingLoadingModalPopupBehavior'); modalPopupBehavior.hide(); } ); Thanks in advance! Daniel.

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• Flash and Google Maps - Only Last Icon showing

  - by Peter

  I have a simple Map and geocoding sample in Flash using CS4 The problem is simple - I can retrieve a short list from the google search api, but when I try to generate the icons on the map using a loop, only the last icon is displayed. (ignore the house icon, it is generated earlier) I feel I am missing something or made a stupid AS3 mistake (like treating it as if it was c#) - or even a stupid wood-for-the-trees mistake. The problem is in the last line of the code. I have added all my code just in case somebody else can find a use for it - lord knows it took me a great while to figure this out :) It runs here (also, if anybody has an idea why the icon is slightly in the wrong place on render, but corrects if you move the map - please let me know) Any help would be great. Thanks. P import com.google.maps.services.ClientGeocoder; import com.google.maps.services.GeocodingEvent; import com.google.maps.LatLng; import com.google.maps.Map; import com.google.maps.MapEvent; import com.google.maps.MapType; import com.google.maps.overlays.Marker; import com.google.maps.overlays.MarkerOptions; import com.google.maps.styles.FillStyle; import com.google.maps.styles.StrokeStyle; import com.google.maps.controls.* import com.google.maps.overlays.* import flash.display.Bitmap; import flash.display.BitmapData; import com.adobe.utils.StringUtil; import be.boulevart.google.ajaxapi.search.GoogleSearchResult; import be.boulevart.google.events.GoogleApiEvent; import be.boulevart.google.ajaxapi.search.local.GoogleLocalSearch; import be.boulevart.google.ajaxapi.search.local.data.GoogleLocalSearchItem; var strZip:String = new String(); strZip="60661"; var strAddress:String = new String(); strAddress ="100 W. Jackson Blvd, chicago, IL 60661"; var IconArray:Array = new Array; var SearchArray:Array = new Array; /*-------------------------------------------------------------- // The returned search data gets placed into this array ---------------------------------------------------------------*/ var LocalInfo:Array = new Array(); var intCount:int = new int; var intMapReady:int=0; /*=================================================================================== We load the map first and then get the search criteria - this will keep the order of operation clean. The ====================================================================================*/ var map:Map = new Map(); map.key = "ABQIAAAAHwSPp7Lhew456ffD6qa2WmxT_VwdLJEfmcCgytxKjcH1jLKkiihQtfC- TbcwryvBQYhRwHWa8F_Gp9Q"; map.setSize(new Point(600, 550)); map.addEventListener(MapEvent.MAP_READY, onMapReady); //Places the map on the page this.addChild(map); map.x=5; map.y=5; function onMapReady(event:Event):void { //Center the map and place the house marker doGeocode(); } /*========================================================================== Goecode to return the LAT and LONG for the specific address, center the map and add the house icon ===========================================================================*/ function doGeocode() { var geocoder:ClientGeocoder = new ClientGeocoder(); geocoder.addEventListener(GeocodingEvent.GEOCODING_SUCCESS, function(event:GeocodingEvent):void { var objPlacemarks:Array = event.response.placemarks; if (objPlacemarks.length > 0) { map.setCenter(objPlacemarks[0].point, 14, MapType.NORMAL_MAP_TYPE); var request:URLRequest = new URLRequest("house.png"); var imageLoader:Loader = new Loader(); imageLoader.load(request); var objMarkerOptions:MarkerOptions = new MarkerOptions(); objMarkerOptions.icon=imageLoader; objMarkerOptions.icon.scaleX=.15; objMarkerOptions.icon.scaleY=.15; objMarkerOptions.iconAlignment = MarkerOptions.ALIGN_HORIZONTAL_CENTER + MarkerOptions.ALIGN_VERTICAL_CENTER; var objMarker:Marker = new Marker(objPlacemarks[0].point, objMarkerOptions); map.addOverlay(objMarker); doLoadSearch() } }); //Failure code - good practice, really geocoder.addEventListener(GeocodingEvent.GEOCODING_FAILURE, function(event:GeocodingEvent):void { txtResult.appendText("Geocoding failed"); }); // generate geocode geocoder.geocode(strAddress); } /*=============================================================== XML Loader - loads icon file and search text pair from xml file =================================================================*/ function doLoadSearch() { var xmlLoader:URLLoader = new URLLoader(); var xmlData:XML = new XML(); xmlLoader.addEventListener(Event.COMPLETE, LoadXML); xmlLoader.load(new URLRequest("config.xml")); function LoadXML(e:Event):void { xmlData = new XML(e.target.data); RetrieveSearch(); } function RetrieveSearch() { //extract the MapData subset var xmlSearch = xmlData.MapData; // push this to an xml list object var xmlChildren:XMLList = xmlSearch.children(); //loop the list and extract the data into an //array of formatted search criteria for each (var Search:XML in xmlChildren) { txtResult.appendText("Searching For: "+Search.Criteria+" Icon=" + Search.Icon+ "Zip=" + strZip +"\r\n\r\n"); //retrieve search criteria loadLocalInfo(Search.Criteria,Search.Icon,strZip); } } } /*================================================================================== Search Functionality - does a google API search and loads the lats and longs required to place the icons on the map - THIS WILL NOT RUN LOCALLY ===================================================================================*/ function loadLocalInfo(strSearch,strIcon,strZip) { var objLocal:GoogleLocalSearch=new GoogleLocalSearch() objLocal.search(strSearch+" "+strZip,0,"0,0","","") objLocal.addEventListener(GoogleApiEvent.LOCAL_SEARCH_RESULT,onSearchComplete) function onSearchComplete(e:GoogleApiEvent):void { var resulta:GoogleSearchResult=e.data as GoogleSearchResult; //------------------------------------------------ // Load the icon for this particular search //------------------------------------------------ var request:URLRequest = new URLRequest(strIcon); var imageLoader:Loader = new Loader(); imageLoader.load(request); //------------------------------------------------------------- // For test purposes txtResult.appendText("Result Count for "+strSearch+" = "+e.data.results.length+"\r\n\r\n"); for each (var result:GoogleLocalSearchItem in e.data.results as Array) { LocalInfo[intCount]=[String(result.title),strIcon,String(result.latitude),String(result.longitude)]; //--------------------------------------- // Pop the icon onto the map //--------------------------------------- var objLatLng:LatLng = new LatLng(parseFloat(result.latitude), parseFloat(result.longitude)); var objMarkerOptions:MarkerOptions = new MarkerOptions(); objMarkerOptions.icon=imageLoader; objMarkerOptions.hasShadow=false; objMarkerOptions.iconAlignment = MarkerOptions.ALIGN_HORIZONTAL_CENTER + MarkerOptions.ALIGN_VERTICAL_CENTER; var objMarker:Marker = new Marker(objLatLng, objMarkerOptions); /********************************************************** *Everything* works to here - I have traced out execution and all variables. It only works on the last item in the array :( ***********************************************************/ map.addOverlay(objMarker); } } }

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• MVC 3 Client Validation works intermittently

  - by Gutek

  I have MVC 3 version, System.Web.Mvc product version is: 3.0.20105.0 modified on 5th of Jan 2011 - i think that's the latest. I’ve notice that client validation is not working as it suppose in the application that we are creating, so I’ve made a quick test. I’ve created basic MVC 3 Application using Internet Application template. I’ve added Test Controller: using System.Web.Mvc; using MvcApplication3.Models; namespace MvcApplication3.Controllers { public class TestController : Controller { public ActionResult Index() { return View(); } public ActionResult Create() { Sample model = new Sample(); return View(model); } [HttpPost] public ActionResult Create(Sample model) { if(!ModelState.IsValid) { return View(); } return RedirectToAction("Display"); } public ActionResult Display() { Sample model = new Sample(); model.Age = 10; model.CardNumber = "1324234"; model.Email = "[email protected]"; model.Title = "hahah"; return View(model); } } } Model: using System.ComponentModel.DataAnnotations; namespace MvcApplication3.Models { public class Sample { [Required] public string Title { get; set; } [Required] public string Email { get; set; } [Required] [Range(4, 120, ErrorMessage = "Oi! Common!")] public short Age { get; set; } [Required] public string CardNumber { get; set; } } } And 3 views: Create: @model MvcApplication3.Models.Sample @{ ViewBag.Title = "Create"; Layout = "~/Views/Shared/_Layout.cshtml"; } <h2>Create</h2> <script src="@Url.Content("~/Scripts/jquery.validate.min.js")" type="text/javascript"></script> <script src="@Url.Content("~/Scripts/jquery.validate.unobtrusive.min.js")" type="text/javascript"></script> @*@{ Html.EnableClientValidation(); }*@ @using (Html.BeginForm()) { @Html.ValidationSummary(false) <fieldset> <legend>Sample</legend> <div class="editor-label"> @Html.LabelFor(model => model.Title) </div> <div class="editor-field"> @Html.EditorFor(model => model.Title) @Html.ValidationMessageFor(model => model.Title) </div> <div class="editor-label"> @Html.LabelFor(model => model.Email) </div> <div class="editor-field"> @Html.EditorFor(model => model.Email) @Html.ValidationMessageFor(model => model.Email) </div> <div class="editor-label"> @Html.LabelFor(model => model.Age) </div> <div class="editor-field"> @Html.EditorFor(model => model.Age) @Html.ValidationMessageFor(model => model.Age) </div> <div class="editor-label"> @Html.LabelFor(model => model.CardNumber) </div> <div class="editor-field"> @Html.EditorFor(model => model.CardNumber) @Html.ValidationMessageFor(model => model.CardNumber) </div> <p> <input type="submit" value="Create" /> </p> </fieldset> @*<fieldset> @Html.EditorForModel() <p> <input type="submit" value="Create" /> </p> </fieldset> *@ } <div> @Html.ActionLink("Back to List", "Index") </div> Display: @model MvcApplication3.Models.Sample @{ ViewBag.Title = "Display"; Layout = "~/Views/Shared/_Layout.cshtml"; } <h2>Display</h2> <fieldset> <legend>Sample</legend> <div class="display-label">Title</div> <div class="display-field">@Model.Title</div> <div class="display-label">Email</div> <div class="display-field">@Model.Email</div> <div class="display-label">Age</div> <div class="display-field">@Model.Age</div> <div class="display-label">CardNumber</div> <div class="display-field">@Model.CardNumber</div> </fieldset> <p> @Html.ActionLink("Back to List", "Index") </p> Index: @{ ViewBag.Title = "Index"; Layout = "~/Views/Shared/_Layout.cshtml"; } <h2>Index</h2> <p> @Html.ActionLink("Create", "Create") </p> <p> @Html.ActionLink("Display", "Display") </p> Everything is default here – Create Controller, AddView from controller action with model specified with proper scaffold template and using provided layout in sample application. When I will go to /Test/Create client validation in most cases works only for Title and Age fields, after clicking Create it works for all fields (create does not goes to server). However in some cases (after a build) Title validation is not working and Email is, or CardNumber or Title and CardNumber but Email is not. But never all validation is working before clicking Create. I’ve tried creating form with Html.EditorForModel as well as enforce client validation just before BeginForm: @{ Html.EnableClientValidation(); } I’m providing a source code for this sample on dropbox – as maybe our dev env is broken :/ I’ve done tests on IE 8 and Chrome 10 beta. Just in case, in web config validation scripts are enabled: <appSettings> <add key="ClientValidationEnabled" value="true"/> <add key="UnobtrusiveJavaScriptEnabled" value="true"/> </appSettings> So my questions are Is there a way to ensure that Client validation will work as it supposed to work and not intermittently? Is this a desired behavior and I'm missing something in configuration/implementation?

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• Android remote service doesn't call service methods

  - by tarantel

  Hello, I'm developing a GPS tracking software on android. I need IPC to control the service from different activities. So I decide to develop a remote service with AIDL. This wasn't a big problem but now it's always running into the methods of the interface and not into those of my service class. Maybe someone could help me? Here my ADIL file: package test.de.android.tracker interface ITrackingServiceRemote { void startTracking(in long trackId); void stopTracking(); void pauseTracking(); void resumeTracking(in long trackId); long trackingState(); } And the here a short version of my service class: public class TrackingService extends Service implements LocationListener{ private LocationManager mLocationManager; private TrackDb db; private long trackId; private boolean isTracking = false; @Override public void onCreate() { super.onCreate(); mNotificationManager = (NotificationManager) this .getSystemService(NOTIFICATION_SERVICE); mLocationManager = (LocationManager) getSystemService(LOCATION_SERVICE); db = new TrackDb(this.getApplicationContext()); } @Override public void onStart(Intent intent, int startId) { super.onStart(intent, startId); } @Override public void onDestroy(){ //TODO super.onDestroy(); } @Override public IBinder onBind(Intent intent){ return this.mBinder; } private IBinder mBinder = new ITrackingServiceRemote.Stub() { public void startTracking(long trackId) throws RemoteException { TrackingService.this.startTracking(trackId); } public void pauseTracking() throws RemoteException { TrackingService.this.pauseTracking(); } public void resumeTracking(long trackId) throws RemoteException { TrackingService.this.resumeTracking(trackId); } public void stopTracking() throws RemoteException { TrackingService.this.stopTracking(); } public long trackingState() throws RemoteException { long state = TrackingService.this.trackingState(); return state; } }; public synchronized void startTracking(long trackId) { // request updates every 250 meters or 0 sec this.trackId = trackId; mLocationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 250, this); isTracking = true; } public synchronized long trackingState() { if(isTracking){ return trackId; } else return -1; } public synchronized void stopTracking() { if(isTracking){ mLocationManager.removeUpdates(this); isTracking = false; } else Log.i(TAG, "Could not stop because service is not tracking at the moment"); } public synchronized void resumeTracking(long trackId) { if(!isTracking){ this.trackId = trackId; mLocationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 250, this); isTracking = true; } else Log.i(TAG, "Could not resume because service is tracking already track " + this.trackId); } public synchronized void pauseTracking() { if(isTracking){ mLocationManager.removeUpdates(this); isTracking = false; } else Log.i(TAG, "Could not pause because service is not tracking at the moment"); } public void onLocationChanged(Location location) { //TODO } For easier access from the client I wrote a ServiceManager class which sets up the ServiceConnection and you can call the service methods. Here my code for this: public class TrackingServiceManager{ private static final String TAG = "TrackingServiceManager"; private ITrackingServiceRemote mService = null; private Context mContext; private Boolean isBound = false; private ServiceConnection mServiceConnection; public TrackingServiceManager(Context ctx){ this.mContext = ctx; } public void start(long trackId) { if (isBound && mService != null) { try { mService.startTracking(trackId); } catch (RemoteException e) { Log.e(TAG, "Could not start tracking!",e); } } else Log.i(TAG, "No Service bound! 1"); } public void stop(){ if (isBound && mService != null) { try { mService.stopTracking(); } catch (RemoteException e) { Log.e(TAG, "Could not stop tracking!",e); } } else Log.i(TAG, "No Service bound!"); } public void pause(){ if (isBound && mService != null) { try { mService.pauseTracking(); } catch (RemoteException e) { Log.e(TAG, "Could not pause tracking!",e); } } else Log.i(TAG, "No Service bound!"); } public void resume(long trackId){ if (isBound && mService != null) { try { mService.resumeTracking(trackId); } catch (RemoteException e) { Log.e(TAG, "Could not resume tracking!",e); } } else Log.i(TAG, "No Service bound!"); } public float state(){ if (isBound && mService != null) { try { return mService.trackingState(); } catch (RemoteException e) { Log.e(TAG, "Could not resume tracking!",e); return -1; } } else Log.i(TAG, "No Service bound!"); return -1; } /** * Method for binding the Service with client */ public boolean connectService(){ mServiceConnection = new ServiceConnection() { @Override public void onServiceConnected(ComponentName name, IBinder service) { TrackingServiceManager.this.mService = ITrackingServiceRemote.Stub.asInterface(service); } } @Override public void onServiceDisconnected(ComponentName name) { if (mService != null) { mService = null; } } }; Intent mIntent = new Intent("test.de.android.tracker.action.intent.TrackingService"); this.isBound = this.mContext.bindService(mIntent, mServiceConnection, Context.BIND_AUTO_CREATE); return this.isBound; } public void disconnectService(){ this.mContext.unbindService(mServiceConnection); this.isBound = false; } } If i now try to call a method from an activity for example start(trackId) nothing happens. The binding is OK. When debugging it always runs into the startTracking() in the generated ITrackingServiceRemote.java file and not into my TrackingService class. Where is the problem? I can't find anything wrong. Thanks in advance! Tobias

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• How is font-size not working here?

  - by markvgti

  Following advice in The 6 Most Important CSS Techniques You Need To Know, I set my body's font-size to 62.5%, the container div's font-size to 1.4 em (slight variation from the article). p.tags and p.published's font-size is set to 1em. However, this doesn't work for me. Both the normal text and text in p.tags and p.published comes out to be the same size (16.8px as computed by Firebug). Can you explain why my code isn't working? I am testing in Firefox 3.6.3. The sample page shown by the author works just fine in the very same browser. I've reproduced the entire page below—apologies for the length of it, but I thought it better to not leave out anything. <html> <head> <title>Title</title> <style type="text/css"> body { font-family: Georgia, "Century Schoolbook", "Times New Roman", Serif; font-size: 62.5%; background-color: #2B3856; /* Dark slate blue */ } h1, h2, h3, h4, h5, h6 { font-family: Verdana, Helvetica, Tahoma, "Sans Serif"; color: #2B3856; margin-top: 2px; } h1 a, h2 a, h3 a, h4 a, h5 a, h6 a { text-decoration: none; color: #2B3856; } h1 a:hover, h2 a:hover, h3 a:hover, h4 a:hover, h5 a:hover, h6 a:hover { text-decoration: underline; } div#container { width: 800px; font-size: 1.4em; margin: 5px auto; background-color: #E3E4FA; /* Lavender */ } #sidebar { width: 200px; float: right; margin: 0px; padding: 0px; } #sidebar div { padding: 0 5px 5px; } #sidebar div.shadowbox { margin-right: 5px; } #content { width: 600px; float: left; margin: 0px; padding: 0px; } #header { /*background-color: white;*/ background-color: #2B3856; /* #E3E4FA; Lavender */ margin-bottom: 5px; height: 100px; } #header h1 { color: #B93B8F; /* Plum */ line-height: 100px; text-align: center; font-size: 45px; } #description { color: #7D1B7E /* Dark Orchid */ } a { text-decoration: underline; color: #153E7E; } a:hover { text-decoration: none; } div#posts { padding: 0px; font-size: 1.2em; margin: 0px; } div#posts div.post { padding: 5px; margin: 0px 5px 15px 5px; } p.tags, p.published { font-size: 1em; } .shadowbox { background: repeat 0 0 url('http://www.jawsalgorhythmics.com/images/darkness-100x100-10pct.png'); } .justifycenter { text-align: center; } .floatright { float:right; } .floatleft { float: left; } .clearright { clear: right; } .clearleft { clear:left; } .clearboth { clear: both; } .halfsidebarwidth { width: 82px; } </style> </head> <body> <div id="container"> <div id="header"> <h1>Odds 'n Ends</h1> </div> <!-- header --> <div id="sidebar"> <div class="shadowbox"> <br /><p class="justifycenter"><img width="64" height="64" src="{PortraitURL-64}" /></p> <div class="floatleft halfsidebarwidth"><a href="/archive" class="archive">Archives</a></div> <div class="floatleft halfsidebarwidth"><a href="{RSS}" class="rss">RSS</a></div> <div class="clearboth"></div> </div> </div> <!-- sidebar --> <div id="content"> <div id="posts"> <div class="post shadowbox"> <span class="quote"> "It does not matter how slow you go so long as you do not stop." <div class="source">Wisdom of <a href="#" title="http://en.wikipedia.org/wiki/Confucius">Confucius</a></div> </span> <p class="tags">Tags: #<a href="#" title="http://demo.tumblr.com/tagged/wisdom">wisdom</a>&nbsp; </p> <p class="published">Posted: Nov 08, 2006 at 2:27 pm &nbsp;&nbsp;<a href="#" title="http://demo.tumblr.com/post/236/it-does-not-matter-how-slow-you-go-so-long-as-you">Permalink</a>&nbsp;&nbsp; <a href="#" title="http://tumblr.com/xr06k">Short URL</a></p> </div> </div> <!-- posts --> </div> <!-- content --> <div class="clearboth"></div> <div id="footer" style="text-align: justify;"> <h1>The footer</h1> </div> </div> <!-- container --> </body> </html>

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• 47 memory leaks. STL pointers.

  - by icelated

  I have a major amount of memory leaks. I know that the Sets have pointers and i cannot change that! I cannot change anything, but clean up the mess i have... I am creating memory with new in just about every function to add information to the sets. I have a Cd/ DVD/book: super classes of ITEM class and a library class.. In the library class i have 2 functions for cleaning up the sets.. Also, the CD, DVD, book destructors are not being called.. here is my potential leaks.. library.h #pragma once #include <ostream> #include <map> #include <set> #include <string> #include "Item.h" using namespace std; typedef set<Item*> ItemSet; typedef map<string,Item*> ItemMap; typedef map<string,ItemSet*> ItemSetMap; class Library { public: // general functions void addKeywordForItem(const Item* const item, const string& keyword); const ItemSet* itemsForKeyword(const string& keyword) const; void printItem(ostream& out, const Item* const item) const; // book-related functions const Item* addBook(const string& title, const string& author, int const nPages); const ItemSet* booksByAuthor(const string& author) const; const ItemSet* books() const; // music-related functions const Item* addMusicCD(const string& title, const string& band, const int nSongs); void addBandMember(const Item* const musicCD, const string& member); const ItemSet* musicByBand(const string& band) const; const ItemSet* musicByMusician(const string& musician) const; const ItemSet* musicCDs() const; // movie-related functions const Item* addMovieDVD(const string& title, const string& director, const int nScenes); void addCastMember(const Item* const movie, const string& member); const ItemSet* moviesByDirector(const string& director) const; const ItemSet* moviesByActor(const string& actor) const; const ItemSet* movies() const; ~Library(); void Purge(ItemSet &set); void Purge(ItemSetMap &map); }; here is some functions for adding info using new in library. Keep in mind i am cutting out alot of code to keep this post short. library.cpp #include "Library.h" #include "book.h" #include "cd.h" #include "dvd.h" #include <iostream> // general functions ItemSet allBooks; ItemSet allCDS; ItemSet allDVDs; ItemSetMap allBooksByAuthor; ItemSetMap allmoviesByDirector; ItemSetMap allmoviesByActor; ItemSetMap allMusicByBand; ItemSetMap allMusicByMusician; const ItemSet* Library::itemsForKeyword(const string& keyword) const { const StringSet* kw; ItemSet* obj = new ItemSet(); return obj; const Item* Library::addBook(const string& title, const string& author, const int nPages) { ItemSet* obj = new ItemSet(); Book* item = new Book(title,author,nPages); allBooks.insert(item); // add to set of all books obj->insert(item); return item; const Item* Library::addMusicCD(const string& title, const string& band, const int nSongs) { ItemSet* obj = new ItemSet(); CD* item = new CD(title,band,nSongs); return item; void Library::addBandMember(const Item* musicCD, const string& member) { ItemSet* obj = new ItemSet(); (((CD*) musicCD)->addBandMember(member)); obj->insert((CD*) musicCD); here is the library destructor..... Library::~Library() { Purge(allBooks); Purge(allCDS); Purge(allDVDs); Purge(allBooksByAuthor); Purge(allmoviesByDirector); Purge(allmoviesByActor); Purge(allMusicByBand); Purge(allMusicByMusician); } void Library::Purge(ItemSet &set) { for (ItemSet::iterator it = set.begin(); it != set.end(); ++it) delete *it; set.clear(); } void Library::Purge(ItemSetMap &map) { for (ItemSetMap::iterator it = map.begin(); it != map.end(); ++it) delete it->second; map.clear(); } so, basically item, cd, dvd class all have a set like this: typedef set<string> StringSet; class CD : public Item StringSet* music; and i am deleting it like: but those superclasses are not being called.. Item destructor is. CD::~CD() { delete music; } Do, i need a copy constructor? and how do i delete those objects i am creating in the library class? and how can i get the cd,dvd, destructor called? would the addbandmember function located in the library.cpp cause me to have a copy constructor? Any real help you can provide me to help me clean up this mess instead of telling me not to use pointers in my sets i would really appreciate. How can i delete the memory i am creating in those functions? I cannot delete them in the function!!

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• Probelm with String.split() in java

  - by Matt

  What I am trying to do is read a .java file, and pick out all of the identifiers and store them in a list. My problem is with the .split() method. If you run this code the way it is, you will get ArrayOutOfBounds, but if you change the delimiter from "." to anything else, the code works. But I need to lines parsed by "." so is there another way I could accomplish this? import java.io.BufferedReader; import java.io.FileNotFoundException; import java.io.FileReader; import java.io.IOException; import java.util.*; public class MyHash { private static String[] reserved = new String[100]; private static List list = new LinkedList(); private static List list2 = new LinkedList(); public static void main (String args[]){ Hashtable hashtable = new Hashtable(997); makeReserved(); readFile(); String line; ListIterator itr = list.listIterator(); int listIndex = 0; while (listIndex < list.size()) { if (itr.hasNext()){ line = itr.next().toString(); //PROBLEM IS HERE!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! String[] words = line.split("."); //CHANGE THIS AND IT WILL WORK System.out.println(words[0]); //TESTING TO SEE IF IT WORKED } listIndex++; } } public static void readFile() { String text; String[] words; BufferedReader in = null; try { in = new BufferedReader(new FileReader("MyHash.java")); //NAME OF INPUT FILE } catch (FileNotFoundException ex) { Logger.getLogger(MyHash.class.getName()).log(Level.SEVERE, null, ex); } try { while ((text = in.readLine()) != null){ text = text.trim(); words = text.split("\\s+"); for (int i = 0; i < words.length; i++){ list.add(words[i]); } for (int j = 0; j < reserved.length; j++){ if (list.contains(reserved[j])){ list.remove(reserved[j]); } } } } catch (IOException ex) { Logger.getLogger(MyHash.class.getName()).log(Level.SEVERE, null, ex); } try { in.close(); } catch (IOException ex) { Logger.getLogger(MyHash.class.getName()).log(Level.SEVERE, null, ex); } } public static int keyIt (int x) { int key = x % 997; return key; } public static int horner (String word){ int length = word.length(); char[] letters = new char[length]; for (int i = 0; i < length; i++){ letters[i]=word.charAt(i); } char[] alphabet = new char[26]; String abc = "abcdefghijklmnopqrstuvwxyz"; for (int i = 0; i < 26; i++){ alphabet[i]=abc.charAt(i); } int[] numbers = new int[length]; int place = 0; for (int i = 0; i < length; i++){ for (int j = 0; j < 26; j++){ if (alphabet[j]==letters[i]){ numbers[place]=j+1; place++; } } } int hornered = numbers[0] * 32; for (int i = 1; i < numbers.length; i++){ hornered += numbers[i]; if (i == numbers.length -1){ return hornered; } hornered = hornered % 997; hornered *= 32; } return hornered; } public static String[] makeReserved (){ reserved[0] = "abstract"; reserved[1] = "assert"; reserved[2] = "boolean"; reserved[3] = "break"; reserved[4] = "byte"; reserved[5] = "case"; reserved[6] = "catch"; reserved[7] = "char"; reserved[8] = "class"; reserved[9] = "const"; reserved[10] = "continue"; reserved[11] = "default"; reserved[12] = "do"; reserved[13] = "double"; reserved[14] = "else"; reserved[15] = "enum"; reserved[16] = "extends"; reserved[17] = "false"; reserved[18] = "final"; reserved[19] = "finally"; reserved[20] = "float"; reserved[21] = "for"; reserved[22] = "goto"; reserved[23] = "if"; reserved[24] = "implements"; reserved[25] = "import"; reserved[26] = "instanceof"; reserved[27] = "int"; reserved[28] = "interface"; reserved[29] = "long"; reserved[30] = "native"; reserved[31] = "new"; reserved[32] = "null"; reserved[33] = "package"; reserved[34] = "private"; reserved[35] = "protected"; reserved[36] = "public"; reserved[37] = "return"; reserved[38] = "short"; reserved[39] = "static"; reserved[40] = "strictfp"; reserved[41] = "super"; reserved[42] = "switch"; reserved[43] = "synchronize"; reserved[44] = "this"; reserved[45] = "throw"; reserved[46] = "throws"; reserved[47] = "trasient"; reserved[48] = "true"; reserved[49] = "try"; reserved[50] = "void"; reserved[51] = "volatile"; reserved[52] = "while"; reserved[53] = "="; reserved[54] = "=="; reserved[55] = "!="; reserved[56] = "+"; reserved[57] = "-"; reserved[58] = "*"; reserved[59] = "/"; reserved[60] = "{"; reserved[61] = "}"; return reserved; } }

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• Null-free "maps": Is a callback solution slower than tryGet()?

  - by David Moles

  In comments to "How to implement List, Set, and Map in null free design?", Steven Sudit and I got into a discussion about using a callback, with handlers for "found" and "not found" situations, vs. a tryGet() method, taking an out parameter and returning a boolean indicating whether the out parameter had been populated. Steven maintained that the callback approach was more complex and almost certain to be slower; I maintained that the complexity was no greater and the performance at worst the same. But code speaks louder than words, so I thought I'd implement both and see what I got. The original question was fairly theoretical with regard to language ("And for argument sake, let's say this language don't even have null") -- I've used Java here because that's what I've got handy. Java doesn't have out parameters, but it doesn't have first-class functions either, so style-wise, it should suck equally for both approaches. (Digression: As far as complexity goes: I like the callback design because it inherently forces the user of the API to handle both cases, whereas the tryGet() design requires callers to perform their own boilerplate conditional check, which they could forget or get wrong. But having now implemented both, I can see why the tryGet() design looks simpler, at least in the short term.) First, the callback example: class CallbackMap<K, V> { private final Map<K, V> backingMap; public CallbackMap(Map<K, V> backingMap) { this.backingMap = backingMap; } void lookup(K key, Callback<K, V> handler) { V val = backingMap.get(key); if (val == null) { handler.handleMissing(key); } else { handler.handleFound(key, val); } } } interface Callback<K, V> { void handleFound(K key, V value); void handleMissing(K key); } class CallbackExample { private final Map<String, String> map; private final List<String> found; private final List<String> missing; private Callback<String, String> handler; public CallbackExample(Map<String, String> map) { this.map = map; found = new ArrayList<String>(map.size()); missing = new ArrayList<String>(map.size()); handler = new Callback<String, String>() { public void handleFound(String key, String value) { found.add(key + ": " + value); } public void handleMissing(String key) { missing.add(key); } }; } void test() { CallbackMap<String, String> cbMap = new CallbackMap<String, String>(map); for (int i = 0, count = map.size(); i < count; i++) { String key = "key" + i; cbMap.lookup(key, handler); } System.out.println(found.size() + " found"); System.out.println(missing.size() + " missing"); } } Now, the tryGet() example -- as best I understand the pattern (and I might well be wrong): class TryGetMap<K, V> { private final Map<K, V> backingMap; public TryGetMap(Map<K, V> backingMap) { this.backingMap = backingMap; } boolean tryGet(K key, OutParameter<V> valueParam) { V val = backingMap.get(key); if (val == null) { return false; } valueParam.value = val; return true; } } class OutParameter<V> { V value; } class TryGetExample { private final Map<String, String> map; private final List<String> found; private final List<String> missing; public TryGetExample(Map<String, String> map) { this.map = map; found = new ArrayList<String>(map.size()); missing = new ArrayList<String>(map.size()); } void test() { TryGetMap<String, String> tgMap = new TryGetMap<String, String>(map); for (int i = 0, count = map.size(); i < count; i++) { String key = "key" + i; OutParameter<String> out = new OutParameter<String>(); if (tgMap.tryGet(key, out)) { found.add(key + ": " + out.value); } else { missing.add(key); } } System.out.println(found.size() + " found"); System.out.println(missing.size() + " missing"); } } And finally, the performance test code: public static void main(String[] args) { int size = 200000; Map<String, String> map = new HashMap<String, String>(); for (int i = 0; i < size; i++) { String val = (i % 5 == 0) ? null : "value" + i; map.put("key" + i, val); } long totalCallback = 0; long totalTryGet = 0; int iterations = 20; for (int i = 0; i < iterations; i++) { { TryGetExample tryGet = new TryGetExample(map); long tryGetStart = System.currentTimeMillis(); tryGet.test(); totalTryGet += (System.currentTimeMillis() - tryGetStart); } System.gc(); { CallbackExample callback = new CallbackExample(map); long callbackStart = System.currentTimeMillis(); callback.test(); totalCallback += (System.currentTimeMillis() - callbackStart); } System.gc(); } System.out.println("Avg. callback: " + (totalCallback / iterations)); System.out.println("Avg. tryGet(): " + (totalTryGet / iterations)); } On my first attempt, I got 50% worse performance for callback than for tryGet(), which really surprised me. But, on a hunch, I added some garbage collection, and the performance penalty vanished. This fits with my instinct, which is that we're basically talking about taking the same number of method calls, conditional checks, etc. and rearranging them. But then, I wrote the code, so I might well have written a suboptimal or subconsicously penalized tryGet() implementation. Thoughts?

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• Migrate existing Maven Project into an OSGI Bundle

  - by user1706291

  i am new to the whole OSGi stuff and my task is to create an OSGi Bundle out from an exisitng maven project. To get started i decided to pick the smallest part and starting with it: Here is the pom.xml project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd"> <modelVersion>4.0.0</modelVersion> <parent> <artifactId>cross</artifactId> <groupId>net.sf.maltcms</groupId> <version>1.2.12-SNAPSHOT</version> </parent> <artifactId>cross-main</artifactId> <packaging>jar</packaging> <name>cross-main</name> <dependencies> <dependency> <groupId>${project.groupId}</groupId> <artifactId>cross-annotations</artifactId> <version>${project.version}</version> </dependency> <dependency> <groupId>${project.groupId}</groupId> <artifactId>cross-event</artifactId> <version>${project.version}</version> </dependency> <dependency> <groupId>${project.groupId}</groupId> <artifactId>cross-tools</artifactId> <version>${project.version}</version> </dependency> <dependency> <groupId>${project.groupId}</groupId> <artifactId>cross-exception</artifactId> <version>${project.version}</version> </dependency> <dependency> <groupId>commons-codec</groupId> <artifactId>commons-codec</artifactId> <version>1.4</version> </dependency> <dependency> <groupId>${project.groupId}</groupId> <artifactId>cross-main-api</artifactId> <version>${project.version}</version> <exclusions> <exclusion> <artifactId>commons-logging</artifactId> <groupId>commons-logging</groupId> </exclusion> </exclusions> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-aop</artifactId> <version>3.0.6.RELEASE</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-asm</artifactId> <version>3.0.6.RELEASE</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-beans</artifactId> <version>3.0.6.RELEASE</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context</artifactId> <version>3.0.6.RELEASE</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-core</artifactId> <version>3.0.6.RELEASE</version> <exclusions> <exclusion> <artifactId>commons-logging</artifactId> <groupId>commons-logging</groupId> </exclusion> </exclusions> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-expression</artifactId> <version>3.0.6.RELEASE</version> </dependency> <dependency> <groupId>commons-io</groupId> <artifactId>commons-io</artifactId> <version>2.1</version> </dependency> <dependency> <groupId>net.sf.ehcache</groupId> <artifactId>ehcache-core</artifactId> <version>2.4.6</version> </dependency> <dependency> <groupId>${project.groupId}</groupId> <artifactId>cross-math</artifactId> <version>${project.version}</version> </dependency> <dependency> <groupId>com.db4o</groupId> <artifactId>db4o-all</artifactId> <version>8.0.249</version> </dependency> <dependency> <groupId>net.sf.mpaxs</groupId> <artifactId>mpaxs-spi</artifactId> <version>1.6.10</version> </dependency> <dependency> <groupId>net.sf.mpaxs</groupId> <artifactId>mpaxs-server</artifactId> <version>1.6.10</version> </dependency> </dependencies> I did some research and found the Apache Bundle Plugin for maven and changed the pom to this <packaging>bundle</packaging> and added <build> <plugins> <plugin> <groupId>org.apache.felix</groupId> <artifactId>maven-bundle-plugin</artifactId> <extensions>true</extensions> <configuration> <instructions> <Bundle-SymbolicName>${pom.artifactId}</Bundle-SymbolicName> </instructions> </configuration> </plugin> </plugins> </build> mvn clean install went fine and i got a jar file containing the manifest, but of course the bundle could not be resolved BundleException: The bundle "cross-main_1.2.12.SNAPSHOT [30]" could not be resolved. Reason: Missing Constraint: Import-Package: com.db4o; version="[8.0.0,9.0.0) To make a long story short: What are the possibiliteis to migrate a maven application into an OSGi Bundle? Espacially how to manage the dependencys

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• How to save/retrieve words to/from SQlite database?

  - by user998032

  Sorry if I repeat my question but I have still had no clues of what to do and how to deal with the question. My app is a dictionary. I assume that users will need to add words that they want to memorise to a Favourite list. Thus, I created a Favorite button that works on two phases: short-click to save the currently-view word into the Favourite list; and long-click to view the Favourite list so that users can click on any words to look them up again. I go for using a SQlite database to store the favourite words but I wonder how I can do this task. Specifically, my questions are: Should I use the current dictionary SQLite database or create a new SQLite database to favorite words? In each case, what codes do I have to write to cope with the mentioned task? Could anyone there kindly help? Here is the dictionary code: package mydict.app; import java.util.ArrayList; import android.database.Cursor; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteException; import android.util.Log; public class DictionaryEngine { static final private String SQL_TAG = "[MyAppName - DictionaryEngine]"; private SQLiteDatabase mDB = null; private String mDBName; private String mDBPath; //private String mDBExtension; public ArrayList<String> lstCurrentWord = null; public ArrayList<String> lstCurrentContent = null; //public ArrayAdapter<String> adapter = null; public DictionaryEngine() { lstCurrentContent = new ArrayList<String>(); lstCurrentWord = new ArrayList<String>(); } public DictionaryEngine(String basePath, String dbName, String dbExtension) { //mDBExtension = getResources().getString(R.string.dbExtension); //mDBExtension = dbExtension; lstCurrentContent = new ArrayList<String>(); lstCurrentWord = new ArrayList<String>(); this.setDatabaseFile(basePath, dbName, dbExtension); } public boolean setDatabaseFile(String basePath, String dbName, String dbExtension) { if (mDB != null) { if (mDB.isOpen() == true) // Database is already opened { if (basePath.equals(mDBPath) && dbName.equals(mDBName)) // the opened database has the same name and path -> do nothing { Log.i(SQL_TAG, "Database is already opened!"); return true; } else { mDB.close(); } } } String fullDbPath=""; try { fullDbPath = basePath + dbName + "/" + dbName + dbExtension; mDB = SQLiteDatabase.openDatabase(fullDbPath, null, SQLiteDatabase.OPEN_READWRITE|SQLiteDatabase.NO_LOCALIZED_COLLATORS); } catch (SQLiteException ex) { ex.printStackTrace(); Log.i(SQL_TAG, "There is no valid dictionary database " + dbName +" at path " + basePath); return false; } if (mDB == null) { return false; } this.mDBName = dbName; this.mDBPath = basePath; Log.i(SQL_TAG,"Database " + dbName + " is opened!"); return true; } public void getWordList(String word) { String query; // encode input String wordEncode = Utility.encodeContent(word); if (word.equals("") || word == null) { query = "SELECT id,word FROM " + mDBName + " LIMIT 0,15" ; } else { query = "SELECT id,word FROM " + mDBName + " WHERE word >= '"+wordEncode+"' LIMIT 0,15"; } //Log.i(SQL_TAG, "query = " + query); Cursor result = mDB.rawQuery(query,null); int indexWordColumn = result.getColumnIndex("Word"); int indexContentColumn = result.getColumnIndex("Content"); if (result != null) { int countRow=result.getCount(); Log.i(SQL_TAG, "countRow = " + countRow); lstCurrentWord.clear(); lstCurrentContent.clear(); if (countRow >= 1) { result.moveToFirst(); String strWord = Utility.decodeContent(result.getString(indexWordColumn)); String strContent = Utility.decodeContent(result.getString(indexContentColumn)); lstCurrentWord.add(0,strWord); lstCurrentContent.add(0,strContent); int i = 0; while (result.moveToNext()) { strWord = Utility.decodeContent(result.getString(indexWordColumn)); strContent = Utility.decodeContent(result.getString(indexContentColumn)); lstCurrentWord.add(i,strWord); lstCurrentContent.add(i,strContent); i++; } } result.close(); } } public Cursor getCursorWordList(String word) { String query; // encode input String wordEncode = Utility.encodeContent(word); if (word.equals("") || word == null) { query = "SELECT id,word FROM " + mDBName + " LIMIT 0,15" ; } else { query = "SELECT id,content,word FROM " + mDBName + " WHERE word >= '"+wordEncode+"' LIMIT 0,15"; } //Log.i(SQL_TAG, "query = " + query); Cursor result = mDB.rawQuery(query,null); return result; } public Cursor getCursorContentFromId(int wordId) { String query; // encode input if (wordId <= 0) { return null; } else { query = "SELECT id,content,word FROM " + mDBName + " WHERE Id = " + wordId ; } //Log.i(SQL_TAG, "query = " + query); Cursor result = mDB.rawQuery(query,null); return result; } public Cursor getCursorContentFromWord(String word) { String query; // encode input if (word == null || word.equals("")) { return null; } else { query = "SELECT id,content,word FROM " + mDBName + " WHERE word = '" + word + "' LIMIT 0,1"; } //Log.i(SQL_TAG, "query = " + query); Cursor result = mDB.rawQuery(query,null); return result; } public void closeDatabase() { mDB.close(); } public boolean isOpen() { return mDB.isOpen(); } public boolean isReadOnly() { return mDB.isReadOnly(); } } And here is the code below the Favourite button to save to and load the Favourite list: btnAddFavourite = (ImageButton) findViewById(R.id.btnAddFavourite); btnAddFavourite.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { // Add code here to save the favourite, e.g. in the db. Toast toast = Toast.makeText(ContentView.this, R.string.messageWordAddedToFarvourite, Toast.LENGTH_SHORT); toast.show(); } }); btnAddFavourite.setOnLongClickListener(new View.OnLongClickListener() { @Override public boolean onLongClick(View v) { // Open the favourite Activity, which in turn will fetch the saved favourites, to show them. Intent intent = new Intent(getApplicationContext(), FavViewFavourite.class); intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK); getApplicationContext().startActivity(intent); return false; } }); }

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• SOA PARTNER COMMUNITY NEWSLETTER JULY 2012

  - by mseika

  SOA PARTNER COMMUNITY NEWSLETTER JULY 2012 Dear SOA partner community member To provide our community members the best of our knowledge, we want your feedback on our SOA Partner community. Thus we are organizing SOA Partner Community Survey 2012. We request you to participate in the survey and give your valuable feedback on various areas of marketing, sales and education. To continue our successful BPM Suite, Oracle is launching together with you Process Accelerators initiative. It’s your opportunity to co-develop and market predefined processes. Oracle Fusion Applications Design Patterns are a great tool to develop your SOA or BPM solution or process accelerators. To promote your SOA & BPM Specialization we continue to offer several benefits. This month we would like to highlight our Specialization Plaques - make sure you request one for your office! Our Fusion Middleware Summer Camps are booked out, if could not get a seat you can attend the SOA & BPM track @ Virtual Developer Day: Oracle Fusion Development Oracle demo systems offer´s two new demos: Business Driven Development based on BPM Suite & SOA Lifecycle Management. Jürgen KressOracle SOA & BPM Partner Adoption EMEA NEW CONTENT Community SurveyProcess Accelerators KitPlaques SOA & BPM SpecializedSOA & BPM at Virtual Developer Day News from our Partners & CommunityOverview of SOA Diagnostics in 11.1.1.6 Business driven development(BDD) demo now available! SOA Lifecycle Management Oracle Fusion applications design patterns Updated material by Oracle Connect and Network SOA Blogs SOA on Facebook SOA on LinkedIn SOA on Twitter Mix SOA Forum COMMUNITY SURVEY Like every year we would like to get your feedback in our SOA Partner Community Survey 2012. Make sure that You attend to further develop our community and support our planning! It is key for us to get your feedback to prepare for the next fiscal year. Back to top PROCESS ACCELERATORS KIT Oracle is very interested to co-develop and market with you, our partners, pre-defined processes for BPM Suite.I am very happy to announce a new program called “Oracle BPM Partner Solution Catalog”. This program will provide a one-stop shop for our customers looking for Oracle BPM partner solutions available in the market today.The Oracle BPM Solution Catalog will be hosted on our very popular Oracle Technology Network (OTN). To give you an idea of the scale of customer visibility, OTN today receives over 1Million hits per day from our business and developer community. We would like to invite you to list your Oracle BPM 11g solutions available today.In order to participate in this program, you need to do the following: Fill in the attached slide templates - #3 and #4 for each Oracle BPM 11g solution you would like to list on OTN.Please add links to whitepapers , videos, references to the specific solution in the template slide. We recommend that you create a landing page on your website for these linked artifacts and just point to the same from within the PowerPoint template. This will give you the flexibility to update the information as frequently as needed. If you have the particular solution in production or a reference available, please list them as well. Send the PowerPoint template slides (1 set of slides for each Oracle BPM solution) to [email protected]. In addition to having the opportunity to list your solutions on OTN for Oracle customers, you will have the chance to advertise your new wins/implementations/solutions in an Oracle Sponsored PM Webinar held every quarter. This program is targeted to go live by the end of summer 2012. At this point, we are targeting a soft launch in July end 2012 so send on your BPM solutions information as soon as possible. We would love to have your solution(s) listed in the “Oracle BPM Partner Solution Catalog” at the time of the launch. This will be a live repository so you can keep adding more solutions as they become available. If you have any questions, please feel free to contact us [email protected], Product Strategy Director, Oracle BPM , Phone +1 650.506.5486.Thank you and look forward to hearing from you. Oracle BPM team Process Accelerators Overview.pdf ProcessAcceleratorsDataSheet.pdf Demos draUPK.zip & trmUPK.zip BPM Solution repository slides.ppt Additional BPM material BPM Process Development Lifecycle Document that describes recommended approach to collaborative process modeling across business and IT tools ADF 11g PS5 Application with Customized BPM Worklist Task Flow (MDS Seeded Customization) by Andrejus Baranovskis BPMN process editor problems in 11.1.1.6 by Mark Nelson BPM – Disable DBMS job to refresh B2B Materialized View by Mark Nelson For the complete kit please visit the BPM folder at our SOA Community Workspace (SOA Community membership required). For the complete presentation please visit our SOA Community Workspace (SOA Community membership required). Information is Oracle and Partner confidential! Back to top PLAQUES SOA & BPM SPECIALIZED We continue to offer you a nice SOA & BPM Specialization plaque with your logo to proof your success. If you are a SOA or BPM Specialized partner and would like to request the plaque please send Brigitte an e-mail with the following information: Partner Name Partner logo (preferred eps file) Partner Status gold or platinum Your shipping address Your Specialization: SOA or BPM We recommend to mount the plaque at your office reception in addition you can use the SOA Specialization logos at your website download Logo: Gold & Platinum or the BPM logos Gold & Platinum Back to top SOA & BPM AT VIRTUAL DEVELOPER DAY Register now for this FREE hands-on online workshop Get up to date and learn everything you wanted to know about Oracle ADF & Fusion Development plus live Q&A chats with Oracle technical staffOracle Application Development Framework (ADF) is the standards based, strategic framework for Oracle Fusion Applications and Oracle Fusion Middleware. Oracle ADF’s integration with the Oracle SOA Suite, Oracle WebCenter and Oracle BI creates a complete productive development platform for your custom applications.Join us at this FREE virtual event and learn the latest in Fusion Development including: Is Oracle ADF development faster and simpler than Forms, Apex or .Net? Mobile Application Development with ADF Mobile Oracle ADF development with Eclipse Oracle WebCenter Portal and ADF Development Application Lifecycle Management with ADF Building Process Centric Applications with ADF and BPM Oracle Business Intelligence and ADF Integration Live Q&A chats with Oracle technical staff Developer lead, manager or architect - this event has something for everyone. Don’t miss this opportunity.Tuesday, July 10, 2012. 9:00 a.m. PT -1:00 p.m. PT 11:00 a.m. CT - 3:00 p.m. CT 12:00 p.m. ET - 4:00 p.m. ET 1:00 p.m. BRT - 5:00 p.m. BRT Register online now! for this FREE event. Agenda: 09:00 am Opening 09:30 am Keynote: Oracle Fusion Development Track1Introduction to Fusion Development Track2What's New in Fusion Development Track3Fusion Development in the Enterprise 10:00 am Is Oracle ADF Development Faster and Simpler than Oracle Forms, APEX or .Net? Mobile Application Development with ADF Mobile Oracle WebCenter Portal and ADF Development 11:00 am Rich Web UI made simple - an ADF Faces Overview Oracle Enterprise Pack for Eclipse - ADF Development Building Process Centric Applications with ADF and BPM 12:00 noon Next Generation Controller for JSF Application Lifecycle Management for ADF Oracle Business Intelligence and ADF Integration *Hands On Lab – WebCenter and ADF Lab w/ JDeveloper - Lab materials will be provided ahead of the event to give you ample time to work through the lab and increase the productivity of the live chat sessions the day of the event. Sessions abstractsRegister online now! for this FREE event Read more on Community Events and post your comment here. Back to top NEWS FROM OUR PARTNERS AND COMMUNITY Send your tweets @soacommunity #soacommunity and follow us at http://twitter.com/soacommunity JDeveloper & ADF?Troubleshooting BPMN process editor problems in 11.1.1.6http://dlvr.it/1p0FfS SOA Community?SOA & BPM @ Virtual Developer Day: Oracle Fusion Development - July 10th 2012https://soacommunity.wordpress.com/2012/07/02/soa-bpm-virtual-developer-day- oracle-fusion-developmentjuly-10th-2012/#soacommunity #soa #bom #education orclateamsoa ?A-Team Blog #ateam: BAM design pointers - In working recently with a large Oracle customer on SOA and BAM, I discove.http://ow.ly/1kYqES SOA CommunitySOA Community Newsletter June 2012http://wp.me/p10C8u-qw SOA CommunityBPMN process editor problems in 11.1.1.6 by Mark Nelsonhttp://redstack.wordpress.com/2012/06/27/ bpmn-process-editor-problems-in-11-1-1-6 #soacommunity #bpm OTNArchBeat ?SOA Learning Library: free short, topic-focused training on Oracle SOA & BPM products | @SOACommunity http://pub.vitrue.com/NE1G Andrejus Baranovskis ?ADF 11g PS5 Application with Customized BPM Worklist Task Flow (MDS Seeded Customization)http://fb.me/1coX4r1X1 SOA CommunitySOA Learning Library provides a comprehensive curriculum for the SOA and BPM product suites https://soacommunity.wordpress.com/2012/06/27/soa-learning-library #soacommunity #soa #bpm OTNArchBeat ?A Universal JMX Client for Weblogic - Part 1: Monitoring BPEL Thread Pools in SOA 11g | Stefan Koserhttp://pub.vitrue.com/mQVZ OTNArchBeat ?BPM - Disable DBMS job to refresh B2B Materialized View | Mark Nelson http://pub.vitrue.com/3PR0Oracle SOA ?Learn how Choice Hotels Implements Innovative Google Maps Solution with #OracleSOA http://bit.ly/MTwIJ3 SOA Communitytop Tweets SOA Partner Community - June 2012 Send your tweets @soacommunity #soacommunity https://soacommunity.wordpress.com/2012/06/25/top-tweets-soa-partner-community-june-2012 Torsten Winterberg#OPITZ is pushing Oracle commitment to the next level: New Specializations done: ADF, BPM, WLS, Exadatahttp://bit.ly/KX1WVS ServiceTechSymposium ?Only 8 more days left until Super Early Bird Registration Discount expires! http://www.servicetechsymposium.com OracleBlogsSOA Management in 3 minutes - Video explainerhttp://ow.ly/1kN5pn SOA Community ?SOA, Cloud & Service Technology Symposium 2012 London - Enter Promo Code: Djmxz370https://soacommunity.wordpress.com/2012/06/22/soa-cloud-service-technology-symposium-2012-london #soasymposium #soacommunity #soa Heidi BuelowGreat course! w David Read RT @soacommunity: product management ADF for BPM training 5 seats left https://soacommunity.wordpress.com/2012/06/12/fusion-middleware-summer-campsadvanced-partner-trainings/ #bpm #soacommunity SOA Community ?product management ADF for BPM training 5 seats lefthttps://soacommunity.wordpress.com/2012/06/12/fusion-middleware-summer-campsadvanced-partner-trainings/ #bpm #soacommunity OTNArchBeat ?Oacle Fusion Applications Design Patterns Now Available For Developers | Ultan O'Broinhttp://pub.vitrue.com/UEiF OTNArchBeat ?SOA, Cloud & Service Technology Symposium 2012London - Special Oracle Discounthttp://pub.vitrue.com/8E0J SOA CommunityBecome a facebook fan of soacommunity http://www.facebook.com/soacommunity #soacommunity SOA Community ?SOA Suite HealthCare Integration Architecture https://blogs.oracle.com/SOAForHealthcare/entry/soa_suite_healthcare_integration_architecture #soacommunity #soa Andrejus Baranovskis ?Running Pre-built Virtual Machine for SOA Suite and BPM Suite 11g PS5 on Mac OS X Snow Leopard (10.6http://fb.me/vB8nO0Vg OracleBlogsPrinciples of Service-Oriented Architecture by Douwe P. van den Bos http://ow.ly/1kIcOP OTNArchBeatOracle Public Cloud Architecture | @TylerJewell http://ow.ly/bHAcL The SOA Network ?Business Process Management, Service-Oriented Architecture, and Web 2.0: Business Transformation or.http://bit.ly/LBgREL #ITNews #SOA OracleBlogs ?Oracle SOA Foundation Practitioner Certificationhttp://ow.ly/1kGYYg Frank Nimphius ?Learn Advanced ADF. ORACLE Fusion Middleware Summer Camps in Lisbon - July 9th - 13thhttp://bit.ly/KGCl3i SOA CommunityTransform Your Application Integration with Best Practices from Oracle Customershttps://blogs.oracle.com/SOA/entry/transform_your_application_integration_with #soacommunity #soa #bpm Simone GeibWhat you always wanted to know about #oraclesoa diagnostics: Shawn Bailey, Overview of SOA Diagnostics in 11.1.1.6,http://ow.ly/bxK0M Oracle SOA ?Save the date: Jun 21 10AM, SOA & BPM Customer Insight Series. Hear how Choice Hotels went from legacy to #oraclesoa http://bit.ly/LsNDGl OTNArchBeat ?New VirtualBox images for Oracle SOA Suite & Oracle BPM Suite 11.1.1.6.0http://ow.ly/bwDAl OracleBlogs ?Process development lifecycle in Oracle BPM 11g http://ow.ly/1ktesY Daniel AmadeiNew post: Oracle BPEL 11g Message Delivery & Recovery.http://amadei.com.br/blog/index.php /oracle-bpel-11g-message-delivery SOA Community ?Sending out the June edition of the #soacommunity newsletter - read it or become a member http://www.oracle.com/goto/emea/soa!#soa #bpm Arun Pareek ?For the past six months Ahmed Aboulnaga and me have been working on Oracle SOA Suite 11g Administrator's Handbook.http://lnkd.in/CAvpUQ SOA CommunitySun shine all day no clouds - solar eclipse is over... #sunshine #cloud http://www.infoq.com/presentations/Swarm-Computing Michel SchildmeijerWatch my blog Oracle Service Bus 11g: listing projects and services with WLST - part 1 http://lnkd.in/B7f3GQ @TITAN_GS @wlscommunity OTNArchBeatBook Review: Oracle Application Integration Architecture (AIA) Foundation Pack 11gR1: Essentials | Rajesh Rahejahttp://ow.ly/bn2cc OTNArchBeat ?Driving from Business Architecture to Business Process Services | @vghariharan http://ow.ly/bn5UB OTNArchBeat ?SOA Analysis within the Department of Defense Architecture Framework (DoDAF) 2.0 - Part II | Dawit Lessanu http://ow.ly/bn6sX Simone Geib ?Contact me directly for ideas how to improvehttp://bit.ly/advancedsoasuite and additional posts, presentations, white papers, ... #soasuite Simone Geib ?#soasuite advanced OTN page has become too cluttered. Broke it into separate pages to start with. http://bit.ly/advancedsoasuite OracleBlogs ?June Webcast: SOA Gateway Implementation and Troubleshooting (2 sessions) http://ow.ly/1kbRFA ServiceTechSymposium ?New session just posted to calendar: "NoSQL for Data Services, Data Virtualization & Big Data" by Guido Schmutz, Trivadis AG ://ow.ly/bjjOeDebra Lilley ?looks good - real proof people are using the apps ! RT @fteter: Very cool Fusion Applications Help site: http://bit.ly/L3nvOR #FusionApps demed ?rapid proliferation of cloud computing will drive convergence of SOA and cloud paradigms" http://ovum.com/2012/05/18/soa-paves-the-way-for-cloud/ SOA CommunityMiddleware Oracle Excellence Awards 2012-HAPPY NEW YEAR! https://soacommunity.wordpress.com/2012/05/31/middleware-oracle-excellence-awards-2012happy-new-year/ #soacommunity #opn #opnaward #specialization #oracle SOA CommunityHappy New Year #soacommunity thanks for the business! Time for a drink http://pic.twitter.com/zkK08KWB OTNArchBeat ?Who should ‘own’ the Enterprise Architecture? | Michael Glas http://bit.ly/K0ge0Q SOA Communitytop Tweets SOA Partner Community &ndash; May 2012 http://wp.me/p10C8u-pP ServiceTechSymposiumNew session just posted to Symposium calendar: "Elastic SOA in the Cloud" by Steve Millidge, C2B2 Consulting http://www.servicetechsymposium.com/agenda2012.php #elastic_soa_in_the_cloud orclateamsoa ?A-Team Blog #ateam: How to Set JVM Parameters in Oracle SOA 11Ghttp://ow.ly/1k2cnl ServiceTechSymposium ?New session just posted to Symposium calendar: "SOA Governance at EDP: A Global Energy Company" by Manuel Rosa, Linkhttp://www.servicetechsymposium.com/agenda2012.php#soa_governance_at_edp SOA Community ?VirtualBox image SOA Suite & BPM Suite 11.1.1.6.0&ndash;Your feedback?http://wp.me/p10C8u-qh Oracle MiddlewareSave the date: Jun 21 10AM, SOA & BPM Customer Insight Series. Hear how Choice Hotels went from legacy to#oraclesoa http://bit.ly/LU1y5N OTNArchBeat ?Goodbye, Silos. Hello SOA. | @stephanieoverbyhttp://pub.vitrue.com/NJJO SOA CommunityBPM Standard Edition - to start your BPM project http://wp.me/p10C8u-qj Please feel free to send us your news! And add your blog to our SOA blog wiki. Back to top OVERVIEW OF SOA DIAGNOSTICS IN 11.1.1.6 What tools are available for diagnosing SOA Suite issues? There are a variety of tools available to help you and Support diagnose SOA Suite issues in 11g but it can be confusing as to which tool is appropriate for a particular situation and what their relationships are. This blog post will introduce the various tools and attempt to clarify what each is for and how they are related. Let's first list the tools we'll be addressing: RDA: Remote Diagnostic Agent DFW: Diagnostic Framework Selective Tracing DMS: Dynamic Monitoring Service ODL: Oracle Diagnostic Logging ADR: Automatic Diagnostics Repository ADRCI: Automatic Diagnostics Repository Command Interpreter WLDF: WebLogic Diagnostic Framework This overview is not mean to be a comprehensive guide on using all of these tools, however, extensive reference materials are included that will provide many more details on their execution. Another point to note is that all of these tools are applicable for Fusion Middleware as a whole but specific products may or may not have implemented features to leverage them. A couple of the tools have a WebLogic Scripting Tool or 'WLST' interface. WLST is a command interface for executing pre-built functions and custom scripts against a domain. A detailed WLST tutorial is beyond the scope of this post but you can find general information here. There are more specific resources in the below sections.In this post when we refer to 'Enterprise Manager' or 'EM' we are referring to Enterprise Manager Fusion Middleware Control. read the full blog post here. Read more on Oracle and post your comment here. Back to top BUSINESS DRIVEN DEVELOPMENT (BDD) DEMO NOW AVAILABLE! For access to the Oracle demo systems please visit OPN and talk to your Partner Expert DSS is pleased to announce the availability of the demo “Business Driven Development“. This innovative demonstration uses a case-study approach to show business users how they can easily streamline their Business Processes - delivering greater efficiency, agility, visibility and collaboration with Oracle BPM and WebCenter. The BDD demonstration uses a case study-based approach to highlight a business problem at a fictional company, Avitek Corporation, and uses Oracle BPM and Oracle WebCenter to solve the business problem. This holistic approach has specifically been used to appeal to a non-technical business analyst user. This demo is NOT focused on product features, but aims to guide users through a complete BPM lifecycle. The scenario is based on improving a simple order process (scenario details are in the demo script). Avitek Corporation is sufferinng from a manual email-driven ordering process. Sales reps don’t know where the customer orders are stuck (no visibility) and finance users are unable to manually approve every order (no automation). There are several areas where this process can be improved with Business Process Management technology. This demo shows how improving following areas will ignificantly help resolve the business problems Avitek Corporation is facing. Areas for improvement include: Utilizing BPM for process management, rather than an unregulated, email-based process. Utilizing automated services, rather than requiring a human to key into a system. For example, Finance checking the customer’s credit rating is something that could be automated. Centralizing business rules that can be integrated into a business process, rather than requiring a human to process them. For example, Finance must determine when orders can be automatically approved. Provide insight and visibility into the process. For example, Sales Rep needs to know the status of their customer’s orders. The BDD Demo uses the following products. Oracle BPM Suite 11g PS4FP Oracle WebCenter 11g PS4FP (for Process Spaces) Oracle Business Activity Monitoring 11g Oracle Database 11g Back to top SOA LIFECYCLE MANAGEMENT For access to the Oracle demo systems please visit OPN and talk to your Partner Expert We are pleased to announce the availability of the SOA Management demo that showcases some of the key provisioning and lifecycle management capabilities of SOA Management Pack Enterprise Edition (EE). This demo specifically focuses on some of the lifecycle management solutions for Oracle SOA Suite and Oracle Service Bus (OSB). Demo Highlights The demo showcases the following capabilities. Provisioning of SOA Composites Provisioning of OSB Projects Provision SOA and OSB artifacts in a future maintenance window Back to top ORACLE FUSION APPLICATIONS DESIGN PATTERNS The Oracle Fusion Applications user experience design patterns are published! These new, reusable usability solutions and best-practices, which will join the Oracle dashboard patterns and guidelines that are already available online, are used by Oracle to artfully bring to life a new standard in the user experience, or UX, of enterprise applications. Now, the Oracle applications development community can benefit from the science behind the Oracle Fusion Applications user experience, too. These Oracle Fusion Applications UX Design Patterns, or blueprints, enable Oracle applications developers and system implementers everywhere to leverage professional usability insight when: tailoring an Oracle Fusion application, creating coexistence solutions that existing users will be delighted with, thus enabling graceful user transitions to Oracle Fusion Applications down the road, or designing exciting, new, highly usable applications in the cloud or on-premise. Based on the Oracle Application Development Framework (ADF) components, the Oracle Fusion Applications patterns and guidelines are proven with real users and in the Applications UX usability labs, so you can get right to work coding productivity-enhancing designs that provide an advantage for your entire business. What’s the best way to get started? We’ve made that easy, too. The Design Filter Tool (DeFT) selects the best pattern for your user type and task. Simply adapt your selection for your own task flow and content, and you’re on your way to a really great applications user experience. More Oracle applications design patterns and training are coming your way in the future. To provide feedback on the sets that are currently available, let me know in the comments! Read more on Fusionapps and post your comment here. Back to top UPDATED ORACLE MATERIAL Integrated SOA Gateway Documentation - Implementation Guide | Developer’s Guide Webcast Series: Oracle’s SOA and Oracle Business Process Management Solutions (Choice Hotels, Eaton, Farmers Insurance) BAM design pointers By Kavitha Srinivasan Seeking Oracle Fusion Middleware Go Live StoriesOracle Fusion Middleware product management is looking for recent go live stories to share with the Oracle sales team, sales consulting, product management and other internal groups. Customer contact details may remain anonymous. Your successful implementation will be featured in a quarterly report. The chance to present on an internal webcast is also available. Contact Maria Forney ([email protected]) if you have a noteworthy implementation success story. This is a good opportunity for partners interested in showcasing Oracle Fusion Middleware implementations, and gaining more exposure within Oracle. Performance tuning resources. All in one: docs, blogs, WPs, ppts: http://bit.ly/soa_resources Back to top HAVE YOU MISSED OUR LAST SOA PARTNER COMMUNITY WEBCASTS? UPK Webcast Business Driven Application Management & BPM11g & Application Grid & GoldenGate & Fusion Middleware Pricing & OC4J to WebLogic & Next Generation SOA & Fusion Middleware in Utility & Fusion Middleware in Communications & Fusion Middleware in Public Services & Fusion Middleware in Financial Services Please check your local OPN trainings calendar for additional training dates and locations. Back to top SOA PARTNER COMMUNITY CALENDAR On-Demand Trainings Event Name Language Type SOA Virtual Developers Day English Tech In-Class Trainings Date Event name Location / Country Contact person Type 09-13.07.2012 BPM Suite 11g advanced training by David Read Lisbon, Portugal Jürgen Kress Tech 09-13.07.2012 ADF 11g advanced training by Grant Ronald and Frank Nimphius Lisbon, Portugal Jürgen Kress Tech 09-13.07.2012 WebCenter Portal advanced training by Stefan Krantz and Angelo Santagata Lisbon, Portugal Jürgen Kress Tech 10.07.2012 Fusion Middleware Virtual Developer Day Online OTN Tech 10- 12.07.2012 WebLogic 12c training by Cosmin Tudor Lisbon, Portugal Jürgen Kress Tech 16-18.07.2012 SOA Suite 11g advanced training by Niall Commiskey Munich, Germany Jürgen Kress Tech 16-18.07.2012 ADF for BPM Suite 11g advanced training by David Read Munich, Germany Jürgen Kress Tech 16-18.07.2012 WebCenter Sites 11g advanced training by Product Management Munich, Germany Jürgen Kress Tech 17-20.07.2012 Oracle BPM 11g Implementation Bootcamp Live Virtual Class Oracle University Tech 23-26.07.2012 Oracle BPM 11g Implementation Bootcamp Utrecht, Netherlands Oracle University Tech 29-31.08.2012 Oracle BPM 11g Implementation Bootcamp Live Virtual Class Oracle University Tech 02-05.10.2012 Oracle BPM 11g Implementation Bootcamp Utrecht, Netherlands Oracle University Tech 15-18.10.2012 Oracle BPM 11g Implementation Bootcamp Utrecht, Netherlands Oracle University Tech 28-30.11.2012 Oracle AIA 11g Implementation Bootcamp Live Virtual Class Oracle University Tech 11-14.12.2012 Oracle BPM 11g Implementation Bootcamp Live Virtual Class Oracle University Tech 20-22.2.2013 Oracle AIA 11g Implementation Bootcamp Utrecht, Netherlands Oracle University Tech 14-17.1.2013 Oracle BPM 11g Implementation Bootcamp Utrecht, Netherlands Oracle University Tech 15-18.3.2013 Oracle BPM 11g Implementation Bootcamp Utrecht, Netherlands Oracle University Tech Please check your local OPN Training Calendar for additional training and locations here. Back to top SOASCHOOL.COM - SOA CERTIFIED PROFESSIONAL(SOACP) PROGRAM The SOASchool.com - SOA Certified Professional (SOACP) program is dedicated to excellence in the field of SOA and service-oriented computing. Through a series of seasoned course modules and exams, IT professionals have the opportunity to obtain a number of different certifications to recognize their accomplishment of gaining "project ready" SOA proficiency. This comprehensive and strictly vendor-neutral program was developed in cooperation with best-selling SOA author Thomas Erl and several major SOA organizations and academic institutions. Through the involvement of the SOA Education Committee, course contents and certification requirements are constantly reviewed and revised to stay current with developments in the service-oriented computing industry. The program is currently comprised of 12 course modules and 5 certifications and is expanding to 18 course modules and 8 certifications throughout 2009. For more information, visit www.soaschool.com and www.soacp.com. Blog Twitter LinkedIn Mix Forum Wiki Back to top YOUR CONTENT ON THE NEWSLETTER AND ON THE SOA COMMUNITY PORTAL Publishing Your StoriesWe would like to invite our partners to publish information in the newsletter or on our SOA Community portal. Especially we are looking for your real life experience with our SOA technology. Please send your documents to Jürgen Kress. We look forward to getting your suggestions! Back to top SOA DISCUSSION FORUM BECOMES INTERACTIVE AT THE SOA COMMUNITY! Do you want to chat to experts, including partners and Oracle SOA Product Development? Do you want to get the latest information about our SOA solutions and events?Attend our private online SOA Discussion Forum at OTN. Please send your OTN forums user name to Brigitte Felisaz. You must be a registered user to access the SOA Discussion Forum. Back to top INVITE YOUR COLLEAGUES TO JOIN THE SOA COMMUNITY Please feel free to invite your colleagues to join the SOA Community and to participate in the SOA Assessment tests. For registration please login the Oracle PartnerNetwork and go to: www.oracle.com/goto/emea/soa For any questions on the above or concerning SOA and Oracle in general please contact the Oracle EMEA Alliances & Channels SOA Team. Best regardsOracle EMEA SOA TeamJürgen Kress Jürgen KressSOA Partner Adoption EMEATel. +49 89 1430 1479E-Mail: [email protected]

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• Service Discovery in WCF 4.0 &ndash; Part 1

  - by Shaun

  When designing a service oriented architecture (SOA) system, there will be a lot of services with many service contracts, endpoints and behaviors. Besides the client calling the service, in a large distributed system a service may invoke other services. In this case, one service might need to know the endpoints it invokes. This might not be a problem in a small system. But when you have more than 10 services this might be a problem. For example in my current product, there are around 10 services, such as the user authentication service, UI integration service, location service, license service, device monitor service, event monitor service, schedule job service, accounting service, player management service, etc..   Benefit of Discovery Service Since almost all my services need to invoke at least one other service. This would be a difficult task to make sure all services endpoints are configured correctly in every service. And furthermore, it would be a nightmare when a service changed its endpoint at runtime. Hence, we need a discovery service to remove the dependency (configuration dependency). A discovery service plays as a service dictionary which stores the relationship between the contracts and the endpoints for every service. By using the discovery service, when service X wants to invoke service Y, it just need to ask the discovery service where is service Y, then the discovery service will return all proper endpoints of service Y, then service X can use the endpoint to send the request to service Y. And when some services changed their endpoint address, all need to do is to update its records in the discovery service then all others will know its new endpoint. In WCF 4.0 Discovery it supports both managed proxy discovery mode and ad-hoc discovery mode. In ad-hoc mode there is no standalone discovery service. When a client wanted to invoke a service, it will broadcast an message (normally in UDP protocol) to the entire network with the service match criteria. All services which enabled the discovery behavior will receive this message and only those matched services will send their endpoint back to the client. The managed proxy discovery service works as I described above. In this post I will only cover the managed proxy mode, where there’s a discovery service. For more information about the ad-hoc mode please refer to the MSDN.   Service Announcement and Probe The main functionality of discovery service should be return the proper endpoint addresses back to the service who is looking for. In most cases the consume service (as a client) will send the contract which it wanted to request to the discovery service. And then the discovery service will find the endpoint and respond. Sometimes the contract and endpoint are not enough. It also contains versioning, extensions attributes. This post I will only cover the case includes contract and endpoint. When a client (or sometimes a service who need to invoke another service) need to connect to a target service, it will firstly request the discovery service through the “Probe” method with the criteria. Basically the criteria contains the contract type name of the target service. Then the discovery service will search its endpoint repository by the criteria. The repository might be a database, a distributed cache or a flat XML file. If it matches, the discovery service will grab the endpoint information (it’s called discovery endpoint metadata in WCF) and send back. And this is called “Probe”. Finally the client received the discovery endpoint metadata and will use the endpoint to connect to the target service. Besides the probe, discovery service should take the responsible to know there is a new service available when it goes online, as well as stopped when it goes offline. This feature is named “Announcement”. When a service started and stopped, it will announce to the discovery service. So the basic functionality of a discovery service should includes: 1, An endpoint which receive the service online message, and add the service endpoint information in the discovery repository. 2, An endpoint which receive the service offline message, and remove the service endpoint information from the discovery repository. 3, An endpoint which receive the client probe message, and return the matches service endpoints, and return the discovery endpoint metadata. WCF 4.0 discovery service just covers all these features in it's infrastructure classes.   Discovery Service in WCF 4.0 WCF 4.0 introduced a new assembly named System.ServiceModel.Discovery which has all necessary classes and interfaces to build a WS-Discovery compliant discovery service. It supports ad-hoc and managed proxy modes. For the case mentioned in this post, what we need to build is a standalone discovery service, which is the managed proxy discovery service mode. To build a managed discovery service in WCF 4.0 just create a new class inherits from the abstract class System.ServiceModel.Discovery.DiscoveryProxy. This class implemented and abstracted the procedures of service announcement and probe. And it exposes 8 abstract methods where we can implement our own endpoint register, unregister and find logic. These 8 methods are asynchronized, which means all invokes to the discovery service are asynchronously, for better service capability and performance. 1, OnBeginOnlineAnnouncement, OnEndOnlineAnnouncement: Invoked when a service sent the online announcement message. We need to add the endpoint information to the repository in this method. 2, OnBeginOfflineAnnouncement, OnEndOfflineAnnouncement: Invoked when a service sent the offline announcement message. We need to remove the endpoint information from the repository in this method. 3, OnBeginFind, OnEndFind: Invoked when a client sent the probe message that want to find the service endpoint information. We need to look for the proper endpoints by matching the client’s criteria through the repository in this method. 4, OnBeginResolve, OnEndResolve: Invoked then a client sent the resolve message. Different from the find method, when using resolve method the discovery service will return the exactly one service endpoint metadata to the client. In our example we will NOT implement this method.   Let’s create our own discovery service, inherit the base System.ServiceModel.Discovery.DiscoveryProxy. We also need to specify the service behavior in this class. Since the build-in discovery service host class only support the singleton mode, we must set its instance context mode to single. 1: using System; 2: using System.Collections.Generic; 3: using System.Linq; 4: using System.Text; 5: using System.ServiceModel.Discovery; 6: using System.ServiceModel; 7:  8: namespace Phare.Service 9: { 10: [ServiceBehavior(InstanceContextMode = InstanceContextMode.Single, ConcurrencyMode = ConcurrencyMode.Multiple)] 11: public class ManagedProxyDiscoveryService : DiscoveryProxy 12: { 13: protected override IAsyncResult OnBeginFind(FindRequestContext findRequestContext, AsyncCallback callback, object state) 14: { 15: throw new NotImplementedException(); 16: } 17:  18: protected override IAsyncResult OnBeginOfflineAnnouncement(DiscoveryMessageSequence messageSequence, EndpointDiscoveryMetadata endpointDiscoveryMetadata, AsyncCallback callback, object state) 19: { 20: throw new NotImplementedException(); 21: } 22:  23: protected override IAsyncResult OnBeginOnlineAnnouncement(DiscoveryMessageSequence messageSequence, EndpointDiscoveryMetadata endpointDiscoveryMetadata, AsyncCallback callback, object state) 24: { 25: throw new NotImplementedException(); 26: } 27:  28: protected override IAsyncResult OnBeginResolve(ResolveCriteria resolveCriteria, AsyncCallback callback, object state) 29: { 30: throw new NotImplementedException(); 31: } 32:  33: protected override void OnEndFind(IAsyncResult result) 34: { 35: throw new NotImplementedException(); 36: } 37:  38: protected override void OnEndOfflineAnnouncement(IAsyncResult result) 39: { 40: throw new NotImplementedException(); 41: } 42:  43: protected override void OnEndOnlineAnnouncement(IAsyncResult result) 44: { 45: throw new NotImplementedException(); 46: } 47:  48: protected override EndpointDiscoveryMetadata OnEndResolve(IAsyncResult result) 49: { 50: throw new NotImplementedException(); 51: } 52: } 53: } Then let’s implement the online, offline and find methods one by one. WCF discovery service gives us full flexibility to implement the endpoint add, remove and find logic. For the demo purpose we will use an internal dictionary to store the services’ endpoint metadata. In the next post we will see how to serialize and store these information in database. Define a concurrent dictionary inside the service class since our it will be used in the multiple threads scenario. 1: [ServiceBehavior(InstanceContextMode = InstanceContextMode.Single, ConcurrencyMode = ConcurrencyMode.Multiple)] 2: public class ManagedProxyDiscoveryService : DiscoveryProxy 3: { 4: private ConcurrentDictionary<EndpointAddress, EndpointDiscoveryMetadata> _services; 5:  6: public ManagedProxyDiscoveryService() 7: { 8: _services = new ConcurrentDictionary<EndpointAddress, EndpointDiscoveryMetadata>(); 9: } 10: } Then we can simply implement the logic of service online and offline. 1: protected override IAsyncResult OnBeginOnlineAnnouncement(DiscoveryMessageSequence messageSequence, EndpointDiscoveryMetadata endpointDiscoveryMetadata, AsyncCallback callback, object state) 2: { 3: _services.AddOrUpdate(endpointDiscoveryMetadata.Address, endpointDiscoveryMetadata, (key, value) => endpointDiscoveryMetadata); 4: return new OnOnlineAnnouncementAsyncResult(callback, state); 5: } 6:  7: protected override void OnEndOnlineAnnouncement(IAsyncResult result) 8: { 9: OnOnlineAnnouncementAsyncResult.End(result); 10: } 11:  12: protected override IAsyncResult OnBeginOfflineAnnouncement(DiscoveryMessageSequence messageSequence, EndpointDiscoveryMetadata endpointDiscoveryMetadata, AsyncCallback callback, object state) 13: { 14: EndpointDiscoveryMetadata endpoint = null; 15: _services.TryRemove(endpointDiscoveryMetadata.Address, out endpoint); 16: return new OnOfflineAnnouncementAsyncResult(callback, state); 17: } 18:  19: protected override void OnEndOfflineAnnouncement(IAsyncResult result) 20: { 21: OnOfflineAnnouncementAsyncResult.End(result); 22: } Regards the find method, the parameter FindRequestContext.Criteria has a method named IsMatch, which can be use for us to evaluate which service metadata is satisfied with the criteria. So the implementation of find method would be like this. 1: protected override IAsyncResult OnBeginFind(FindRequestContext findRequestContext, AsyncCallback callback, object state) 2: { 3: _services.Where(s => findRequestContext.Criteria.IsMatch(s.Value)) 4: .Select(s => s.Value) 5: .All(meta => 6: { 7: findRequestContext.AddMatchingEndpoint(meta); 8: return true; 9: }); 10: return new OnFindAsyncResult(callback, state); 11: } 12:  13: protected override void OnEndFind(IAsyncResult result) 14: { 15: OnFindAsyncResult.End(result); 16: } As you can see, we checked all endpoints metadata in repository by invoking the IsMatch method. Then add all proper endpoints metadata into the parameter. Finally since all these methods are asynchronized we need some AsyncResult classes as well. Below are the base class and the inherited classes used in previous methods. 1: using System; 2: using System.Collections.Generic; 3: using System.Linq; 4: using System.Text; 5: using System.Threading; 6:  7: namespace Phare.Service 8: { 9: abstract internal class AsyncResult : IAsyncResult 10: { 11: AsyncCallback callback; 12: bool completedSynchronously; 13: bool endCalled; 14: Exception exception; 15: bool isCompleted; 16: ManualResetEvent manualResetEvent; 17: object state; 18: object thisLock; 19:  20: protected AsyncResult(AsyncCallback callback, object state) 21: { 22: this.callback = callback; 23: this.state = state; 24: this.thisLock = new object(); 25: } 26:  27: public object AsyncState 28: { 29: get 30: { 31: return state; 32: } 33: } 34:  35: public WaitHandle AsyncWaitHandle 36: { 37: get 38: { 39: if (manualResetEvent != null) 40: { 41: return manualResetEvent; 42: } 43: lock (ThisLock) 44: { 45: if (manualResetEvent == null) 46: { 47: manualResetEvent = new ManualResetEvent(isCompleted); 48: } 49: } 50: return manualResetEvent; 51: } 52: } 53:  54: public bool CompletedSynchronously 55: { 56: get 57: { 58: return completedSynchronously; 59: } 60: } 61:  62: public bool IsCompleted 63: { 64: get 65: { 66: return isCompleted; 67: } 68: } 69:  70: object ThisLock 71: { 72: get 73: { 74: return this.thisLock; 75: } 76: } 77:  78: protected static TAsyncResult End<TAsyncResult>(IAsyncResult result) 79: where TAsyncResult : AsyncResult 80: { 81: if (result == null) 82: { 83: throw new ArgumentNullException("result"); 84: } 85:  86: TAsyncResult asyncResult = result as TAsyncResult; 87:  88: if (asyncResult == null) 89: { 90: throw new ArgumentException("Invalid async result.", "result"); 91: } 92:  93: if (asyncResult.endCalled) 94: { 95: throw new InvalidOperationException("Async object already ended."); 96: } 97:  98: asyncResult.endCalled = true; 99:  100: if (!asyncResult.isCompleted) 101: { 102: asyncResult.AsyncWaitHandle.WaitOne(); 103: } 104:  105: if (asyncResult.manualResetEvent != null) 106: { 107: asyncResult.manualResetEvent.Close(); 108: } 109:  110: if (asyncResult.exception != null) 111: { 112: throw asyncResult.exception; 113: } 114:  115: return asyncResult; 116: } 117:  118: protected void Complete(bool completedSynchronously) 119: { 120: if (isCompleted) 121: { 122: throw new InvalidOperationException("This async result is already completed."); 123: } 124:  125: this.completedSynchronously = completedSynchronously; 126:  127: if (completedSynchronously) 128: { 129: this.isCompleted = true; 130: } 131: else 132: { 133: lock (ThisLock) 134: { 135: this.isCompleted = true; 136: if (this.manualResetEvent != null) 137: { 138: this.manualResetEvent.Set(); 139: } 140: } 141: } 142:  143: if (callback != null) 144: { 145: callback(this); 146: } 147: } 148:  149: protected void Complete(bool completedSynchronously, Exception exception) 150: { 151: this.exception = exception; 152: Complete(completedSynchronously); 153: } 154: } 155: } 1: using System; 2: using System.Collections.Generic; 3: using System.Linq; 4: using System.Text; 5: using System.ServiceModel.Discovery; 6: using Phare.Service; 7:  8: namespace Phare.Service 9: { 10: internal sealed class OnOnlineAnnouncementAsyncResult : AsyncResult 11: { 12: public OnOnlineAnnouncementAsyncResult(AsyncCallback callback, object state) 13: : base(callback, state) 14: { 15: this.Complete(true); 16: } 17:  18: public static void End(IAsyncResult result) 19: { 20: AsyncResult.End<OnOnlineAnnouncementAsyncResult>(result); 21: } 22:  23: } 24:  25: sealed class OnOfflineAnnouncementAsyncResult : AsyncResult 26: { 27: public OnOfflineAnnouncementAsyncResult(AsyncCallback callback, object state) 28: : base(callback, state) 29: { 30: this.Complete(true); 31: } 32:  33: public static void End(IAsyncResult result) 34: { 35: AsyncResult.End<OnOfflineAnnouncementAsyncResult>(result); 36: } 37: } 38:  39: sealed class OnFindAsyncResult : AsyncResult 40: { 41: public OnFindAsyncResult(AsyncCallback callback, object state) 42: : base(callback, state) 43: { 44: this.Complete(true); 45: } 46:  47: public static void End(IAsyncResult result) 48: { 49: AsyncResult.End<OnFindAsyncResult>(result); 50: } 51: } 52:  53: sealed class OnResolveAsyncResult : AsyncResult 54: { 55: EndpointDiscoveryMetadata matchingEndpoint; 56:  57: public OnResolveAsyncResult(EndpointDiscoveryMetadata matchingEndpoint, AsyncCallback callback, object state) 58: : base(callback, state) 59: { 60: this.matchingEndpoint = matchingEndpoint; 61: this.Complete(true); 62: } 63:  64: public static EndpointDiscoveryMetadata End(IAsyncResult result) 65: { 66: OnResolveAsyncResult thisPtr = AsyncResult.End<OnResolveAsyncResult>(result); 67: return thisPtr.matchingEndpoint; 68: } 69: } 70: } Now we have finished the discovery service. The next step is to host it. The discovery service is a standard WCF service. So we can use ServiceHost on a console application, windows service, or in IIS as usual. The following code is how to host the discovery service we had just created in a console application. 1: static void Main(string[] args) 2: { 3: using (var host = new ServiceHost(new ManagedProxyDiscoveryService())) 4: { 5: host.Opened += (sender, e) => 6: { 7: host.Description.Endpoints.All((ep) => 8: { 9: Console.WriteLine(ep.ListenUri); 10: return true; 11: }); 12: }; 13:  14: try 15: { 16: // retrieve the announcement, probe endpoint and binding from configuration 17: var announcementEndpointAddress = new EndpointAddress(ConfigurationManager.AppSettings["announcementEndpointAddress"]); 18: var probeEndpointAddress = new EndpointAddress(ConfigurationManager.AppSettings["probeEndpointAddress"]); 19: var binding = Activator.CreateInstance(Type.GetType(ConfigurationManager.AppSettings["bindingType"], true, true)) as Binding; 20: var announcementEndpoint = new AnnouncementEndpoint(binding, announcementEndpointAddress); 21: var probeEndpoint = new DiscoveryEndpoint(binding, probeEndpointAddress); 22: probeEndpoint.IsSystemEndpoint = false; 23: // append the service endpoint for announcement and probe 24: host.AddServiceEndpoint(announcementEndpoint); 25: host.AddServiceEndpoint(probeEndpoint); 26:  27: host.Open(); 28:  29: Console.WriteLine("Press any key to exit."); 30: Console.ReadKey(); 31: } 32: catch (Exception ex) 33: { 34: Console.WriteLine(ex.ToString()); 35: } 36: } 37:  38: Console.WriteLine("Done."); 39: Console.ReadKey(); 40: } What we need to notice is that, the discovery service needs two endpoints for announcement and probe. In this example I just retrieve them from the configuration file. I also specified the binding of these two endpoints in configuration file as well. 1: <?xml version="1.0"?> 2: <configuration> 3: <startup> 4: <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/> 5: </startup> 6: <appSettings> 7: <add key="announcementEndpointAddress" value="net.tcp://localhost:10010/announcement"/> 8: <add key="probeEndpointAddress" value="net.tcp://localhost:10011/probe"/> 9: <add key="bindingType" value="System.ServiceModel.NetTcpBinding, System.ServiceModel, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/> 10: </appSettings> 11: </configuration> And this is the console screen when I ran my discovery service. As you can see there are two endpoints listening for announcement message and probe message.   Discoverable Service and Client Next, let’s create a WCF service that is discoverable, which means it can be found by the discovery service. To do so, we need to let the service send the online announcement message to the discovery service, as well as offline message before it shutdown. Just create a simple service which can make the incoming string to upper. The service contract and implementation would be like this. 1: [ServiceContract] 2: public interface IStringService 3: { 4: [OperationContract] 5: string ToUpper(string content); 6: } 1: public class StringService : IStringService 2: { 3: public string ToUpper(string content) 4: { 5: return content.ToUpper(); 6: } 7: } Then host this service in the console application. In order to make the discovery service easy to be tested the service address will be changed each time it’s started. 1: static void Main(string[] args) 2: { 3: var baseAddress = new Uri(string.Format("net.tcp://localhost:11001/stringservice/{0}/", Guid.NewGuid().ToString())); 4:  5: using (var host = new ServiceHost(typeof(StringService), baseAddress)) 6: { 7: host.Opened += (sender, e) => 8: { 9: Console.WriteLine("Service opened at {0}", host.Description.Endpoints.First().ListenUri); 10: }; 11:  12: host.AddServiceEndpoint(typeof(IStringService), new NetTcpBinding(), string.Empty); 13:  14: host.Open(); 15:  16: Console.WriteLine("Press any key to exit."); 17: Console.ReadKey(); 18: } 19: } Currently this service is NOT discoverable. We need to add a special service behavior so that it could send the online and offline message to the discovery service announcement endpoint when the host is opened and closed. WCF 4.0 introduced a service behavior named ServiceDiscoveryBehavior. When we specified the announcement endpoint address and appended it to the service behaviors this service will be discoverable. 1: var announcementAddress = new EndpointAddress(ConfigurationManager.AppSettings["announcementEndpointAddress"]); 2: var announcementBinding = Activator.CreateInstance(Type.GetType(ConfigurationManager.AppSettings["bindingType"], true, true)) as Binding; 3: var announcementEndpoint = new AnnouncementEndpoint(announcementBinding, announcementAddress); 4: var discoveryBehavior = new ServiceDiscoveryBehavior(); 5: discoveryBehavior.AnnouncementEndpoints.Add(announcementEndpoint); 6: host.Description.Behaviors.Add(discoveryBehavior); The ServiceDiscoveryBehavior utilizes the service extension and channel dispatcher to implement the online and offline announcement logic. In short, it injected the channel open and close procedure and send the online and offline message to the announcement endpoint.   On client side, when we have the discovery service, a client can invoke a service without knowing its endpoint. WCF discovery assembly provides a class named DiscoveryClient, which can be used to find the proper service endpoint by passing the criteria. In the code below I initialized the DiscoveryClient, specified the discovery service probe endpoint address. Then I created the find criteria by specifying the service contract I wanted to use and invoke the Find method. This will send the probe message to the discovery service and it will find the endpoints back to me. The discovery service will return all endpoints that matches the find criteria, which means in the result of the find method there might be more than one endpoints. In this example I just returned the first matched one back. In the next post I will show how to extend our discovery service to make it work like a service load balancer. 1: static EndpointAddress FindServiceEndpoint() 2: { 3: var probeEndpointAddress = new EndpointAddress(ConfigurationManager.AppSettings["probeEndpointAddress"]); 4: var probeBinding = Activator.CreateInstance(Type.GetType(ConfigurationManager.AppSettings["bindingType"], true, true)) as Binding; 5: var discoveryEndpoint = new DiscoveryEndpoint(probeBinding, probeEndpointAddress); 6:  7: EndpointAddress address = null; 8: FindResponse result = null; 9: using (var discoveryClient = new DiscoveryClient(discoveryEndpoint)) 10: { 11: result = discoveryClient.Find(new FindCriteria(typeof(IStringService))); 12: } 13:  14: if (result != null && result.Endpoints.Any()) 15: { 16: var endpointMetadata = result.Endpoints.First(); 17: address = endpointMetadata.Address; 18: } 19: return address; 20: } Once we probed the discovery service we will receive the endpoint. So in the client code we can created the channel factory from the endpoint and binding, and invoke to the service. When creating the client side channel factory we need to make sure that the client side binding should be the same as the service side. WCF discovery service can be used to find the endpoint for a service contract, but the binding is NOT included. This is because the binding was not in the WS-Discovery specification. In the next post I will demonstrate how to add the binding information into the discovery service. At that moment the client don’t need to create the binding by itself. Instead it will use the binding received from the discovery service. 1: static void Main(string[] args) 2: { 3: Console.WriteLine("Say something..."); 4: var content = Console.ReadLine(); 5: while (!string.IsNullOrWhiteSpace(content)) 6: { 7: Console.WriteLine("Finding the service endpoint..."); 8: var address = FindServiceEndpoint(); 9: if (address == null) 10: { 11: Console.WriteLine("There is no endpoint matches the criteria."); 12: } 13: else 14: { 15: Console.WriteLine("Found the endpoint {0}", address.Uri); 16:  17: var factory = new ChannelFactory<IStringService>(new NetTcpBinding(), address); 18: factory.Opened += (sender, e) => 19: { 20: Console.WriteLine("Connecting to {0}.", factory.Endpoint.ListenUri); 21: }; 22: var proxy = factory.CreateChannel(); 23: using (proxy as IDisposable) 24: { 25: Console.WriteLine("ToUpper: {0} => {1}", content, proxy.ToUpper(content)); 26: } 27: } 28:  29: Console.WriteLine("Say something..."); 30: content = Console.ReadLine(); 31: } 32: } Similarly, the discovery service probe endpoint and binding were defined in the configuration file. 1: <?xml version="1.0"?> 2: <configuration> 3: <startup> 4: <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/> 5: </startup> 6: <appSettings> 7: <add key="announcementEndpointAddress" value="net.tcp://localhost:10010/announcement"/> 8: <add key="probeEndpointAddress" value="net.tcp://localhost:10011/probe"/> 9: <add key="bindingType" value="System.ServiceModel.NetTcpBinding, System.ServiceModel, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/> 10: </appSettings> 11: </configuration> OK, now let’s have a test. Firstly start the discovery service, and then start our discoverable service. When it started it will announced to the discovery service and registered its endpoint into the repository, which is the local dictionary. And then start the client and type something. As you can see the client asked the discovery service for the endpoint and then establish the connection to the discoverable service. And more interesting, do NOT close the client console but terminate the discoverable service but press the enter key. This will make the service send the offline message to the discovery service. Then start the discoverable service again. Since we made it use a different address each time it started, currently it should be hosted on another address. If we enter something in the client we could see that it asked the discovery service and retrieve the new endpoint, and connect the the service.   Summary In this post I discussed the benefit of using the discovery service and the procedures of service announcement and probe. I also demonstrated how to leverage the WCF Discovery feature in WCF 4.0 to build a simple managed discovery service. For test purpose, in this example I used the in memory dictionary as the discovery endpoint metadata repository. And when finding I also just return the first matched endpoint back. I also hard coded the bindings between the discoverable service and the client. In next post I will show you how to solve the problem mentioned above, as well as some additional feature for production usage. You can download the code here.   Hope this helps, Shaun All documents and related graphics, codes are provided "AS IS" without warranty of any kind. Copyright © Shaun Ziyan Xu. This work is licensed under the Creative Commons License.

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• The Incremental Architect&rsquo;s Napkin - #5 - Design functions for extensibility and readability

  - by Ralf Westphal

  Originally posted on: http://geekswithblogs.net/theArchitectsNapkin/archive/2014/08/24/the-incremental-architectrsquos-napkin---5---design-functions-for.aspx The functionality of programs is entered via Entry Points. So what we´re talking about when designing software is a bunch of functions handling the requests represented by and flowing in through those Entry Points. Designing software thus consists of at least three phases: Analyzing the requirements to find the Entry Points and their signatures Designing the functionality to be executed when those Entry Points get triggered Implementing the functionality according to the design aka coding I presume, you´re familiar with phase 1 in some way. And I guess you´re proficient in implementing functionality in some programming language. But in my experience developers in general are not experienced in going through an explicit phase 2. “Designing functionality? What´s that supposed to mean?” you might already have thought. Here´s my definition: To design functionality (or functional design for short) means thinking about… well, functions. You find a solution for what´s supposed to happen when an Entry Point gets triggered in terms of functions. A conceptual solution that is, because those functions only exist in your head (or on paper) during this phase. But you may have guess that, because it´s “design” not “coding”. And here is, what functional design is not: It´s not about logic. Logic is expressions (e.g. +, -, && etc.) and control statements (e.g. if, switch, for, while etc.). Also I consider calling external APIs as logic. It´s equally basic. It´s what code needs to do in order to deliver some functionality or quality. Logic is what´s doing that needs to be done by software. Transformations are either done through expressions or API-calls. And then there is alternative control flow depending on the result of some expression. Basically it´s just jumps in Assembler, sometimes to go forward (if, switch), sometimes to go backward (for, while, do). But calling your own function is not logic. It´s not necessary to produce any outcome. Functionality is not enhanced by adding functions (subroutine calls) to your code. Nor is quality increased by adding functions. No performance gain, no higher scalability etc. through functions. Functions are not relevant to functionality. Strange, isn´t it. What they are important for is security of investment. By introducing functions into our code we can become more productive (re-use) and can increase evolvability (higher unterstandability, easier to keep code consistent). That´s no small feat, however. Evolvable code can hardly be overestimated. That´s why to me functional design is so important. It´s at the core of software development. To sum this up: Functional design is on a level of abstraction above (!) logical design or algorithmic design. Functional design is only done until you get to a point where each function is so simple you are very confident you can easily code it. Functional design an logical design (which mostly is coding, but can also be done using pseudo code or flow charts) are complementary. Software needs both. If you start coding right away you end up in a tangled mess very quickly. Then you need back out through refactoring. Functional design on the other hand is bloodless without actual code. It´s just a theory with no experiments to prove it. But how to do functional design? An example of functional design Let´s assume a program to de-duplicate strings. The user enters a number of strings separated by commas, e.g. a, b, a, c, d, b, e, c, a. And the program is supposed to clear this list of all doubles, e.g. a, b, c, d, e. There is only one Entry Point to this program: the user triggers the de-duplication by starting the program with the string list on the command line C:\>deduplicate "a, b, a, c, d, b, e, c, a" a, b, c, d, e …or by clicking on a GUI button. This leads to the Entry Point function to get called. It´s the program´s main function in case of the batch version or a button click event handler in the GUI version. That´s the physical Entry Point so to speak. It´s inevitable. What then happens is a three step process: Transform the input data from the user into a request. Call the request handler. Transform the output of the request handler into a tangible result for the user. Or to phrase it a bit more generally: Accept input. Transform input into output. Present output. This does not mean any of these steps requires a lot of effort. Maybe it´s just one line of code to accomplish it. Nevertheless it´s a distinct step in doing the processing behind an Entry Point. Call it an aspect or a responsibility - and you will realize it most likely deserves a function of its own to satisfy the Single Responsibility Principle (SRP). Interestingly the above list of steps is already functional design. There is no logic, but nevertheless the solution is described - albeit on a higher level of abstraction than you might have done yourself. But it´s still on a meta-level. The application to the domain at hand is easy, though: Accept string list from command line De-duplicate Present de-duplicated strings on standard output And this concrete list of processing steps can easily be transformed into code:static void Main(string[] args) { var input = Accept_string_list(args); var output = Deduplicate(input); Present_deduplicated_string_list(output); } Instead of a big problem there are three much smaller problems now. If you think each of those is trivial to implement, then go for it. You can stop the functional design at this point. But maybe, just maybe, you´re not so sure how to go about with the de-duplication for example. Then just implement what´s easy right now, e.g.private static string Accept_string_list(string[] args) { return args[0]; } private static void Present_deduplicated_string_list( string[] output) { var line = string.Join(", ", output); Console.WriteLine(line); } Accept_string_list() contains logic in the form of an API-call. Present_deduplicated_string_list() contains logic in the form of an expression and an API-call. And then repeat the functional design for the remaining processing step. What´s left is the domain logic: de-duplicating a list of strings. How should that be done? Without any logic at our disposal during functional design you´re left with just functions. So which functions could make up the de-duplication? Here´s a suggestion: De-duplicate Parse the input string into a true list of strings. Register each string in a dictionary/map/set. That way duplicates get cast away. Transform the data structure into a list of unique strings. Processing step 2 obviously was the core of the solution. That´s where real creativity was needed. That´s the core of the domain. But now after this refinement the implementation of each step is easy again:private static string[] Parse_string_list(string input) { return input.Split(',') .Select(s => s.Trim()) .ToArray(); } private static Dictionary<string,object> Compile_unique_strings(string[] strings) { return strings.Aggregate( new Dictionary<string, object>(), (agg, s) => { agg[s] = null; return agg; }); } private static string[] Serialize_unique_strings( Dictionary<string,object> dict) { return dict.Keys.ToArray(); } With these three additional functions Main() now looks like this:static void Main(string[] args) { var input = Accept_string_list(args); var strings = Parse_string_list(input); var dict = Compile_unique_strings(strings); var output = Serialize_unique_strings(dict); Present_deduplicated_string_list(output); } I think that´s very understandable code: just read it from top to bottom and you know how the solution to the problem works. It´s a mirror image of the initial design: Accept string list from command line Parse the input string into a true list of strings. Register each string in a dictionary/map/set. That way duplicates get cast away. Transform the data structure into a list of unique strings. Present de-duplicated strings on standard output You can even re-generate the design by just looking at the code. Code and functional design thus are always in sync - if you follow some simple rules. But about that later. And as a bonus: all the functions making up the process are small - which means easy to understand, too. So much for an initial concrete example. Now it´s time for some theory. Because there is method to this madness ;-) The above has only scratched the surface. Introducing Flow Design Functional design starts with a given function, the Entry Point. Its goal is to describe the behavior of the program when the Entry Point is triggered using a process, not an algorithm. An algorithm consists of logic, a process on the other hand consists just of steps or stages. Each processing step transforms input into output or a side effect. Also it might access resources, e.g. a printer, a database, or just memory. Processing steps thus can rely on state of some sort. This is different from Functional Programming, where functions are supposed to not be stateful and not cause side effects.[1] In its simplest form a process can be written as a bullet point list of steps, e.g. Get data from user Output result to user Transform data Parse data Map result for output Such a compilation of steps - possibly on different levels of abstraction - often is the first artifact of functional design. It can be generated by a team in an initial design brainstorming. Next comes ordering the steps. What should happen first, what next etc.? Get data from user Parse data Transform data Map result for output Output result to user That´s great for a start into functional design. It´s better than starting to code right away on a given function using TDD. Please get me right: TDD is a valuable practice. But it can be unnecessarily hard if the scope of a functionn is too large. But how do you know beforehand without investing some thinking? And how to do this thinking in a systematic fashion? My recommendation: For any given function you´re supposed to implement first do a functional design. Then, once you´re confident you know the processing steps - which are pretty small - refine and code them using TDD. You´ll see that´s much, much easier - and leads to cleaner code right away. For more information on this approach I call “Informed TDD” read my book of the same title. Thinking before coding is smart. And writing down the solution as a bunch of functions possibly is the simplest thing you can do, I´d say. It´s more according to the KISS (Keep It Simple, Stupid) principle than returning constants or other trivial stuff TDD development often is started with. So far so good. A simple ordered list of processing steps will do to start with functional design. As shown in the above example such steps can easily be translated into functions. Moving from design to coding thus is simple. However, such a list does not scale. Processing is not always that simple to be captured in a list. And then the list is just text. Again. Like code. That means the design is lacking visuality. Textual representations need more parsing by your brain than visual representations. Plus they are limited in their “dimensionality”: text just has one dimension, it´s sequential. Alternatives and parallelism are hard to encode in text. In addition the functional design using numbered lists lacks data. It´s not visible what´s the input, output, and state of the processing steps. That´s why functional design should be done using a lightweight visual notation. No tool is necessary to draw such designs. Use pen and paper; a flipchart, a whiteboard, or even a napkin is sufficient. Visualizing processes The building block of the functional design notation is a functional unit. I mostly draw it like this: Something is done, it´s clear what goes in, it´s clear what comes out, and it´s clear what the processing step requires in terms of state or hardware. Whenever input flows into a functional unit it gets processed and output is produced and/or a side effect occurs. Flowing data is the driver of something happening. That´s why I call this approach to functional design Flow Design. It´s about data flow instead of control flow. Control flow like in algorithms is of no concern to functional design. Thinking about control flow simply is too low level. Once you start with control flow you easily get bogged down by tons of details. That´s what you want to avoid during design. Design is supposed to be quick, broad brush, abstract. It should give overview. But what about all the details? As Robert C. Martin rightly said: “Programming is abot detail”. Detail is a matter of code. Once you start coding the processing steps you designed you can worry about all the detail you want. Functional design does not eliminate all the nitty gritty. It just postpones tackling them. To me that´s also an example of the SRP. Function design has the responsibility to come up with a solution to a problem posed by a single function (Entry Point). And later coding has the responsibility to implement the solution down to the last detail (i.e. statement, API-call). TDD unfortunately mixes both responsibilities. It´s just coding - and thereby trying to find detailed implementations (green phase) plus getting the design right (refactoring). To me that´s one reason why TDD has failed to deliver on its promise for many developers. Using functional units as building blocks of functional design processes can be depicted very easily. Here´s the initial process for the example problem: For each processing step draw a functional unit and label it. Choose a verb or an “action phrase” as a label, not a noun. Functional design is about activities, not state or structure. Then make the output of an upstream step the input of a downstream step. Finally think about the data that should flow between the functional units. Write the data above the arrows connecting the functional units in the direction of the data flow. Enclose the data description in brackets. That way you can clearly see if all flows have already been specified. Empty brackets mean “no data is flowing”, but nevertheless a signal is sent. A name like “list” or “strings” in brackets describes the data content. Use lower case labels for that purpose. A name starting with an upper case letter like “String” or “Customer” on the other hand signifies a data type. If you like, you also can combine descriptions with data types by separating them with a colon, e.g. (list:string) or (strings:string[]). But these are just suggestions from my practice with Flow Design. You can do it differently, if you like. Just be sure to be consistent. Flows wired-up in this manner I call one-dimensional (1D). Each functional unit just has one input and/or one output. A functional unit without an output is possible. It´s like a black hole sucking up input without producing any output. Instead it produces side effects. A functional unit without an input, though, does make much sense. When should it start to work? What´s the trigger? That´s why in the above process even the first processing step has an input. If you like, view such 1D-flows as pipelines. Data is flowing through them from left to right. But as you can see, it´s not always the same data. It get´s transformed along its passage: (args) becomes a (list) which is turned into (strings). The Principle of Mutual Oblivion A very characteristic trait of flows put together from function units is: no functional units knows another one. They are all completely independent of each other. Functional units don´t know where their input is coming from (or even when it´s gonna arrive). They just specify a range of values they can process. And they promise a certain behavior upon input arriving. Also they don´t know where their output is going. They just produce it in their own time independent of other functional units. That means at least conceptually all functional units work in parallel. Functional units don´t know their “deployment context”. They now nothing about the overall flow they are place in. They are just consuming input from some upstream, and producing output for some downstream. That makes functional units very easy to test. At least as long as they don´t depend on state or resources. I call this the Principle of Mutual Oblivion (PoMO). Functional units are oblivious of others as well as an overall context/purpose. They are just parts of a whole focused on a single responsibility. How the whole is built, how a larger goal is achieved, is of no concern to the single functional units. By building software in such a manner, functional design interestingly follows nature. Nature´s building blocks for organisms also follow the PoMO. The cells forming your body do not know each other. Take a nerve cell “controlling” a muscle cell for example:[2] The nerve cell does not know anything about muscle cells, let alone the specific muscel cell it is “attached to”. Likewise the muscle cell does not know anything about nerve cells, let a lone a specific nerve cell “attached to” it. Saying “the nerve cell is controlling the muscle cell” thus only makes sense when viewing both from the outside. “Control” is a concept of the whole, not of its parts. Control is created by wiring-up parts in a certain way. Both cells are mutually oblivious. Both just follow a contract. One produces Acetylcholine (ACh) as output, the other consumes ACh as input. Where the ACh is going, where it´s coming from neither cell cares about. Million years of evolution have led to this kind of division of labor. And million years of evolution have produced organism designs (DNA) which lead to the production of these different cell types (and many others) and also to their co-location. The result: the overall behavior of an organism. How and why this happened in nature is a mystery. For our software, though, it´s clear: functional and quality requirements needs to be fulfilled. So we as developers have to become “intelligent designers” of “software cells” which we put together to form a “software organism” which responds in satisfying ways to triggers from it´s environment. My bet is: If nature gets complex organisms working by following the PoMO, who are we to not apply this recipe for success to our much simpler “machines”? So my rule is: Wherever there is functionality to be delivered, because there is a clear Entry Point into software, design the functionality like nature would do it. Build it from mutually oblivious functional units. That´s what Flow Design is about. In that way it´s even universal, I´d say. Its notation can also be applied to biology: Never mind labeling the functional units with nouns. That´s ok in Flow Design. You´ll do that occassionally for functional units on a higher level of abstraction or when their purpose is close to hardware. Getting a cockroach to roam your bedroom takes 1,000,000 nerve cells (neurons). Getting the de-duplication program to do its job just takes 5 “software cells” (functional units). Both, though, follow the same basic principle. Translating functional units into code Moving from functional design to code is no rocket science. In fact it´s straightforward. There are two simple rules: Translate an input port to a function. Translate an output port either to a return statement in that function or to a function pointer visible to that function. The simplest translation of a functional unit is a function. That´s what you saw in the above example. Functions are mutually oblivious. That why Functional Programming likes them so much. It makes them composable. Which is the reason, nature works according to the PoMO. Let´s be clear about one thing: There is no dependency injection in nature. For all of an organism´s complexity no DI container is used. Behavior is the result of smooth cooperation between mutually oblivious building blocks. Functions will often be the adequate translation for the functional units in your designs. But not always. Take for example the case, where a processing step should not always produce an output. Maybe the purpose is to filter input. Here the functional unit consumes words and produces words. But it does not pass along every word flowing in. Some words are swallowed. Think of a spell checker. It probably should not check acronyms for correctness. There are too many of them. Or words with no more than two letters. Such words are called “stop words”. In the above picture the optionality of the output is signified by the astrisk outside the brackets. It means: Any number of (word) data items can flow from the functional unit for each input data item. It might be none or one or even more. This I call a stream of data. Such behavior cannot be translated into a function where output is generated with return. Because a function always needs to return a value. So the output port is translated into a function pointer or continuation which gets passed to the subroutine when called:[3]void filter_stop_words( string word, Action<string> onNoStopWord) { if (...check if not a stop word...) onNoStopWord(word); } If you want to be nitpicky you might call such a function pointer parameter an injection. And technically you´re right. Conceptually, though, it´s not an injection. Because the subroutine is not functionally dependent on the continuation. Firstly continuations are procedures, i.e. subroutines without a return type. Remember: Flow Design is about unidirectional data flow. Secondly the name of the formal parameter is chosen in a way as to not assume anything about downstream processing steps. onNoStopWord describes a situation (or event) within the functional unit only. Translating output ports into function pointers helps keeping functional units mutually oblivious in cases where output is optional or produced asynchronically. Either pass the function pointer to the function upon call. Or make it global by putting it on the encompassing class. Then it´s called an event. In C# that´s even an explicit feature.class Filter { public void filter_stop_words( string word) { if (...check if not a stop word...) onNoStopWord(word); } public event Action<string> onNoStopWord; } When to use a continuation and when to use an event dependens on how a functional unit is used in flows and how it´s packed together with others into classes. You´ll see examples further down the Flow Design road. Another example of 1D functional design Let´s see Flow Design once more in action using the visual notation. How about the famous word wrap kata? Robert C. Martin has posted a much cited solution including an extensive reasoning behind his TDD approach. So maybe you want to compare it to Flow Design. The function signature given is:string WordWrap(string text, int maxLineLength) {...} That´s not an Entry Point since we don´t see an application with an environment and users. Nevertheless it´s a function which is supposed to provide a certain functionality. The text passed in has to be reformatted. The input is a single line of arbitrary length consisting of words separated by spaces. The output should consist of one or more lines of a maximum length specified. If a word is longer than a the maximum line length it can be split in multiple parts each fitting in a line. Flow Design Let´s start by brainstorming the process to accomplish the feat of reformatting the text. What´s needed? Words need to be assembled into lines Words need to be extracted from the input text The resulting lines need to be assembled into the output text Words too long to fit in a line need to be split Does sound about right? I guess so. And it shows a kind of priority. Long words are a special case. So maybe there is a hint for an incremental design here. First let´s tackle “average words” (words not longer than a line). Here´s the Flow Design for this increment: The the first three bullet points turned into functional units with explicit data added. As the signature requires a text is transformed into another text. See the input of the first functional unit and the output of the last functional unit. In between no text flows, but words and lines. That´s good to see because thereby the domain is clearly represented in the design. The requirements are talking about words and lines and here they are. But note the asterisk! It´s not outside the brackets but inside. That means it´s not a stream of words or lines, but lists or sequences. For each text a sequence of words is output. For each sequence of words a sequence of lines is produced. The asterisk is used to abstract from the concrete implementation. Like with streams. Whether the list of words gets implemented as an array or an IEnumerable is not important during design. It´s an implementation detail. Does any processing step require further refinement? I don´t think so. They all look pretty “atomic” to me. And if not… I can always backtrack and refine a process step using functional design later once I´ve gained more insight into a sub-problem. Implementation The implementation is straightforward as you can imagine. The processing steps can all be translated into functions. Each can be tested easily and separately. Each has a focused responsibility. And the process flow becomes just a sequence of function calls: Easy to understand. It clearly states how word wrapping works - on a high level of abstraction. And it´s easy to evolve as you´ll see. Flow Design - Increment 2 So far only texts consisting of “average words” are wrapped correctly. Words not fitting in a line will result in lines too long. Wrapping long words is a feature of the requested functionality. Whether it´s there or not makes a difference to the user. To quickly get feedback I decided to first implement a solution without this feature. But now it´s time to add it to deliver the full scope. Fortunately Flow Design automatically leads to code following the Open Closed Principle (OCP). It´s easy to extend it - instead of changing well tested code. How´s that possible? Flow Design allows for extension of functionality by inserting functional units into the flow. That way existing functional units need not be changed. The data flow arrow between functional units is a natural extension point. No need to resort to the Strategy Pattern. No need to think ahead where extions might need to be made in the future. I just “phase in” the remaining processing step: Since neither Extract words nor Reformat know of their environment neither needs to be touched due to the “detour”. The new processing step accepts the output of the existing upstream step and produces data compatible with the existing downstream step. Implementation - Increment 2 A trivial implementation checking the assumption if this works does not do anything to split long words. The input is just passed on: Note how clean WordWrap() stays. The solution is easy to understand. A developer looking at this code sometime in the future, when a new feature needs to be build in, quickly sees how long words are dealt with. Compare this to Robert C. Martin´s solution:[4] How does this solution handle long words? Long words are not even part of the domain language present in the code. At least I need considerable time to understand the approach. Admittedly the Flow Design solution with the full implementation of long word splitting is longer than Robert C. Martin´s. At least it seems. Because his solution does not cover all the “word wrap situations” the Flow Design solution handles. Some lines would need to be added to be on par, I guess. But even then… Is a difference in LOC that important as long as it´s in the same ball park? I value understandability and openness for extension higher than saving on the last line of code. Simplicity is not just less code, it´s also clarity in design. But don´t take my word for it. Try Flow Design on larger problems and compare for yourself. What´s the easier, more straightforward way to clean code? And keep in mind: You ain´t seen all yet ;-) There´s more to Flow Design than described in this chapter. In closing I hope I was able to give you a impression of functional design that makes you hungry for more. To me it´s an inevitable step in software development. Jumping from requirements to code does not scale. And it leads to dirty code all to quickly. Some thought should be invested first. Where there is a clear Entry Point visible, it´s functionality should be designed using data flows. Because with data flows abstraction is possible. For more background on why that´s necessary read my blog article here. For now let me point out to you - if you haven´t already noticed - that Flow Design is a general purpose declarative language. It´s “programming by intention” (Shalloway et al.). Just write down how you think the solution should work on a high level of abstraction. This breaks down a large problem in smaller problems. And by following the PoMO the solutions to those smaller problems are independent of each other. So they are easy to test. Or you could even think about getting them implemented in parallel by different team members. Flow Design not only increases evolvability, but also helps becoming more productive. All team members can participate in functional design. This goes beyon collective code ownership. We´re talking collective design/architecture ownership. Because with Flow Design there is a common visual language to talk about functional design - which is the foundation for all other design activities.   PS: If you like what you read, consider getting my ebook “The Incremental Architekt´s Napkin”. It´s where I compile all the articles in this series for easier reading. I like the strictness of Function Programming - but I also find it quite hard to live by. And it certainly is not what millions of programmers are used to. Also to me it seems, the real world is full of state and side effects. So why give them such a bad image? That´s why functional design takes a more pragmatic approach. State and side effects are ok for processing steps - but be sure to follow the SRP. Don´t put too much of it into a single processing step. ? Image taken from www.physioweb.org ? My code samples are written in C#. C# sports typed function pointers called delegates. Action is such a function pointer type matching functions with signature void someName(T t). Other languages provide similar ways to work with functions as first class citizens - even Java now in version 8. I trust you find a way to map this detail of my translation to your favorite programming language. I know it works for Java, C++, Ruby, JavaScript, Python, Go. And if you´re using a Functional Programming language it´s of course a no brainer. ? Taken from his blog post “The Craftsman 62, The Dark Path”. ?

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• AngularJS on top of ASP.NET: Moving the MVC framework out to the browser

  - by Varun Chatterji

  Heavily drawing inspiration from Ruby on Rails, MVC4’s convention over configuration model of development soon became the Holy Grail of .NET web development. The MVC model brought with it the goodness of proper separation of concerns between business logic, data, and the presentation logic. However, the MVC paradigm, was still one in which server side .NET code could be mixed with presentation code. The Razor templating engine, though cleaner than its predecessors, still encouraged and allowed you to mix .NET server side code with presentation logic. Thus, for example, if the developer required a certain <div> tag to be shown if a particular variable ShowDiv was true in the View’s model, the code could look like the following: Fig 1: To show a div or not. Server side .NET code is used in the View Mixing .NET code with HTML in views can soon get very messy. Wouldn’t it be nice if the presentation layer (HTML) could be pure HTML? Also, in the ASP.NET MVC model, some of the business logic invariably resides in the controller. It is tempting to use an anti­pattern like the one shown above to control whether a div should be shown or not. However, best practice would indicate that the Controller should not be aware of the div. The ShowDiv variable in the model should not exist. A controller should ideally, only be used to do the plumbing of getting the data populated in the model and nothing else. The view (ideally pure HTML) should render the presentation layer based on the model. In this article we will see how Angular JS, a new JavaScript framework by Google can be used effectively to build web applications where: 1. Views are pure HTML 2. Controllers (in the server sense) are pure REST based API calls 3. The presentation layer is loaded as needed from partial HTML only files. What is MVVM? MVVM short for Model View View Model is a new paradigm in web development. In this paradigm, the Model and View stuff exists on the client side through javascript instead of being processed on the server through postbacks. These frameworks are JavaScript frameworks that facilitate the clear separation of the “frontend” or the data rendering logic from the “backend” which is typically just a REST based API that loads and processes data through a resource model. The frameworks are called MVVM as a change to the Model (through javascript) gets reflected in the view immediately i.e. Model > View. Also, a change on the view (through manual input) gets reflected in the model immediately i.e. View > Model. The following figure shows this conceptually (comments are shown in red): Fig 2: Demonstration of MVVM in action In Fig 2, two text boxes are bound to the same variable model.myInt. Thus, changing the view manually (changing one text box through keyboard input) also changes the other textbox in real time demonstrating V > M property of a MVVM framework. Furthermore, clicking the button adds 1 to the value of model.myInt thus changing the model through JavaScript. This immediately updates the view (the value in the two textboxes) thus demonstrating the M > V property of a MVVM framework. Thus we see that the model in a MVVM JavaScript framework can be regarded as “the single source of truth“. This is an important concept. Angular is one such MVVM framework. We shall use it to build a simple app that sends SMS messages to a particular number. Application, Routes, Views, Controllers, Scope and Models Angular can be used in many ways to construct web applications. For this article, we shall only focus on building Single Page Applications (SPAs). Many of the approaches we will follow in this article have alternatives. It is beyond the scope of this article to explain every nuance in detail but we shall try to touch upon the basic concepts and end up with a working application that can be used to send SMS messages using Sent.ly Plus (a service that is itself built using Angular). Before you read on, we would like to urge you to forget what you know about Models, Views, Controllers and Routes in the ASP.NET MVC4 framework. All these words have different meanings in the Angular world. Whenever these words are used in this article, they will refer to Angular concepts and not ASP.NET MVC4 concepts. The following figure shows the skeleton of the root page of an SPA: Fig 3: The skeleton of a SPA The skeleton of the application is based on the Bootstrap starter template which can be found at: http://getbootstrap.com/examples/starter­template/ Apart from loading the Angular, jQuery and Bootstrap JavaScript libraries, it also loads our custom scripts /app/js/controllers.js /app/js/app.js These scripts define the routes, views and controllers which we shall come to in a moment. Application Notice that the body tag (Fig. 3) has an extra attribute: ng­app=”smsApp” Providing this tag “bootstraps” our single page application. It tells Angular to load a “module” called smsApp. This “module” is defined /app/js/app.js angular.module('smsApp', ['smsApp.controllers', function () {}]) Fig 4: The definition of our application module The line shows above, declares a module called smsApp. It also declares that this module “depends” on another module called “smsApp.controllers”. The smsApp.controllers module will contain all the controllers for our SPA. Routing and Views Notice that in the Navbar (in Fig 3) we have included two hyperlinks to: “#/app” “#/help” This is how Angular handles routing. Since the URLs start with “#”, they are actually just bookmarks (and not server side resources). However, our route definition (in /app/js/app.js) gives these URLs a special meaning within the Angular framework. angular.module('smsApp', ['smsApp.controllers', function () { }]) //Configure the routes .config(['$routeProvider', function ($routeProvider) { $routeProvider.when('/binding', { templateUrl: '/app/partials/bindingexample.html', controller: 'BindingController' }); }]); Fig 5: The definition of a route with an associated partial view and controller As we can see from the previous code sample, we are using the $routeProvider object in the configuration of our smsApp module. Notice how the code “asks for” the $routeProvider object by specifying it as a dependency in the [] braces and then defining a function that accepts it as a parameter. This is known as dependency injection. Please refer to the following link if you want to delve into this topic: http://docs.angularjs.org/guide/di What the above code snippet is doing is that it is telling Angular that when the URL is “#/binding”, then it should load the HTML snippet (“partial view”) found at /app/partials/bindingexample.html. Also, for this URL, Angular should load the controller called “BindingController”. We have also marked the div with the class “container” (in Fig 3) with the ng­view attribute. This attribute tells Angular that views (partial HTML pages) defined in the routes will be loaded within this div. You can see that the Angular JavaScript framework, unlike many other frameworks, works purely by extending HTML tags and attributes. It also allows you to extend HTML with your own tags and attributes (through directives) if you so desire, you can find out more about directives at the following URL: http://www.codeproject.com/Articles/607873/Extending­HTML­with­AngularJS­Directives Controllers and Models We have seen how we define what views and controllers should be loaded for a particular route. Let us now consider how controllers are defined. Our controllers are defined in the file /app/js/controllers.js. The following snippet shows the definition of the “BindingController” which is loaded when we hit the URL http://localhost:port/index.html#/binding (as we have defined in the route earlier as shown in Fig 5). Remember that we had defined that our application module “smsApp” depends on the “smsApp.controllers” module (see Fig 4). The code snippet below shows how the “BindingController” defined in the route shown in Fig 5 is defined in the module smsApp.controllers: angular.module('smsApp.controllers', [function () { }]) .controller('BindingController', ['$scope', function ($scope) { $scope.model = {}; $scope.model.myInt = 6; $scope.addOne = function () { $scope.model.myInt++; } }]); Fig 6: The definition of a controller in the “smsApp.controllers” module. The pieces are falling in place! Remember Fig.2? That was the code of a partial view that was loaded within the container div of the skeleton SPA shown in Fig 3. The route definition shown in Fig 5 also defined that the controller called “BindingController” (shown in Fig 6.) was loaded when we loaded the URL: http://localhost:22544/index.html#/binding The button in Fig 2 was marked with the attribute ng­click=”addOne()” which added 1 to the value of model.myInt. In Fig 6, we can see that this function is actually defined in the “BindingController”. Scope We can see from Fig 6, that in the definition of “BindingController”, we defined a dependency on $scope and then, as usual, defined a function which “asks for” $scope as per the dependency injection pattern. So what is $scope? Any guesses? As you might have guessed a scope is a particular “address space” where variables and functions may be defined. This has a similar meaning to scope in a programming language like C#. Model: The Scope is not the Model It is tempting to assign variables in the scope directly. For example, we could have defined myInt as $scope.myInt = 6 in Fig 6 instead of $scope.model.myInt = 6. The reason why this is a bad idea is that scope in hierarchical in Angular. Thus if we were to define a controller which was defined within the another controller (nested controllers), then the inner controller would inherit the scope of the parent controller. This inheritance would follow JavaScript prototypal inheritance. Let’s say the parent controller defined a variable through $scope.myInt = 6. The child controller would inherit the scope through java prototypical inheritance. This basically means that the child scope has a variable myInt that points to the parent scopes myInt variable. Now if we assigned the value of myInt in the parent, the child scope would be updated with the same value as the child scope’s myInt variable points to the parent scope’s myInt variable. However, if we were to assign the value of the myInt variable in the child scope, then the link of that variable to the parent scope would be broken as the variable myInt in the child scope now points to the value 6 and not to the parent scope’s myInt variable. But, if we defined a variable model in the parent scope, then the child scope will also have a variable model that points to the model variable in the parent scope. Updating the value of $scope.model.myInt in the parent scope would change the model variable in the child scope too as the variable is pointed to the model variable in the parent scope. Now changing the value of $scope.model.myInt in the child scope would ALSO change the value in the parent scope. This is because the model reference in the child scope is pointed to the scope variable in the parent. We did no new assignment to the model variable in the child scope. We only changed an attribute of the model variable. Since the model variable (in the child scope) points to the model variable in the parent scope, we have successfully changed the value of myInt in the parent scope. Thus the value of $scope.model.myInt in the parent scope becomes the “single source of truth“. This is a tricky concept, thus it is considered good practice to NOT use scope inheritance. More info on prototypal inheritance in Angular can be found in the “JavaScript Prototypal Inheritance” section at the following URL: https://github.com/angular/angular.js/wiki/Understanding­Scopes. Building It: An Angular JS application using a .NET Web API Backend Now that we have a perspective on the basic components of an MVVM application built using Angular, let’s build something useful. We will build an application that can be used to send out SMS messages to a given phone number. The following diagram describes the architecture of the application we are going to build: Fig 7: Broad application architecture We are going to add an HTML Partial to our project. This partial will contain the form fields that will accept the phone number and message that needs to be sent as an SMS. It will also display all the messages that have previously been sent. All the executable code that is run on the occurrence of events (button clicks etc.) in the view resides in the controller. The controller interacts with the ASP.NET WebAPI to get a history of SMS messages, add a message etc. through a REST based API. For the purposes of simplicity, we will use an in memory data structure for the purposes of creating this application. Thus, the tasks ahead of us are: Creating the REST WebApi with GET, PUT, POST, DELETE methods. Creating the SmsView.html partial Creating the SmsController controller with methods that are called from the SmsView.html partial Add a new route that loads the controller and the partial. 1. Creating the REST WebAPI This is a simple task that should be quite straightforward to any .NET developer. The following listing shows our ApiController: public class SmsMessage { public string to { get; set; } public string message { get; set; } } public class SmsResource : SmsMessage { public int smsId { get; set; } } public class SmsResourceController : ApiController { public static Dictionary<int, SmsResource> messages = new Dictionary<int, SmsResource>(); public static int currentId = 0; // GET api/<controller> public List<SmsResource> Get() { List<SmsResource> result = new List<SmsResource>(); foreach (int key in messages.Keys) { result.Add(messages[key]); } return result; } // GET api/<controller>/5 public SmsResource Get(int id) { if (messages.ContainsKey(id)) return messages[id]; return null; } // POST api/<controller> public List<SmsResource> Post([FromBody] SmsMessage value) { //Synchronize on messages so we don't have id collisions lock (messages) { SmsResource res = (SmsResource) value; res.smsId = currentId++; messages.Add(res.smsId, res); //SentlyPlusSmsSender.SendMessage(value.to, value.message); return Get(); } } // PUT api/<controller>/5 public List<SmsResource> Put(int id, [FromBody] SmsMessage value) { //Synchronize on messages so we don't have id collisions lock (messages) { if (messages.ContainsKey(id)) { //Update the message messages[id].message = value.message; messages[id].to = value.message; } return Get(); } } // DELETE api/<controller>/5 public List<SmsResource> Delete(int id) { if (messages.ContainsKey(id)) { messages.Remove(id); } return Get(); } } Once this class is defined, we should be able to access the WebAPI by a simple GET request using the browser: http://localhost:port/api/SmsResource Notice the commented line: //SentlyPlusSmsSender.SendMessage The SentlyPlusSmsSender class is defined in the attached solution. We have shown this line as commented as we want to explain the core Angular concepts. If you load the attached solution, this line is uncommented in the source and an actual SMS will be sent! By default, the API returns XML. For consumption of the API in Angular, we would like it to return JSON. To change the default to JSON, we make the following change to WebApiConfig.cs file located in the App_Start folder. public static class WebApiConfig { public static void Register(HttpConfiguration config) { config.Routes.MapHttpRoute( name: "DefaultApi", routeTemplate: "api/{controller}/{id}", defaults: new { id = RouteParameter.Optional } ); var appXmlType = config.Formatters.XmlFormatter. SupportedMediaTypes. FirstOrDefault( t => t.MediaType == "application/xml"); config.Formatters.XmlFormatter.SupportedMediaTypes.Remove(appXmlType); } } We now have our backend REST Api which we can consume from Angular! 2. Creating the SmsView.html partial This simple partial will define two fields: the destination phone number (international format starting with a +) and the message. These fields will be bound to model.phoneNumber and model.message. We will also add a button that we shall hook up to sendMessage() in the controller. A list of all previously sent messages (bound to model.allMessages) will also be displayed below the form input. The following code shows the code for the partial: <!--­­ If model.errorMessage is defined, then render the error div -­­> <div class="alert alert-­danger alert-­dismissable" style="margin­-top: 30px;" ng­-show="model.errorMessage != undefined"> <button type="button" class="close" data­dismiss="alert" aria­hidden="true">&times;</button> <strong>Error!</strong> <br /> {{ model.errorMessage }} </div> <!--­­ The input fields bound to the model --­­> <div class="well" style="margin-­top: 30px;"> <table style="width: 100%;"> <tr> <td style="width: 45%; text-­align: center;"> <input type="text" placeholder="Phone number (eg; +44 7778 609466)" ng­-model="model.phoneNumber" class="form-­control" style="width: 90%" onkeypress="return checkPhoneInput();" /> </td> <td style="width: 45%; text-­align: center;"> <input type="text" placeholder="Message" ng­-model="model.message" class="form-­control" style="width: 90%" /> </td> <td style="text-­align: center;"> <button class="btn btn-­danger" ng-­click="sendMessage();" ng-­disabled="model.isAjaxInProgress" style="margin­right: 5px;">Send</button> <img src="/Content/ajax-­loader.gif" ng­-show="model.isAjaxInProgress" /> </td> </tr> </table> </div> <!--­­ The past messages ­­--> <div style="margin-­top: 30px;"> <!­­-- The following div is shown if there are no past messages --­­> <div ng­-show="model.allMessages.length == 0"> No messages have been sent yet! </div> <!--­­ The following div is shown if there are some past messages --­­> <div ng-­show="model.allMessages.length == 0"> <table style="width: 100%;" class="table table-­striped"> <tr> <td>Phone Number</td> <td>Message</td> <td></td> </tr> <!--­­ The ng-­repeat directive is line the repeater control in .NET, but as you can see this partial is pure HTML which is much cleaner --> <tr ng-­repeat="message in model.allMessages"> <td>{{ message.to }}</td> <td>{{ message.message }}</td> <td> <button class="btn btn-­danger" ng-­click="delete(message.smsId);" ng­-disabled="model.isAjaxInProgress">Delete</button> </td> </tr> </table> </div> </div> The above code is commented and should be self explanatory. Conditional rendering is achieved through using the ng-­show=”condition” attribute on various div tags. Input fields are bound to the model and the send button is bound to the sendMessage() function in the controller as through the ng­click=”sendMessage()” attribute defined on the button tag. While AJAX calls are taking place, the controller sets model.isAjaxInProgress to true. Based on this variable, buttons are disabled through the ng-­disabled directive which is added as an attribute to the buttons. The ng-­repeat directive added as an attribute to the tr tag causes the table row to be rendered multiple times much like an ASP.NET repeater. 3. Creating the SmsController controller The penultimate piece of our application is the controller which responds to events from our view and interacts with our MVC4 REST WebAPI. The following listing shows the code we need to add to /app/js/controllers.js. Note that controller definitions can be chained. Also note that this controller “asks for” the $http service. The $http service is a simple way in Angular to do AJAX. So far we have only encountered modules, controllers, views and directives in Angular. The $http is new entity in Angular called a service. More information on Angular services can be found at the following URL: http://docs.angularjs.org/guide/dev_guide.services.understanding_services. .controller('SmsController', ['$scope', '$http', function ($scope, $http) { //We define the model $scope.model = {}; //We define the allMessages array in the model //that will contain all the messages sent so far $scope.model.allMessages = []; //The error if any $scope.model.errorMessage = undefined; //We initially load data so set the isAjaxInProgress = true; $scope.model.isAjaxInProgress = true; //Load all the messages $http({ url: '/api/smsresource', method: "GET" }). success(function (data, status, headers, config) { this callback will be called asynchronously //when the response is available $scope.model.allMessages = data; //We are done with AJAX loading $scope.model.isAjaxInProgress = false; }). error(function (data, status, headers, config) { //called asynchronously if an error occurs //or server returns response with an error status. $scope.model.errorMessage = "Error occurred status:" + status; //We are done with AJAX loading $scope.model.isAjaxInProgress = false; }); $scope.delete = function (id) { //We are making an ajax call so we set this to true $scope.model.isAjaxInProgress = true; $http({ url: '/api/smsresource/' + id, method: "DELETE" }). success(function (data, status, headers, config) { // this callback will be called asynchronously // when the response is available $scope.model.allMessages = data; //We are done with AJAX loading $scope.model.isAjaxInProgress = false; }); error(function (data, status, headers, config) { // called asynchronously if an error occurs // or server returns response with an error status. $scope.model.errorMessage = "Error occurred status:" + status; //We are done with AJAX loading $scope.model.isAjaxInProgress = false; }); } $scope.sendMessage = function () { $scope.model.errorMessage = undefined; var message = ''; if($scope.model.message != undefined) message = $scope.model.message.trim(); if ($scope.model.phoneNumber == undefined || $scope.model.phoneNumber == '' || $scope.model.phoneNumber.length < 10 || $scope.model.phoneNumber[0] != '+') { $scope.model.errorMessage = "You must enter a valid phone number in international format. Eg: +44 7778 609466"; return; } if (message.length == 0) { $scope.model.errorMessage = "You must specify a message!"; return; } //We are making an ajax call so we set this to true $scope.model.isAjaxInProgress = true; $http({ url: '/api/smsresource', method: "POST", data: { to: $scope.model.phoneNumber, message: $scope.model.message } }). success(function (data, status, headers, config) { // this callback will be called asynchronously // when the response is available $scope.model.allMessages = data; //We are done with AJAX loading $scope.model.isAjaxInProgress = false; }). error(function (data, status, headers, config) { // called asynchronously if an error occurs // or server returns response with an error status. $scope.model.errorMessage = "Error occurred status:" + status // We are done with AJAX loading $scope.model.isAjaxInProgress = false; }); } }]); We can see from the previous listing how the functions that are called from the view are defined in the controller. It should also be evident how easy it is to make AJAX calls to consume our MVC4 REST WebAPI. Now we are left with the final piece. We need to define a route that associates a particular path with the view we have defined and the controller we have defined. 4. Add a new route that loads the controller and the partial This is the easiest part of the puzzle. We simply define another route in the /app/js/app.js file: $routeProvider.when('/sms', { templateUrl: '/app/partials/smsview.html', controller: 'SmsController' }); Conclusion In this article we have seen how much of the server side functionality in the MVC4 framework can be moved to the browser thus delivering a snappy and fast user interface. We have seen how we can build client side HTML only views that avoid the messy syntax offered by server side Razor views. We have built a functioning app from the ground up. The significant advantage of this approach to building web apps is that the front end can be completely platform independent. Even though we used ASP.NET to create our REST API, we could just easily have used any other language such as Node.js, Ruby etc without changing a single line of our front end code. Angular is a rich framework and we have only touched on basic functionality required to create a SPA. For readers who wish to delve further into the Angular framework, we would recommend the following URL as a starting point: http://docs.angularjs.org/misc/started. To get started with the code for this project: Sign up for an account at http://plus.sent.ly (free) Add your phone number Go to the “My Identies Page” Note Down your Sender ID, Consumer Key and Consumer Secret Download the code for this article at: https://docs.google.com/file/d/0BzjEWqSE31yoZjZlV0d0R2Y3eW8/edit?usp=sharing Change the values of Sender Id, Consumer Key and Consumer Secret in the web.config file Run the project through Visual Studio!

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• Silverlight for Windows Embedded tutorial (step 4)

  - by Valter Minute

  I’m back with my Silverlight for Windows Embedded tutorial. Sorry for the long delay between step 3 and step 4, the MVP summit and some work related issue prevented me from working on the tutorial during the last weeks. In our first,  second and third tutorial steps we implemented some very simple applications, just to understand the basic structure of a Silverlight for Windows Embedded application, learn how to handle events and how to operate on images. In this third step our sample application will be slightly more complicated, to introduce two new topics: list boxes and custom control. We will also learn how to create controls at runtime. I choose to explain those topics together and provide a sample a bit more complicated than usual just to start to give the feeling of how a “real” Silverlight for Windows Embedded application is organized. As usual we can start using Expression Blend to define our main page. In this case we will have a listbox and a textblock. Here’s the XAML code: <UserControl xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" x:Class="ListDemo.Page" Width="640" Height="480" x:Name="ListPage" xmlns:ListDemo="clr-namespace:ListDemo">   <Grid x:Name="LayoutRoot" Background="White"> <ListBox Margin="19,57,19,66" x:Name="FileList" SelectionChanged="Filelist_SelectionChanged"/> <TextBlock Height="35" Margin="19,8,19,0" VerticalAlignment="Top" TextWrapping="Wrap" x:Name="CurrentDir" Text="TextBlock" FontSize="20"/> </Grid> </UserControl> In our listbox we will load a list of directories, starting from the filesystem root (there are no drives in Windows CE, the filesystem has a single root named “\”). When the user clicks on an item inside the list, the corresponding directory path will be displayed in the TextBlock object and the subdirectories of the selected branch will be shown inside the list. As you can see we declared an event handler for the SelectionChanged event of our listbox. We also used a different font size for the TextBlock, to make it more readable. XAML and Expression Blend allow you to customize your UI pretty heavily, experiment with the tools and discover how you can completely change the aspect of your application without changing a single line of code! Inside our ListBox we want to insert the directory presenting a nice icon and their name, just like you are used to see them inside Windows 7 file explorer, for example. To get this we will define a user control. This is a custom object that will behave like “regular” Silverlight for Windows Embedded objects inside our application. First of all we have to define the look of our custom control, named DirectoryItem, using XAML: <UserControl xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" mc:Ignorable="d" x:Class="ListDemo.DirectoryItem" Width="500" Height="80">   <StackPanel x:Name="LayoutRoot" Orientation="Horizontal"> <Canvas Width="31.6667" Height="45.9583" Margin="10,10,10,10" RenderTransformOrigin="0.5,0.5"> <Canvas.RenderTransform> <TransformGroup> <ScaleTransform/> <SkewTransform/> <RotateTransform Angle="-31.27"/> <TranslateTransform/> </TransformGroup> </Canvas.RenderTransform> <Rectangle Width="31.6667" Height="45.8414" Canvas.Left="0" Canvas.Top="0.116943" Stretch="Fill"> <Rectangle.Fill> <LinearGradientBrush StartPoint="0.142631,0.75344" EndPoint="1.01886,0.75344"> <LinearGradientBrush.RelativeTransform> <TransformGroup> <SkewTransform CenterX="0.142631" CenterY="0.75344" AngleX="19.3128" AngleY="0"/> <RotateTransform CenterX="0.142631" CenterY="0.75344" Angle="-35.3436"/> </TransformGroup> </LinearGradientBrush.RelativeTransform> <LinearGradientBrush.GradientStops> <GradientStop Color="#FF7B6802" Offset="0"/> <GradientStop Color="#FFF3D42C" Offset="1"/> </LinearGradientBrush.GradientStops> </LinearGradientBrush> </Rectangle.Fill> </Rectangle> <Rectangle Width="29.8441" Height="43.1517" Canvas.Left="0.569519" Canvas.Top="1.05249" Stretch="Fill"> <Rectangle.Fill> <LinearGradientBrush StartPoint="0.142632,0.753441" EndPoint="1.01886,0.753441"> <LinearGradientBrush.RelativeTransform> <TransformGroup> <SkewTransform CenterX="0.142632" CenterY="0.753441" AngleX="19.3127" AngleY="0"/> <RotateTransform CenterX="0.142632" CenterY="0.753441" Angle="-35.3437"/> </TransformGroup> </LinearGradientBrush.RelativeTransform> <LinearGradientBrush.GradientStops> <GradientStop Color="#FFCDCDCD" Offset="0.0833333"/> <GradientStop Color="#FFFFFFFF" Offset="1"/> </LinearGradientBrush.GradientStops> </LinearGradientBrush> </Rectangle.Fill> </Rectangle> <Rectangle Width="29.8441" Height="43.1517" Canvas.Left="0.455627" Canvas.Top="2.28036" Stretch="Fill"> <Rectangle.Fill> <LinearGradientBrush StartPoint="0.142631,0.75344" EndPoint="1.01886,0.75344"> <LinearGradientBrush.RelativeTransform> <TransformGroup> <SkewTransform CenterX="0.142631" CenterY="0.75344" AngleX="19.3128" AngleY="0"/> <RotateTransform CenterX="0.142631" CenterY="0.75344" Angle="-35.3436"/> </TransformGroup> </LinearGradientBrush.RelativeTransform> <LinearGradientBrush.GradientStops> <GradientStop Color="#FFCDCDCD" Offset="0.0833333"/> <GradientStop Color="#FFFFFFFF" Offset="1"/> </LinearGradientBrush.GradientStops> </LinearGradientBrush> </Rectangle.Fill> </Rectangle> <Rectangle Width="29.8441" Height="43.1517" Canvas.Left="0.455627" Canvas.Top="1.34485" Stretch="Fill"> <Rectangle.Fill> <LinearGradientBrush StartPoint="0.142631,0.75344" EndPoint="1.01886,0.75344"> <LinearGradientBrush.RelativeTransform> <TransformGroup> <SkewTransform CenterX="0.142631" CenterY="0.75344" AngleX="19.3128" AngleY="0"/> <RotateTransform CenterX="0.142631" CenterY="0.75344" Angle="-35.3436"/> </TransformGroup> </LinearGradientBrush.RelativeTransform> <LinearGradientBrush.GradientStops> <GradientStop Color="#FFCDCDCD" Offset="0.0833333"/> <GradientStop Color="#FFFFFFFF" Offset="1"/> </LinearGradientBrush.GradientStops> </LinearGradientBrush> </Rectangle.Fill> </Rectangle> <Rectangle Width="26.4269" Height="45.8414" Canvas.Left="0.227798" Canvas.Top="0" Stretch="Fill"> <Rectangle.Fill> <LinearGradientBrush StartPoint="0.142631,0.75344" EndPoint="1.01886,0.75344"> <LinearGradientBrush.RelativeTransform> <TransformGroup> <SkewTransform CenterX="0.142631" CenterY="0.75344" AngleX="19.3127" AngleY="0"/> <RotateTransform CenterX="0.142631" CenterY="0.75344" Angle="-35.3436"/> </TransformGroup> </LinearGradientBrush.RelativeTransform> <LinearGradientBrush.GradientStops> <GradientStop Color="#FF7B6802" Offset="0"/> <GradientStop Color="#FFF3D42C" Offset="1"/> </LinearGradientBrush.GradientStops> </LinearGradientBrush> </Rectangle.Fill> </Rectangle> <Rectangle Width="1.25301" Height="45.8414" Canvas.Left="1.70862" Canvas.Top="0.116943" Stretch="Fill" Fill="#FFEBFF07"/> </Canvas> <TextBlock Height="80" x:Name="Name" Width="448" TextWrapping="Wrap" VerticalAlignment="Center" FontSize="24" Text="Directory"/> </StackPanel> </UserControl> As you can see, this XAML contains many graphic elements. Those elements are used to design the folder icon. The original drawing has been designed in Expression Design and then exported as XAML. In Silverlight for Windows Embedded you can use vector images. This means that your images will look good even when scaled or rotated. In our DirectoryItem custom control we have a TextBlock named Name, that will be used to display….(suspense)…. the directory name (I’m too lazy to invent fancy names for controls, and using “boring” intuitive names will make code more readable, I hope!). Now that we have some XAML code, we may execute XAML2CPP to generate part of the aplication code for us. We should then add references to our XAML2CPP generated resource file and include in our code and add a reference to the XAML runtime library to our sources file (you can follow the instruction of the first tutorial step to do that), To generate the code used in this tutorial you need XAML2CPP ver 1.0.1.0, that is downloadable here: http://geekswithblogs.net/WindowsEmbeddedCookbook/archive/2010/03/08/xaml2cpp-1.0.1.0.aspx We can now create our usual simple Win32 application inside Platform Builder, using the same step described in the first chapter of this tutorial (http://geekswithblogs.net/WindowsEmbeddedCookbook/archive/2009/10/01/silverlight-for-embedded-tutorial.aspx). We can declare a class for our main page, deriving it from the template that XAML2CPP generated for us: class ListPage : public TListPage<ListPage> { ... } We will see the ListPage class code in a short time, but before we will see the code of our DirectoryItem user control. This object will be used to populate our list, one item for each directory. To declare a user control things are a bit more complicated (but also in this case XAML2CPP will write most of the “boilerplate” code for use. To interact with a user control you should declare an interface. An interface defines the functions of a user control that can be called inside the application code. Our custom control is currently quite simple and we just need some member functions to store and retrieve a full pathname inside our control. The control will display just the last part of the path inside the control. An interface is declared as a C++ class that has only abstract virtual members. It should also have an UUID associated with it. UUID means Universal Unique IDentifier and it’s a 128 bit number that will identify our interface without the need of specifying its fully qualified name. UUIDs are used to identify COM interfaces and, as we discovered in chapter one, Silverlight for Windows Embedded is based on COM or, at least, provides a COM-like Application Programming Interface (API). Here’s the declaration of the DirectoryItem interface: class __declspec(novtable,uuid("{D38C66E5-2725-4111-B422-D75B32AA8702}")) IDirectoryItem : public IXRCustomUserControl { public:   virtual HRESULT SetFullPath(BSTR fullpath) = 0; virtual HRESULT GetFullPath(BSTR* retval) = 0; }; The interface is derived from IXRCustomControl, this will allow us to add our object to a XAML tree. It declares the two functions needed to set and get the full path, but don’t implement them. Implementation will be done inside the control class. The interface only defines the functions of our control class that are accessible from the outside. It’s a sort of “contract” between our control and the applications that will use it. We must support what’s inside the contract and the application code should know nothing else about our own control. To reference our interface we will use the UUID, to make code more readable we can declare a #define in this way: #define IID_IDirectoryItem __uuidof(IDirectoryItem) Silverlight for Windows Embedded objects (like COM objects) use a reference counting mechanism to handle object destruction. Every time you store a pointer to an object you should call its AddRef function and every time you no longer need that pointer you should call Release. The object keeps an internal counter, incremented for each AddRef and decremented on Release. When the counter reaches 0, the object is destroyed. Managing reference counting in our code can be quite complicated and, since we are lazy (I am, at least!), we will use a great feature of Silverlight for Windows Embedded: smart pointers.A smart pointer can be connected to a Silverlight for Windows Embedded object and manages its reference counting. To declare a smart pointer we must use the XRPtr template: typedef XRPtr<IDirectoryItem> IDirectoryItemPtr; Now that we have defined our interface, it’s time to implement our user control class. XAML2CPP has implemented a class for us, and we have only to derive our class from it, defining the main class and interface of our new custom control: class DirectoryItem : public DirectoryItemUserControlRegister<DirectoryItem,IDirectoryItem> { ... } XAML2CPP has generated some code for us to support the user control, we don’t have to mind too much about that code, since it will be generated (or written by hand, if you like) always in the same way, for every user control. But knowing how does this works “under the hood” is still useful to understand the architecture of Silverlight for Windows Embedded. Our base class declaration is a bit more complex than the one we used for a simple page in the previous chapters: template <class A,class B> class DirectoryItemUserControlRegister : public XRCustomUserControlImpl<A,B>,public TDirectoryItem<A,XAML2CPPUserControl> { ... } This class derives from the XAML2CPP generated template class, like the ListPage class, but it uses XAML2CPPUserControl for the implementation of some features. This class shares the same ancestor of XAML2CPPPage (base class for “regular” XAML pages), XAML2CPPBase, implements binding of member variables and event handlers but, instead of loading and creating its own XAML tree, it attaches to an existing one. The XAML tree (and UI) of our custom control is created and loaded by the XRCustomUserControlImpl class. This class is part of the Silverlight for Windows Embedded framework and implements most of the functions needed to build-up a custom control in Silverlight (the guys that developed Silverlight for Windows Embedded seem to care about lazy programmers!). We have just to initialize it, providing our class (DirectoryItem) and interface (IDirectoryItem). Our user control class has also a static member: protected:   static HINSTANCE hInstance; This is used to store the HINSTANCE of the modules that contain our user control class. I don’t like this implementation, but I can’t find a better one, so if somebody has good ideas about how to handle the HINSTANCE object, I’ll be happy to hear suggestions! It also implements two static members required by XRCustomUserControlImpl. The first one is used to load the XAML UI of our custom control: static HRESULT GetXamlSource(XRXamlSource* pXamlSource) { pXamlSource->SetResource(hInstance,TEXT("XAML"),IDR_XAML_DirectoryItem); return S_OK; }   It initializes a XRXamlSource object, connecting it to the XAML resource that XAML2CPP has included in our resource script. The other method is used to register our custom control, allowing Silverlight for Windows Embedded to create it when it load some XAML or when an application creates a new control at runtime (more about this later): static HRESULT Register() { return XRCustomUserControlImpl<A,B>::Register(__uuidof(B), L"DirectoryItem", L"clr-namespace:DirectoryItemNamespace"); } To register our control we should provide its interface UUID, the name of the corresponding element in the XAML tree and its current namespace (namespaces compatible with Silverlight must use the “clr-namespace” prefix. We may also register additional properties for our objects, allowing them to be loaded and saved inside XAML. In this case we have no permanent properties and the Register method will just register our control. An additional static method is implemented to allow easy registration of our custom control inside our application WinMain function: static HRESULT RegisterUserControl(HINSTANCE hInstance) { DirectoryItemUserControlRegister::hInstance=hInstance; return DirectoryItemUserControlRegister<A,B>::Register(); } Now our control is registered and we will be able to create it using the Silverlight for Windows Embedded runtime functions. But we need to bind our members and event handlers to have them available like we are used to do for other XAML2CPP generated objects. To bind events and members we need to implement the On_Loaded function: virtual HRESULT OnLoaded(__in IXRDependencyObject* pRoot) { HRESULT retcode; IXRApplicationPtr app; if (FAILED(retcode=GetXRApplicationInstance(&app))) return retcode; return ((A*)this)->Init(pRoot,hInstance,app); } This function will call the XAML2CPPUserControl::Init member that will connect the “root” member with the XAML sub tree that has been created for our control and then calls BindObjects and BindEvents to bind members and events to our code. Now we can go back to our application code (the code that you’ll have to actually write) to see the contents of our DirectoryItem class: class DirectoryItem : public DirectoryItemUserControlRegister<DirectoryItem,IDirectoryItem> { protected:   WCHAR fullpath[_MAX_PATH+1];   public:   DirectoryItem() { *fullpath=0; }   virtual HRESULT SetFullPath(BSTR fullpath) { wcscpy_s(this->fullpath,fullpath);   WCHAR* p=fullpath;   for(WCHAR*q=wcsstr(p,L"\\");q;p=q+1,q=wcsstr(p,L"\\")) ;   Name->SetText(p); return S_OK; }   virtual HRESULT GetFullPath(BSTR* retval) { *retval=SysAllocString(fullpath); return S_OK; } }; It’s pretty easy and contains a fullpath member (used to store that path of the directory connected with the user control) and the implementation of the two interface members that can be used to set and retrieve the path. The SetFullPath member parses the full path and displays just the last branch directory name inside the “Name” TextBlock object. As you can see, implementing a user control in Silverlight for Windows Embedded is not too complex and using XAML also for the UI of the control allows us to re-use the same mechanisms that we learnt and used in the previous steps of our tutorial. Now let’s see how the main page is managed by the ListPage class. class ListPage : public TListPage<ListPage> { protected:   // current path TCHAR curpath[_MAX_PATH+1]; It has a member named “curpath” that is used to store the current directory. It’s initialized inside the constructor: ListPage() { *curpath=0; } And it’s value is displayed inside the “CurrentDir” TextBlock inside the initialization function: virtual HRESULT Init(HINSTANCE hInstance,IXRApplication* app) { HRESULT retcode;   if (FAILED(retcode=TListPage<ListPage>::Init(hInstance,app))) return retcode;   CurrentDir->SetText(L"\\"); return S_OK; } The FillFileList function is used to enumerate subdirectories of the current dir and add entries for each one inside the list box that fills most of the client area of our main page: HRESULT FillFileList() { HRESULT retcode; IXRItemCollectionPtr items; IXRApplicationPtr app;   if (FAILED(retcode=GetXRApplicationInstance(&app))) return retcode; // retrieves the items contained in the listbox if (FAILED(retcode=FileList->GetItems(&items))) return retcode;   // clears the list if (FAILED(retcode=items->Clear())) return retcode;   // enumerates files and directory in the current path WCHAR filemask[_MAX_PATH+1];   wcscpy_s(filemask,curpath); wcscat_s(filemask,L"\\*.*");   WIN32_FIND_DATA finddata; HANDLE findhandle;   findhandle=FindFirstFile(filemask,&finddata);   // the directory is empty? if (findhandle==INVALID_HANDLE_VALUE) return S_OK;   do { if (finddata.dwFileAttributes&=FILE_ATTRIBUTE_DIRECTORY) { IXRListBoxItemPtr listboxitem;   // add a new item to the listbox if (FAILED(retcode=app->CreateObject(IID_IXRListBoxItem,&listboxitem))) { FindClose(findhandle); return retcode; }   if (FAILED(retcode=items->Add(listboxitem,NULL))) { FindClose(findhandle); return retcode; }   IDirectoryItemPtr directoryitem;   if (FAILED(retcode=app->CreateObject(IID_IDirectoryItem,&directoryitem))) { FindClose(findhandle); return retcode; }   WCHAR fullpath[_MAX_PATH+1];   wcscpy_s(fullpath,curpath); wcscat_s(fullpath,L"\\"); wcscat_s(fullpath,finddata.cFileName);   if (FAILED(retcode=directoryitem->SetFullPath(fullpath))) { FindClose(findhandle); return retcode; }   XAML2CPPXRValue value((IXRDependencyObject*)directoryitem);   if (FAILED(retcode=listboxitem->SetContent(&value))) { FindClose(findhandle); return retcode; } } } while (FindNextFile(findhandle,&finddata));   FindClose(findhandle); return S_OK; } This functions retrieve a pointer to the collection of the items contained in the directory listbox. The IXRItemCollection interface is used by listboxes and comboboxes and allow you to clear the list (using Clear(), as our function does at the beginning) and change its contents by adding and removing elements. This function uses the FindFirstFile/FindNextFile functions to enumerate all the objects inside our current directory and for each subdirectory creates a IXRListBoxItem object. You can insert any kind of control inside a list box, you don’t need a IXRListBoxItem, but using it will allow you to handle the selected state of an item, highlighting it inside the list. The function creates a list box item using the CreateObject function of XRApplication. The same function is then used to create an instance of our custom control. The function returns a pointer to the control IDirectoryItem interface and we can use it to store the directory full path inside the object and add it as content of the IXRListBox item object, adding it to the listbox contents. The listbox generates an event (SelectionChanged) each time the user clicks on one of the items contained in the listbox. We implement an event handler for that event and use it to change our current directory and repopulate the listbox. The current directory full path will be displayed in the TextBlock: HRESULT Filelist_SelectionChanged(IXRDependencyObject* source,XRSelectionChangedEventArgs* args) { HRESULT retcode;   IXRListBoxItemPtr listboxitem;   if (!args->pAddedItem) return S_OK;   if (FAILED(retcode=args->pAddedItem->QueryInterface(IID_IXRListBoxItem,(void**)&listboxitem))) return retcode;   XRValue content; if (FAILED(retcode=listboxitem->GetContent(&content))) return retcode;   if (content.vType!=VTYPE_OBJECT) return E_FAIL;   IDirectoryItemPtr directoryitem;   if (FAILED(retcode=content.pObjectVal->QueryInterface(IID_IDirectoryItem,(void**)&directoryitem))) return retcode;   content.pObjectVal->Release(); content.pObjectVal=NULL;   BSTR fullpath=NULL;   if (FAILED(retcode=directoryitem->GetFullPath(&fullpath))) return retcode;   CurrentDir->SetText(fullpath);   wcscpy_s(curpath,fullpath); FillFileList(); SysFreeString(fullpath);     return S_OK; } }; The function uses the pAddedItem member of the XRSelectionChangedEventArgs object to retrieve the currently selected item, converts it to a IXRListBoxItem interface using QueryInterface, and then retrives its contents (IDirectoryItem object). Using the GetFullPath method we can get the full path of our selected directory and assing it to the curdir member. A call to FillFileList will update the listbox contents, displaying the list of subdirectories of the selected folder. To build our sample we just need to add code to our WinMain function: int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPTSTR lpCmdLine, int nCmdShow) { if (!XamlRuntimeInitialize()) return -1;   HRESULT retcode;   IXRApplicationPtr app; if (FAILED(retcode=GetXRApplicationInstance(&app))) return -1;   if (FAILED(retcode=DirectoryItem::RegisterUserControl(hInstance))) return retcode;   ListPage page;   if (FAILED(page.Init(hInstance,app))) return -1;   page.FillFileList();   UINT exitcode;   if (FAILED(page.GetVisualHost()->StartDialog(&exitcode))) return -1;   return 0; } This code is very similar to the one of the WinMains of our previous samples. The main differences are that we register our custom control (you should do that as soon as you have initialized the XAML runtime) and call FillFileList after the initialization of our ListPage object to load the contents of the root folder of our device inside the listbox. As usual you can download the full sample source code from here: http://cid-9b7b0aefe3514dc5.skydrive.live.com/self.aspx/.Public/ListBoxTest.zip

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• SQL Server 2012 - AlwaysOn

  - by Claus Jandausch

  Ich war nicht nur irritiert, ich war sogar regelrecht schockiert - und für einen kurzen Moment sprachlos (was nur selten der Fall ist). Gerade eben hatte mich jemand gefragt "Wann Oracle denn etwas Vergleichbares wie AlwaysOn bieten würde - und ob überhaupt?" War ich hier im falschen Film gelandet? Ich konnte nicht anders, als meinen Unmut kundzutun und zu erklären, dass die Fragestellung normalerweise anders herum läuft. Zugegeben - es mag vielleicht strittige Punkte geben im Vergleich zwischen Oracle und SQL Server - bei denen nicht unbedingt immer Oracle die Nase vorn haben muss - aber das Thema Clustering für Hochverfügbarkeit (HA), Disaster Recovery (DR) und Skalierbarkeit gehört mit Sicherheit nicht dazu. Dieses Erlebnis hakte ich am Nachgang als Einzelfall ab, der so nie wieder vorkommen würde. Bis ich kurz darauf eines Besseren belehrt wurde und genau die selbe Frage erneut zu hören bekam. Diesmal sogar im Exadata-Umfeld und einem Oracle Stretch Cluster. Einmal ist keinmal, doch zweimal ist einmal zu viel... Getreu diesem alten Motto war mir klar, dass man das so nicht länger stehen lassen konnte. Ich habe keine Ahnung, wie die Microsoft Marketing Abteilung es geschafft hat, unter dem AlwaysOn Brading eine innovative Technologie vermuten zu lassen - aber sie hat ihren Job scheinbar gut gemacht. Doch abgesehen von einem guten Marketing, stellt sich natürlich die Frage, was wirklich dahinter steckt und wie sich das Ganze mit Oracle vergleichen lässt - und ob überhaupt? Damit wären wir wieder bei der ursprünglichen Frage angelangt.  So viel zum Hintergrund dieses Blogbeitrags - von meiner Antwort handelt der restliche Blog. "Windows was the God ..." Um den wahren Unterschied zwischen Oracle und Microsoft verstehen zu können, muss man zunächst das bedeutendste Microsoft Dogma kennen. Es lässt sich schlicht und einfach auf den Punkt bringen: "Alles muss auf Windows basieren." Die Überschrift dieses Absatzes ist kein von mir erfundener Ausspruch, sondern ein Zitat. Konkret stammt es aus einem längeren Artikel von Kurt Eichenwald in der Vanity Fair aus dem August 2012. Er lautet Microsoft's Lost Decade und sei jedem ans Herz gelegt, der die "Microsoft-Maschinerie" unter Steve Ballmer und einige ihrer Kuriositäten besser verstehen möchte. "YOU TALKING TO ME?" Microsoft C.E.O. Steve Ballmer bei seiner Keynote auf der 2012 International Consumer Electronics Show in Las Vegas am 9. Januar   Manche Dinge in diesem Artikel mögen überspitzt dargestellt erscheinen - sind sie aber nicht. Vieles davon kannte ich bereits aus eigener Erfahrung und kann es nur bestätigen. Anderes hat sich mir erst so richtig erschlossen. Insbesondere die folgenden Passagen führten zum Aha-Erlebnis: “Windows was the god—everything had to work with Windows,” said Stone... “Every little thing you want to write has to build off of Windows (or other existing roducts),” one software engineer said. “It can be very confusing, …” Ich habe immer schon darauf hingewiesen, dass in einem SQL Server Failover Cluster die Microsoft Datenbank eigentlich nichts Nenneswertes zum Geschehen beiträgt, sondern sich voll und ganz auf das Windows Betriebssystem verlässt. Deshalb muss man auch die Windows Server Enterprise Edition installieren, soll ein Failover Cluster für den SQL Server eingerichtet werden. Denn hier werden die Cluster Services geliefert - nicht mit dem SQL Server. Er ist nur lediglich ein weiteres Server Produkt, für das Windows in Ausfallszenarien genutzt werden kann - so wie Microsoft Exchange beispielsweise, oder Microsoft SharePoint, oder irgendein anderes Server Produkt das auf Windows gehostet wird. Auch Oracle kann damit genutzt werden. Das Stichwort lautet hier: Oracle Failsafe. Nur - warum sollte man das tun, wenn gleichzeitig eine überlegene Technologie wie die Oracle Real Application Clusters (RAC) zur Verfügung steht, die dann auch keine Windows Enterprise Edition voraussetzen, da Oracle die eigene Clusterware liefert. Welche darüber hinaus für kürzere Failover-Zeiten sorgt, da diese Cluster-Technologie Datenbank-integriert ist und sich nicht auf "Dritte" verlässt. Wenn man sich also schon keine technischen Vorteile mit einem SQL Server Failover Cluster erkauft, sondern zusätzlich noch versteckte Lizenzkosten durch die Lizenzierung der Windows Server Enterprise Edition einhandelt, warum hat Microsoft dann in den vergangenen Jahren seit SQL Server 2000 nicht ebenfalls an einer neuen und innovativen Lösung gearbeitet, die mit Oracle RAC mithalten kann? Entwickler hat Microsoft genügend? Am Geld kann es auch nicht liegen? Lesen Sie einfach noch einmal die beiden obenstehenden Zitate und sie werden den Grund verstehen. Anders lässt es sich ja auch gar nicht mehr erklären, dass AlwaysOn aus zwei unterschiedlichen Technologien besteht, die beide jedoch wiederum auf dem Windows Server Failover Clustering (WSFC) basieren. Denn daraus ergeben sich klare Nachteile - aber dazu später mehr. Um AlwaysOn zu verstehen, sollte man sich zunächst kurz in Erinnerung rufen, was Microsoft bisher an HA/DR (High Availability/Desaster Recovery) Lösungen für SQL Server zur Verfügung gestellt hat. Replikation Basiert auf logischer Replikation und Pubisher/Subscriber Architektur Transactional Replication Merge Replication Snapshot Replication Microsoft's Replikation ist vergleichbar mit Oracle GoldenGate. Oracle GoldenGate stellt jedoch die umfassendere Technologie dar und bietet High Performance. Log Shipping Microsoft's Log Shipping stellt eine einfache Technologie dar, die vergleichbar ist mit Oracle Managed Recovery in Oracle Version 7. Das Log Shipping besitzt folgende Merkmale: Transaction Log Backups werden von Primary nach Secondary/ies geschickt Einarbeitung (z.B. Restore) auf jedem Secondary individuell Optionale dritte Server Instanz (Monitor Server) für Überwachung und Alarm Log Restore Unterbrechung möglich für Read-Only Modus (Secondary) Keine Unterstützung von Automatic Failover Database Mirroring Microsoft's Database Mirroring wurde verfügbar mit SQL Server 2005, sah aus wie Oracle Data Guard in Oracle 9i, war funktional jedoch nicht so umfassend. Für ein HA/DR Paar besteht eine 1:1 Beziehung, um die produktive Datenbank (Principle DB) abzusichern. Auf der Standby Datenbank (Mirrored DB) werden alle Insert-, Update- und Delete-Operationen nachgezogen. Modi Synchron (High-Safety Modus) Asynchron (High-Performance Modus) Automatic Failover Unterstützt im High-Safety Modus (synchron) Witness Server vorausgesetzt     Zur Frage der Kontinuität Es stellt sich die Frage, wie es um diesen Technologien nun im Zusammenhang mit SQL Server 2012 bestellt ist. Unter Fanfaren seinerzeit eingeführt, war Database Mirroring das erklärte Mittel der Wahl. Ich bin kein Produkt Manager bei Microsoft und kann hierzu nur meine Meinung äußern, aber zieht man den SQL AlwaysOn Team Blog heran, so sieht es nicht gut aus für das Database Mirroring - zumindest nicht langfristig. "Does AlwaysOn Availability Group replace Database Mirroring going forward?” “The short answer is we recommend that you migrate from the mirroring configuration or even mirroring and log shipping configuration to using Availability Group. Database Mirroring will still be available in the Denali release but will be phased out over subsequent releases. Log Shipping will continue to be available in future releases.” Damit wären wir endlich beim eigentlichen Thema angelangt. Was ist eine sogenannte Availability Group und was genau hat es mit der vielversprechend klingenden Bezeichnung AlwaysOn auf sich?   SQL Server 2012 - AlwaysOn Zwei HA-Features verstekcne sich hinter dem “AlwaysOn”-Branding. Einmal das AlwaysOn Failover Clustering aka SQL Server Failover Cluster Instances (FCI) - zum Anderen die AlwaysOn Availability Groups. Failover Cluster Instances (FCI) Entspricht ungefähr dem Stretch Cluster Konzept von Oracle Setzt auf Windows Server Failover Clustering (WSFC) auf Bietet HA auf Instanz-Ebene AlwaysOn Availability Groups (Verfügbarkeitsgruppen) Ähnlich der Idee von Consistency Groups, wie in Storage-Level Replikations-Software von z.B. EMC SRDF Abhängigkeiten zu Windows Server Failover Clustering (WSFC) Bietet HA auf Datenbank-Ebene   Hinweis: Verwechseln Sie nicht eine SQL Server Datenbank mit einer Oracle Datenbank. Und auch nicht eine Oracle Instanz mit einer SQL Server Instanz. Die gleichen Begriffe haben hier eine andere Bedeutung - nicht selten ein Grund, weshalb Oracle- und Microsoft DBAs schnell aneinander vorbei reden. Denken Sie bei einer SQL Server Datenbank eher an ein Oracle Schema, das kommt der Sache näher. So etwas wie die SQL Server Northwind Datenbank ist vergleichbar mit dem Oracle Scott Schema. Wenn Sie die genauen Unterschiede kennen möchten, finden Sie eine detaillierte Beschreibung in meinem Buch "Oracle10g Release 2 für Windows und .NET", erhältich bei Lehmanns, Amazon, etc.   Windows Server Failover Clustering (WSFC) Wie man sieht, basieren beide AlwaysOn Technologien wiederum auf dem Windows Server Failover Clustering (WSFC), um einerseits Hochverfügbarkeit auf Ebene der Instanz zu gewährleisten und andererseits auf der Datenbank-Ebene. Deshalb nun eine kurze Beschreibung der WSFC. Die WSFC sind ein mit dem Windows Betriebssystem geliefertes Infrastruktur-Feature, um HA für Server Anwendungen, wie Microsoft Exchange, SharePoint, SQL Server, etc. zu bieten. So wie jeder andere Cluster, besteht ein WSFC Cluster aus einer Gruppe unabhängiger Server, die zusammenarbeiten, um die Verfügbarkeit einer Applikation oder eines Service zu erhöhen. Falls ein Cluster-Knoten oder -Service ausfällt, kann der auf diesem Knoten bisher gehostete Service automatisch oder manuell auf einen anderen im Cluster verfügbaren Knoten transferriert werden - was allgemein als Failover bekannt ist. Unter SQL Server 2012 verwenden sowohl die AlwaysOn Avalability Groups, als auch die AlwaysOn Failover Cluster Instances die WSFC als Plattformtechnologie, um Komponenten als WSFC Cluster-Ressourcen zu registrieren. Verwandte Ressourcen werden in eine Ressource Group zusammengefasst, die in Abhängigkeit zu anderen WSFC Cluster-Ressourcen gebracht werden kann. Der WSFC Cluster Service kann jetzt die Notwendigkeit zum Neustart der SQL Server Instanz erfassen oder einen automatischen Failover zu einem anderen Server-Knoten im WSFC Cluster auslösen.   Failover Cluster Instances (FCI) Eine SQL Server Failover Cluster Instanz (FCI) ist eine einzelne SQL Server Instanz, die in einem Failover Cluster betrieben wird, der aus mehreren Windows Server Failover Clustering (WSFC) Knoten besteht und so HA (High Availability) auf Ebene der Instanz bietet. Unter Verwendung von Multi-Subnet FCI kann auch Remote DR (Disaster Recovery) unterstützt werden. Eine weitere Option für Remote DR besteht darin, eine unter FCI gehostete Datenbank in einer Availability Group zu betreiben. Hierzu später mehr. FCI und WSFC Basis FCI, das für lokale Hochverfügbarkeit der Instanzen genutzt wird, ähnelt der veralteten Architektur eines kalten Cluster (Aktiv-Passiv). Unter SQL Server 2008 wurde diese Technologie SQL Server 2008 Failover Clustering genannt. Sie nutzte den Windows Server Failover Cluster. In SQL Server 2012 hat Microsoft diese Basistechnologie unter der Bezeichnung AlwaysOn zusammengefasst. Es handelt sich aber nach wie vor um die klassische Aktiv-Passiv-Konfiguration. Der Ablauf im Failover-Fall ist wie folgt: Solange kein Hardware-oder System-Fehler auftritt, werden alle Dirty Pages im Buffer Cache auf Platte geschrieben Alle entsprechenden SQL Server Services (Dienste) in der Ressource Gruppe werden auf dem aktiven Knoten gestoppt Die Ownership der Ressource Gruppe wird auf einen anderen Knoten der FCI transferriert Der neue Owner (Besitzer) der Ressource Gruppe startet seine SQL Server Services (Dienste) Die Connection-Anforderungen einer Client-Applikation werden automatisch auf den neuen aktiven Knoten mit dem selben Virtuellen Network Namen (VNN) umgeleitet Abhängig vom Zeitpunkt des letzten Checkpoints, kann die Anzahl der Dirty Pages im Buffer Cache, die noch auf Platte geschrieben werden müssen, zu unvorhersehbar langen Failover-Zeiten führen. Um diese Anzahl zu drosseln, besitzt der SQL Server 2012 eine neue Fähigkeit, die Indirect Checkpoints genannt wird. Indirect Checkpoints ähnelt dem Fast-Start MTTR Target Feature der Oracle Datenbank, das bereits mit Oracle9i verfügbar war.   SQL Server Multi-Subnet Clustering Ein SQL Server Multi-Subnet Failover Cluster entspricht vom Konzept her einem Oracle RAC Stretch Cluster. Doch dies ist nur auf den ersten Blick der Fall. Im Gegensatz zu RAC ist in einem lokalen SQL Server Failover Cluster jeweils nur ein Knoten aktiv für eine Datenbank. Für die Datenreplikation zwischen geografisch entfernten Sites verlässt sich Microsoft auf 3rd Party Lösungen für das Storage Mirroring.     Die Verbesserung dieses Szenario mit einer SQL Server 2012 Implementierung besteht schlicht darin, dass eine VLAN-Konfiguration (Virtual Local Area Network) nun nicht mehr benötigt wird, so wie dies bisher der Fall war. Das folgende Diagramm stellt dar, wie der Ablauf mit SQL Server 2012 gehandhabt wird. In Site A und Site B wird HA jeweils durch einen lokalen Aktiv-Passiv-Cluster sichergestellt.     Besondere Aufmerksamkeit muss hier der Konfiguration und dem Tuning geschenkt werden, da ansonsten völlig inakzeptable Failover-Zeiten resultieren. Dies liegt darin begründet, weil die Downtime auf Client-Seite nun nicht mehr nur von der reinen Failover-Zeit abhängt, sondern zusätzlich von der Dauer der DNS Replikation zwischen den DNS Servern. (Rufen Sie sich in Erinnerung, dass wir gerade von Multi-Subnet Clustering sprechen). Außerdem ist zu berücksichtigen, wie schnell die Clients die aktualisierten DNS Informationen abfragen. Spezielle Konfigurationen für Node Heartbeat, HostRecordTTL (Host Record Time-to-Live) und Intersite Replication Frequeny für Active Directory Sites und Services werden notwendig. Default TTL für Windows Server 2008 R2: 20 Minuten Empfohlene Einstellung: 1 Minute DNS Update Replication Frequency in Windows Umgebung: 180 Minuten Empfohlene Einstellung: 15 Minuten (minimaler Wert)   Betrachtet man diese Werte, muss man feststellen, dass selbst eine optimale Konfiguration die rigiden SLAs (Service Level Agreements) heutiger geschäftskritischer Anwendungen für HA und DR nicht erfüllen kann. Denn dies impliziert eine auf der Client-Seite erlebte Failover-Zeit von insgesamt 16 Minuten. Hierzu ein Auszug aus der SQL Server 2012 Online Dokumentation: Cons: If a cross-subnet failover occurs, the client recovery time could be 15 minutes or longer, depending on your HostRecordTTL setting and the setting of your cross-site DNS/AD replication schedule.    Wir sind hier an einem Punkt unserer Überlegungen angelangt, an dem sich erklärt, weshalb ich zuvor das "Windows was the God ..." Zitat verwendet habe. Die unbedingte Abhängigkeit zu Windows wird zunehmend zum Problem, da sie die Komplexität einer Microsoft-basierenden Lösung erhöht, anstelle sie zu reduzieren. Und Komplexität ist das Letzte, was sich CIOs heutzutage wünschen.  Zur Ehrenrettung des SQL Server 2012 und AlwaysOn muss man sagen, dass derart lange Failover-Zeiten kein unbedingtes "Muss" darstellen, sondern ein "Kann". Doch auch ein "Kann" kann im unpassenden Moment unvorhersehbare und kostspielige Folgen haben. Die Unabsehbarkeit ist wiederum Ursache vieler an der Implementierung beteiligten Komponenten und deren Abhängigkeiten, wie beispielsweise drei Cluster-Lösungen (zwei von Microsoft, eine 3rd Party Lösung). Wie man die Sache auch dreht und wendet, kommt man an diesem Fakt also nicht vorbei - ganz unabhängig von der Dauer einer Downtime oder Failover-Zeiten. Im Gegensatz zu AlwaysOn und der hier vorgestellten Version eines Stretch-Clusters, vermeidet eine entsprechende Oracle Implementierung eine derartige Komplexität, hervorgerufen duch multiple Abhängigkeiten. Den Unterschied machen Datenbank-integrierte Mechanismen, wie Fast Application Notification (FAN) und Fast Connection Failover (FCF). Für Oracle MAA Konfigurationen (Maximum Availability Architecture) sind Inter-Site Failover-Zeiten im Bereich von Sekunden keine Seltenheit. Wenn Sie dem Link zur Oracle MAA folgen, finden Sie außerdem eine Reihe an Customer Case Studies. Auch dies ist ein wichtiges Unterscheidungsmerkmal zu AlwaysOn, denn die Oracle Technologie hat sich bereits zigfach in höchst kritischen Umgebungen bewährt.   Availability Groups (Verfügbarkeitsgruppen) Die sogenannten Availability Groups (Verfügbarkeitsgruppen) sind - neben FCI - der weitere Baustein von AlwaysOn.   Hinweis: Bevor wir uns näher damit beschäftigen, sollten Sie sich noch einmal ins Gedächtnis rufen, dass eine SQL Server Datenbank nicht die gleiche Bedeutung besitzt, wie eine Oracle Datenbank, sondern eher einem Oracle Schema entspricht. So etwas wie die SQL Server Northwind Datenbank ist vergleichbar mit dem Oracle Scott Schema.   Eine Verfügbarkeitsgruppe setzt sich zusammen aus einem Set mehrerer Benutzer-Datenbanken, die im Falle eines Failover gemeinsam als Gruppe behandelt werden. Eine Verfügbarkeitsgruppe unterstützt ein Set an primären Datenbanken (primäres Replikat) und einem bis vier Sets von entsprechenden sekundären Datenbanken (sekundäre Replikate).       Es können jedoch nicht alle SQL Server Datenbanken einer AlwaysOn Verfügbarkeitsgruppe zugeordnet werden. Der SQL Server Spezialist Michael Otey zählt in seinem SQL Server Pro Artikel folgende Anforderungen auf: Verfügbarkeitsgruppen müssen mit Benutzer-Datenbanken erstellt werden. System-Datenbanken können nicht verwendet werden Die Datenbanken müssen sich im Read-Write Modus befinden. Read-Only Datenbanken werden nicht unterstützt Die Datenbanken in einer Verfügbarkeitsgruppe müssen Multiuser Datenbanken sein Sie dürfen nicht das AUTO_CLOSE Feature verwenden Sie müssen das Full Recovery Modell nutzen und es muss ein vollständiges Backup vorhanden sein Eine gegebene Datenbank kann sich nur in einer einzigen Verfügbarkeitsgruppe befinden und diese Datenbank düerfen nicht für Database Mirroring konfiguriert sein Microsoft empfiehl außerdem, dass der Verzeichnispfad einer Datenbank auf dem primären und sekundären Server identisch sein sollte Wie man sieht, eignen sich Verfügbarkeitsgruppen nicht, um HA und DR vollständig abzubilden. Die Unterscheidung zwischen der Instanzen-Ebene (FCI) und Datenbank-Ebene (Availability Groups) ist von hoher Bedeutung. Vor kurzem wurde mir gesagt, dass man mit den Verfügbarkeitsgruppen auf Shared Storage verzichten könne und dadurch Kosten spart. So weit so gut ... Man kann natürlich eine Installation rein mit Verfügbarkeitsgruppen und ohne FCI durchführen - aber man sollte sich dann darüber bewusst sein, was man dadurch alles nicht abgesichert hat - und dies wiederum für Desaster Recovery (DR) und SLAs (Service Level Agreements) bedeutet. Kurzum, um die Kombination aus beiden AlwaysOn Produkten und der damit verbundene Komplexität kommt man wohl in der Praxis nicht herum.    Availability Groups und WSFC AlwaysOn hängt von Windows Server Failover Clustering (WSFC) ab, um die aktuellen Rollen der Verfügbarkeitsreplikate einer Verfügbarkeitsgruppe zu überwachen und zu verwalten, und darüber zu entscheiden, wie ein Failover-Ereignis die Verfügbarkeitsreplikate betrifft. Das folgende Diagramm zeigt de Beziehung zwischen Verfügbarkeitsgruppen und WSFC:   Der Verfügbarkeitsmodus ist eine Eigenschaft jedes Verfügbarkeitsreplikats. Synychron und Asynchron können also gemischt werden: Availability Modus (Verfügbarkeitsmodus) Asynchroner Commit-Modus Primäres replikat schließt Transaktionen ohne Warten auf Sekundäres Synchroner Commit-Modus Primäres Replikat wartet auf Commit von sekundärem Replikat Failover Typen Automatic Manual Forced (mit möglichem Datenverlust) Synchroner Commit-Modus Geplanter, manueller Failover ohne Datenverlust Automatischer Failover ohne Datenverlust Asynchroner Commit-Modus Nur Forced, manueller Failover mit möglichem Datenverlust   Der SQL Server kennt keinen separaten Switchover Begriff wie in Oracle Data Guard. Für SQL Server werden alle Role Transitions als Failover bezeichnet. Tatsächlich unterstützt der SQL Server keinen Switchover für asynchrone Verbindungen. Es gibt nur die Form des Forced Failover mit möglichem Datenverlust. Eine ähnliche Fähigkeit wie der Switchover unter Oracle Data Guard ist so nicht gegeben.   SQL Sever FCI mit Availability Groups (Verfügbarkeitsgruppen) Neben den Verfügbarkeitsgruppen kann eine zweite Failover-Ebene eingerichtet werden, indem SQL Server FCI (auf Shared Storage) mit WSFC implementiert wird. Ein Verfügbarkeitesreplikat kann dann auf einer Standalone Instanz gehostet werden, oder einer FCI Instanz. Zum Verständnis: Die Verfügbarkeitsgruppen selbst benötigen kein Shared Storage. Diese Kombination kann verwendet werden für lokale HA auf Ebene der Instanz und DR auf Datenbank-Ebene durch Verfügbarkeitsgruppen. Das folgende Diagramm zeigt dieses Szenario:   Achtung! Hier handelt es sich nicht um ein Pendant zu Oracle RAC plus Data Guard, auch wenn das Bild diesen Eindruck vielleicht vermitteln mag - denn alle sekundären Knoten im FCI sind rein passiv. Es existiert außerdem eine weitere und ernsthafte Einschränkung: SQL Server Failover Cluster Instanzen (FCI) unterstützen nicht das automatische AlwaysOn Failover für Verfügbarkeitsgruppen. Jedes unter FCI gehostete Verfügbarkeitsreplikat kann nur für manuelles Failover konfiguriert werden.   Lesbare Sekundäre Replikate Ein oder mehrere Verfügbarkeitsreplikate in einer Verfügbarkeitsgruppe können für den lesenden Zugriff konfiguriert werden, wenn sie als sekundäres Replikat laufen. Dies ähnelt Oracle Active Data Guard, jedoch gibt es Einschränkungen. Alle Abfragen gegen die sekundäre Datenbank werden automatisch auf das Snapshot Isolation Level abgebildet. Es handelt sich dabei um eine Versionierung der Rows. Microsoft versuchte hiermit die Oracle MVRC (Multi Version Read Consistency) nachzustellen. Tatsächlich muss man die SQL Server Snapshot Isolation eher mit Oracle Flashback vergleichen. Bei der Implementierung des Snapshot Isolation Levels handelt sich um ein nachträglich aufgesetztes Feature und nicht um einen inhärenten Teil des Datenbank-Kernels, wie im Falle Oracle. (Ich werde hierzu in Kürze einen weiteren Blogbeitrag verfassen, wenn ich mich mit der neuen SQL Server 2012 Core Lizenzierung beschäftige.) Für die Praxis entstehen aus der Abbildung auf das Snapshot Isolation Level ernsthafte Restriktionen, derer man sich für den Betrieb in der Praxis bereits vorab bewusst sein sollte: Sollte auf der primären Datenbank eine aktive Transaktion zu dem Zeitpunkt existieren, wenn ein lesbares sekundäres Replikat in die Verfügbarkeitsgruppe aufgenommen wird, werden die Row-Versionen auf der korrespondierenden sekundären Datenbank nicht sofort vollständig verfügbar sein. Eine aktive Transaktion auf dem primären Replikat muss zuerst abgeschlossen (Commit oder Rollback) und dieser Transaktions-Record auf dem sekundären Replikat verarbeitet werden. Bis dahin ist das Isolation Level Mapping auf der sekundären Datenbank unvollständig und Abfragen sind temporär geblockt. Microsoft sagt dazu: "This is needed to guarantee that row versions are available on the secondary replica before executing the query under snapshot isolation as all isolation levels are implicitly mapped to snapshot isolation." (SQL Storage Engine Blog: AlwaysOn: I just enabled Readable Secondary but my query is blocked?)  Grundlegend bedeutet dies, dass ein aktives lesbares Replikat nicht in die Verfügbarkeitsgruppe aufgenommen werden kann, ohne das primäre Replikat vorübergehend stillzulegen. Da Leseoperationen auf das Snapshot Isolation Transaction Level abgebildet werden, kann die Bereinigung von Ghost Records auf dem primären Replikat durch Transaktionen auf einem oder mehreren sekundären Replikaten geblockt werden - z.B. durch eine lang laufende Abfrage auf dem sekundären Replikat. Diese Bereinigung wird auch blockiert, wenn die Verbindung zum sekundären Replikat abbricht oder der Datenaustausch unterbrochen wird. Auch die Log Truncation wird in diesem Zustant verhindert. Wenn dieser Zustand längere Zeit anhält, empfiehlt Microsoft das sekundäre Replikat aus der Verfügbarkeitsgruppe herauszunehmen - was ein ernsthaftes Downtime-Problem darstellt. Die Read-Only Workload auf den sekundären Replikaten kann eingehende DDL Änderungen blockieren. Obwohl die Leseoperationen aufgrund der Row-Versionierung keine Shared Locks halten, führen diese Operatioen zu Sch-S Locks (Schemastabilitätssperren). DDL-Änderungen durch Redo-Operationen können dadurch blockiert werden. Falls DDL aufgrund konkurrierender Lese-Workload blockiert wird und der Schwellenwert für 'Recovery Interval' (eine SQL Server Konfigurationsoption) überschritten wird, generiert der SQL Server das Ereignis sqlserver.lock_redo_blocked, welches Microsoft zum Kill der blockierenden Leser empfiehlt. Auf die Verfügbarkeit der Anwendung wird hierbei keinerlei Rücksicht genommen.   Keine dieser Einschränkungen existiert mit Oracle Active Data Guard.   Backups auf sekundären Replikaten  Über die sekundären Replikate können Backups (BACKUP DATABASE via Transact-SQL) nur als copy-only Backups einer vollständigen Datenbank, Dateien und Dateigruppen erstellt werden. Das Erstellen inkrementeller Backups ist nicht unterstützt, was ein ernsthafter Rückstand ist gegenüber der Backup-Unterstützung physikalischer Standbys unter Oracle Data Guard. Hinweis: Ein möglicher Workaround via Snapshots, bleibt ein Workaround. Eine weitere Einschränkung dieses Features gegenüber Oracle Data Guard besteht darin, dass das Backup eines sekundären Replikats nicht ausgeführt werden kann, wenn es nicht mit dem primären Replikat kommunizieren kann. Darüber hinaus muss das sekundäre Replikat synchronisiert sein oder sich in der Synchronisation befinden, um das Beackup auf dem sekundären Replikat erstellen zu können.   Vergleich von Microsoft AlwaysOn mit der Oracle MAA Ich komme wieder zurück auf die Eingangs erwähnte, mehrfach an mich gestellte Frage "Wann denn - und ob überhaupt - Oracle etwas Vergleichbares wie AlwaysOn bieten würde?" und meine damit verbundene (kurze) Irritation. Wenn Sie diesen Blogbeitrag bis hierher gelesen haben, dann kennen Sie jetzt meine darauf gegebene Antwort. Der eine oder andere Punkt traf dabei nicht immer auf Jeden zu, was auch nicht der tiefere Sinn und Zweck meiner Antwort war. Wenn beispielsweise kein Multi-Subnet mit im Spiel ist, sind alle diesbezüglichen Kritikpunkte zunächst obsolet. Was aber nicht bedeutet, dass sie nicht bereits morgen schon wieder zum Thema werden könnten (Sag niemals "Nie"). In manch anderes Fettnäpfchen tritt man wiederum nicht unbedingt in einer Testumgebung, sondern erst im laufenden Betrieb. Erst recht nicht dann, wenn man sich potenzieller Probleme nicht bewusst ist und keine dedizierten Tests startet. Und wer AlwaysOn erfolgreich positionieren möchte, wird auch gar kein Interesse daran haben, auf mögliche Schwachstellen und den besagten Teufel im Detail aufmerksam zu machen. Das ist keine Unterstellung - es ist nur menschlich. Außerdem ist es verständlich, dass man sich in erster Linie darauf konzentriert "was geht" und "was gut läuft", anstelle auf das "was zu Problemen führen kann" oder "nicht funktioniert". Wer will schon der Miesepeter sein? Für mich selbst gesprochen, kann ich nur sagen, dass ich lieber vorab von allen möglichen Einschränkungen wissen möchte, anstelle sie dann nach einer kurzen Zeit der heilen Welt schmerzhaft am eigenen Leib erfahren zu müssen. Ich bin davon überzeugt, dass es Ihnen nicht anders geht. Nachfolgend deshalb eine Zusammenfassung all jener Punkte, die ich im Vergleich zur Oracle MAA (Maximum Availability Architecture) als unbedingt Erwähnenswert betrachte, falls man eine Evaluierung von Microsoft AlwaysOn in Betracht zieht. 1. AlwaysOn ist eine komplexe Technologie Der SQL Server AlwaysOn Stack ist zusammengesetzt aus drei verschiedenen Technlogien: Windows Server Failover Clustering (WSFC) SQL Server Failover Cluster Instances (FCI) SQL Server Availability Groups (Verfügbarkeitsgruppen) Man kann eine derartige Lösung nicht als nahtlos bezeichnen, wofür auch die vielen von Microsoft dargestellten Einschränkungen sprechen. Während sich frühere SQL Server Versionen in Richtung eigener HA/DR Technologien entwickelten (wie Database Mirroring), empfiehlt Microsoft nun die Migration. Doch weshalb dieser Schwenk? Er führt nicht zu einem konsisten und robusten Angebot an HA/DR Technologie für geschäftskritische Umgebungen.  Liegt die Antwort in meiner These begründet, nach der "Windows was the God ..." noch immer gilt und man die Nachteile der allzu engen Kopplung mit Windows nicht sehen möchte? Entscheiden Sie selbst ... 2. Failover Cluster Instanzen - Kein RAC-Pendant Die SQL Server und Windows Server Clustering Technologie basiert noch immer auf dem veralteten Aktiv-Passiv Modell und führt zu einer Verschwendung von Systemressourcen. In einer Betrachtung von lediglich zwei Knoten erschließt sich auf Anhieb noch nicht der volle Mehrwert eines Aktiv-Aktiv Clusters (wie den Real Application Clusters), wie er von Oracle bereits vor zehn Jahren entwickelt wurde. Doch kennt man die Vorzüge der Skalierbarkeit durch einfaches Hinzufügen weiterer Cluster-Knoten, die dann alle gemeinsam als ein einziges logisches System zusammenarbeiten, versteht man was hinter dem Motto "Pay-as-you-Grow" steckt. In einem Aktiv-Aktiv Cluster geht es zwar auch um Hochverfügbarkeit - und ein Failover erfolgt zudem schneller, als in einem Aktiv-Passiv Modell - aber es geht eben nicht nur darum. An dieser Stelle sei darauf hingewiesen, dass die Oracle 11g Standard Edition bereits die Nutzung von Oracle RAC bis zu vier Sockets kostenfrei beinhaltet. Möchten Sie dazu Windows nutzen, benötigen Sie keine Windows Server Enterprise Edition, da Oracle 11g die eigene Clusterware liefert. Sie kommen in den Genuss von Hochverfügbarkeit und Skalierbarkeit und können dazu die günstigere Windows Server Standard Edition nutzen. 3. SQL Server Multi-Subnet Clustering - Abhängigkeit zu 3rd Party Storage Mirroring  Die SQL Server Multi-Subnet Clustering Architektur unterstützt den Aufbau eines Stretch Clusters, basiert dabei aber auf dem Aktiv-Passiv Modell. Das eigentlich Problematische ist jedoch, dass man sich zur Absicherung der Datenbank auf 3rd Party Storage Mirroring Technologie verlässt, ohne Integration zwischen dem Windows Server Failover Clustering (WSFC) und der darunterliegenden Mirroring Technologie. Wenn nun im Cluster ein Failover auf Instanzen-Ebene erfolgt, existiert keine Koordination mit einem möglichen Failover auf Ebene des Storage-Array. 4. Availability Groups (Verfügbarkeitsgruppen) - Vier, oder doch nur Zwei? Ein primäres Replikat erlaubt bis zu vier sekundäre Replikate innerhalb einer Verfügbarkeitsgruppe, jedoch nur zwei im Synchronen Commit Modus. Während dies zwar einen Vorteil gegenüber dem stringenten 1:1 Modell unter Database Mirroring darstellt, fällt der SQL Server 2012 damit immer noch weiter zurück hinter Oracle Data Guard mit bis zu 30 direkten Stanbdy Zielen - und vielen weiteren durch kaskadierende Ziele möglichen. Damit eignet sich Oracle Active Data Guard auch für die Bereitstellung einer Reader-Farm Skalierbarkeit für Internet-basierende Unternehmen. Mit AwaysOn Verfügbarkeitsgruppen ist dies nicht möglich. 5. Availability Groups (Verfügbarkeitsgruppen) - kein asynchrones Switchover  Die Technologie der Verfügbarkeitsgruppen wird auch als geeignetes Mittel für administrative Aufgaben positioniert - wie Upgrades oder Wartungsarbeiten. Man muss sich jedoch einem gravierendem Defizit bewusst sein: Im asynchronen Verfügbarkeitsmodus besteht die einzige Möglichkeit für Role Transition im Forced Failover mit Datenverlust! Um den Verlust von Daten durch geplante Wartungsarbeiten zu vermeiden, muss man den synchronen Verfügbarkeitsmodus konfigurieren, was jedoch ernstzunehmende Auswirkungen auf WAN Deployments nach sich zieht. Spinnt man diesen Gedanken zu Ende, kommt man zu dem Schluss, dass die Technologie der Verfügbarkeitsgruppen für geplante Wartungsarbeiten in einem derartigen Umfeld nicht effektiv genutzt werden kann. 6. Automatisches Failover - Nicht immer möglich Sowohl die SQL Server FCI, als auch Verfügbarkeitsgruppen unterstützen automatisches Failover. Möchte man diese jedoch kombinieren, wird das Ergebnis kein automatisches Failover sein. Denn ihr Zusammentreffen im Failover-Fall führt zu Race Conditions (Wettlaufsituationen), weshalb diese Konfiguration nicht länger das automatische Failover zu einem Replikat in einer Verfügbarkeitsgruppe erlaubt. Auch hier bestätigt sich wieder die tiefere Problematik von AlwaysOn, mit einer Zusammensetzung aus unterschiedlichen Technologien und der Abhängigkeit zu Windows. 7. Problematische RTO (Recovery Time Objective) Microsoft postioniert die SQL Server Multi-Subnet Clustering Architektur als brauchbare HA/DR Architektur. Bedenkt man jedoch die Problematik im Zusammenhang mit DNS Replikation und den möglichen langen Wartezeiten auf Client-Seite von bis zu 16 Minuten, sind strenge RTO Anforderungen (Recovery Time Objectives) nicht erfüllbar. Im Gegensatz zu Oracle besitzt der SQL Server keine Datenbank-integrierten Technologien, wie Oracle Fast Application Notification (FAN) oder Oracle Fast Connection Failover (FCF). 8. Problematische RPO (Recovery Point Objective) SQL Server ermöglicht Forced Failover (erzwungenes Failover), bietet jedoch keine Möglichkeit zur automatischen Übertragung der letzten Datenbits von einem alten zu einem neuen primären Replikat, wenn der Verfügbarkeitsmodus asynchron war. Oracle Data Guard hingegen bietet diese Unterstützung durch das Flush Redo Feature. Dies sichert "Zero Data Loss" und beste RPO auch in erzwungenen Failover-Situationen. 9. Lesbare Sekundäre Replikate mit Einschränkungen Aufgrund des Snapshot Isolation Transaction Level für lesbare sekundäre Replikate, besitzen diese Einschränkungen mit Auswirkung auf die primäre Datenbank. Die Bereinigung von Ghost Records auf der primären Datenbank, wird beeinflusst von lang laufenden Abfragen auf der lesabaren sekundären Datenbank. Die lesbare sekundäre Datenbank kann nicht in die Verfügbarkeitsgruppe aufgenommen werden, wenn es aktive Transaktionen auf der primären Datenbank gibt. Zusätzlich können DLL Änderungen auf der primären Datenbank durch Abfragen auf der sekundären blockiert werden. Und imkrementelle Backups werden hier nicht unterstützt.   Keine dieser Restriktionen existiert unter Oracle Data Guard.

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