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  • PWC1406: Servlet.service() threw exception java.io.IOException: Invalid chunk header When client se

    - by Nivek
    I am developing an application using J2ME to send the GPS coordinates received to the server and i am new to developing client server application. Everything works fine with the use of Nokia N97mini or E71. But when i tried it on HTC HD2, i get the exception from the server. I am using Netbeans 6.5.1 GlassFish V2 as Server. I have no idea why this error occurs only on the HTC HD2. Any help will be greatly appreciated. Thanks... Below is the error message: StandardWrapperValve[FindHospitalServlet]: PWC1406: Servlet.service() for servlet FindHospitalServlet threw exception java.io.IOException: Invalid chunk header at org.apache.coyote.http11.filters.ChunkedInputFilter.doRead(ChunkedInputFilter.java:171) at org.apache.coyote.http11.InternalInputBuffer.doRead(InternalInputBuffer.java:719) at org.apache.coyote.Request.doRead(Request.java:482) at org.apache.coyote.tomcat5.InputBuffer.realReadBytes(InputBuffer.java:342) at org.apache.tomcat.util.buf.ByteChunk.substract(ByteChunk.java:378) at org.apache.coyote.tomcat5.InputBuffer.readByte(InputBuffer.java:351) at org.apache.coyote.tomcat5.CoyoteInputStream.read(CoyoteInputStream.java:159) at java.io.DataInputStream.readUnsignedShort(DataInputStream.java:320) at java.io.DataInputStream.readUTF(DataInputStream.java:572) at java.io.DataInputStream.readUTF(DataInputStream.java:547) at myPackage.FindHospitalServlet.doPost(FindHospitalServlet.java:28) at javax.servlet.http.HttpServlet.service(HttpServlet.java:754) at javax.servlet.http.HttpServlet.service(HttpServlet.java:847) at org.apache.catalina.core.ApplicationFilterChain.servletService(ApplicationFilterChain.java:427) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:315) at org.apache.catalina.core.StandardContextValve.invokeInternal(StandardContextValve.java:287) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:218) at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:648) at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:593) at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:94) at com.sun.enterprise.web.PESessionLockingStandardPipeline.invoke(PESessionLockingStandardPipeline.java:98) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:222) at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:648) at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:593) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:587) at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:1096) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:166) at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:648) at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:593) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:587) at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:1096) at org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:288) at com.sun.enterprise.web.connector.grizzly.DefaultProcessorTask.invokeAdapter(DefaultProcessorTask.java:647) at com.sun.enterprise.web.connector.grizzly.DefaultProcessorTask.doProcess(DefaultProcessorTask.java:579) at com.sun.enterprise.web.connector.grizzly.DefaultProcessorTask.process(DefaultProcessorTask.java:831) at com.sun.enterprise.web.connector.grizzly.DefaultReadTask.executeProcessorTask(DefaultReadTask.java:341) at com.sun.enterprise.web.connector.grizzly.DefaultReadTask.doTask(DefaultReadTask.java:263) at com.sun.enterprise.web.connector.grizzly.DefaultReadTask.doTask(DefaultReadTask.java:214) at com.sun.enterprise.web.portunif.PortUnificationPipeline$PUTask.doTask(PortUnificationPipeline.java:380) at com.sun.enterprise.web.connector.grizzly.TaskBase.run(TaskBase.java:265) at com.sun.enterprise.web.connector.grizzly.ssl.SSLWorkerThread.run(SSLWorkerThread.java:106) Below is the code that i wrote to connect to the server: private void connectFindHospServlet() { String url = "http://172.22.190.13:8080/UpdateServlet/FindHospitalServlet"; StringBuffer sb = new StringBuffer(); String info = lat+"!"+lng+"!"; try { HttpConnection c = (HttpConnection) Connector.open(url); c.setRequestProperty("User-Agent","Profile/MIDP-2.0, Configuration/CLDC-1.0"); c.setRequestProperty("Content-Language","en-US"); c.setRequestMethod(HttpConnection.POST); DataOutputStream os = (DataOutputStream)c.openDataOutputStream(); os.writeUTF(info); os.flush(); os.close(); // Get the response from the servlet page. DataInputStream is =(DataInputStream)c.openDataInputStream(); int ch; sb = new StringBuffer(); while ((ch = is.read()) != -1) sb.append((char)ch); is.close(); c.close(); if(sb.toString().charAt(0) == 'n') { formDisplayResultFindHosp(); display.setCurrent(formDisplayResultFindHosp); } else { PlannerMain pm = new PlannerMain(); hospInfo = pm.getFindHospInfo(sb.toString().substring(0, sb.length()-2)); formDisplayResultFindHosp(hospInfo); display.setCurrent(formDisplayResultFindHosp); } } catch (Exception e) { System.out.println("Error recieve find user"); } } Any information needed to better help in understanding the problem, do let me know. I will try to provide as much as possible.

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  • Calling webservice from WCF service

    - by Balaji
    I am having an issue consuming a webservice (c#.net) from a WCF service. The error i am getting is EndPointNotFoundException "TCP error code 10061: No connection could be made because the target machine actively refused it" I wrote a unit test to check if i could send a request to the web service and it worked fine [The unit test is using the same binding configuration as my WCF service] The web service and WCF service (client) have basichttp binding. Did anyone had similar kind of issue calling a webservice from a WCF service? The service Model section is as follows <system.serviceModel> <bindings> <basicHttpBinding> <binding name="DataService" closeTimeout="00:05:00" openTimeout="00:05:00" receiveTimeout="00:10:00" sendTimeout="00:05:00" allowCookies="false" bypassProxyOnLocal="false" hostNameComparisonMode="StrongWildcard" maxBufferSize="65536" maxBufferPoolSize="524288" maxReceivedMessageSize="65536" messageEncoding="Text" textEncoding="utf-8" transferMode="Buffered" useDefaultWebProxy="true"> <readerQuotas maxDepth="32" maxStringContentLength="8192" maxArrayLength="16384" maxBytesPerRead="4096" maxNameTableCharCount="16384"/> <security mode="None"> <transport clientCredentialType="None" proxyCredentialType="None" realm=""/> <message clientCredentialType="UserName" algorithmSuite="Default"/> </security> </binding> </basicHttpBinding> </bindings> <client> <endpoint address="http://10.22.33.67/Service/DataService.asmx" binding="basicHttpBinding" bindingConfiguration="DataService" contract="Service.DataService" name="DataService"/> </client> <services> <service name="TestToConsumeDataService.WCFHost.Service1" behaviorConfiguration="TestToConsumeDataService.WCFHost.Service1Behavior"> <!-- Service Endpoints --> <endpoint address="" binding="basicHttpBinding" contract="TestToConsumeDataService.WCFHost.IService1"> <!-- Upon deployment, the following identity element should be removed or replaced to reflect the identity under which the deployed service runs. If removed, WCF will infer an appropriate identity automatically. --> <identity> <dns value="localhost"/> </identity> </endpoint> <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange"/> </service> </services> <behaviors> <serviceBehaviors> <behavior name="TestToConsumeDataService.WCFHost.Service1Behavior"> <!-- To avoid disclosing metadata information, set the value below to false and remove the metadata endpoint above before deployment --> <serviceMetadata httpGetEnabled="true"/> <!-- To receive exception details in faults for debugging purposes, set the value below to true. Set to false before deployment to avoid disclosing exception information --> <serviceDebug includeExceptionDetailInFaults="false"/> </behavior> </serviceBehaviors> </behaviors> </system.serviceModel> The unit test project is also using the same service model section and it works. The only issue is while calling the service from another WCF service. Could you please suggest.

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  • RSS feed doesnt display items. Only title

    - by Quaze
    So i just made my first RSS feed, or so i tought, in combination with CI. Now my view DOES display the top of my rss page (Title and Description), But all items are omitted. When i rightclick-view source it DOES contain all the items within the item tags. Can anyone help me? View (rss.php): <?php echo '<?xml version="1.0" encoding="'.$encoding.'"?>'."\n"; ?> <rss version="2.0" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:sy="http://purl.org/rss/1.0/modules/syndication/" xmlns:admin="http://webns.net/mvcb/" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:content="http://purl.org/rss/1.0/modules/content/"> <channel> <title><?php echo $feed_name; ?></title> <link><?php echo $feed_url; ?></link> <description><?php echo $page_description; ?></description> <dc:language><?php echo $page_language; ?></dc:language> <dc:creator><?php echo $creator_email; ?></dc:creator> <dc:rights>Copyright <?php echo gmdate("%Y", time()); ?></dc:rights> <dc:date><?php echo gmdate("%Y-%m-&#xdT;%H:%i:%s%Q", time()); ?></dc:date> <admin:generatorAgent rdf:resource="http://www.codeigniter.com/" /> <?php foreach($items as $entry): ?> <?php $entry_url = base_url().$this->lang->lang().$localized_news[$this->lang->lang()].'/'.print_date(strtotime($entry->published), "{year}/{month2}").'/'.$entry->slug; ?> <item> <title><?php echo xml_convert($entry->title); ?></title> <link><?php echo $entry_url; ?></link> <guid><?php echo $entry_url; ?></guid> <description><?php echo $entry->summary; ?></description> <pubDate><?php echo date('r', $entry->published); ?></pubDate> </item> <?php endforeach; ?> </channel> This is what the output looks like: screenshot and in the source, every item needed to be displayed is there. with <item> <link> <description> <guid> and <pubdate> tags. Ive been looking for the cause for about 1.5 hours now. and i cant find anything. Can someone tell me if i did anything wrong? Appreciate the help! ~Menno

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  • loading xml into SQL Server 2008 using sqlbulkload component

    - by mohamed
    "Error: Schema: relationship expected on 'headerRecord'." I get the above error while load xml file to SQL Server 2008 using SQLXMLBulkLoad4 Component , the xml file contains Call Detail records, I have generated schema file from xml file using both , Dataset and XSD.exe tool, but the error remains same., if there is another way to imports xml file with multiple tables that have relationship in each file into SQL Server 2008? . Here the xml file: <CallEventDataFile> <headerRecord> <productionDateTime>0912021247482B0300</productionDateTime> <recordingEntity>00</recordingEntity> <extensions/> </headerRecord> <callEventRecords> <mtSMSRecord> <recordType>7</recordType> <serviceCentre>91521230</serviceCentre> <servedIMSI>36570000031728F2</servedIMSI> <servedIMEI>53886000707896F0</servedIMEI> <servedMSISDN>915212454503F2</servedMSISDN> <msClassmark>3319A1</msClassmark> <recordingEntity>915212110100</recordingEntity> <location> <locationAreaCode>0006</locationAreaCode> <cellIdentifier>0C6E</cellIdentifier> </location> <deliveryTime>0912021535412B0300</deliveryTime> <systemType> <gERAN/> </systemType> <basicService> <teleservice>21</teleservice> </basicService> <additionalChgInfo> <chargeIndicator>2</chargeIndicator> </additionalChgInfo> <chargedParty> <calledParty/> </chargedParty> <orgRNCorBSCId>8E1A</orgRNCorBSCId> <orgMSCId>921A</orgMSCId> <globalAreaID>36F70500060C6E</globalAreaID> <subscriberCategory>0A</subscriberCategory> <firstmccmnc>36F705</firstmccmnc> <smsUserDataType>FF</smsUserDataType> <origination>8191F2</origination> <callReference>1605EB2FE1</callReference> </mtSMSRecord> <moSMSRecord> <recordType>6</recordType> <servedIMSI>36570000238707F9</servedIMSI> <servedIMEI>53928320195925F0</servedIMEI> <servedMSISDN>915212159430F2</servedMSISDN> <msClassmark>3319A2</msClassmark> <serviceCentre>91521230</serviceCentre> <recordingEntity>915212110100</recordingEntity> <location> <locationAreaCode>001B</locationAreaCode> <cellIdentifier>6983</cellIdentifier> </location> <messageReference>01</messageReference> <originationTime>0912021535412B0300</originationTime> <destinationNumber>8111F1</destinationNumber> <systemType> <gERAN/> </systemType> <basicService> <teleservice>22</teleservice> </basicService> <additionalChgInfo> <chargeIndicator>2</chargeIndicator> </additionalChgInfo> <chargedParty> <callingParty/> </chargedParty> <orgRNCorBSCId>8F1A</orgRNCorBSCId> <orgMSCId>921A</orgMSCId> <globalAreaID>36F705001B6983</globalAreaID> <subscriberCategory>0A</subscriberCategory> <firstmccmnc>36F705</firstmccmnc> <smsUserDataType>FF</smsUserDataType> <callReference>1701BED4FF</callReference> </moSMSRecord> <ssActionRecord> <recordType>10</recordType> <servedIMSI>36570000636448F8</servedIMSI> <servedIMEI>53246030714961F0</servedIMEI> <servedMSISDN>915212056928F8</servedMSISDN> <msClassmark>3018A1</msClassmark> <recordingEntity>915212110100</recordingEntity> <location> <locationAreaCode>000C</locationAreaCode> <cellIdentifier>05A5</cellIdentifier> </location> <supplService>FF</supplService> <ssAction> <ussdInvocation/> </ssAction> <ssActionTime>0912021535412B0300</ssActionTime> <ssParameters> <unstructuredData>AA5C2E3702</unstructuredData> </ssParameters> <callReference>1701BED500</callReference> <systemType> <gERAN/> </systemType> <ussdCodingScheme>0F</ussdCodingScheme> <ussdString> <UssdString>AA5C2E3702</UssdString> </ussdString> <ussdRequestCounter>1</ussdRequestCounter> <additionalChgInfo> <chargeIndicator>1</chargeIndicator> </additionalChgInfo> <orgRNCorBSCId>8E1A</orgRNCorBSCId> <orgMSCId>921A</orgMSCId> <globalAreaID>36F705000C05A5</globalAreaID> <subscriberCategory>0A</subscriberCategory> <firstmccmnc>36F705</firstmccmnc> </ssActionRecord> <moCallRecord> <recordType>0</recordType> <servedIMSI>36570000807501F5</servedIMSI> <servedIMEI>53246030713955F0</servedIMEI> <servedMSISDN>915212157901F0</servedMSISDN> <callingNumber>A151911700</callingNumber> <calledNumber>8151677589</calledNumber> <roamingNumber>A111113850</roamingNumber> <recordingEntity>915212110100</recordingEntity> <mscIncomingROUTE> <rOUTEName>HWBSC2</rOUTEName> </mscIncomingROUTE> <mscOutgoingROUTE> <rOUTEName>HWBSC2</rOUTEName> </mscOutgoingROUTE> <location> <locationAreaCode>0006</locationAreaCode> <cellIdentifier>0C2F</cellIdentifier> </location> <basicService> <teleservice>11</teleservice> </basicService> <msClassmark>3319A1</msClassmark> <answerTime>0912021535382B0300</answerTime> <releaseTime>0912021535422B0300</releaseTime> <callDuration>4</callDuration> <radioChanRequested> <dualFullRatePreferred/> </radioChanRequested> <radioChanUsed> <halfRate/> </radioChanUsed> <causeForTerm>0</causeForTerm> <diagnostics> <gsm0408Cause>144</gsm0408Cause> </diagnostics> <callReference>1701BED501</callReference> <additionalChgInfo> <chargeIndicator>2</chargeIndicator> </additionalChgInfo> <gsm-SCFAddress>915212110130</gsm-SCFAddress> <serviceKey>1</serviceKey> <networkCallReference>171D555132</networkCallReference> <mSCAddress>915212110100</mSCAddress> <speechVersionSupported>25</speechVersionSupported> <speechVersionUsed>21</speechVersionUsed> <numberOfDPEncountered>3</numberOfDPEncountered> <levelOfCAMELService>01</levelOfCAMELService> <freeFormatData>800130</freeFormatData> <systemType> <gERAN/> </systemType> <classmark3>C000</classmark3> <chargedParty> <callingParty/> </chargedParty> <mscOutgoingCircuit>1051</mscOutgoingCircuit> <orgRNCorBSCId>8E1A</orgRNCorBSCId> <orgMSCId>921A</orgMSCId> <calledIMSI>36570000635618F8</calledIMSI> <globalAreaID>36F70500060C2F</globalAreaID> <subscriberCategory>0A</subscriberCategory> <firstmccmnc>36F705</firstmccmnc> <lastmccmnc>36F705</lastmccmnc> </moCallRecord> <mtCallRecord> <recordType>1</recordType> <servedIMSI>36570000635618F8</servedIMSI> <servedIMEI>53464010474309F0</servedIMEI> <servedMSISDN>915212755697F8</servedMSISDN> <callingNumber>A151911700</callingNumber> <recordingEntity>915212110100</recordingEntity> <mscIncomingROUTE> <rOUTEName>HWBSC2</rOUTEName> </mscIncomingROUTE> <mscOutgoingROUTE> <rOUTEName>HWBSC2</rOUTEName> </mscOutgoingROUTE> <location> <locationAreaCode>0006</locationAreaCode> <cellIdentifier>0C2D</cellIdentifier> </location> <basicService> <teleservice>11</teleservice> </basicService> <supplServicesUsed> <SuppServiceUsedid> <ssCode>11</ssCode> <ssTime>0912021535382B0300</ssTime> </SuppServiceUsedid> </supplServicesUsed> <msClassmark>331981</msClassmark> <answerTime>0912021535382B0300</answerTime> <releaseTime>0912021535422B0300</releaseTime> <callDuration>4</callDuration> <radioChanRequested> <dualFullRatePreferred/> </radioChanRequested> <radioChanUsed> <halfRate/> </radioChanUsed> <causeForTerm>0</causeForTerm> <diagnostics> <gsm0408Cause>144</gsm0408Cause> </diagnostics> <callReference>1701BED502</callReference> <additionalChgInfo> <chargeIndicator>2</chargeIndicator> </additionalChgInfo> <networkCallReference>171D555132</networkCallReference> <mSCAddress>915212110100</mSCAddress> <speechVersionSupported>25</speechVersionSupported> <speechVersionUsed>21</speechVersionUsed> <systemType> <gERAN/> </systemType> <classmark3>C000</classmark3> <chargedParty> <calledParty/> </chargedParty> <roamingNumber>A111113850</roamingNumber> <mscIncomingCircuit>9119</mscIncomingCircuit> <orgRNCorBSCId>8E1A</orgRNCorBSCId> <orgMSCId>921A</orgMSCId> <globalAreaID>36F70500060C2D</globalAreaID> <subscriberCategory>0A</subscriberCategory> <firstmccmnc>36F705</firstmccmnc> <lastmccmnc>36F705</lastmccmnc> </mtCallRecord> <incGatewayRecord> <recordType>3</recordType> <callingNumber>A17005991565</callingNumber> <calledNumber>A1853643F7</calledNumber> <recordingEntity>915212110100</recordingEntity> <mscIncomingROUTE> <rOUTEName>ZPSTN</rOUTEName> </mscIncomingROUTE> <mscOutgoingROUTE> <rOUTEName>ZTEBSC3</rOUTEName> </mscOutgoingROUTE> <answerTime>0912021535302B0300</answerTime> <releaseTime>0912021535422B0300</releaseTime> <callDuration>12</callDuration> <causeForTerm>0</causeForTerm> <diagnostics> <gsm0408Cause>144</gsm0408Cause> </diagnostics> <callReference>2203AFBF84</callReference> <basicService> <teleservice>11</teleservice> </basicService> <additionalChgInfo> <chargeIndicator>2</chargeIndicator> </additionalChgInfo> <roamingNumber>A111111980</roamingNumber> <mscIncomingCircuit>934</mscIncomingCircuit> <orgMSCId>921A</orgMSCId> <mscIncomingRouteAttribute> <isup/> </mscIncomingRouteAttribute> <networkCallReference>22432B5132</networkCallReference> </incGatewayRecord> <outGatewayRecord> <recordType>4</recordType> <callingNumber>A151012431</callingNumber> <calledNumber>817026936873</calledNumber> <recordingEntity>915212110100</recordingEntity> <mscIncomingROUTE> <rOUTEName>HWBSC</rOUTEName> </mscIncomingROUTE> <mscOutgoingROUTE> <rOUTEName>ZPSTN</rOUTEName> </mscOutgoingROUTE> <answerTime>0912021535192B0300</answerTime> <releaseTime>0912021535432B0300</releaseTime> <callDuration>24</callDuration> <causeForTerm>0</causeForTerm> <diagnostics> <gsm0408Cause>144</gsm0408Cause> </diagnostics> <callReference>2303B19880</callReference> <basicService> <teleservice>11</teleservice> </basicService> <additionalChgInfo> <chargeIndicator>2</chargeIndicator> </additionalChgInfo> <mscOutgoingCircuit>398</mscOutgoingCircuit> <orgMSCId>921A</orgMSCId> <mscOutgoingRouteAttribute> <isup/> </mscOutgoingRouteAttribute> <networkCallReference>238BE55132</networkCallReference> </outGatewayRecord> </callEventRecords> <trailerRecord> <productionDateTime>0912021247512B0300</productionDateTime> <recordingEntity>00</recordingEntity> <firstCallDateTime>000000000000000000</firstCallDateTime> <lastCallDateTime>000000000000000000</lastCallDateTime> <noOfRecords>521</noOfRecords> <extensions/> </trailerRecord> <extensions/> </CallEventDataFile> Schema File generated by Dataset: <?xml version="1.0" standalone="yes"?> <xs:schema id="NewDataSet" xmlns="" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata"> <xs:element name="location"> <xs:complexType> <xs:sequence> <xs:element name="locationAreaCode" type="xs:string" minOccurs="0" /> <xs:element name="cellIdentifier" type="xs:string" minOccurs="0" /> </xs:sequence> </xs:complexType> </xs:element> <xs:element name="systemType"> <xs:complexType> <xs:sequence> <xs:element name="gERAN" type="xs:string" minOccurs="0" /> </xs:sequence> </xs:complexType> </xs:element> <xs:element name="basicService"> <xs:complexType> <xs:sequence> <xs:element name="teleservice" type="xs:string" minOccurs="0" /> </xs:sequence> </xs:complexType> </xs:element> <xs:element name="additionalChgInfo"> <xs:complexType> <xs:sequence> <xs:element name="chargeIndicator" type="xs:string" minOccurs="0" /> </xs:sequence> </xs:complexType> </xs:element> <xs:element name="chargedParty"> <xs:complexType> <xs:sequence> <xs:element name="calledParty" type="xs:string" minOccurs="0" /> <xs:element name="callingParty" type="xs:string" minOccurs="0" /> </xs:sequence> </xs:complexType> </xs:element> <xs:element name="mscIncomingROUTE"> <xs:complexType> <xs:sequence> <xs:element name="rOUTEName" type="xs:string" minOccurs="0" /> </xs:sequence> </xs:complexType> </xs:element> <xs:element name="mscOutgoingROUTE"> <xs:complexType> <xs:sequence> <xs:element name="rOUTEName" type="xs:string" minOccurs="0" /> </xs:sequence> </xs:complexType> </xs:element> <xs:element name="radioChanRequested"> <xs:complexType> <xs:sequence> <xs:element name="dualFullRatePreferred" type="xs:string" minOccurs="0" /> </xs:sequence> </xs:complexType> </xs:element> <xs:element name="radioChanUsed"> <xs:complexType> <xs:sequence> <xs:element name="halfRate" type="xs:string" minOccurs="0" /> </xs:sequence> </xs:complexType> </xs:element> <xs:element name="diagnostics"> <xs:complexType> <xs:sequence> <xs:element name="gsm0408Cause" type="xs:string" minOccurs="0" /> </xs:sequence> </xs:complexType> </xs:element> <xs:element name="CallEventDataFile"> <xs:complexType> <xs:sequence> <xs:element name="extensions" type="xs:string" minOccurs="0" /> <xs:element name="headerRecord" minOccurs="0" maxOccurs="unbounded"> <xs:complexType> <xs:sequence> <xs:element name="productionDateTime" type="xs:string" minOccurs="0" /> <xs:element name="recordingEntity" type="xs:string" minOccurs="0" /> <xs:element name="extensions" type="xs:string" minOccurs="0" /> </xs:sequence> </xs:complexType> </xs:element> <xs:element name="callEventRecords" minOccurs="0" maxOccurs="unbounded"> <xs:complexType> <xs:sequence> <xs:element name="mtSMSRecord" minOccurs="0" maxOccurs="unbounded"> <xs:complexType> <xs:sequence> <xs:element name="recordType" type="xs:string" minOccurs="0" /> <xs:element name="serviceCentre" type="xs:string" minOccurs="0" /> <xs:element name="servedIMSI" type="xs:string" minOccurs="0" /> <xs:element name="servedIMEI" type="xs:string" minOccurs="0" /> <xs:element name="servedMSISDN" type="xs:string" minOccurs="0" /> <xs:element name="msClassmark" type="xs:string" minOccurs="0" /> <xs:element name="recordingEntity" type="xs:string" minOccurs="0" /> <xs:element name="deliveryTime" type="xs:string" minOccurs="0" /> <xs:element name="orgRNCorBSCId" type="xs:string" minOccurs="0" /> <xs:element name="orgMSCId" type="xs:string" minOccurs="0" /> <xs:element name="globalAreaID" type="xs:string" minOccurs="0" /> <xs:element name="subscriberCategory" type="xs:string" minOccurs="0" /> <xs:element name="firstmccmnc" type="xs:string" minOccurs="0" /> <xs:element name="smsUserDataType" type="xs:string" minOccurs="0" /> <xs:element name="origination" type="xs:string" minOccurs="0" /> <xs:element name="callReference" type="xs:string" minOccurs="0" /> <xs:element ref="location" minOccurs="0" maxOccurs="unbounded" /> <xs:element ref="systemType" minOccurs="0" maxOccurs="unbounded" /> <xs:element ref="basicService" minOccurs="0" maxOccurs="unbounded" /> <xs:element ref="additionalChgInfo" minOccurs="0" maxOccurs="unbounded" /> <xs:element ref="chargedParty" minOccurs="0" maxOccurs="unbounded" /> </xs:sequence> </xs:complexType> </xs:element> <xs:element name="moSMSRecord" minOccurs="0" maxOccurs="unbounded"> <xs:complexType> <xs:sequence> <xs:element name="recordType" type="xs:string" minOccurs="0" /> <xs:element name="servedIMSI" type="xs:string" minOccurs="0" /> <xs:element name="servedIMEI" type="xs:string" minOccurs="0" /> <xs:element name="servedMSISDN" type="xs:string" minOccurs="0" /> <xs:element name="msClassmark" type="xs:string" minOccurs="0" /> <xs:element name="serviceCentre" type="xs:string" minOccurs="0" /> <xs:element name="recordingEntity" type="xs:string" minOccurs="0" /> <xs:element name="messageReference" type="xs:string" minOccurs="0" /> <xs:element name="originationTime" type="xs:string" minOccurs="0" /> <xs:element name="destinationNumber" type="xs:string" minOccurs="0" /> <xs:element name="orgRNCorBSCId" type="xs:string" minOccurs="0" /> <xs:element name="orgMSCId" type="xs:string" minOccurs="0" /> <xs:element name="globalAreaID" type="xs:string" minOccurs="0" /> <xs:element name="subscriberCategory" type="xs:string" minOccurs="0" /> <xs:element name="firstmccmnc" type="xs:string" minOccurs="0" /> <xs:element name="smsUserDataType" type="xs:string" minOccurs="0" /> <xs:element name="callReference" type="xs:string" minOccurs="0" /> <xs:element ref="location" minOccurs="0" maxOccurs="unbounded" /> <xs:element ref="systemType" minOccurs="0" maxOccurs="unbounded" /> <xs:element ref="basicService" minOccurs="0" maxOccurs="unbounded" /> <xs:element ref="additionalChgInfo" minOccurs="0" maxOccurs="unbounded" /> <xs:element ref="chargedParty" minOccurs="0" maxOccurs="unbounded" /> </xs:sequence> </xs:complexType> </xs:element> <xs:element name="ssActionRecord" minOccurs="0" maxOccurs="unbounded"> <xs:complexType> <xs:sequence> <xs:element name="recordType" type="xs:string" minOccurs="0" /> <xs:element name="servedIMSI" type="xs:string" minOccurs="0" /> <xs:element name="servedIMEI" type="xs:string" minOccurs="0" /> <xs:element name="servedMSISDN" type="xs:string" minOccurs="0" /> <xs:element name="msClassmark" type="xs:string" minOccurs="0" /> <xs:element name="recordingEntity" type="xs:string" minOccurs="0" /> <xs:element name="supplService" type="xs:string" minOccurs="0" /> <xs:element name="ssActionTime" type="xs:string" minOccurs="0" /> <xs:element name="callReference" type="xs:string" minOccurs="0" /> <xs:element name="ussdCodingScheme" type="xs:string" minOccurs="0" /> <xs:element name="ussdRequestCounter" type="xs:string" minOccurs="0" /> <xs:element name="orgRNCorBSCId" type="xs:string" minOccurs="0" /> <xs:element name="orgMSCId" type="xs:string" minOccurs="0" /> <xs:element name="globalAreaID" type="xs:string" minOccurs="0" /> <xs:element name="subscriberCategory" type="xs:string" minOccurs="0" /> <xs:element name="firstmccmnc" type="xs:string" minOccurs="0" /> <xs:element ref="location" minOccurs="0" maxOccurs="unbounded" /> <xs:element name="ssAction" minOccurs="0" maxOccurs="unbounded"> <xs:complexType> <xs:sequence> <xs:element name="ussdInvocation" type="xs:string" minOccurs="0" /> </xs:sequence> </xs:complexType> </xs:element> <xs:element name="ssParameters" minOccurs="0" maxOccurs="unbounded"> <xs:complexType> <xs:sequence> <xs:element name="unstructuredData" type="xs:string" minOccurs="0" /> </xs:sequence> </xs:complexType> </xs:element> <xs:element ref="systemType" minOccurs="0" maxOccurs="unbounded" /> <xs:element name="ussdString" minOccurs="0" maxOccurs="unbounded"> <xs:complexType> <xs:sequence> <xs:element name="UssdString" type="xs:string" minOccurs="0" /> </xs:sequence> </xs:complexType> </xs:element> <xs:element ref="additionalChgInfo" minOccurs="0" maxOccurs="unbounded" /> </xs:sequence> </xs:complexType> </xs:element> <xs:element name="moCallRecord" minOccurs="0" maxOccurs="unbounded"> <xs:complexType> <xs:sequence> <xs:element name="recordType" type="xs:string" minOccurs="0" /> <xs:element name="servedIMSI" type="xs:string" minOccurs="0" /> <xs:element name="servedIMEI" type="xs:string" minOccurs="0" /> <xs:element name="servedMSISDN" type="xs:string" minOccurs="0" /> <xs:element name="callingNumber" type="xs:string" minOccurs="0" /> <xs:element name="calledNumber" type="xs:string" minOccurs="0" /> <xs:element name="roamingNumber" type="xs:string" minOccurs="0" /> <xs:element name="recordingEntity" type="xs:string" minOccurs="0" /> <xs:element name="msClassmark" type="xs:string" minOccurs="0" /> <xs:element name="answerTime" type="xs:string" minOccurs="0" /> <xs:element name="releaseTime" type="xs:string" minOccurs="0" /> <xs:element name="callDuration" type="xs:string" minOccurs="0" /> <xs:element name="causeForTerm" type="xs:string" minOccurs="0" /> <xs:element name="callReference" type="xs:string" minOccurs="0" /> <xs:element name="gsm-SCFAddress" type="xs:string" minOccurs="0" /> <xs:element name="serviceKey" type="xs:string" minOccurs="0" /> <xs:element name="networkCallReference" type="xs:string" minOccurs="0" /> <xs:element name="mSCAddress" type="xs:string" minOccurs="0" /> <xs:element name="speechVersionSupported" type="xs:string" minOccurs="0" /> <xs:element name="speechVersionUsed" type="xs:string" minOccurs="0" /> <xs:element name="numberOfDPEncountered" type="xs:string" minOccurs="0" /> <xs:element name="levelOfCAMELService" type="xs:string" minOccurs="0" /> <xs:element name="freeFormatData" type="xs:string" minOccurs="0" /> <xs:element name="classmark3" type="xs:string" minOccurs="0" /> <xs:element name="mscOutgoingCircuit" type="xs:string" minOccurs="0" /> <xs:element name="orgRNCorBSCId" type="xs:string" minOccurs="0" /> <xs:element name="orgMSCId" type="xs:string" minOccurs="0" /> <xs:element name="calledIMSI" type="xs:string" minOccurs="0" /> <xs:element name="globalAreaID" type="xs:string" minOccurs="0" /> <xs:element name="subscriberCategory" type="xs:string" minOccurs="0" /> <xs:element name="firstmccmnc" type="xs:string" minOccurs="0" /> <xs:element name="lastmccmnc" type="xs:string" minOccurs="0" /> <xs:element ref="mscIncomingROUTE" minOccurs="0" maxOccurs="unbounded" /> <xs:element ref="mscOutgoingROUTE" minOccurs="0" maxOccurs="unbounded" /> <xs:element ref="location" minOccurs="0" maxOccurs="unbounded" /> <xs:element ref="basicService" minOccurs="0" maxOccurs="unbounded" /> <xs:element ref="radioChanRequested" minOccurs="0" maxOccurs="unbounded" /> <xs:element ref="radioChanUsed" minOccurs="0" maxOccurs="unbounded" /> <xs:element ref="diagnostics" minOccurs="0" maxOccurs="unbounded" /> <xs:element ref="additionalChgInfo" minOccurs="0" maxOccurs="unbounded" /> <xs:element ref="systemType" minOccurs="0" maxOccurs="unbounded" /> <xs:element ref="chargedParty" minOccurs="0" maxOccurs="unbounded" /> </xs:sequence> </xs:complexType> </xs:element> <xs:element name="mtCallRecord" minOccurs="0" maxOccurs="unbounded"> <xs:complexType> <xs:sequence> <xs:element name="recordType" type="xs:string" minOccurs="0" /> <xs:element name="servedIMSI" type="xs:string" minOccurs="0" /> <xs:element name="servedIMEI" type="xs:string" minOccurs="0" /> <xs:element name="servedMSISDN" type="xs:string" minOccurs="0" /> <xs:element name="callingNumber" type="xs:string" minOccurs="0" /> <xs:element name="recordingEntity" type="xs:string" minOccurs="0" /> <xs:element name="msClassmark" type="xs:string" minOccurs="0" /> <xs:element name="answerTime" type="xs:string" minOccurs="0" /> <xs:element name="releaseTime" type="xs:string" minOccurs="0" /> <xs:element name="callDuration" type="xs:string" minOccurs="0" /> <xs:element name="causeForTerm" type="xs:string" minOccurs="0" /> <xs:element name="callReference" type="xs:string" minOccurs="0" /> <xs:element name="networkCallReference" type="xs:string" minOccurs="0" /> <xs:element name="mSCAddress" type="xs:string" minOccurs="0" /> <xs:element name="speechVersionSupported" type="xs:string" minOccurs="0" /> <xs:element name="speechVersionUsed" type="xs:string" minOccurs="0" /> <xs:element name="classmark3" type="xs:string" minOccurs="0" /> <xs:element name="roamingNumber" type="xs:string" minOccurs="0" /> <xs:element name="mscIncomingCircuit" type="xs:string" minOccurs="0" /> <xs:element name="orgRNCorBSCId" type="xs:string" minOccurs="0" /> <xs:element name="orgMSCId" type="xs:string" minOccurs="0" /> <xs:element name="globalAreaID" type="xs:string" minOccurs="0" /> <xs:element name="subscriberCategory" type="xs:string" minOccurs="0" /> <xs:element name="firstmccmnc" type="xs:string" minOccurs="0" /> <xs:element name="lastmccmnc" type="xs:string" minOccurs="0" /> <xs:element ref="mscIncomingROUTE" minOccurs="0" maxOccurs="unbounded" /> <xs:element ref="mscOutgoingROUTE" minOccurs="0" maxOccurs="unbounded" /> <xs:element ref="location" minOccurs="0" maxOccurs="unbounded" /> <xs:element ref="basicService" minOccurs="0" maxOccurs="unbounded" /> <xs:element name="supplServicesUsed" minOccurs="0" maxOccurs="unbounded"> <xs:complexType> <xs:sequence> <xs:element name="SuppServiceUsedid" minOccurs="0" maxOccurs="unbounded"> <xs:complexType> <xs:sequence> <xs:element name="ssCode" type="xs:string" minOccurs="0" /> <xs:element name="ssTime" type="xs:string" minOccurs="0" /> </xs:sequence>

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  • How about a new platform for your next API&hellip; a CMS?

    - by Elton Stoneman
    Originally posted on: http://geekswithblogs.net/EltonStoneman/archive/2014/05/22/how-about-a-new-platform-for-your-next-apihellip-a.aspxSay what? I’m seeing a type of API emerge which serves static or long-lived resources, which are mostly read-only and have a controlled process to update the data that gets served. Think of something like an app configuration API, where you want a central location for changeable settings. You could use this server side to store database connection strings and keep all your instances in sync, or it could be used client side to push changes out to all users (and potentially driving A/B or MVT testing). That’s a good candidate for a RESTful API which makes proper use of HTTP expiration and validation caching to minimise traffic, but really you want a front end UI where you can edit the current config that the API returns and publish your changes. Sound like a Content Mangement System would be a good fit? I’ve been looking at that and it’s a great fit for this scenario. You get a lot of what you need out of the box, the amount of custom code you need to write is minimal, and you get a whole lot of extra stuff from using CMS which is very useful, but probably not something you’d build if you had to put together a quick UI over your API content (like a publish workflow, fine-grained security and an audit trail). You typically use a CMS for HTML resources, but it’s simple to expose JSON instead – or to do content negotiation to support both, so you can open a resource in a browser and see a nice visual representation, or request it with: Accept=application/json and get the same content rendered as JSON for the app to use. Enter Umbraco Umbraco is an open source .NET CMS that’s been around for a while. It has very good adoption, a lively community and a good release cycle. It’s easy to use, has all the functionality you need for a CMS-driven API, and it’s scalable (although you won’t necessarily put much scale on the CMS layer). In the rest of this post, I’ll build out a simple app config API using Umbraco. We’ll define the structure of the configuration resource by creating a new Document Type and setting custom properties; then we’ll build a very simple Razor template to return configuration documents as JSON; then create a resource and see how it looks. And we’ll look at how you could build this into a wider solution. If you want to try this for yourself, it’s ultra easy – there’s an Umbraco image in the Azure Website gallery, so all you need to to is create a new Website, select Umbraco from the image and complete the installation. It will create a SQL Azure website to store all the content, as well as a Website instance for editing and accessing content. They’re standard Azure resources, so you can scale them as you need. The default install creates a starter site for some HTML content, which you can use to learn your way around (or just delete). 1. Create Configuration Document Type In Umbraco you manage content by creating and modifying documents, and every document has a known type, defining what properties it holds. We’ll create a new Document Type to describe some basic config settings. In the Settings section from the left navigation (spanner icon), expand Document Types and Master, hit the ellipsis and select to create a new Document Type: This will base your new type off the Master type, which gives you some existing properties that we’ll use – like the Page Title which will be the resource URL. In the Generic Properties tab for the new Document Type, you set the properties you’ll be able to edit and return for the resource: Here I’ve added a text string where I’ll set a default cache lifespan, an image which I can use for a banner display, and a date which could show the user when the next release is due. This is the sort of thing that sits nicely in an app config API. It’s likely to change during the life of the product, but not very often, so it’s good to have a centralised place where you can make and publish changes easily and safely. It also enables A/B and MVT testing, as you can change the response each client gets based on your set logic, and their apps will behave differently without needing a release. 2. Define the response template Now we’ve defined the structure of the resource (as a document), in Umbraco we can define a C# Razor template to say how that resource gets rendered to the client. If you only want to provide JSON, it’s easy to render the content of the document by building each property in the response (Umbraco uses dynamic objects so you can specify document properties as object properties), or you can support content negotiation with very little effort. Here’s a template to render the document as HTML or JSON depending on the Accept header, using JSON.NET for the API rendering: @inherits Umbraco.Web.Mvc.UmbracoTemplatePage @using Newtonsoft.Json @{ Layout = null; } @if(UmbracoContext.HttpContext.Request.Headers["accept"] != null &amp;&amp; UmbracoContext.HttpContext.Request.Headers["accept"] == "application/json") { Response.ContentType = "application/json"; @Html.Raw(JsonConvert.SerializeObject(new { cacheLifespan = CurrentPage.cacheLifespan, bannerImageUrl = CurrentPage.bannerImage, nextReleaseDate = CurrentPage.nextReleaseDate })) } else { <h1>App configuration</h1> <p>Cache lifespan: <b>@CurrentPage.cacheLifespan</b></p> <p>Banner Image: </p> <img src="@CurrentPage.bannerImage"> <p>Next Release Date: <b>@CurrentPage.nextReleaseDate</b></p> } That’s a rough-and ready example of what you can do. You could make it completely generic and just render all the document’s properties as JSON, but having a specific template for each resource gives you control over what gets sent out. And the templates are evaluated at run-time, so if you need to change the output – or extend it, say to add caching response headers – you just edit the template and save, and the next client request gets rendered from the new template. No code to build and ship. 3. Create the content With your document type created, in  the Content pane you can create a new instance of that document, where Umbraco gives you a nice UI to input values for the properties we set up on the Document Type: Here I’ve set the cache lifespan to an xs:duration value, uploaded an image for the banner and specified a release date. Each property gets the appropriate input control – text box, file upload and date picker. At the top of the page is the name of the resource – myapp in this example. That specifies the URL for the resource, so if I had a DNS entry pointing to my Umbraco instance, I could access the config with a URL like http://static.x.y.z.com/config/myapp. The setup is all done now, so when we publish this resource it’ll be available to access.  4. Access the resource Now if you open  that URL in the browser, you’ll see the HTML version rendered: - complete with the  image and formatted date. Umbraco lets you save changes and preview them before publishing, so the HTML view could be a good way of showing editors their changes in a usable view, before they confirm them. If you browse the same URL from a REST client, specifying the Accept=application/json request header, you get this response:   That’s the exact same resource, with a managed UI to publish it, being accessed as HTML or JSON with a tiny amount of effort. 5. The wider landscape If you have fairy stable content to expose as an API, I think  this approach is really worth considering. Umbraco scales very nicely, but in a typical solution you probably wouldn’t need it to. When you have additional requirements, like logging API access requests - but doing it out-of-band so clients aren’t impacted, you can put a very thin API layer on top of Umbraco, and cache the CMS responses in your API layer:   Here the API does a passthrough to CMS, so the CMS still controls the content, but it caches the response. If the response is cached for 1 minute, then Umbraco only needs to handle 1 request per minute (multiplied by the number of API instances), so if you need to support 1000s of request per second, you’re scaling a thin, simple API layer rather than having to scale the more complex CMS infrastructure (including the database). This diagram also shows an approach to logging, by asynchronously publishing a message to a queue (Redis in this case), which can be picked up later and persisted by a different process. Does it work? Beautifully. Using Azure, I spiked the solution above (including the Redis logging framework which I’ll blog about later) in half a day. That included setting up different roles in Umbraco to demonstrate a managed workflow for publishing changes, and a couple of document types representing different resources. Is it maintainable? We have three moving parts, which are all managed resources in Azure –  an Azure Website for Umbraco which may need a couple of instances for HA (or may not, depending on how long the content can be cached), a message queue (Redis is in preview in Azure, but you can easily use Service Bus Queues if performance is less of a concern), and the Web Role for the API. Two of the components are off-the-shelf, from open source projects, and the only custom code is the API which is very simple. Does it scale? Pretty nicely. With a single Umbraco instance running as an Azure Website, and with 4x instances for my API layer (Standard sized Web Roles), I got just under 4,000 requests per second served reliably, with a Worker Role in the background saving the access logs. So we had a nice UI to publish app config changes, with a friendly Web preview and a publishing workflow, capable of supporting 14 million requests in an hour, with less than a day’s effort. Worth considering if you’re publishing long-lived resources through your API.

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  • Metro: Understanding Observables

    - by Stephen.Walther
    The goal of this blog entry is to describe how the Observer Pattern is implemented in the WinJS library. You learn how to create observable objects which trigger notifications automatically when their properties are changed. Observables enable you to keep your user interface and your application data in sync. For example, by taking advantage of observables, you can update your user interface automatically whenever the properties of a product change. Observables are the foundation of declarative binding in the WinJS library. The WinJS library is not the first JavaScript library to include support for observables. For example, both the KnockoutJS library and the Microsoft Ajax Library (now part of the Ajax Control Toolkit) support observables. Creating an Observable Imagine that I have created a product object like this: var product = { name: "Milk", description: "Something to drink", price: 12.33 }; Nothing very exciting about this product. It has three properties named name, description, and price. Now, imagine that I want to be notified automatically whenever any of these properties are changed. In that case, I can create an observable product from my product object like this: var observableProduct = WinJS.Binding.as(product); This line of code creates a new JavaScript object named observableProduct from the existing JavaScript object named product. This new object also has a name, description, and price property. However, unlike the properties of the original product object, the properties of the observable product object trigger notifications when the properties are changed. Each of the properties of the new observable product object has been changed into accessor properties which have both a getter and a setter. For example, the observable product price property looks something like this: price: { get: function () { return this.getProperty(“price”); } set: function (value) { this.setProperty(“price”, value); } } When you read the price property then the getProperty() method is called and when you set the price property then the setProperty() method is called. The getProperty() and setProperty() methods are methods of the observable product object. The observable product object supports the following methods and properties: · addProperty(name, value) – Adds a new property to an observable and notifies any listeners. · backingData – An object which represents the value of each property. · bind(name, action) – Enables you to execute a function when a property changes. · getProperty(name) – Returns the value of a property using the string name of the property. · notify(name, newValue, oldValue) – A private method which executes each function in the _listeners array. · removeProperty(name) – Removes a property and notifies any listeners. · setProperty(name, value) – Updates a property and notifies any listeners. · unbind(name, action) – Enables you to stop executing a function in response to a property change. · updateProperty(name, value) – Updates a property and notifies any listeners. So when you create an observable, you get a new object with the same properties as an existing object. However, when you modify the properties of an observable object, then you can notify any listeners of the observable that the value of a particular property has changed automatically. Imagine that you change the value of the price property like this: observableProduct.price = 2.99; In that case, the following sequence of events is triggered: 1. The price setter calls the setProperty(“price”, 2.99) method 2. The setProperty() method updates the value of the backingData.price property and calls the notify() method 3. The notify() method executes each function in the collection of listeners associated with the price property Creating Observable Listeners If you want to be notified when a property of an observable object is changed, then you need to register a listener. You register a listener by using the bind() method like this: (function () { "use strict"; var app = WinJS.Application; app.onactivated = function (eventObject) { if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) { // Simple product object var product = { name: "Milk", description: "Something to drink", price: 12.33 }; // Create observable product var observableProduct = WinJS.Binding.as(product); // Execute a function when price is changed observableProduct.bind("price", function (newValue) { console.log(newValue); }); // Change the price observableProduct.price = 2.99; } }; app.start(); })(); In the code above, the bind() method is used to associate the price property with a function. When the price property is changed, the function logs the new value of the price property to the Visual Studio JavaScript console. The price property is associated with the function using the following line of code: // Execute a function when price is changed observableProduct.bind("price", function (newValue) { console.log(newValue); }); Coalescing Notifications If you make multiple changes to a property – one change immediately following another – then separate notifications won’t be sent. Instead, any listeners are notified only once. The notifications are coalesced into a single notification. For example, in the following code, the product price property is updated three times. However, only one message is written to the JavaScript console. Only the last value assigned to the price property is written to the JavaScript Console window: // Simple product object var product = { name: "Milk", description: "Something to drink", price: 12.33 }; // Create observable product var observableProduct = WinJS.Binding.as(product); // Execute a function when price is changed observableProduct.bind("price", function (newValue) { console.log(newValue); }); // Change the price observableProduct.price = 3.99; observableProduct.price = 2.99; observableProduct.price = 1.99; Only the last value assigned to price, the value 1.99, appears in the console: If there is a time delay between changes to a property then changes result in different notifications. For example, the following code updates the price property every second: // Simple product object var product = { name: "Milk", description: "Something to drink", price: 12.33 }; // Create observable product var observableProduct = WinJS.Binding.as(product); // Execute a function when price is changed observableProduct.bind("price", function (newValue) { console.log(newValue); }); // Add 1 to price every second window.setInterval(function () { observableProduct.price += 1; }, 1000); In this case, separate notification messages are logged to the JavaScript Console window: If you need to prevent multiple notifications from being coalesced into one then you can take advantage of promises. I discussed WinJS promises in a previous blog entry: http://stephenwalther.com/blog/archive/2012/02/22/windows-web-applications-promises.aspx Because the updateProperty() method returns a promise, you can create different notifications for each change in a property by using the following code: // Change the price observableProduct.updateProperty("price", 3.99) .then(function () { observableProduct.updateProperty("price", 2.99) .then(function () { observableProduct.updateProperty("price", 1.99); }); }); In this case, even though the price is immediately changed from 3.99 to 2.99 to 1.99, separate notifications for each new value of the price property are sent. Bypassing Notifications Normally, if a property of an observable object has listeners and you change the property then the listeners are notified. However, there are certain situations in which you might want to bypass notification. In other words, you might need to change a property value silently without triggering any functions registered for notification. If you want to change a property without triggering notifications then you should change the property by using the backingData property. The following code illustrates how you can change the price property silently: // Simple product object var product = { name: "Milk", description: "Something to drink", price: 12.33 }; // Create observable product var observableProduct = WinJS.Binding.as(product); // Execute a function when price is changed observableProduct.bind("price", function (newValue) { console.log(newValue); }); // Change the price silently observableProduct.backingData.price = 5.99; console.log(observableProduct.price); // Writes 5.99 The price is changed to the value 5.99 by changing the value of backingData.price. Because the observableProduct.price property is not set directly, any listeners associated with the price property are not notified. When you change the value of a property by using the backingData property, the change in the property happens synchronously. However, when you change the value of an observable property directly, the change is always made asynchronously. Summary The goal of this blog entry was to describe observables. In particular, we discussed how to create observables from existing JavaScript objects and bind functions to observable properties. You also learned how notifications are coalesced (and ways to prevent this coalescing). Finally, we discussed how you can use the backingData property to update an observable property without triggering notifications. In the next blog entry, we’ll see how observables are used with declarative binding to display the values of properties in an HTML document.

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  • top tweets WebLogic Partner Community – November 2012

    - by JuergenKress
    Send us your tweets @wlscommunity #WebLogicCommunity and follow us on twitter http://twitter.com/wlscommunity Please feel free to send us your news! Andrejus Baranovskis ADF BC View Accessor To Centralize Business Logic Processing http://fb.me/ZdH3reTC OracleBlogs? Devoxx Coming Up! http://ow.ly/2t855p OTNArchBeat Webcast: #JMX with #Oracle #WebLogic Server 12c - featuring @FrankMunz Nov 13 10am PT 1pm ET http://pub.vitrue.com/ulyl OracleSupport_ Detailed nomenclature of #weblogic logging services http://pub.vitrue.com/LwLK WebLogic Community Java Management Extensions with Oracle WebLogic Server 12c&ndash;Webcast Nocember 13th 2012 http://wp.me/p1LMIb-oH Andrejus Baranovskis? Difference Between Initialized and New Mode in ADF BC http://fb.me/1d00veJLm Oracle Technet? Ondrej Brejla shares information on the release of NetbBeans IDE 7.3 Beta 2. http://pub.vitrue.com/Q0Ji OracleBlogs? Oracle ADF Essentials & ADF training material now on the iPad By Grant Ronald http://ow.ly/2t6m7y Markus Eisele #NetBeans 7.3 Beta2 is Out! https://blogs.oracle.com/netbeansphp/entry/netbeans_7_3_beta2_is … WebLogic Community Oracle ADF Essentials & ADF training material now on the iPad By Grant Ronald http://wp.me/p1LMIb-oj Frank Munz? Also next week, Tue, 10am PST: @Oracle devcast about WLS 12c JMX ecosystem 4 DevOps. Join now: http://goo.gl/oikWX Oracle WebLogic #EclipseLink #JPA deployed on #webLogic using #Eclipse #WTP very detailed tutorial http://pub.vitrue.com/tckQ Middleware Magic Middleware Magic Completes 2 year of spreading its Magic http://goo.gl/fb/8vdA4 #Weblogic #J2EE #news Adam Bien? Interview In The "Java Spotlight Episode 107" Podcast: I had a nice chat during the JavaOne 2012 conference in ... http://bit.ly/VBLiij OracleSupport_WLS? #WebLogic 12c example code projects with a focus on #Java EE 6 http://pub.vitrue.com/Og8C JDeveloper & ADF? ADF Insider: Angels in the ADF Architecture http://dlvr.it/2RYBjq Andreas Koop [blog post] ADF: Smart Input Date Client Converter: EnvironmentTested with JDeveloper / ADF 11.1.2.3(Should also... http://bit.ly/SIValJ Steven Davelaar Added 16 new ADF samples from @andrejusb http://java.net/projects/smuenchadf/pages/ADFSamplesAuthorABA1 … JDeveloper & ADF? Transaction Level ADF BC Entity Validation http://dlvr.it/2QWN7K Oracle Exalogic? Do you know the secret to Exalogic's speed? It's called Exabus. More at the OTN Garage - http://youtu.be/dreH2XmplyA OracleSupport_WLS New tutorial: configure and administrate #clusters http://pub.vitrue.com/Gduy JDeveloper & ADF? Workaround for an Xcode/iOS SDK Issue http://dlvr.it/2QTRlJ Masoud Kalali? #GlassFish trunk will switch to require JDK 7 to build, details at GlassFish #JDK 7 Switch FAQ: https://wikis.oracle.com/display/GlassFish/JDK+7+Switch+FAQ … ADF Code Corner? ADF Oracle Magazine Article "Master and Commander" about global command pattern strategy for regions with ctx events http://bit.ly/PLvxUL Maciej Gruszka? @wlscommunity Cloud Application Foundation webcast about OOW announcements soon avail for replay Adam Bien? Real World Java EE Patterns Book ("Green Edition") is available for lending. For unlimited time and free: http://www.amazon.com/gp/feature.html/?ie=UTF8&camp=1789&creative=390957&docId=1000739811&linkCode=ur2&tag=wwwadambienco-20 … WebLogic Community Slides for todays #WebLogicCommunity are uploaded to the workspace. Not yet a member http://www.oracle.com/partners/goto/wls-emea … #weblogic Adam Bien? My (unprepared) night hacking starts at 11 AM CET: http://nighthacking.com WebLogic Community We will start our ExaLogic webcast in 5 minutes http://weblogiccommunity.wordpress.com/2012/10/31/join-us-for-our-weblogic-communtiy-webcast-on-november-2nd-2012-oow-update-weblogic-exalogic/ … Gertjan van het Hof? WebLogic Communtiy webcast on November 2nd 2012 11:00 CET! OOW update WebLogic & ExaLogic « WebLogic Community http://weblogiccommunity.wordpress.com/2012/10/31/join-us-for-our-weblogic-communtiy-webcast-on-november-2nd-2012-oow-update-weblogic-exalogic/ … GlassFish? Java EE 7 scheduled posted http://java.net/projects/javaee-spec/pages/Home … slated for final release on 4/29/2013 OracleSupport_WLS? Updating #EclipseLink in #WebLogic http://pub.vitrue.com/j2wc WebLogic Community Join us for our WebLogicCommunity Webcast tomorrow November 2nd. Ge tan update an all OOW announcements http://weblogiccommunity.wordpress.com/2012/10/31/join-us-for-our-weblogic-communtiy-webcast-on-november-2nd-2012-oow-update-weblogic-exalogic/ … #wlscommunity OTNArchBeat? Oracle ADF Mobile - Login Functionality | @AndrejusB http://pub.vitrue.com/Wqqk WebLogic Community? OpenWorld General Session 2012: Middleware & JavaOne http://wp.me/p1LMIb-oe OracleSupport_WLS? How to use RDA to generate #Weblogic thread dumps at specified Intervals? http://pub.vitrue.com/auuP OracleBlogs? Join us for our WebLogic Communtiy webcast on November 2nd 2012! OOW update WebLogic & ExaLogic http://ow.ly/2sXAel OracleSupport_WLS? Monitoring #Spring in #WebLogic - #Middleware magic blog post http://pub.vitrue.com/OcSq ultan? Oracle Launches Mobile Applications User Experience Design Patterns https://blogs.oracle.com/userassistance/entry/oracle_launches_mobile_applications_user … @odtug @adf_emg @tapadoo #xcake #android WebLogic Community? Managing EclipseLink using JMX http://wp.me/p1LMIb-oh WebLogic Community? WebLogic Partner Community Newsletter October 2012 http://wp.me/p1LMIb-n5 Simon Haslam? #ukoug Oracle Scene mag: "Getting to Know Oracle Fusion Middleware" into by @wlscommunity & myself http://viewer.zmags.com/publication/81b2adef#/81b2adef/30 … Andrejus Baranovskis LOV Validation and Programmatic Row Insert Performance http://fb.me/167ehvEBL Andrejus Baranovskis? ADF Project Development Time Distribution http://fb.me/zMijgiKF Edwin Biemond? Using JSON-REST in ADF Mobile: In the current version of ADF Mobile the ADF DataControls ( URL and WS ) only sup... http://bit.ly/Rdr9IX WebLogic Community Oracle Enterprise Manager Cloud Control 12c: Best Practices for Middleware Management http://wp.me/p1LMIb-mA WebLogic Community? Tuxedo 12c http://wp.me/p1LMIb-my Lucas Jellema? Online and free: ADF Advanced eCourses from Oracle - http://download.oracle.com/tutorials/jtcd3/ecourse_adf_part1/html/temp_frameset/index.htm … and http://download.oracle.com/tutorials/jtcd3/ecourse_adf_part2/html/temp_frameset/index.htm … Lucas Jellema? Finally Luc can tell all his stories on ADF Mobile - he is Mr ADF Mobile after all. On the AMIS Blog: http://technology.amis.nl/2012/10/22/adf-mobile-is-now-generally-available/ … with more coming! Gerkmann-Bartels [blog] ADF Mobile Samples are still there... http://maybe-interesting.blogspot.de/ Markus Eisele Do you know the #Oracle #Parcel #Service? A #weblogic #JavaEE6 example app on #github! http://bit.ly/XNVnqS by @jeffreyawest ! Contribute! WebLogic Community? Distribute the WebLogic Community newsletter October editoin - read it! or register for #wlscommunity http://www.oracle.com/partners/goto/wls-emea … #opn #oracle OracleBlogs? Getting Started with ADF Mobile Sample Apps http://ow.ly/2sOJOi Pieter Kranenburg? Oracle Forms Modernization? Checkout: http://forms.qafe.com for retainment of investment, knowledge and being future proof #OracleForms Markus Eisele [blog] Review: "Java EE 6 Cookbook for Securing, Tuning, and Extending Enterprise... http://dlvr.it/2MWGCq #packtpub #javaee #review Gertjan van het Hof ADF Mobile HTML5 is available. https://blogs.oracle.com/fusionmiddleware/ … Adam Bien? My (Adam Bien) JavaOne Session Videos and Resources: CON3896 - Interactive Onstage Java EE Overengineering, Mond... http://bit.ly/XNpSNm Torsten Winterberg? #ADF Mobile is GA now on OTN: http://www.oracle.com/technetwork/developer-tools/adf/overview/adf-mobile-096323.html … Finally! Oracle WebLogic? New Blog Post: Instructions on how to configure a WebLogic Cluster and use it with Oracle Http Server http://ow.ly/2sOdPJ luc bors? #Oracle #ADF Mobile is production Download the extension here http://bit.ly/TChziZ WebLogic Community? Move Data into the Grid for Scalable, Predictable Response Times http://wp.me/p1LMIb-mw Andrejus Baranovskis? Why Oracle ADF Developers are Sensitive People http://fb.me/209osORtC Lucas Jellema? Article by Edwin Biemond on the AMIS blog on Configuring FMW Servers using Puppet - http://technology.amis.nl/2012/10/13/configure-fmw-servers-with-puppet/ … - integration of WebLogic in Puppet Oracle UsableApps Must Read: New Oracle Applications UX White Paper: Research and Design Process: http://www.oracle.com/webfolder/ux/applications/Fusion/whitePapers.html … @oracle #usableapps Sten Vesterli? You know ADF Security is missing from the free ADF Essentials? Check out a solution by @andrejusb: http://andrejusb.blogspot.com/2012/10/adf-essentials-security-implementation.html … Oracle WebLogic Monitoring #Spring in #WebLogic - #Middleware magic blog post http://pub.vitrue.com/uT69 WebLogic Community Java Cloud Service for developers http://wp.me/p1LMIb-mu Gerkmann-Bartels #MUST read 4 #WLS Admins: How to Analyze Java Thread WebLogic Community? top tweets WebLogic Partner Community &ndash; October 2012 http://wp.me/p1LMIb-ob Andrejus Baranovskis? ADF Mobile - Login Functionality http://fb.me/2gxwZV9jc WebLogic Community? “@MaciejGruszka: Another #WebLogic bootcamp for #Oracle partners. Right now - Copenhagen Denmark” THANKs trainings at https://blogs.oracle.com/emeapartnerweblogic/ … Dumps http://zite.to/RKyx2x OracleBlogs? top tweets WebLogic Partner Community October 2012 http://ow.ly/2sXuAn eclipsecon? Today is the Call for Papers early bird deadline. Submit a session now! http://eclipsecon.org/2013/early-talk-selection … WebLogic Community? Join us for our WebLogic Communtiy webcast on November 2nd 2012! OOW update WebLogic & ExaLogic http://wp.me/p1LMIb-oA WebLogic Partner Community For regular information become a member in the WebLogic Partner Community please visit: http://www.oracle.com/partners/goto/wls-emea ( OPN account required). If you need support with your account please contact the Oracle Partner Business Center. Blog Twitter LinkedIn Mix Forum Wiki Technorati Tags: twitter,WebLogic,WebLogic Community,Oracle,OPN,Jürgen Kress

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  • Agile Development

    - by James Oloo Onyango
    Alot of literature has and is being written about agile developement and its surrounding philosophies. In my quest to find the best way to express the importance of agile methodologies, i have found Robert C. Martin's "A Satire Of Two Companies" to be both the most concise and thorough! Enjoy the read! Rufus Inc Project Kick Off Your name is Bob. The date is January 3, 2001, and your head still aches from the recent millennial revelry. You are sitting in a conference room with several managers and a group of your peers. You are a project team leader. Your boss is there, and he has brought along all of his team leaders. His boss called the meeting. "We have a new project to develop," says your boss's boss. Call him BB. The points in his hair are so long that they scrape the ceiling. Your boss's points are just starting to grow, but he eagerly awaits the day when he can leave Brylcream stains on the acoustic tiles. BB describes the essence of the new market they have identified and the product they want to develop to exploit this market. "We must have this new project up and working by fourth quarter October 1," BB demands. "Nothing is of higher priority, so we are cancelling your current project." The reaction in the room is stunned silence. Months of work are simply going to be thrown away. Slowly, a murmur of objection begins to circulate around the conference table.   His points give off an evil green glow as BB meets the eyes of everyone in the room. One by one, that insidious stare reduces each attendee to quivering lumps of protoplasm. It is clear that he will brook no discussion on this matter. Once silence has been restored, BB says, "We need to begin immediately. How long will it take you to do the analysis?" You raise your hand. Your boss tries to stop you, but his spitwad misses you and you are unaware of his efforts.   "Sir, we can't tell you how long the analysis will take until we have some requirements." "The requirements document won't be ready for 3 or 4 weeks," BB says, his points vibrating with frustration. "So, pretend that you have the requirements in front of you now. How long will you require for analysis?" No one breathes. Everyone looks around to see whether anyone has some idea. "If analysis goes beyond April 1, we have a problem. Can you finish the analysis by then?" Your boss visibly gathers his courage: "We'll find a way, sir!" His points grow 3 mm, and your headache increases by two Tylenol. "Good." BB smiles. "Now, how long will it take to do the design?" "Sir," you say. Your boss visibly pales. He is clearly worried that his 3 mms are at risk. "Without an analysis, it will not be possible to tell you how long design will take." BB's expression shifts beyond austere.   "PRETEND you have the analysis already!" he says, while fixing you with his vacant, beady little eyes. "How long will it take you to do the design?" Two Tylenol are not going to cut it. Your boss, in a desperate attempt to save his new growth, babbles: "Well, sir, with only six months left to complete the project, design had better take no longer than 3 months."   "I'm glad you agree, Smithers!" BB says, beaming. Your boss relaxes. He knows his points are secure. After a while, he starts lightly humming the Brylcream jingle. BB continues, "So, analysis will be complete by April 1, design will be complete by July 1, and that gives you 3 months to implement the project. This meeting is an example of how well our new consensus and empowerment policies are working. Now, get out there and start working. I'll expect to see TQM plans and QIT assignments on my desk by next week. Oh, and don't forget that your crossfunctional team meetings and reports will be needed for next month's quality audit." "Forget the Tylenol," you think to yourself as you return to your cubicle. "I need bourbon."   Visibly excited, your boss comes over to you and says, "Gosh, what a great meeting. I think we're really going to do some world shaking with this project." You nod in agreement, too disgusted to do anything else. "Oh," your boss continues, "I almost forgot." He hands you a 30-page document. "Remember that the SEI is coming to do an evaluation next week. This is the evaluation guide. You need to read through it, memorize it, and then shred it. It tells you how to answer any questions that the SEI auditors ask you. It also tells you what parts of the building you are allowed to take them to and what parts to avoid. We are determined to be a CMM level 3 organization by June!"   You and your peers start working on the analysis of the new project. This is difficult because you have no requirements. But from the 10-minute introduction given by BB on that fateful morning, you have some idea of what the product is supposed to do.   Corporate process demands that you begin by creating a use case document. You and your team begin enumerating use cases and drawing oval and stick diagrams. Philosophical debates break out among the team members. There is disagreement as to whether certain use cases should be connected with <<extends>> or <<includes>> relationships. Competing models are created, but nobody knows how to evaluate them. The debate continues, effectively paralyzing progress.   After a week, somebody finds the iceberg.com Web site, which recommends disposing entirely of <<extends>> and <<includes>> and replacing them with <<precedes>> and <<uses>>. The documents on this Web site, authored by Don Sengroiux, describes a method known as stalwart-analysis, which claims to be a step-by-step method for translating use cases into design diagrams. More competing use case models are created using this new scheme, but again, people can't agree on how to evaluate them. The thrashing continues. More and more, the use case meetings are driven by emotion rather than by reason. If it weren't for the fact that you don't have requirements, you'd be pretty upset by the lack of progress you are making. The requirements document arrives on February 15. And then again on February 20, 25, and every week thereafter. Each new version contradicts the previous one. Clearly, the marketing folks who are writing the requirements, empowered though they might be, are not finding consensus.   At the same time, several new competing use case templates have been proposed by the various team members. Each template presents its own particularly creative way of delaying progress. The debates rage on. On March 1, Prudence Putrigence, the process proctor, succeeds in integrating all the competing use case forms and templates into a single, all-encompassing form. Just the blank form is 15 pages long. She has managed to include every field that appeared on all the competing templates. She also presents a 159- page document describing how to fill out the use case form. All current use cases must be rewritten according to the new standard.   You marvel to yourself that it now requires 15 pages of fill-in-the-blank and essay questions to answer the question: What should the system do when the user presses Return? The corporate process (authored by L. E. Ott, famed author of "Holistic Analysis: A Progressive Dialectic for Software Engineers") insists that you discover all primary use cases, 87 percent of all secondary use cases, and 36.274 percent of all tertiary use cases before you can complete analysis and enter the design phase. You have no idea what a tertiary use case is. So in an attempt to meet this requirement, you try to get your use case document reviewed by the marketing department, which you hope will know what a tertiary use case is.   Unfortunately, the marketing folks are too busy with sales support to talk to you. Indeed, since the project started, you have not been able to get a single meeting with marketing, which has provided a never-ending stream of changing and contradictory requirements documents.   While one team has been spinning endlessly on the use case document, another team has been working out the domain model. Endless variations of UML documents are pouring out of this team. Every week, the model is reworked.   The team members can't decide whether to use <<interfaces>> or <<types>> in the model. A huge disagreement has been raging on the proper syntax and application of OCL. Others on the team just got back from a 5-day class on catabolism, and have been producing incredibly detailed and arcane diagrams that nobody else can fathom.   On March 27, with one week to go before analysis is to be complete, you have produced a sea of documents and diagrams but are no closer to a cogent analysis of the problem than you were on January 3. **** And then, a miracle happens.   **** On Saturday, April 1, you check your e-mail from home. You see a memo from your boss to BB. It states unequivocally that you are done with the analysis! You phone your boss and complain. "How could you have told BB that we were done with the analysis?" "Have you looked at a calendar lately?" he responds. "It's April 1!" The irony of that date does not escape you. "But we have so much more to think about. So much more to analyze! We haven't even decided whether to use <<extends>> or <<precedes>>!" "Where is your evidence that you are not done?" inquires your boss, impatiently. "Whaaa . . . ." But he cuts you off. "Analysis can go on forever; it has to be stopped at some point. And since this is the date it was scheduled to stop, it has been stopped. Now, on Monday, I want you to gather up all existing analysis materials and put them into a public folder. Release that folder to Prudence so that she can log it in the CM system by Monday afternoon. Then get busy and start designing."   As you hang up the phone, you begin to consider the benefits of keeping a bottle of bourbon in your bottom desk drawer. They threw a party to celebrate the on-time completion of the analysis phase. BB gave a colon-stirring speech on empowerment. And your boss, another 3 mm taller, congratulated his team on the incredible show of unity and teamwork. Finally, the CIO takes the stage to tell everyone that the SEI audit went very well and to thank everyone for studying and shredding the evaluation guides that were passed out. Level 3 now seems assured and will be awarded by June. (Scuttlebutt has it that managers at the level of BB and above are to receive significant bonuses once the SEI awards level 3.)   As the weeks flow by, you and your team work on the design of the system. Of course, you find that the analysis that the design is supposedly based on is flawedno, useless; no, worse than useless. But when you tell your boss that you need to go back and work some more on the analysis to shore up its weaker sections, he simply states, "The analysis phase is over. The only allowable activity is design. Now get back to it."   So, you and your team hack the design as best you can, unsure of whether the requirements have been properly analyzed. Of course, it really doesn't matter much, since the requirements document is still thrashing with weekly revisions, and the marketing department still refuses to meet with you.     The design is a nightmare. Your boss recently misread a book named The Finish Line in which the author, Mark DeThomaso, blithely suggested that design documents should be taken down to code-level detail. "If we are going to be working at that level of detail," you ask, "why don't we simply write the code instead?" "Because then you wouldn't be designing, of course. And the only allowable activity in the design phase is design!" "Besides," he continues, "we have just purchased a companywide license for Dandelion! This tool enables 'Round the Horn Engineering!' You are to transfer all design diagrams into this tool. It will automatically generate our code for us! It will also keep the design diagrams in sync with the code!" Your boss hands you a brightly colored shrinkwrapped box containing the Dandelion distribution. You accept it numbly and shuffle off to your cubicle. Twelve hours, eight crashes, one disk reformatting, and eight shots of 151 later, you finally have the tool installed on your server. You consider the week your team will lose while attending Dandelion training. Then you smile and think, "Any week I'm not here is a good week." Design diagram after design diagram is created by your team. Dandelion makes it very difficult to draw these diagrams. There are dozens and dozens of deeply nested dialog boxes with funny text fields and check boxes that must all be filled in correctly. And then there's the problem of moving classes between packages. At first, these diagram are driven from the use cases. But the requirements are changing so often that the use cases rapidly become meaningless. Debates rage about whether VISITOR or DECORATOR design patterns should be used. One developer refuses to use VISITOR in any form, claiming that it's not a properly object-oriented construct. Someone refuses to use multiple inheritance, since it is the spawn of the devil. Review meetings rapidly degenerate into debates about the meaning of object orientation, the definition of analysis versus design, or when to use aggregation versus association. Midway through the design cycle, the marketing folks announce that they have rethought the focus of the system. Their new requirements document is completely restructured. They have eliminated several major feature areas and replaced them with feature areas that they anticipate customer surveys will show to be more appropriate. You tell your boss that these changes mean that you need to reanalyze and redesign much of the system. But he says, "The analysis phase is system. But he says, "The analysis phase is over. The only allowable activity is design. Now get back to it."   You suggest that it might be better to create a simple prototype to show to the marketing folks and even some potential customers. But your boss says, "The analysis phase is over. The only allowable activity is design. Now get back to it." Hack, hack, hack, hack. You try to create some kind of a design document that might reflect the new requirements documents. However, the revolution of the requirements has not caused them to stop thrashing. Indeed, if anything, the wild oscillations of the requirements document have only increased in frequency and amplitude.   You slog your way through them.   On June 15, the Dandelion database gets corrupted. Apparently, the corruption has been progressive. Small errors in the DB accumulated over the months into bigger and bigger errors. Eventually, the CASE tool just stopped working. Of course, the slowly encroaching corruption is present on all the backups. Calls to the Dandelion technical support line go unanswered for several days. Finally, you receive a brief e-mail from Dandelion, informing you that this is a known problem and that the solution is to purchase the new version, which they promise will be ready some time next quarter, and then reenter all the diagrams by hand.   ****   Then, on July 1 another miracle happens! You are done with the design!   Rather than go to your boss and complain, you stock your middle desk drawer with some vodka.   **** They threw a party to celebrate the on-time completion of the design phase and their graduation to CMM level 3. This time, you find BB's speech so stirring that you have to use the restroom before it begins. New banners and plaques are all over your workplace. They show pictures of eagles and mountain climbers, and they talk about teamwork and empowerment. They read better after a few scotches. That reminds you that you need to clear out your file cabinet to make room for the brandy. You and your team begin to code. But you rapidly discover that the design is lacking in some significant areas. Actually, it's lacking any significance at all. You convene a design session in one of the conference rooms to try to work through some of the nastier problems. But your boss catches you at it and disbands the meeting, saying, "The design phase is over. The only allowable activity is coding. Now get back to it."   ****   The code generated by Dandelion is really hideous. It turns out that you and your team were using association and aggregation the wrong way, after all. All the generated code has to be edited to correct these flaws. Editing this code is extremely difficult because it has been instrumented with ugly comment blocks that have special syntax that Dandelion needs in order to keep the diagrams in sync with the code. If you accidentally alter one of these comments, the diagrams will be regenerated incorrectly. It turns out that "Round the Horn Engineering" requires an awful lot of effort. The more you try to keep the code compatible with Dandelion, the more errors Dandelion generates. In the end, you give up and decide to keep the diagrams up to date manually. A second later, you decide that there's no point in keeping the diagrams up to date at all. Besides, who has time?   Your boss hires a consultant to build tools to count the number of lines of code that are being produced. He puts a big thermometer graph on the wall with the number 1,000,000 on the top. Every day, he extends the red line to show how many lines have been added. Three days after the thermometer appears on the wall, your boss stops you in the hall. "That graph isn't growing quickly enough. We need to have a million lines done by October 1." "We aren't even sh-sh-sure that the proshect will require a m-million linezh," you blather. "We have to have a million lines done by October 1," your boss reiterates. His points have grown again, and the Grecian formula he uses on them creates an aura of authority and competence. "Are you sure your comment blocks are big enough?" Then, in a flash of managerial insight, he says, "I have it! I want you to institute a new policy among the engineers. No line of code is to be longer than 20 characters. Any such line must be split into two or more preferably more. All existing code needs to be reworked to this standard. That'll get our line count up!"   You decide not to tell him that this will require two unscheduled work months. You decide not to tell him anything at all. You decide that intravenous injections of pure ethanol are the only solution. You make the appropriate arrangements. Hack, hack, hack, and hack. You and your team madly code away. By August 1, your boss, frowning at the thermometer on the wall, institutes a mandatory 50-hour workweek.   Hack, hack, hack, and hack. By September 1st, the thermometer is at 1.2 million lines and your boss asks you to write a report describing why you exceeded the coding budget by 20 percent. He institutes mandatory Saturdays and demands that the project be brought back down to a million lines. You start a campaign of remerging lines. Hack, hack, hack, and hack. Tempers are flaring; people are quitting; QA is raining trouble reports down on you. Customers are demanding installation and user manuals; salespeople are demanding advance demonstrations for special customers; the requirements document is still thrashing, the marketing folks are complaining that the product isn't anything like they specified, and the liquor store won't accept your credit card anymore. Something has to give.    On September 15, BB calls a meeting. As he enters the room, his points are emitting clouds of steam. When he speaks, the bass overtones of his carefully manicured voice cause the pit of your stomach to roll over. "The QA manager has told me that this project has less than 50 percent of the required features implemented. He has also informed me that the system crashes all the time, yields wrong results, and is hideously slow. He has also complained that he cannot keep up with the continuous train of daily releases, each more buggy than the last!" He stops for a few seconds, visibly trying to compose himself. "The QA manager estimates that, at this rate of development, we won't be able to ship the product until December!" Actually, you think it's more like March, but you don't say anything. "December!" BB roars with such derision that people duck their heads as though he were pointing an assault rifle at them. "December is absolutely out of the question. Team leaders, I want new estimates on my desk in the morning. I am hereby mandating 65-hour work weeks until this project is complete. And it better be complete by November 1."   As he leaves the conference room, he is heard to mutter: "Empowermentbah!" * * * Your boss is bald; his points are mounted on BB's wall. The fluorescent lights reflecting off his pate momentarily dazzle you. "Do you have anything to drink?" he asks. Having just finished your last bottle of Boone's Farm, you pull a bottle of Thunderbird from your bookshelf and pour it into his coffee mug. "What's it going to take to get this project done? " he asks. "We need to freeze the requirements, analyze them, design them, and then implement them," you say callously. "By November 1?" your boss exclaims incredulously. "No way! Just get back to coding the damned thing." He storms out, scratching his vacant head.   A few days later, you find that your boss has been transferred to the corporate research division. Turnover has skyrocketed. Customers, informed at the last minute that their orders cannot be fulfilled on time, have begun to cancel their orders. Marketing is re-evaluating whether this product aligns with the overall goals of the company. Memos fly, heads roll, policies change, and things are, overall, pretty grim. Finally, by March, after far too many sixty-five hour weeks, a very shaky version of the software is ready. In the field, bug-discovery rates are high, and the technical support staff are at their wits' end, trying to cope with the complaints and demands of the irate customers. Nobody is happy.   In April, BB decides to buy his way out of the problem by licensing a product produced by Rupert Industries and redistributing it. The customers are mollified, the marketing folks are smug, and you are laid off.     Rupert Industries: Project Alpha   Your name is Robert. The date is January 3, 2001. The quiet hours spent with your family this holiday have left you refreshed and ready for work. You are sitting in a conference room with your team of professionals. The manager of the division called the meeting. "We have some ideas for a new project," says the division manager. Call him Russ. He is a high-strung British chap with more energy than a fusion reactor. He is ambitious and driven but understands the value of a team. Russ describes the essence of the new market opportunity the company has identified and introduces you to Jane, the marketing manager, who is responsible for defining the products that will address it. Addressing you, Jane says, "We'd like to start defining our first product offering as soon as possible. When can you and your team meet with me?" You reply, "We'll be done with the current iteration of our project this Friday. We can spare a few hours for you between now and then. After that, we'll take a few people from the team and dedicate them to you. We'll begin hiring their replacements and the new people for your team immediately." "Great," says Russ, "but I want you to understand that it is critical that we have something to exhibit at the trade show coming up this July. If we can't be there with something significant, we'll lose the opportunity."   "I understand," you reply. "I don't yet know what it is that you have in mind, but I'm sure we can have something by July. I just can't tell you what that something will be right now. In any case, you and Jane are going to have complete control over what we developers do, so you can rest assured that by July, you'll have the most important things that can be accomplished in that time ready to exhibit."   Russ nods in satisfaction. He knows how this works. Your team has always kept him advised and allowed him to steer their development. He has the utmost confidence that your team will work on the most important things first and will produce a high-quality product.   * * *   "So, Robert," says Jane at their first meeting, "How does your team feel about being split up?" "We'll miss working with each other," you answer, "but some of us were getting pretty tired of that last project and are looking forward to a change. So, what are you people cooking up?" Jane beams. "You know how much trouble our customers currently have . . ." And she spends a half hour or so describing the problem and possible solution. "OK, wait a second" you respond. "I need to be clear about this." And so you and Jane talk about how this system might work. Some of her ideas aren't fully formed. You suggest possible solutions. She likes some of them. You continue discussing.   During the discussion, as each new topic is addressed, Jane writes user story cards. Each card represents something that the new system has to do. The cards accumulate on the table and are spread out in front of you. Both you and Jane point at them, pick them up, and make notes on them as you discuss the stories. The cards are powerful mnemonic devices that you can use to represent complex ideas that are barely formed.   At the end of the meeting, you say, "OK, I've got a general idea of what you want. I'm going to talk to the team about it. I imagine they'll want to run some experiments with various database structures and presentation formats. Next time we meet, it'll be as a group, and we'll start identifying the most important features of the system."   A week later, your nascent team meets with Jane. They spread the existing user story cards out on the table and begin to get into some of the details of the system. The meeting is very dynamic. Jane presents the stories in the order of their importance. There is much discussion about each one. The developers are concerned about keeping the stories small enough to estimate and test. So they continually ask Jane to split one story into several smaller stories. Jane is concerned that each story have a clear business value and priority, so as she splits them, she makes sure that this stays true.   The stories accumulate on the table. Jane writes them, but the developers make notes on them as needed. Nobody tries to capture everything that is said; the cards are not meant to capture everything but are simply reminders of the conversation.   As the developers become more comfortable with the stories, they begin writing estimates on them. These estimates are crude and budgetary, but they give Jane an idea of what the story will cost.   At the end of the meeting, it is clear that many more stories could be discussed. It is also clear that the most important stories have been addressed and that they represent several months worth of work. Jane closes the meeting by taking the cards with her and promising to have a proposal for the first release in the morning.   * * *   The next morning, you reconvene the meeting. Jane chooses five cards and places them on the table. "According to your estimates, these cards represent about one perfect team-week's worth of work. The last iteration of the previous project managed to get one perfect team-week done in 3 real weeks. If we can get these five stories done in 3 weeks, we'll be able to demonstrate them to Russ. That will make him feel very comfortable about our progress." Jane is pushing it. The sheepish look on her face lets you know that she knows it too. You reply, "Jane, this is a new team, working on a new project. It's a bit presumptuous to expect that our velocity will be the same as the previous team's. However, I met with the team yesterday afternoon, and we all agreed that our initial velocity should, in fact, be set to one perfectweek for every 3 real-weeks. So you've lucked out on this one." "Just remember," you continue, "that the story estimates and the story velocity are very tentative at this point. We'll learn more when we plan the iteration and even more when we implement it."   Jane looks over her glasses at you as if to say "Who's the boss around here, anyway?" and then smiles and says, "Yeah, don't worry. I know the drill by now."Jane then puts 15 more cards on the table. She says, "If we can get all these cards done by the end of March, we can turn the system over to our beta test customers. And we'll get good feedback from them."   You reply, "OK, so we've got our first iteration defined, and we have the stories for the next three iterations after that. These four iterations will make our first release."   "So," says Jane, can you really do these five stories in the next 3 weeks?" "I don't know for sure, Jane," you reply. "Let's break them down into tasks and see what we get."   So Jane, you, and your team spend the next several hours taking each of the five stories that Jane chose for the first iteration and breaking them down into small tasks. The developers quickly realize that some of the tasks can be shared between stories and that other tasks have commonalities that can probably be taken advantage of. It is clear that potential designs are popping into the developers' heads. From time to time, they form little discussion knots and scribble UML diagrams on some cards.   Soon, the whiteboard is filled with the tasks that, once completed, will implement the five stories for this iteration. You start the sign-up process by saying, "OK, let's sign up for these tasks." "I'll take the initial database generation." Says Pete. "That's what I did on the last project, and this doesn't look very different. I estimate it at two of my perfect workdays." "OK, well, then, I'll take the login screen," says Joe. "Aw, darn," says Elaine, the junior member of the team, "I've never done a GUI, and kinda wanted to try that one."   "Ah, the impatience of youth," Joe says sagely, with a wink in your direction. "You can assist me with it, young Jedi." To Jane: "I think it'll take me about three of my perfect workdays."   One by one, the developers sign up for tasks and estimate them in terms of their own perfect workdays. Both you and Jane know that it is best to let the developers volunteer for tasks than to assign the tasks to them. You also know full well that you daren't challenge any of the developers' estimates. You know these people, and you trust them. You know that they are going to do the very best they can.   The developers know that they can't sign up for more perfect workdays than they finished in the last iteration they worked on. Once each developer has filled his or her schedule for the iteration, they stop signing up for tasks.   Eventually, all the developers have stopped signing up for tasks. But, of course, tasks are still left on the board.   "I was worried that that might happen," you say, "OK, there's only one thing to do, Jane. We've got too much to do in this iteration. What stories or tasks can we remove?" Jane sighs. She knows that this is the only option. Working overtime at the beginning of a project is insane, and projects where she's tried it have not fared well.   So Jane starts to remove the least-important functionality. "Well, we really don't need the login screen just yet. We can simply start the system in the logged-in state." "Rats!" cries Elaine. "I really wanted to do that." "Patience, grasshopper." says Joe. "Those who wait for the bees to leave the hive will not have lips too swollen to relish the honey." Elaine looks confused. Everyone looks confused. "So . . .," Jane continues, "I think we can also do away with . . ." And so, bit by bit, the list of tasks shrinks. Developers who lose a task sign up for one of the remaining ones.   The negotiation is not painless. Several times, Jane exhibits obvious frustration and impatience. Once, when tensions are especially high, Elaine volunteers, "I'll work extra hard to make up some of the missing time." You are about to correct her when, fortunately, Joe looks her in the eye and says, "When once you proceed down the dark path, forever will it dominate your destiny."   In the end, an iteration acceptable to Jane is reached. It's not what Jane wanted. Indeed, it is significantly less. But it's something the team feels that can be achieved in the next 3 weeks.   And, after all, it still addresses the most important things that Jane wanted in the iteration. "So, Jane," you say when things had quieted down a bit, "when can we expect acceptance tests from you?" Jane sighs. This is the other side of the coin. For every story the development team implements,   Jane must supply a suite of acceptance tests that prove that it works. And the team needs these long before the end of the iteration, since they will certainly point out differences in the way Jane and the developers imagine the system's behaviour.   "I'll get you some example test scripts today," Jane promises. "I'll add to them every day after that. You'll have the entire suite by the middle of the iteration."   * * *   The iteration begins on Monday morning with a flurry of Class, Responsibilities, Collaborators sessions. By midmorning, all the developers have assembled into pairs and are rapidly coding away. "And now, my young apprentice," Joe says to Elaine, "you shall learn the mysteries of test-first design!"   "Wow, that sounds pretty rad," Elaine replies. "How do you do it?" Joe beams. It's clear that he has been anticipating this moment. "OK, what does the code do right now?" "Huh?" replied Elaine, "It doesn't do anything at all; there is no code."   "So, consider our task; can you think of something the code should do?" "Sure," Elaine said with youthful assurance, "First, it should connect to the database." "And thereupon, what must needs be required to connecteth the database?" "You sure talk weird," laughed Elaine. "I think we'd have to get the database object from some registry and call the Connect() method. "Ah, astute young wizard. Thou perceives correctly that we requireth an object within which we can cacheth the database object." "Is 'cacheth' really a word?" "It is when I say it! So, what test can we write that we know the database registry should pass?" Elaine sighs. She knows she'll just have to play along. "We should be able to create a database object and pass it to the registry in a Store() method. And then we should be able to pull it out of the registry with a Get() method and make sure it's the same object." "Oh, well said, my prepubescent sprite!" "Hay!" "So, now, let's write a test function that proves your case." "But shouldn't we write the database object and registry object first?" "Ah, you've much to learn, my young impatient one. Just write the test first." "But it won't even compile!" "Are you sure? What if it did?" "Uh . . ." "Just write the test, Elaine. Trust me." And so Joe, Elaine, and all the other developers began to code their tasks, one test case at a time. The room in which they worked was abuzz with the conversations between the pairs. The murmur was punctuated by an occasional high five when a pair managed to finish a task or a difficult test case.   As development proceeded, the developers changed partners once or twice a day. Each developer got to see what all the others were doing, and so knowledge of the code spread generally throughout the team.   Whenever a pair finished something significant whether a whole task or simply an important part of a task they integrated what they had with the rest of the system. Thus, the code base grew daily, and integration difficulties were minimized.   The developers communicated with Jane on a daily basis. They'd go to her whenever they had a question about the functionality of the system or the interpretation of an acceptance test case.   Jane, good as her word, supplied the team with a steady stream of acceptance test scripts. The team read these carefully and thereby gained a much better understanding of what Jane expected the system to do. By the beginning of the second week, there was enough functionality to demonstrate to Jane. She watched eagerly as the demonstration passed test case after test case. "This is really cool," Jane said as the demonstration finally ended. "But this doesn't seem like one-third of the tasks. Is your velocity slower than anticipated?"   You grimace. You'd been waiting for a good time to mention this to Jane but now she was forcing the issue. "Yes, unfortunately, we are going more slowly than we had expected. The new application server we are using is turning out to be a pain to configure. Also, it takes forever to reboot, and we have to reboot it whenever we make even the slightest change to its configuration."   Jane eyes you with suspicion. The stress of last Monday's negotiations had still not entirely dissipated. She says, "And what does this mean to our schedule? We can't slip it again, we just can't. Russ will have a fit! He'll haul us all into the woodshed and ream us some new ones."   You look Jane right in the eyes. There's no pleasant way to give someone news like this. So you just blurt out, "Look, if things keep going like they're going, we're not going to be done with everything by next Friday. Now it's possible that we'll figure out a way to go faster. But, frankly, I wouldn't depend on that. You should start thinking about one or two tasks that could be removed from the iteration without ruining the demonstration for Russ. Come hell or high water, we are going to give that demonstration on Friday, and I don't think you want us to choose which tasks to omit."   "Aw forchrisakes!" Jane barely manages to stifle yelling that last word as she stalks away, shaking her head. Not for the first time, you say to yourself, "Nobody ever promised me project management would be easy." You are pretty sure it won't be the last time, either.   Actually, things went a bit better than you had hoped. The team did, in fact, have to drop one task from the iteration, but Jane had chosen wisely, and the demonstration for Russ went without a hitch. Russ was not impressed with the progress, but neither was he dismayed. He simply said, "This is pretty good. But remember, we have to be able to demonstrate this system at the trade show in July, and at this rate, it doesn't look like you'll have all that much to show." Jane, whose attitude had improved dramatically with the completion of the iteration, responded to Russ by saying, "Russ, this team is working hard, and well. When July comes around, I am confident that we'll have something significant to demonstrate. It won't be everything, and some of it may be smoke and mirrors, but we'll have something."   Painful though the last iteration was, it had calibrated your velocity numbers. The next iteration went much better. Not because your team got more done than in the last iteration but simply because the team didn't have to remove any tasks or stories in the middle of the iteration.   By the start of the fourth iteration, a natural rhythm has been established. Jane, you, and the team know exactly what to expect from one another. The team is running hard, but the pace is sustainable. You are confident that the team can keep up this pace for a year or more.   The number of surprises in the schedule diminishes to near zero; however, the number of surprises in the requirements does not. Jane and Russ frequently look over the growing system and make recommendations or changes to the existing functionality. But all parties realize that these changes take time and must be scheduled. So the changes do not cause anyone's expectations to be violated. In March, there is a major demonstration of the system to the board of directors. The system is very limited and is not yet in a form good enough to take to the trade show, but progress is steady, and the board is reasonably impressed.   The second release goes even more smoothly than the first. By now, the team has figured out a way to automate Jane's acceptance test scripts. The team has also refactored the design of the system to the point that it is really easy to add new features and change old ones. The second release was done by the end of June and was taken to the trade show. It had less in it than Jane and Russ would have liked, but it did demonstrate the most important features of the system. Although customers at the trade show noticed that certain features were missing, they were very impressed overall. You, Russ, and Jane all returned from the trade show with smiles on your faces. You all felt as though this project was a winner.   Indeed, many months later, you are contacted by Rufus Inc. That company had been working on a system like this for its internal operations. Rufus has canceled the development of that system after a death-march project and is negotiating to license your technology for its environment.   Indeed, things are looking up!

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  • Abstracting functionality

    - by Ralf Westphal
    Originally posted on: http://geekswithblogs.net/theArchitectsNapkin/archive/2014/08/22/abstracting-functionality.aspxWhat is more important than data? Functionality. Yes, I strongly believe we should switch to a functionality over data mindset in programming. Or actually switch back to it. Focus on functionality Functionality once was at the core of software development. Back when algorithms were the first thing you heard about in CS classes. Sure, data structures, too, were important - but always from the point of view of algorithms. (Niklaus Wirth gave one of his books the title “Algorithms + Data Structures” instead of “Data Structures + Algorithms” for a reason.) The reason for the focus on functionality? Firstly, because software was and is about doing stuff. Secondly because sufficient performance was hard to achieve, and only thirdly memory efficiency. But then hardware became more powerful. That gave rise to a new mindset: object orientation. And with it functionality was devalued. Data took over its place as the most important aspect. Now discussions revolved around structures motivated by data relationships. (John Beidler gave his book the title “Data Structures and Algorithms: An Object Oriented Approach” instead of the other way around for a reason.) Sure, this data could be embellished with functionality. But nevertheless functionality was second. When you look at (domain) object models what you mostly find is (domain) data object models. The common object oriented approach is: data aka structure over functionality. This is true even for the most modern modeling approaches like Domain Driven Design. Look at the literature and what you find is recommendations on how to get data structures right: aggregates, entities, value objects. I´m not saying this is what object orientation was invented for. But I´m saying that´s what I happen to see across many teams now some 25 years after object orientation became mainstream through C++, Delphi, and Java. But why should we switch back? Because software development cannot become truly agile with a data focus. The reason for that lies in what customers need first: functionality, behavior, operations. To be clear, that´s not why software is built. The purpose of software is to be more efficient than the alternative. Money mainly is spent to get a certain level of quality (e.g. performance, scalability, security etc.). But without functionality being present, there is nothing to work on the quality of. What customers want is functionality of a certain quality. ASAP. And tomorrow new functionality needs to be added, existing functionality needs to be changed, and quality needs to be increased. No customer ever wanted data or structures. Of course data should be processed. Data is there, data gets generated, transformed, stored. But how the data is structured for this to happen efficiently is of no concern to the customer. Ask a customer (or user) whether she likes the data structured this way or that way. She´ll say, “I don´t care.” But ask a customer (or user) whether he likes the functionality and its quality this way or that way. He´ll say, “I like it” (or “I don´t like it”). Build software incrementally From this very natural focus of customers and users on functionality and its quality follows we should develop software incrementally. That´s what Agility is about. Deliver small increments quickly and often to get frequent feedback. That way less waste is produced, and learning can take place much easier (on the side of the customer as well as on the side of developers). An increment is some added functionality or quality of functionality.[1] So as it turns out, Agility is about functionality over whatever. But software developers’ thinking is still stuck in the object oriented mindset of whatever over functionality. Bummer. I guess that (at least partly) explains why Agility always hits a glass ceiling in projects. It´s a clash of mindsets, of cultures. Driving software development by demanding small increases in functionality runs against thinking about software as growing (data) structures sprinkled with functionality. (Excuse me, if this sounds a bit broad-brush. But you get my point.) The need for abstraction In the end there need to be data structures. Of course. Small and large ones. The phrase functionality over data does not deny that. It´s not functionality instead of data or something. It´s just over, i.e. functionality should be thought of first. It´s a tad more important. It´s what the customer wants. That´s why we need a way to design functionality. Small and large. We need to be able to think about functionality before implementing it. We need to be able to reason about it among team members. We need to be able to communicate our mental models of functionality not just by speaking about them, but also on paper. Otherwise reasoning about it does not scale. We learned thinking about functionality in the small using flow charts, Nassi-Shneiderman diagrams, pseudo code, or UML sequence diagrams. That´s nice and well. But it does not scale. You can use these tools to describe manageable algorithms. But it does not work for the functionality triggered by pressing the “1-Click Order” on an amazon product page for example. There are several reasons for that, I´d say. Firstly, the level of abstraction over code is negligible. It´s essentially non-existent. Drawing a flow chart or writing pseudo code or writing actual code is very, very much alike. All these tools are about control flow like code is.[2] In addition all tools are computationally complete. They are about logic which is expressions and especially control statements. Whatever you code in Java you can fully (!) describe using a flow chart. And then there is no data. They are about control flow and leave out the data altogether. Thus data mostly is assumed to be global. That´s shooting yourself in the foot, as I hope you agree. Even if it´s functionality over data that does not mean “don´t think about data”. Right to the contrary! Functionality only makes sense with regard to data. So data needs to be in the picture right from the start - but it must not dominate the thinking. The above tools fail on this. Bottom line: So far we´re unable to reason in a scalable and abstract manner about functionality. That´s why programmers are so driven to start coding once they are presented with a problem. Programming languages are the only tool they´ve learned to use to reason about functional solutions. Or, well, there might be exceptions. Mathematical notation and SQL may have come to your mind already. Indeed they are tools on a higher level of abstraction than flow charts etc. That´s because they are declarative and not computationally complete. They leave out details - in order to deliver higher efficiency in devising overall solutions. We can easily reason about functionality using mathematics and SQL. That´s great. Except for that they are domain specific languages. They are not general purpose. (And they don´t scale either, I´d say.) Bummer. So to be more precise we need a scalable general purpose tool on a higher than code level of abstraction not neglecting data. Enter: Flow Design. Abstracting functionality using data flows I believe the solution to the problem of abstracting functionality lies in switching from control flow to data flow. Data flow very naturally is not about logic details anymore. There are no expressions and no control statements anymore. There are not even statements anymore. Data flow is declarative by nature. With data flow we get rid of all the limiting traits of former approaches to modeling functionality. In addition, nomen est omen, data flows include data in the functionality picture. With data flows, data is visibly flowing from processing step to processing step. Control is not flowing. Control is wherever it´s needed to process data coming in. That´s a crucial difference and needs some rewiring in your head to be fully appreciated.[2] Since data flows are declarative they are not the right tool to describe algorithms, though, I´d say. With them you don´t design functionality on a low level. During design data flow processing steps are black boxes. They get fleshed out during coding. Data flow design thus is more coarse grained than flow chart design. It starts on a higher level of abstraction - but then is not limited. By nesting data flows indefinitely you can design functionality of any size, without losing sight of your data. Data flows scale very well during design. They can be used on any level of granularity. And they can easily be depicted. Communicating designs using data flows is easy and scales well, too. The result of functional design using data flows is not algorithms (too low level), but processes. Think of data flows as descriptions of industrial production lines. Data as material runs through a number of processing steps to be analyzed, enhances, transformed. On the top level of a data flow design might be just one processing step, e.g. “execute 1-click order”. But below that are arbitrary levels of flows with smaller and smaller steps. That´s not layering as in “layered architecture”, though. Rather it´s a stratified design à la Abelson/Sussman. Refining data flows is not your grandpa´s functional decomposition. That was rooted in control flows. Refining data flows does not suffer from the limits of functional decomposition against which object orientation was supposed to be an antidote. Summary I´ve been working exclusively with data flows for functional design for the past 4 years. It has changed my life as a programmer. What once was difficult is now easy. And, no, I´m not using Clojure or F#. And I´m not a async/parallel execution buff. Designing the functionality of increments using data flows works great with teams. It produces design documentation which can easily be translated into code - in which then the smallest data flow processing steps have to be fleshed out - which is comparatively easy. Using a systematic translation approach code can mirror the data flow design. That way later on the design can easily be reproduced from the code if need be. And finally, data flow designs play well with object orientation. They are a great starting point for class design. But that´s a story for another day. To me data flow design simply is one of the missing links of systematic lightweight software design. There are also other artifacts software development can produce to get feedback, e.g. process descriptions, test cases. But customers can be delighted more easily with code based increments in functionality. ? No, I´m not talking about the endless possibilities this opens for parallel processing. Data flows are useful independently of multi-core processors and Actor-based designs. That´s my whole point here. Data flows are good for reasoning and evolvability. So forget about any special frameworks you might need to reap benefits from data flows. None are necessary. Translating data flow designs even into plain of Java is possible. ?

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  • How to access members of an rdf list with rdflib (or plain sparql)

    - by tjb
    What is the best way to access the members of an rdf list? I'm using rdflib (python) but an answer given in plain SPARQL is also ok (this type of answer can be used through rdfextras, a rdflib helper library). I'm trying to access the authors of a particular journal article in rdf produced by Zotero (some fields have been removed for brevity): <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:z="http://www.zotero.org/namespaces/export#" xmlns:dcterms="http://purl.org/dc/terms/" xmlns:bib="http://purl.org/net/biblio#" xmlns:foaf="http://xmlns.com/foaf/0.1/" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:prism="http://prismstandard.org/namespaces/1.2/basic/" xmlns:link="http://purl.org/rss/1.0/modules/link/"> <bib:Article rdf:about="http://www.ncbi.nlm.nih.gov/pubmed/18273724"> <z:itemType>journalArticle</z:itemType> <dcterms:isPartOf rdf:resource="urn:issn:0954-6634"/> <bib:authors> <rdf:Seq> <rdf:li> <foaf:Person> <foaf:surname>Lee</foaf:surname> <foaf:givenname>Hyoun Seung</foaf:givenname> </foaf:Person> </rdf:li> <rdf:li> <foaf:Person> <foaf:surname>Lee</foaf:surname> <foaf:givenname>Jong Hee</foaf:givenname> </foaf:Person> </rdf:li> <rdf:li> <foaf:Person> <foaf:surname>Ahn</foaf:surname> <foaf:givenname>Gun Young</foaf:givenname> </foaf:Person> </rdf:li> <rdf:li> <foaf:Person> <foaf:surname>Lee</foaf:surname> <foaf:givenname>Dong Hun</foaf:givenname> </foaf:Person> </rdf:li> <rdf:li> <foaf:Person> <foaf:surname>Shin</foaf:surname> <foaf:givenname>Jung Won</foaf:givenname> </foaf:Person> </rdf:li> <rdf:li> <foaf:Person> <foaf:surname>Kim</foaf:surname> <foaf:givenname>Dong Hyun</foaf:givenname> </foaf:Person> </rdf:li> <rdf:li> <foaf:Person> <foaf:surname>Chung</foaf:surname> <foaf:givenname>Jin Ho</foaf:givenname> </foaf:Person> </rdf:li> </rdf:Seq> </bib:authors> <dc:title>Fractional photothermolysis for the treatment of acne scars: a report of 27 Korean patients</dc:title> <dcterms:abstract>OBJECTIVES: Atrophic post-acne scarring remains a therapeutically challe *CUT*, erythema and edema. CONCLUSIONS: The 1550-nm erbium-doped FP is associated with significant patient-reported improvement in the appearance of acne scars, with minimal downtime.</dcterms:abstract> <bib:pages>45-49</bib:pages> <dc:date>2008</dc:date> <z:shortTitle>Fractional photothermolysis for the treatment of acne scars</z:shortTitle> <dc:identifier> <dcterms:URI> <rdf:value>http://www.ncbi.nlm.nih.gov/pubmed/18273724</rdf:value> </dcterms:URI> </dc:identifier> <dcterms:dateSubmitted>2010-12-06 11:36:52</dcterms:dateSubmitted> <z:libraryCatalog>NCBI PubMed</z:libraryCatalog> <dc:description>PMID: 18273724</dc:description> </bib:Article> <bib:Journal rdf:about="urn:issn:0954-6634"> <dc:title>The Journal of Dermatological Treatment</dc:title> <prism:volume>19</prism:volume> <prism:number>1</prism:number> <dcterms:alternative>J Dermatolog Treat</dcterms:alternative> <dc:identifier>DOI 10.1080/09546630701691244</dc:identifier> <dc:identifier>ISSN 0954-6634</dc:identifier> </bib:Journal>

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  • Strange Recurrent Excessive I/O Wait

    - by Chris
    I know quite well that I/O wait has been discussed multiple times on this site, but all the other topics seem to cover constant I/O latency, while the I/O problem we need to solve on our server occurs at irregular (short) intervals, but is ever-present with massive spikes of up to 20k ms a-wait and service times of 2 seconds. The disk affected is /dev/sdb (Seagate Barracuda, for details see below). A typical iostat -x output would at times look like this, which is an extreme sample but by no means rare: iostat (Oct 6, 2013) tps rd_sec/s wr_sec/s avgrq-sz avgqu-sz await svctm %util 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 16.00 0.00 156.00 9.75 21.89 288.12 36.00 57.60 5.50 0.00 44.00 8.00 48.79 2194.18 181.82 100.00 2.00 0.00 16.00 8.00 46.49 3397.00 500.00 100.00 4.50 0.00 40.00 8.89 43.73 5581.78 222.22 100.00 14.50 0.00 148.00 10.21 13.76 5909.24 68.97 100.00 1.50 0.00 12.00 8.00 8.57 7150.67 666.67 100.00 0.50 0.00 4.00 8.00 6.31 10168.00 2000.00 100.00 2.00 0.00 16.00 8.00 5.27 11001.00 500.00 100.00 0.50 0.00 4.00 8.00 2.96 17080.00 2000.00 100.00 34.00 0.00 1324.00 9.88 1.32 137.84 4.45 59.60 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 22.00 44.00 204.00 11.27 0.01 0.27 0.27 0.60 Let me provide you with some more information regarding the hardware. It's a Dell 1950 III box with Debian as OS where uname -a reports the following: Linux xx 2.6.32-5-amd64 #1 SMP Fri Feb 15 15:39:52 UTC 2013 x86_64 GNU/Linux The machine is a dedicated server that hosts an online game without any databases or I/O heavy applications running. The core application consumes about 0.8 of the 8 GBytes RAM, and the average CPU load is relatively low. The game itself, however, reacts rather sensitive towards I/O latency and thus our players experience massive ingame lag, which we would like to address as soon as possible. iostat: avg-cpu: %user %nice %system %iowait %steal %idle 1.77 0.01 1.05 1.59 0.00 95.58 Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn sdb 13.16 25.42 135.12 504701011 2682640656 sda 1.52 0.74 20.63 14644533 409684488 Uptime is: 19:26:26 up 229 days, 17:26, 4 users, load average: 0.36, 0.37, 0.32 Harddisk controller: 01:00.0 RAID bus controller: LSI Logic / Symbios Logic MegaRAID SAS 1078 (rev 04) Harddisks: Array 1, RAID-1, 2x Seagate Cheetah 15K.5 73 GB SAS Array 2, RAID-1, 2x Seagate ST3500620SS Barracuda ES.2 500GB 16MB 7200RPM SAS Partition information from df: Filesystem 1K-blocks Used Available Use% Mounted on /dev/sdb1 480191156 30715200 425083668 7% /home /dev/sda2 7692908 437436 6864692 6% / /dev/sda5 15377820 1398916 13197748 10% /usr /dev/sda6 39159724 19158340 18012140 52% /var Some more data samples generated with iostat -dx sdb 1 (Oct 11, 2013) Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s avgrq-sz avgqu-sz await svctm %util sdb 0.00 15.00 0.00 70.00 0.00 656.00 9.37 4.50 1.83 4.80 33.60 sdb 0.00 0.00 0.00 2.00 0.00 16.00 8.00 12.00 836.00 500.00 100.00 sdb 0.00 0.00 0.00 3.00 0.00 32.00 10.67 9.96 1990.67 333.33 100.00 sdb 0.00 0.00 0.00 4.00 0.00 40.00 10.00 6.96 3075.00 250.00 100.00 sdb 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4.00 0.00 0.00 100.00 sdb 0.00 0.00 0.00 2.00 0.00 16.00 8.00 2.62 4648.00 500.00 100.00 sdb 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2.00 0.00 0.00 100.00 sdb 0.00 0.00 0.00 1.00 0.00 16.00 16.00 1.69 7024.00 1000.00 100.00 sdb 0.00 74.00 0.00 124.00 0.00 1584.00 12.77 1.09 67.94 6.94 86.00 Characteristic charts generated with rrdtool can be found here: iostat plot 1, 24 min interval: http://imageshack.us/photo/my-images/600/yqm3.png/ iostat plot 2, 120 min interval: http://imageshack.us/photo/my-images/407/griw.png/ As we have a rather large cache of 5.5 GBytes, we thought it might be a good idea to test if the I/O wait spikes would perhaps be caused by cache miss events. Therefore, we did a sync and then this to flush the cache and buffers: echo 3 > /proc/sys/vm/drop_caches and directly afterwards the I/O wait and service times virtually went through the roof, and everything on the machine felt like slow motion. During the next few hours the latency recovered and everything was as before - small to medium lags in short, unpredictable intervals. Now my question is: does anybody have any idea what might cause this annoying behaviour? Is it the first indication of the disk array or the raid controller dying, or something that can be easily mended by rebooting? (At the moment we're very reluctant to do this, however, because we're afraid that the disks might not come back up again.) Any help is greatly appreciated. Thanks in advance, Chris. Edited to add: we do see one or two processes go to 'D' state in top, one of which seems to be kjournald rather frequently. If I'm not mistaken, however, this does not indicate the processes causing the latency, but rather those affected by it - correct me if I'm wrong. Does the information about uninterruptibly sleeping processes help us in any way to address the problem? @Andy Shinn requested smartctl data, here it is: smartctl -a -d megaraid,2 /dev/sdb yields: smartctl 5.40 2010-07-12 r3124 [x86_64-unknown-linux-gnu] (local build) Copyright (C) 2002-10 by Bruce Allen, http://smartmontools.sourceforge.net Device: SEAGATE ST3500620SS Version: MS05 Serial number: Device type: disk Transport protocol: SAS Local Time is: Mon Oct 14 20:37:13 2013 CEST Device supports SMART and is Enabled Temperature Warning Disabled or Not Supported SMART Health Status: OK Current Drive Temperature: 20 C Drive Trip Temperature: 68 C Elements in grown defect list: 0 Vendor (Seagate) cache information Blocks sent to initiator = 1236631092 Blocks received from initiator = 1097862364 Blocks read from cache and sent to initiator = 1383620256 Number of read and write commands whose size <= segment size = 531295338 Number of read and write commands whose size > segment size = 51986460 Vendor (Seagate/Hitachi) factory information number of hours powered up = 36556.93 number of minutes until next internal SMART test = 32 Error counter log: Errors Corrected by Total Correction Gigabytes Total ECC rereads/ errors algorithm processed uncorrected fast | delayed rewrites corrected invocations [10^9 bytes] errors read: 509271032 47 0 509271079 509271079 20981.423 0 write: 0 0 0 0 0 5022.039 0 verify: 1870931090 196 0 1870931286 1870931286 100558.708 0 Non-medium error count: 0 SMART Self-test log Num Test Status segment LifeTime LBA_first_err [SK ASC ASQ] Description number (hours) # 1 Background short Completed 16 36538 - [- - -] # 2 Background short Completed 16 36514 - [- - -] # 3 Background short Completed 16 36490 - [- - -] # 4 Background short Completed 16 36466 - [- - -] # 5 Background short Completed 16 36442 - [- - -] # 6 Background long Completed 16 36420 - [- - -] # 7 Background short Completed 16 36394 - [- - -] # 8 Background short Completed 16 36370 - [- - -] # 9 Background long Completed 16 36364 - [- - -] #10 Background short Completed 16 36361 - [- - -] #11 Background long Completed 16 2 - [- - -] #12 Background short Completed 16 0 - [- - -] Long (extended) Self Test duration: 6798 seconds [113.3 minutes] smartctl -a -d megaraid,3 /dev/sdb yields: smartctl 5.40 2010-07-12 r3124 [x86_64-unknown-linux-gnu] (local build) Copyright (C) 2002-10 by Bruce Allen, http://smartmontools.sourceforge.net Device: SEAGATE ST3500620SS Version: MS05 Serial number: Device type: disk Transport protocol: SAS Local Time is: Mon Oct 14 20:37:26 2013 CEST Device supports SMART and is Enabled Temperature Warning Disabled or Not Supported SMART Health Status: OK Current Drive Temperature: 19 C Drive Trip Temperature: 68 C Elements in grown defect list: 0 Vendor (Seagate) cache information Blocks sent to initiator = 288745640 Blocks received from initiator = 1097848399 Blocks read from cache and sent to initiator = 1304149705 Number of read and write commands whose size <= segment size = 527414694 Number of read and write commands whose size > segment size = 51986460 Vendor (Seagate/Hitachi) factory information number of hours powered up = 36596.83 number of minutes until next internal SMART test = 28 Error counter log: Errors Corrected by Total Correction Gigabytes Total ECC rereads/ errors algorithm processed uncorrected fast | delayed rewrites corrected invocations [10^9 bytes] errors read: 610862490 44 0 610862534 610862534 20470.133 0 write: 0 0 0 0 0 5022.480 0 verify: 2861227413 203 0 2861227616 2861227616 100872.443 0 Non-medium error count: 1 SMART Self-test log Num Test Status segment LifeTime LBA_first_err [SK ASC ASQ] Description number (hours) # 1 Background short Completed 16 36580 - [- - -] # 2 Background short Completed 16 36556 - [- - -] # 3 Background short Completed 16 36532 - [- - -] # 4 Background short Completed 16 36508 - [- - -] # 5 Background short Completed 16 36484 - [- - -] # 6 Background long Completed 16 36462 - [- - -] # 7 Background short Completed 16 36436 - [- - -] # 8 Background short Completed 16 36412 - [- - -] # 9 Background long Completed 16 36404 - [- - -] #10 Background short Completed 16 36401 - [- - -] #11 Background long Completed 16 2 - [- - -] #12 Background short Completed 16 0 - [- - -] Long (extended) Self Test duration: 6798 seconds [113.3 minutes]

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  • Metro: Declarative Data Binding

    - by Stephen.Walther
    The goal of this blog post is to describe how declarative data binding works in the WinJS library. In particular, you learn how to use both the data-win-bind and data-win-bindsource attributes. You also learn how to use calculated properties and converters to format the value of a property automatically when performing data binding. By taking advantage of WinJS data binding, you can use the Model-View-ViewModel (MVVM) pattern when building Metro style applications with JavaScript. By using the MVVM pattern, you can prevent your JavaScript code from spinning into chaos. The MVVM pattern provides you with a standard pattern for organizing your JavaScript code which results in a more maintainable application. Using Declarative Bindings You can use the data-win-bind attribute with any HTML element in a page. The data-win-bind attribute enables you to bind (associate) an attribute of an HTML element to the value of a property. Imagine, for example, that you want to create a product details page. You want to show a product object in a page. In that case, you can create the following HTML page to display the product details: <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>Application1</title> <!-- WinJS references --> <link href="//Microsoft.WinJS.0.6/css/ui-dark.css" rel="stylesheet"> <script src="//Microsoft.WinJS.0.6/js/base.js"></script> <script src="//Microsoft.WinJS.0.6/js/ui.js"></script> <!-- Application1 references --> <link href="/css/default.css" rel="stylesheet"> <script src="/js/default.js"></script> </head> <body> <h1>Product Details</h1> <div class="field"> Product Name: <span data-win-bind="innerText:name"></span> </div> <div class="field"> Product Price: <span data-win-bind="innerText:price"></span> </div> <div class="field"> Product Picture: <br /> <img data-win-bind="src:photo;alt:name" /> </div> </body> </html> The HTML page above contains three data-win-bind attributes – one attribute for each product property displayed. You use the data-win-bind attribute to set properties of the HTML element associated with the data-win-attribute. The data-win-bind attribute takes a semicolon delimited list of element property names and data source property names: data-win-bind=”elementPropertyName:datasourcePropertyName; elementPropertyName:datasourcePropertyName;…” In the HTML page above, the first two data-win-bind attributes are used to set the values of the innerText property of the SPAN elements. The last data-win-bind attribute is used to set the values of the IMG element’s src and alt attributes. By the way, using data-win-bind attributes is perfectly valid HTML5. The HTML5 standard enables you to add custom attributes to an HTML document just as long as the custom attributes start with the prefix data-. So you can add custom attributes to an HTML5 document with names like data-stephen, data-funky, or data-rover-dog-is-hungry and your document will validate. The product object displayed in the page above with the data-win-bind attributes is created in the default.js file: (function () { "use strict"; var app = WinJS.Application; app.onactivated = function (eventObject) { if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) { var product = { name: "Tesla", price: 80000, photo: "/images/TeslaPhoto.png" }; WinJS.Binding.processAll(null, product); } }; app.start(); })(); In the code above, a product object is created with a name, price, and photo property. The WinJS.Binding.processAll() method is called to perform the actual binding (Don’t confuse WinJS.Binding.processAll() and WinJS.UI.processAll() – these are different methods). The first parameter passed to the processAll() method represents the root element for the binding. In other words, binding happens on this element and its child elements. If you provide the value null, then binding happens on the entire body of the document (document.body). The second parameter represents the data context. This is the object that has the properties which are displayed with the data-win-bind attributes. In the code above, the product object is passed as the data context parameter. Another word for data context is view model.  Creating Complex View Models In the previous section, we used the data-win-bind attribute to display the properties of a simple object: a single product. However, you can use binding with more complex view models including view models which represent multiple objects. For example, the view model in the following default.js file represents both a customer and a product object. Furthermore, the customer object has a nested address object: (function () { "use strict"; var app = WinJS.Application; app.onactivated = function (eventObject) { if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) { var viewModel = { customer: { firstName: "Fred", lastName: "Flintstone", address: { street: "1 Rocky Way", city: "Bedrock", country: "USA" } }, product: { name: "Bowling Ball", price: 34.55 } }; WinJS.Binding.processAll(null, viewModel); } }; app.start(); })(); The following page displays the customer (including the customer address) and the product. Notice that you can use dot notation to refer to child objects in a view model such as customer.address.street. <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>Application1</title> <!-- WinJS references --> <link href="//Microsoft.WinJS.0.6/css/ui-dark.css" rel="stylesheet"> <script src="//Microsoft.WinJS.0.6/js/base.js"></script> <script src="//Microsoft.WinJS.0.6/js/ui.js"></script> <!-- Application1 references --> <link href="/css/default.css" rel="stylesheet"> <script src="/js/default.js"></script> </head> <body> <h1>Customer Details</h1> <div class="field"> First Name: <span data-win-bind="innerText:customer.firstName"></span> </div> <div class="field"> Last Name: <span data-win-bind="innerText:customer.lastName"></span> </div> <div class="field"> Address: <address> <span data-win-bind="innerText:customer.address.street"></span> <br /> <span data-win-bind="innerText:customer.address.city"></span> <br /> <span data-win-bind="innerText:customer.address.country"></span> </address> </div> <h1>Product</h1> <div class="field"> Name: <span data-win-bind="innerText:product.name"></span> </div> <div class="field"> Price: <span data-win-bind="innerText:product.price"></span> </div> </body> </html> A view model can be as complicated as you need and you can bind the view model to a view (an HTML document) by using declarative bindings. Creating Calculated Properties You might want to modify a property before displaying the property. For example, you might want to format the product price property before displaying the property. You don’t want to display the raw product price “80000”. Instead, you want to display the formatted price “$80,000”. You also might need to combine multiple properties. For example, you might need to display the customer full name by combining the values of the customer first and last name properties. In these situations, it is tempting to call a function when performing binding. For example, you could create a function named fullName() which concatenates the customer first and last name. Unfortunately, the WinJS library does not support the following syntax: <span data-win-bind=”innerText:fullName()”></span> Instead, in these situations, you should create a new property in your view model that has a getter. For example, the customer object in the following default.js file includes a property named fullName which combines the values of the firstName and lastName properties: (function () { "use strict"; var app = WinJS.Application; app.onactivated = function (eventObject) { if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) { var customer = { firstName: "Fred", lastName: "Flintstone", get fullName() { return this.firstName + " " + this.lastName; } }; WinJS.Binding.processAll(null, customer); } }; app.start(); })(); The customer object has a firstName, lastName, and fullName property. Notice that the fullName property is defined with a getter function. When you read the fullName property, the values of the firstName and lastName properties are concatenated and returned. The following HTML page displays the fullName property in an H1 element. You can use the fullName property in a data-win-bind attribute in exactly the same way as any other property. <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>Application1</title> <!-- WinJS references --> <link href="//Microsoft.WinJS.0.6/css/ui-dark.css" rel="stylesheet"> <script src="//Microsoft.WinJS.0.6/js/base.js"></script> <script src="//Microsoft.WinJS.0.6/js/ui.js"></script> <!-- Application1 references --> <link href="/css/default.css" rel="stylesheet"> <script src="/js/default.js"></script> </head> <body> <h1 data-win-bind="innerText:fullName"></h1> <div class="field"> First Name: <span data-win-bind="innerText:firstName"></span> </div> <div class="field"> Last Name: <span data-win-bind="innerText:lastName"></span> </div> </body> </html> Creating a Converter In the previous section, you learned how to format the value of a property by creating a property with a getter. This approach makes sense when the formatting logic is specific to a particular view model. If, on the other hand, you need to perform the same type of formatting for multiple view models then it makes more sense to create a converter function. A converter function is a function which you can apply whenever you are using the data-win-bind attribute. Imagine, for example, that you want to create a general function for displaying dates. You always want to display dates using a short format such as 12/25/1988. The following JavaScript file – named converters.js – contains a shortDate() converter: (function (WinJS) { var shortDate = WinJS.Binding.converter(function (date) { return date.getMonth() + 1 + "/" + date.getDate() + "/" + date.getFullYear(); }); // Export shortDate WinJS.Namespace.define("MyApp.Converters", { shortDate: shortDate }); })(WinJS); The file above uses the Module Pattern, a pattern which is used through the WinJS library. To learn more about the Module Pattern, see my blog entry on namespaces and modules: http://stephenwalther.com/blog/archive/2012/02/22/windows-web-applications-namespaces-and-modules.aspx The file contains the definition for a converter function named shortDate(). This function converts a JavaScript date object into a short date string such as 12/1/1988. The converter function is created with the help of the WinJS.Binding.converter() method. This method takes a normal function and converts it into a converter function. Finally, the shortDate() converter is added to the MyApp.Converters namespace. You can call the shortDate() function by calling MyApp.Converters.shortDate(). The default.js file contains the customer object that we want to bind. Notice that the customer object has a firstName, lastName, and birthday property. We will use our new shortDate() converter when displaying the customer birthday property: (function () { "use strict"; var app = WinJS.Application; app.onactivated = function (eventObject) { if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) { var customer = { firstName: "Fred", lastName: "Flintstone", birthday: new Date("12/1/1988") }; WinJS.Binding.processAll(null, customer); } }; app.start(); })(); We actually use our shortDate converter in the HTML document. The following HTML document displays all of the customer properties: <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>Application1</title> <!-- WinJS references --> <link href="//Microsoft.WinJS.0.6/css/ui-dark.css" rel="stylesheet"> <script src="//Microsoft.WinJS.0.6/js/base.js"></script> <script src="//Microsoft.WinJS.0.6/js/ui.js"></script> <!-- Application1 references --> <link href="/css/default.css" rel="stylesheet"> <script src="/js/default.js"></script> <script type="text/javascript" src="js/converters.js"></script> </head> <body> <h1>Customer Details</h1> <div class="field"> First Name: <span data-win-bind="innerText:firstName"></span> </div> <div class="field"> Last Name: <span data-win-bind="innerText:lastName"></span> </div> <div class="field"> Birthday: <span data-win-bind="innerText:birthday MyApp.Converters.shortDate"></span> </div> </body> </html> Notice the data-win-bind attribute used to display the birthday property. It looks like this: <span data-win-bind="innerText:birthday MyApp.Converters.shortDate"></span> The shortDate converter is applied to the birthday property when the birthday property is bound to the SPAN element’s innerText property. Using data-win-bindsource Normally, you pass the view model (the data context) which you want to use with the data-win-bind attributes in a page by passing the view model to the WinJS.Binding.processAll() method like this: WinJS.Binding.processAll(null, viewModel); As an alternative, you can specify the view model declaratively in your markup by using the data-win-datasource attribute. For example, the following default.js script exposes a view model with the fully-qualified name of MyWinWebApp.viewModel: (function () { "use strict"; var app = WinJS.Application; app.onactivated = function (eventObject) { if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) { // Create view model var viewModel = { customer: { firstName: "Fred", lastName: "Flintstone" }, product: { name: "Bowling Ball", price: 12.99 } }; // Export view model to be seen by universe WinJS.Namespace.define("MyWinWebApp", { viewModel: viewModel }); // Process data-win-bind attributes WinJS.Binding.processAll(); } }; app.start(); })(); In the code above, a view model which represents a customer and a product is exposed as MyWinWebApp.viewModel. The following HTML page illustrates how you can use the data-win-bindsource attribute to bind to this view model: <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>Application1</title> <!-- WinJS references --> <link href="//Microsoft.WinJS.0.6/css/ui-dark.css" rel="stylesheet"> <script src="//Microsoft.WinJS.0.6/js/base.js"></script> <script src="//Microsoft.WinJS.0.6/js/ui.js"></script> <!-- Application1 references --> <link href="/css/default.css" rel="stylesheet"> <script src="/js/default.js"></script> </head> <body> <h1>Customer Details</h1> <div data-win-bindsource="MyWinWebApp.viewModel.customer"> <div class="field"> First Name: <span data-win-bind="innerText:firstName"></span> </div> <div class="field"> Last Name: <span data-win-bind="innerText:lastName"></span> </div> </div> <h1>Product</h1> <div data-win-bindsource="MyWinWebApp.viewModel.product"> <div class="field"> Name: <span data-win-bind="innerText:name"></span> </div> <div class="field"> Price: <span data-win-bind="innerText:price"></span> </div> </div> </body> </html> The data-win-bindsource attribute is used twice in the page above: it is used with the DIV element which contains the customer details and it is used with the DIV element which contains the product details. If an element has a data-win-bindsource attribute then all of the child elements of that element are affected. The data-win-bind attributes of all of the child elements are bound to the data source represented by the data-win-bindsource attribute. Summary The focus of this blog entry was data binding using the WinJS library. You learned how to use the data-win-bind attribute to bind the properties of an HTML element to a view model. We also discussed several advanced features of data binding. We examined how to create calculated properties by including a property with a getter in your view model. We also discussed how you can create a converter function to format the value of a view model property when binding the property. Finally, you learned how to use the data-win-bindsource attribute to specify a view model declaratively.

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