Search Results

Search found 33453 results on 1339 pages for 'alias method'.

Page 217/1339 | < Previous Page | 213 214 215 216 217 218 219 220 221 222 223 224  | Next Page >

  • In Icinga (Nagios), how do I configure hosts with multiple IPs?

    - by gertvdijk
    I'm setting up Icinga (Nagios fork) and I have some machines with multiple interfaces. Some services are only listening on one of them and to check them correctly, I like to know if it's possible to have multiple IP addresses configured for a single host in Icinga. Here's a minimal example: Remote Server: eth0: 1.2.3.4 (public IP) eth1: 10.1.2.3 (private IP, secure tunnel) Apache listening on 1.2.3.4:80. (public only) OpenSSH listening on 10.1.2.3:22. (internal network only) Postfix SMTP listening on 0.0.0.0:25 (all interfaces) Icinga Server: eth0: 10.2.3.4 (private IP, internet access) Now if I define a host: define host { use generic-host host_name server1 alias server1.gertvandijk.net address 10.1.2.3 } This will not check the HTTP status correctly. And defining an additional host: define host { use generic-host host_name server1-public alias server1.gertvandijk.net address 1.2.3.4 } will check everything, but shows up as two independent hosts. Now I want to 'aggregate' these two hosts to show up as a single host, yet providing an easy configuration to check the services on their proper address. What is the most elegant number-of-configuration-lines-saving solution to this? I read about several plugins available to workaround this, but I can't figure out what is the current way to address it. Solutions go back to 2003, but I'm running Icinga 1.7.1, already capable of the address6 option, yet that triggers IPv6-only resolving on the hostname... Ideally, I wish to configure Icinga to be intelligent enough to know that the Postfix instance running on 10.1.2.3:25 is the same as 1.2.3.4:25 and thus not triggering two alarms. I guess this must have been tackled before and sysadmins have it set up now. Please share your solution to this. Thanks! :)

    Read the article

  • Time Machine is getting stuck at "Preparing to Back Up" and my Trash isn't emptying

    - by zarose
    I have encountered two separate problems, but I am putting them in the same question in case they are related. First, my Trash would not empty. It seems to be getting stuck on certain files, because I will reset my Macbook and some of the files will be deleted, and then if I remove a file or two at random, more can be deleted. Some of these files had strange characters in their names. I tried changing the names to single characters, but this did not help. Next, I attempted to backup my Macbook using Time Machine. I plugged in the HDD I've been using for this, but every time I try to start the backup, Time Machine gets stuck at "Preparing to Back Up". I definitely need to know how to fix the Time Machine problem, but I am curious how to solve the trash problem as well, and whether or not these problems are related. EDIT: Console.app logged the following this morning before I left on a trip. I did not bring the HDD with me. 6/5/12 7:41:28.312 AM com.apple.backupd: Starting standard backup 6/5/12 7:41:46.877 AM com.apple.backupd: Error -35 while resolving alias to backup target 6/5/12 7:41:58.368 AM com.apple.backupd: Backup failed with error: 19 6/5/12 7:59:08.999 AM com.apple.backupd: Starting standard backup 6/5/12 7:59:10.187 AM com.apple.backupd: Backing up to: /Volumes/Seagate 3TB Mac/Backups.backupdb 6/5/12 7:59:13.308 AM com.apple.backupd: Event store UUIDs don't match for volume: Macintosh HD 6/5/12 7:59:13.331 AM com.apple.backupd: Event store UUIDs don't match for volume: Blank 6/5/12 7:59:13.683 AM com.apple.backupd: Deep event scan at path:/ reason:must scan subdirs|new event db| 6/5/12 8:23:31.807 AM com.apple.backupd: Backup canceled. 6/5/12 8:23:33.373 AM com.apple.backupd: Stopping backup to allow backup destination disk to be unmounted or ejected. 6/5/12 9:51:21.572 PM com.apple.backupd: Starting standard backup 6/5/12 9:51:22.515 PM com.apple.backupd: Error -35 while resolving alias to backup target 6/5/12 9:51:32.741 PM com.apple.backupd: Backup failed with error: 19

    Read the article

  • Nagios send mail when server is down

    - by tzulberti
    I am using nagios 3.06 to monitor the servers. When a service is critical, it sends a mail, but when a server is down no mail is sent. Even if all the services go to critical state, no mail is sent. I have the following configuration: define command {     command_name notify-host-by-email     command_line python /etc/nagios3/send_mail.py "[Nagios] $HOSTNAME$" "******** Nagios ****\n\n Host: $HOSTNAME$\n Description: the server is down" } define command{     command_name notify-service-by-email     command_line python /etc/nagios3/send_mail.py "[Nagios] $HOSTNAME$: $SERVICEDESC$ ($NOTIFICATIONTYPE$)" "***** Nagios *****\n\nNotification Type: $NOTIFICATIONTYPE$\nService: $SERVICEDESC$\nHost: $HOSTALIAS$\nAddress: $HOSTADDRESS$\nState: $SERVICESTATE$\nDate/Time: $LONGDATETIME$\nAdditional Info:$SERVICEOUTPUT$" } The python script is a script to sent a mail. It works if I execute it from the command line, but it doesn't sents an email from nagios. What I am doing wrong? UPDATE: The contact data is: define contact{     contact_name root     alias Root     service_notification_period 24x7     host_notification_period 24x7     service_notification_options w,u,c,r     host_notification_options d,r     service_notification_commands notify-service-by-email     host_notification_commands notify-host-by-email     email [email protected] } define contactgroup{     contactgroup_name admins     alias Nagios Administrators     members root }

    Read the article

  • phpmyadmin “Forbidden: You don't have permission to access /phpmyadmin on this server.”

    - by Caterpillar
    I need to modify the file /etc/httpd/conf.d/phpMyAdmin.conf in order to allow remote users (not only localhost) to login # phpMyAdmin - Web based MySQL browser written in php # # Allows only localhost by default # # But allowing phpMyAdmin to anyone other than localhost should be considered # dangerous unless properly secured by SSL Alias /phpMyAdmin /usr/share/phpMyAdmin Alias /phpmyadmin /usr/share/phpMyAdmin <Directory "/usr/share/phpMyAdmin/"> Options Indexes FollowSymLinks MultiViews AllowOverride all Order Allow,Deny Allow from all </Directory> <Directory /usr/share/phpMyAdmin/setup/> <IfModule mod_authz_core.c> # Apache 2.4 <RequireAny> Require ip 127.0.0.1 Require ip ::1 </RequireAny> </IfModule> <IfModule !mod_authz_core.c> # Apache 2.2 Order Deny,Allow Allow from All Allow from 127.0.0.1 Allow from ::1 </IfModule> </Directory> # These directories do not require access over HTTP - taken from the original # phpMyAdmin upstream tarball # <Directory /usr/share/phpMyAdmin/libraries/> Order Deny,Allow Deny from All Allow from None </Directory> <Directory /usr/share/phpMyAdmin/setup/lib/> Order Deny,Allow Deny from All Allow from None </Directory> <Directory /usr/share/phpMyAdmin/setup/frames/> Order Deny,Allow Deny from All Allow from None </Directory> # This configuration prevents mod_security at phpMyAdmin directories from # filtering SQL etc. This may break your mod_security implementation. # #<IfModule mod_security.c> # <Directory /usr/share/phpMyAdmin/> # SecRuleInheritance Off # </Directory> #</IfModule> When I get into phpmyadmin webpage, I am not prompted for user and password, before getting the error message: Forbidden: You don't have permission to access /phpmyadmin on this server. My system is Fedora 20

    Read the article

  • Enable SSL with Jetty 8

    - by Jerec TheSith
    I received certificates from GoDaddy an I'm trying to enable SSL with Jetty but receive an error 107 SSL protocol error when connecting to https://server.com:8443 I generated the keystore using these commands : keytool -keystore keystore -import -alias gd_bundle -trustcacerts -file gd_bundle.crt keytool -keystore keystore -import -alias server.com -trustcacerts -file server.com.crt and placed it in /opt/jetty/etc/ And used the following configuration in jetty.xml : <Call name="addConnector"> <Arg> <New class="org.eclipse.jetty.server.ssl.SslSelectChannelConnector"> <Arg> <New class="org.eclipse.jetty.http.ssl.SslContextFactory"> <Set name="keyStore"><SystemProperty name="jetty.home" default="."/>/etc/keystore</Set> <Set name="keyStorePassword">**password1**</Set> <Set name="keyManagerPassword">**password1**</Set> <Set name="trustStore"><SystemProperty name="jetty.home" default="."/>/etc/keystore</Set> <Set name="trustStorePassword">**password1**</Set> </New> </Arg> <Set name="port">8443</Set> <Set name="maxIdleTime">30000</Set> <Set name="Acceptors">2</Set> <Set name="statsOn">false</Set> <Set name="lowResourcesConnections">20000</Set> <Set name="lowResourcesMaxIdleTime">5000</Set> </New> </Arg> </Call> Am I missing something in jetty's configuration ?

    Read the article

  • 400 error with nginx subdomains over https

    - by aquavitae
    Not sure what I'm doing wrong, but I'm trying to get gunicorn/django through nginx using only https. Here is my nginx configuration: upstream app_server { server unix:/srv/django/app/run/gunicorn.sock fail_timeout=0; } server { listen 80; return 301 https://$host$request_uri; } server { listen 443; server_name app.mydomain.com; ssl on; ssl_certificate /etc/nginx/ssl/nginx.crt; ssl_certificate_key /etc/nginx/ssl/nginx.key; client_max_body_size 4G; access_log /srv/django/app/logs/nginx-access.log; error_log /srv/django/app/logs/nginx-error.log; location /static/ { alias /srv/django/app/data/static/; } location /media/ { alias /wrv/django/app/data/media/; } location / { proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; proxy_set_header X-Forwarded-Proto https; proxy_set_header Host $http_host; proxy_pass http://app_server; } } I get a 400 error on app.mydomain.com, but the app is published on mydomain.com. Is there an error in my configuration?

    Read the article

  • Accessing a webpage folder with .htaccess in it via apache webdav?

    - by pingo
    I have setup webdav access in order to enable an external user to upload the content of his web page to his folder on my server that is served by apache to the web. This way he could update his web page via webdav. Now the problem is that the user requires a .htaccess file and of course .htaccess breaks webdav probably because it overrides settings. (new files cannot be uploaded anymore via webdav if below specified .htaccess exists) I am running Apache2.2.17 and this is my webdav config: Alias /folderDAV "d:/wamp/www/somewebsite/" <Location /folderDAV> Order Allow,Deny Allow from all Dav On AuthType Digest AuthName DAV-upload AuthUserFile "D:/wamp/passtore/user.passwd" AuthDigestProvider file require valid-user </Location> This config is part of my naive solution to fixing this problem. The idea was to specify an alias to the web page folder where webdav would be enabled and then set AllowOverride to none so that the .htaccess would have no effect. Of course I then found out that in <Location /> AllowOverride directive is not valid. The .htaccess file looks like this: #opencart settings Options +FollowSymlinks Options -Indexes <FilesMatch "\.(tpl|ini)"> Order deny,allow Deny from all </FilesMatch> RewriteEngine On RewriteBase / RewriteCond %{REQUEST_FILENAME} !-f RewriteCond %{REQUEST_FILENAME} !-d RewriteRule ^(.*)\?*$ index.php?_route_=$1 [L,QSA] ErrorDocument 403 /403.html deny from 1.1.1.1/19 allow from 2.2.2.2 What would be the solution here? I would like to have the web page accessible from the web but at the same time be able to access and modify it via apache's webdav (with digest auth). How would I do that? Also if possible I would like a solution that permits the existence of the .htaccess so that the user still has the power to setup access rules for his web page.

    Read the article

  • 404 with serving static files in a custom nginx configuration

    - by code90
    In my nginx configuration, I have the following: location /admin/ { alias /usr/share/php/wtlib_4/apps/admin/; location ~* .*\.php$ { try_files $uri $uri/ @php_admin; } location ~* \.(js|css|png|jpg|jpeg|gif|ico|pdf|zip|rar|air)$ { expires 7d; access_log off; } } location ~ ^/admin/modules/([^/]+)(.*\.(html|js|json|css|png|jpg|jpeg|gif|ico|pdf|zip|rar|air))$ { alias /usr/share/php/wtlib_4/modules/$1/admin/$2; } location ~ ^/admin/modules/([^/]+)(.*)$ { try_files $uri @php_admin_modules; } location @php_admin { if ($fastcgi_script_name ~ /admin(/.*\.php)$) { set $valid_fastcgi_script_name $1; } fastcgi_pass $byr_pass; fastcgi_index index.php; fastcgi_param SCRIPT_FILENAME /usr/share/php/wtlib_4/apps/admin$valid_fastcgi_script_name; fastcgi_param REDIRECT_STATUS 200; include /etc/nginx/fastcgi_params; } location @php_admin_modules { if ($fastcgi_script_name ~ /admin/modules/([^/]+)(.*)$) { set $byr_module $1; set $byr_rest $2; } fastcgi_pass $byr_pass; fastcgi_index index.php; fastcgi_param SCRIPT_FILENAME /usr/share/php/wtlib_4/modules/$byr_module/admin$byr_rest; fastcgi_param REDIRECT_STATUS 200; include /etc/nginx/fastcgi_params; } Following is the requested url which ends up with "404": http://www.{domainname}.com/admin/modules/cms/styles/cms.css Following is the error log: [error] 19551#0: *28 open() "/usr/share/php/wtlib_4/apps/admin/modules/cms/styles/cms.css" failed (2: No such file or directory), client: xxx.xxx.xxx.xxx, server: {domainname}.com, request: "GET /admin/modules/cms/styles/cms.css HTTP/1.1", host: "www.{domainname}.com" Following urls works fine: http://www.{domainname}.com/admin/modules/store/?a=manage http://www.{domainname}.com/admin/modules/cms/?a=cms.load Can anyone see what the problem could be? Thanks. PS. I am trying to migrate existing sites from apache to nginx.

    Read the article

  • Hyper-V vss-writer not making current copies [migrated]

    - by Martinnj
    I'm using diskshadow to backup live Hyper-V machines on a Windows 2008 server. The backup consists of 3 scripts, the first will create the shadow copies and expose them, the second uses robocopy to copy them to a remote location and the third unexposes the shadow copies again. The first script – the one that runs correctly but fails to do what it's supposed to: # DiskShadow script file to backup VM from a Hyper-V host # First, delete any shadow copies of the drives. System Drives needs to be included. Delete Shadows volume C: Delete Shadows volume D: Delete Shadows volume E: #Ensure that shadow copies will persist after DiskShadow has run set context persistent # make sure the path already exists set verbose on begin backup add volume D: alias VirtualDisk add volume C: alias SystemDrive # verify the "Microsoft Hyper-V VSS Writer" writer will be included in the snapshot # NOTE: The writer GUID is exclusive for this install/machine, must be changed on other machines! writer verify {66841cd4-6ded-4f4b-8f17-fd23f8ddc3de} create end backup # Backup is exposed as drive X: make sure your drive letter X is not in use Expose %VirtualDisk% X: Exit The next is just a robocopy and then an unexpose. Now, when I run the above script, I get no errors from it, except that the "BITS" writer has been excluded because none of its components are included. That's okay because I really only need the Hyper-V writer. Also I double checked the GUID for the writer, it's correct. During the time when the Hyper-V writer becomes active, 2 things will happen on the guest machines: The Debian/Linux machine will go to a saved state and restore when done, all fine. The Windows guests will "creating vss snapshop-sets" or something similar. Then X: gets exposed and I can copy the .vhd files over. The problem is, for some reason, the VHD files I get over seems to be old copies, they miss files, users and updates that are on the actual machines. I also tried putting the machines in a saved sate manually, didn't change the outcome. I hope someone here has an idea of how to solve this.

    Read the article

  • Nagios send mail when server is down

    - by tzulberti
    I am using nagios 3.06 to monitor the servers. When a service is critical, it sends a mail, but when a server is down no mail is sent. Even if all the services go to critical state, no mail is sent. I have the following configuration: define command {     command_name notify-host-by-email     command_line python /etc/nagios3/send_mail.py "[Nagios] $HOSTNAME$" "******** Nagios ****\n\n Host: $HOSTNAME$\n Description: the server is down" } define command{     command_name notify-service-by-email     command_line python /etc/nagios3/send_mail.py "[Nagios] $HOSTNAME$: $SERVICEDESC$ ($NOTIFICATIONTYPE$)" "***** Nagios *****\n\nNotification Type: $NOTIFICATIONTYPE$\nService: $SERVICEDESC$\nHost: $HOSTALIAS$\nAddress: $HOSTADDRESS$\nState: $SERVICESTATE$\nDate/Time: $LONGDATETIME$\nAdditional Info:$SERVICEOUTPUT$" } The python script is a script to sent a mail. It works if I execute it from the command line, but it doesn't sents an email from nagios. What I am doing wrong? UPDATE: The contact data is: define contact{     contact_name root     alias Root     service_notification_period 24x7     host_notification_period 24x7     service_notification_options w,u,c,r     host_notification_options d,r     service_notification_commands notify-service-by-email     host_notification_commands notify-host-by-email     email [email protected] } define contactgroup{     contactgroup_name admins     alias Nagios Administrators     members root }

    Read the article

  • Timeperiod Setting

    - by Alvin G. Matunog
    I am running Nagios 3.2.3 on CentOS 5.7 32bit and I have a bit of a problem scheduling timeperiods. Please help me. Objective, to stop monitoring during server restart (since the server will be restarted and will be restarted automatically because of updates and system backup). The restart is scheduled every 1st Sunday of every month. My monitoring runs 24x7 but during restarts I want to stop the monitoring and resume after 30 mins. So every 1st Sunday I want my schedule to be 00:00-11:30,12:00-24:00. This means that it will stop at 11:30 and resumes on 12:00nn. If I set this on every Sunday there is no problem. But if I set this time on every 1st Sundays, it stops at 11:30 but resumes on the next day (Monday) and not on 12:00nn Sunday. I don't know what I am missing. If I set on regular weekdays there is no problem. But on Offset weekdays (1st Sunday) it doesn`t work the way it should have. Here is my definition; define timeperiod{ name 1st_sunday timeperiod_name 1st_sunday alias No monitoring every 1st Sunday thursday 1 00:00-11:30,12:00-24:00 } define timeperiod{ timeperiod_name irregular alias regular checking use 1st_sunday sunday 08:30-22:00 monday 08:30-22:00 tuesday 08:30-22:00 wednesday 08:30-22:00 thursday 08:30-19:10,19:20-22:00 friday 08:30-22:00 saturday 08:30-22:00 } Can anyone help me? Please? Thank you.

    Read the article

  • apache subdomain configuration

    - by terrid25
    I seem to be having a small problem with setting up a subdomain in apache under CentOS. I have the following: <VirtualHost *:80> ServerName www.domain.co.uk ServerAlias domain.co.uk dev.domain.co.uk DocumentRoot "/var/www/html/domain/web" DirectoryIndex index.php Alias /sf /var/www/html/symfony14/web/sf <Directory "/var/www/html/domain/web"> AllowOverride All Allow from All </Directory> </VirtualHost> <Directory "/var/www/html/symfony14/web/sf"> AllowOverride All Allow from All </Directory> <VirtualHost *:80> ServerName test.domain.co.uk DocumentRoot "/var/www/html/domain_test/web" DirectoryIndex index.php Alias /sf /var/www/html/symfony14/web/sf <Directory "/var/www/html/domain_test/web"> AllowOverride All Allow from All </Directory> </VirtualHost> So going to www.domain.co.uk and domain.co.uk display the contents from /var/www/html/domain, but going to test.domain.co.uk also displays the same folder contents. Is this because of the ServerAlias ? Thanks

    Read the article

  • Spring Security beginner's question. Build failed

    - by Nitesh Panchal
    Hello, I downloaded all jar files for Spring Security 3.0 and added them to my lib folder in Netbeans 6.8. Then i added Spring framework to my web application and tried to modify applicationContext.xml as given in the pdf that shipped with Spring Security. This is it's code :- <?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:security="http://www.springframework.org/schema/security" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/security http://www.springframework.org/schema/security/spring-security-3.0.xsd"> <http auto-config='true'> <intercept-url pattern="/**" access="ROLE_USER" /> </http> <authentication-manager> <authentication-provider> <user-service> <user name="jimi" password="jimispassword" authorities="ROLE_USER, ROLE_ADMIN" /> <user name="bob" password="bobspassword" authorities="ROLE_USER" /> </user-service> </authentication-provider> </authentication-manager> <!--bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer" p:location="/WEB-INF/jdbc.properties" /> <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource" p:driverClassName="${jdbc.driverClassName}" p:url="${jdbc.url}" p:username="${jdbc.username}" p:password="${jdbc.password}" /--> <!-- ADD PERSISTENCE SUPPORT HERE (jpa, hibernate, etc) --> </beans> This is my web.xml :- <?xml version="1.0" encoding="UTF-8"?> <web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"> <listener> <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class> </listener> <servlet> <servlet-name>dispatcher</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <load-on-startup>2</load-on-startup> </servlet> <servlet-mapping> <servlet-name>dispatcher</servlet-name> <url-pattern>*.htm</url-pattern> </servlet-mapping> <session-config> <session-timeout> 30 </session-timeout> </session-config> <context-param> <param-name>contextConfigLocation</param-name> <param-value>/WEB-INF/applicationContext.xml</param-value> </context-param> <listener> <listener-class> org.springframework.web.context.ContextLoaderListener </listener-class> </listener> <listener> <listener-class> org.springframework.web.context.request.RequestContextListener </listener-class> </listener> <filter> <filter-name>springSecurityFilterChain</filter-name> <filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class> </filter> <filter-mapping> <filter-name>springSecurityFilterChain</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> <welcome-file-list> <welcome-file>redirect.jsp</welcome-file> </welcome-file-list> </web-app> My web application doesn't compile. I simply keep getting build failed. This is the stacktrace :- INFO: PWC1412: WebModule[/SpringSecurityDemo] ServletContext.log():Initializing Spring root WebApplicationContext INFO: Root WebApplicationContext: initialization started INFO: Refreshing org.springframework.web.context.support.XmlWebApplicationContext@108026d: display name [Root WebApplicationContext]; startup date [Mon Mar 22 18:23:37 PDT 2010]; root of context hierarchy INFO: Loading XML bean definitions from ServletContext resource [/WEB-INF/applicationContext.xml] SEVERE: Context initialization failed org.springframework.beans.factory.xml.XmlBeanDefinitionStoreException: Line 11 in XML document from ServletContext resource [/WEB-INF/applicationContext.xml] is invalid; nested exception is org.xml.sax.SAXParseException: cvc-complex-type.2.4.a: Invalid content was found starting with element 'http'. One of '{"http://www.springframework.org/schema/beans":description, "http://www.springframework.org/schema/beans":import, "http://www.springframework.org/schema/beans":alias, "http://www.springframework.org/schema/beans":bean, WC[##other:"http://www.springframework.org/schema/beans"]}' is expected. at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.doLoadBeanDefinitions(XmlBeanDefinitionReader.java:369) at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:313) at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:290) at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:142) at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:158) at org.springframework.web.context.support.XmlWebApplicationContext.loadBeanDefinitions(XmlWebApplicationContext.java:124) at org.springframework.web.context.support.XmlWebApplicationContext.loadBeanDefinitions(XmlWebApplicationContext.java:92) at org.springframework.context.support.AbstractRefreshableApplicationContext.refreshBeanFactory(AbstractRefreshableApplicationContext.java:97) at org.springframework.context.support.AbstractApplicationContext.obtainFreshBeanFactory(AbstractApplicationContext.java:411) at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:338) at org.springframework.web.context.ContextLoader.createWebApplicationContext(ContextLoader.java:251) at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:190) at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:45) at org.apache.catalina.core.StandardContext.contextListenerStart(StandardContext.java:4591) at com.sun.enterprise.web.WebModule.contextListenerStart(WebModule.java:535) at org.apache.catalina.core.StandardContext.start(StandardContext.java:5193) at com.sun.enterprise.web.WebModule.start(WebModule.java:499) at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:928) at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:912) at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:694) at com.sun.enterprise.web.WebContainer.loadWebModule(WebContainer.java:1933) at com.sun.enterprise.web.WebContainer.loadWebModule(WebContainer.java:1605) at com.sun.enterprise.web.WebApplication.start(WebApplication.java:90) at org.glassfish.internal.data.EngineRef.start(EngineRef.java:126) at org.glassfish.internal.data.ModuleInfo.start(ModuleInfo.java:241) at org.glassfish.internal.data.ApplicationInfo.start(ApplicationInfo.java:236) at com.sun.enterprise.v3.server.ApplicationLifecycle.deploy(ApplicationLifecycle.java:339) at com.sun.enterprise.v3.server.ApplicationLifecycle.deploy(ApplicationLifecycle.java:183) at org.glassfish.deployment.admin.DeployCommand.execute(DeployCommand.java:272) at com.sun.enterprise.v3.admin.CommandRunnerImpl$1.execute(CommandRunnerImpl.java:305) at com.sun.enterprise.v3.admin.CommandRunnerImpl.doCommand(CommandRunnerImpl.java:320) at com.sun.enterprise.v3.admin.CommandRunnerImpl.doCommand(CommandRunnerImpl.java:1176) at com.sun.enterprise.v3.admin.CommandRunnerImpl.access$900(CommandRunnerImpl.java:83) at com.sun.enterprise.v3.admin.CommandRunnerImpl$ExecutionContext.execute(CommandRunnerImpl.java:1235) at com.sun.enterprise.v3.admin.CommandRunnerImpl$ExecutionContext.execute(CommandRunnerImpl.java:1224) at com.sun.enterprise.v3.admin.AdminAdapter.doCommand(AdminAdapter.java:365) at com.sun.enterprise.v3.admin.AdminAdapter.service(AdminAdapter.java:204) at com.sun.grizzly.tcp.http11.GrizzlyAdapter.service(GrizzlyAdapter.java:166) at com.sun.enterprise.v3.server.HK2Dispatcher.dispath(HK2Dispatcher.java:100) at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:245) at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:791) at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:693) at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:954) at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:170) at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:135) at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:102) at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:88) at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:76) at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:53) at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:57) at com.sun.grizzly.ContextTask.run(ContextTask.java:69) at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:330) at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:309) at java.lang.Thread.run(Thread.java:619) Caused by: org.xml.sax.SAXParseException: cvc-complex-type.2.4.a: Invalid content was found starting with element 'http'. One of '{"http://www.springframework.org/schema/beans":description, "http://www.springframework.org/schema/beans":import, "http://www.springframework.org/schema/beans":alias, "http://www.springframework.org/schema/beans":bean, WC[##other:"http://www.springframework.org/schema/beans"]}' is expected. at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.createSAXParseException(ErrorHandlerWrapper.java:195) at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.error(ErrorHandlerWrapper.java:131) at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:384) at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:318) at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator$XSIErrorReporter.reportError(XMLSchemaValidator.java:410) at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator.reportSchemaError(XMLSchemaValidator.java:3165) at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator.handleStartElement(XMLSchemaValidator.java:1777) at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator.startElement(XMLSchemaValidator.java:685) at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.scanStartElement(XMLNSDocumentScannerImpl.java:400) at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:2747) at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:648) at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.next(XMLNSDocumentScannerImpl.java:140) at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:510) at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:807) at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:737) at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:107) at com.sun.org.apache.xerces.internal.parsers.DOMParser.parse(DOMParser.java:225) at com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:283) at org.springframework.beans.factory.xml.DefaultDocumentLoader.loadDocument(DefaultDocumentLoader.java:78) at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.doLoadBeanDefinitions(XmlBeanDefinitionReader.java:361) ... 53 more SEVERE: PWC1306: Startup of context /SpringSecurityDemo failed due to previous errors SEVERE: PWC1305: Exception during cleanup after start failed org.apache.catalina.LifecycleException: PWC2769: Manager has not yet been started at org.apache.catalina.session.StandardManager.stop(StandardManager.java:892) at org.apache.catalina.core.StandardContext.stop(StandardContext.java:5383) at com.sun.enterprise.web.WebModule.stop(WebModule.java:530) at org.apache.catalina.core.StandardContext.start(StandardContext.java:5211) at com.sun.enterprise.web.WebModule.start(WebModule.java:499) at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:928) at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:912) at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:694) at com.sun.enterprise.web.WebContainer.loadWebModule(WebContainer.java:1933) at com.sun.enterprise.web.WebContainer.loadWebModule(WebContainer.java:1605) at com.sun.enterprise.web.WebApplication.start(WebApplication.java:90) at org.glassfish.internal.data.EngineRef.start(EngineRef.java:126) at org.glassfish.internal.data.ModuleInfo.start(ModuleInfo.java:241) at org.glassfish.internal.data.ApplicationInfo.start(ApplicationInfo.java:236) at com.sun.enterprise.v3.server.ApplicationLifecycle.deploy(ApplicationLifecycle.java:339) at com.sun.enterprise.v3.server.ApplicationLifecycle.deploy(ApplicationLifecycle.java:183) at org.glassfish.deployment.admin.DeployCommand.execute(DeployCommand.java:272) at com.sun.enterprise.v3.admin.CommandRunnerImpl$1.execute(CommandRunnerImpl.java:305) at com.sun.enterprise.v3.admin.CommandRunnerImpl.doCommand(CommandRunnerImpl.java:320) at com.sun.enterprise.v3.admin.CommandRunnerImpl.doCommand(CommandRunnerImpl.java:1176) at com.sun.enterprise.v3.admin.CommandRunnerImpl.access$900(CommandRunnerImpl.java:83) at com.sun.enterprise.v3.admin.CommandRunnerImpl$ExecutionContext.execute(CommandRunnerImpl.java:1235) at com.sun.enterprise.v3.admin.CommandRunnerImpl$ExecutionContext.execute(CommandRunnerImpl.java:1224) at com.sun.enterprise.v3.admin.AdminAdapter.doCommand(AdminAdapter.java:365) at com.sun.enterprise.v3.admin.AdminAdapter.service(AdminAdapter.java:204) at com.sun.grizzly.tcp.http11.GrizzlyAdapter.service(GrizzlyAdapter.java:166) at com.sun.enterprise.v3.server.HK2Dispatcher.dispath(HK2Dispatcher.java:100) at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:245) at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:791) at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:693) at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:954) at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:170) at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:135) at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:102) at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:88) at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:76) at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:53) at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:57) at com.sun.grizzly.ContextTask.run(ContextTask.java:69) at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:330) at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:309) at java.lang.Thread.run(Thread.java:619) SEVERE: ContainerBase.addChild: start: org.apache.catalina.LifecycleException: org.springframework.beans.factory.xml.XmlBeanDefinitionStoreException: Line 11 in XML document from ServletContext resource [/WEB-INF/applicationContext.xml] is invalid; nested exception is org.xml.sax.SAXParseException: cvc-complex-type.2.4.a: Invalid content was found starting with element 'http'. One of '{"http://www.springframework.org/schema/beans":description, "http://www.springframework.org/schema/beans":import, "http://www.springframework.org/schema/beans":alias, "http://www.springframework.org/schema/beans":bean, WC[##other:"http://www.springframework.org/schema/beans"]}' is expected. at org.apache.catalina.core.StandardContext.start(StandardContext.java:5216) at com.sun.enterprise.web.WebModule.start(WebModule.java:499) at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:928) at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:912) at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:694) at com.sun.enterprise.web.WebContainer.loadWebModule(WebContainer.java:1933) at com.sun.enterprise.web.WebContainer.loadWebModule(WebContainer.java:1605) at com.sun.enterprise.web.WebApplication.start(WebApplication.java:90) at org.glassfish.internal.data.EngineRef.start(EngineRef.java:126) at org.glassfish.internal.data.ModuleInfo.start(ModuleInfo.java:241) at org.glassfish.internal.data.ApplicationInfo.start(ApplicationInfo.java:236) at com.sun.enterprise.v3.server.ApplicationLifecycle.deploy(ApplicationLifecycle.java:339) at com.sun.enterprise.v3.server.ApplicationLifecycle.deploy(ApplicationLifecycle.java:183) at org.glassfish.deployment.admin.DeployCommand.execute(DeployCommand.java:272) at com.sun.enterprise.v3.admin.CommandRunnerImpl$1.execute(CommandRunnerImpl.java:305) at com.sun.enterprise.v3.admin.CommandRunnerImpl.doCommand(CommandRunnerImpl.java:320) at com.sun.enterprise.v3.admin.CommandRunnerImpl.doCommand(CommandRunnerImpl.java:1176) at com.sun.enterprise.v3.admin.CommandRunnerImpl.access$900(CommandRunnerImpl.java:83) at com.sun.enterprise.v3.admin.CommandRunnerImpl$ExecutionContext.execute(CommandRunnerImpl.java:1235) at com.sun.enterprise.v3.admin.CommandRunnerImpl$ExecutionContext.execute(CommandRunnerImpl.java:1224) at com.sun.enterprise.v3.admin.AdminAdapter.doCommand(AdminAdapter.java:365) at com.sun.enterprise.v3.admin.AdminAdapter.service(AdminAdapter.java:204) at com.sun.grizzly.tcp.http11.GrizzlyAdapter.service(GrizzlyAdapter.java:166) at com.sun.enterprise.v3.server.HK2Dispatcher.dispath(HK2Dispatcher.java:100) at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:245) at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:791) at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:693) at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:954) at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:170) at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:135) at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:102) at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:88) at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:76) at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:53) at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:57) at com.sun.grizzly.ContextTask.run(ContextTask.java:69) at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:330) at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:309) at java.lang.Thread.run(Thread.java:619) Caused by: org.springframework.beans.factory.xml.XmlBeanDefinitionStoreException: Line 11 in XML document from ServletContext resource [/WEB-INF/applicationContext.xml] is invalid; nested exception is org.xml.sax.SAXParseException: cvc-complex-type.2.4.a: Invalid content was found starting with element 'http'. One of '{"http://www.springframework.org/schema/beans":description, "http://www.springframework.org/schema/beans":import, "http://www.springframework.org/schema/beans":alias, "http://www.springframework.org/schema/beans":bean, WC[##other:"http://www.springframework.org/schema/beans"]}' is expected. at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.doLoadBeanDefinitions(XmlBeanDefinitionReader.java:369) at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:313) at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:290) at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:142) at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:158) at org.springframework.web.context.support.XmlWebApplicationContext.loadBeanDefinitions(XmlWebApplicationContext.java:124) at org.springframework.web.context.support.XmlWebApplicationContext.loadBeanDefinitions(XmlWebApplicationContext.java:92) at org.springframework.context.support.AbstractRefreshableApplicationContext.refreshBeanFactory(AbstractRefreshableApplicationContext.java:97) at org.springframework.context.support.AbstractApplicationContext.obtainFreshBeanFactory(AbstractApplicationContext.java:411) at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:338) at org.springframework.web.context.ContextLoader.createWebApplicationContext(ContextLoader.java:251) at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:190) at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:45) at org.apache.catalina.core.StandardContext.contextListenerStart(StandardContext.java:4591) at com.sun.enterprise.web.WebModule.contextListenerStart(WebModule.java:535) at org.apache.catalina.core.StandardContext.start(StandardContext.java:5193) ... 38 more Caused by: org.xml.sax.SAXParseException: cvc-complex-type.2.4.a: Invalid content was found starting with element 'http'. One of '{"http://www.springframework.org/schema/beans":description, "http://www.springframework.org/schema/beans":import, "http://www.springframework.org/schema/beans":alias, "http://www.springframework.org/schema/beans":bean, WC[##other:"http://www.springframework.org/schema/beans"]}' is expected. at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.createSAXParseException(ErrorHandlerWrapper.java:195) at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.error(ErrorHandlerWrapper.java:131) at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:384) at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:318) at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator$XSIErrorReporter.reportError(XMLSchemaValidator.java:410) at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator.reportSchemaError(XMLSchemaValidator.java:3165) at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator.handleStartElement(XMLSchemaValidator.java:1777) at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator.startElement(XMLSchemaValidator.java:685) at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.scanStartElement(XMLNSDocumentScannerImpl.java:400) at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:2747) at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:648) at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.next(XMLNSDocumentScannerImpl.java:140) at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:510) at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:807) at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:737) at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:107) at com.sun.org.apache.xerces.internal.parsers.DOMParser.parse(DOMParser.java:225) at com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:283) at org.springframework.beans.factory.xml.DefaultDocumentLoader.loadDocument(DefaultDocumentLoader.java:78) at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.doLoadBeanDefinitions(XmlBeanDefinitionReader.java:361) ... 53 more

    Read the article

  • Interview questions about ASP.NET Web services.

    - by Jalpesh P. Vadgama
    I have seen there are lots of myth’s about asp.net web services in fresher level asp.net developers. So I decided to write a blog post about asp.net web services interview questions. Because I think this is the best way to reach fresher asp.net developers. Followings are few questions about asp.net web services. 1) What is asp.net web services? Ans: Web services are used to support http requests that formatted using xml,http and SOAP syntax. They interact with through standards xml messages through Soap. They are used to support interoperability. It has .asmx extension and .NET framework contains http handlers for web services to support http requested directly. 2) What kind of data can be returned web services web methods? Ans: It supports all the primitive data types and custom data types that can be encoded and serialized by xml. You can find more information about that from the following link. http://msdn.microsoft.com/en-us/library/bb552900.aspx 3) Is web services are only written in asp.net? Ans: No, It can be written by Java and PHP languages also. 4) Explain web method attributes in web services Ans: Web method attributes are added to a public class method to indicate that this method is exposed as a part of XML web services. You can have multiple web methods in a class. But it should be having public attributes as it will be exposed as xml web service part. You can find more information about web method attributes from following link. http://msdn.microsoft.com/en-us/library/byxd99hx(v=vs.71).aspx 5) What is SOA? Ans: SOA stands for “Services Oriented Architecture”. It is kind of service oriented architecture used to support different kind of computing platforms and applications. Web services in asp.net are one of the technologies that supports that kind of architecture.  You can call asp.net web services from any computing platforms and applications. 6) What is SOAP,WDSL and UDDI? Ans: SOAP stands “Simple Object Access protocol”. Web services will be interact with SOAP messages written in XML. SOAP is sometimes referred as “data wrapper” or “data envelope”.Its contains different xml tag that creates a whole SOAP message.  WSDL stand for “Web services Description Language”.  It is an xml document which is written according to standard specified by W3c. It is a kind of manual or document that describes how we can use and consume web service. Web services development software processes the WSDL document and generates SOAP messages that are needed for specific web service. UDDI stand for “Universal Discovery, Description and Integration”. Its is used for web services registries. You can find addresses of web services from UDDI.

    Read the article

  • Subterranean IL: Pseudo custom attributes

    - by Simon Cooper
    Custom attributes were designed to make the .NET framework extensible; if a .NET language needs to store additional metadata on an item that isn't expressible in IL, then an attribute could be applied to the IL item to represent this metadata. For instance, the C# compiler uses DecimalConstantAttribute and DateTimeConstantAttribute to represent compile-time decimal or datetime constants, which aren't allowed in pure IL, and FixedBufferAttribute to represent fixed struct fields. How attributes are compiled Within a .NET assembly are a series of tables containing all the metadata for items within the assembly; for instance, the TypeDef table stores metadata on all the types in the assembly, and MethodDef does the same for all the methods and constructors. Custom attribute information is stored in the CustomAttribute table, which has references to the IL item the attribute is applied to, the constructor used (which implies the type of attribute applied), and a binary blob representing the arguments and name/value pairs used in the attribute application. For example, the following C# class: [Obsolete("Please use MyClass2", true)] public class MyClass { // ... } corresponds to the following IL class definition: .class public MyClass { .custom instance void [mscorlib]System.ObsoleteAttribute::.ctor(string, bool) = { string('Please use MyClass2' bool(true) } // ... } and results in the following entry in the CustomAttribute table: TypeDef(MyClass) MemberRef(ObsoleteAttribute::.ctor(string, bool)) blob -> {string('Please use MyClass2' bool(true)} However, there are some attributes that don't compile in this way. Pseudo custom attributes Just like there are some concepts in a language that can't be represented in IL, there are some concepts in IL that can't be represented in a language. This is where pseudo custom attributes come into play. The most obvious of these is SerializableAttribute. Although it looks like an attribute, it doesn't compile to a CustomAttribute table entry; it instead sets the serializable bit directly within the TypeDef entry for the type. This flag is fully expressible within IL; this C#: [Serializable] public class MySerializableClass {} compiles to this IL: .class public serializable MySerializableClass {} For those interested, a full list of pseudo custom attributes is available here. For the rest of this post, I'll be concentrating on the ones that deal with P/Invoke. P/Invoke attributes P/Invoke is built right into the CLR at quite a deep level; there are 2 metadata tables within an assembly dedicated solely to p/invoke interop, and many more that affect it. Furthermore, all the attributes used to specify p/invoke methods in C# or VB have their own keywords and syntax within IL. For example, the following C# method declaration: [DllImport("mscorsn.dll", SetLastError = true)] [return: MarshalAs(UnmanagedType.U1)] private static extern bool StrongNameSignatureVerificationEx( [MarshalAs(UnmanagedType.LPWStr)] string wszFilePath, [MarshalAs(UnmanagedType.U1)] bool fForceVerification, [MarshalAs(UnmanagedType.U1)] ref bool pfWasVerified); compiles to the following IL definition: .method private static pinvokeimpl("mscorsn.dll" lasterr winapi) bool marshal(unsigned int8) StrongNameSignatureVerificationEx( string marshal(lpwstr) wszFilePath, bool marshal(unsigned int8) fForceVerification, bool& marshal(unsigned int8) pfWasVerified) cil managed preservesig {} As you can see, all the p/invoke and marshal properties are specified directly in IL, rather than using attributes. And, rather than creating entries in CustomAttribute, a whole bunch of metadata is emitted to represent this information. This single method declaration results in the following metadata being output to the assembly: A MethodDef entry containing basic information on the method Four ParamDef entries for the 3 method parameters and return type An entry in ModuleRef to mscorsn.dll An entry in ImplMap linking ModuleRef and MethodDef, along with the name of the function to import and the pinvoke options (lasterr winapi) Four FieldMarshal entries containing the marshal information for each parameter. Phew! Applying attributes Most of the time, when you apply an attribute to an element, an entry in the CustomAttribute table will be created to represent that application. However, some attributes represent concepts in IL that aren't expressible in the language you're coding in, and can instead result in a single bit change (SerializableAttribute and NonSerializedAttribute), or many extra metadata table entries (the p/invoke attributes) being emitted to the output assembly.

    Read the article

  • MongoDB usage best practices

    - by andresv
    The project I'm working on uses MongoDB for some stuff so I'm creating some documents to help developers speedup the learning curve and also avoid mistakes and help them write clean & reliable code. This is my first version of it, so I'm pretty sure I will be adding more stuff to it, so stay tuned! C# Official driver notes The 10gen official MongoDB driver should always be referenced in projects by using NUGET. Do not manually download and reference assemblies in any project. C# driver quickstart guide: http://www.mongodb.org/display/DOCS/CSharp+Driver+Quickstart Reference links C# Language Center: http://www.mongodb.org/display/DOCS/CSharp+Language+Center MongoDB Server Documentation: http://www.mongodb.org/display/DOCS/Home MongoDB Server Downloads: http://www.mongodb.org/downloads MongoDB client drivers download: http://www.mongodb.org/display/DOCS/Drivers MongoDB Community content: http://www.mongodb.org/display/DOCS/CSharp+Community+Projects Tutorials Tutorial MongoDB con ASP.NET MVC - Ejemplo Práctico (Spanish):http://geeks.ms/blogs/gperez/archive/2011/12/02/tutorial-mongodb-con-asp-net-mvc-ejemplo-pr-225-ctico.aspx MongoDB and C#:http://www.codeproject.com/Articles/87757/MongoDB-and-C C# driver LINQ tutorial:http://www.mongodb.org/display/DOCS/CSharp+Driver+LINQ+Tutorial C# driver reference: http://www.mongodb.org/display/DOCS/CSharp+Driver+Tutorial Safe Mode Connection The C# driver supports two connection modes: safe and unsafe. Safe connection mode (only applies to methods that modify data in a database like Inserts, Deletes and Updates. While the current driver defaults to unsafe mode (safeMode == false) it's recommended to always enable safe mode, and force unsafe mode on specific things we know aren't critical. When safe mode is enabled, the driver internal code calls the MongoDB "getLastError" function to ensure the last operation is completed before returning control the the caller. For more information on using safe mode and their implicancies on performance and data reliability see: http://www.mongodb.org/display/DOCS/getLastError+Command If safe mode is not enabled, all data modification calls to the database are executed asynchronously (fire & forget) without waiting for the result of the operation. This mode could be useful for creating / updating non-critical data like performance counters, usage logging and so on. It's important to know that not using safe mode implies that data loss can occur without any notification to the caller. As with any wait operation, enabling safe mode also implies dealing with timeouts. For more information about C# driver safe mode configuration see: http://www.mongodb.org/display/DOCS/CSharp+getLastError+and+SafeMode The safe mode configuration can be specified at different levels: Connection string: mongodb://hostname/?safe=true Database: when obtaining a database instance using the server.GetDatabase(name, safeMode) method Collection: when obtaining a collection instance using the database.GetCollection(name, safeMode) method Operation: for example, when executing the collection.Insert(document, safeMode) method Some useful SafeMode article: http://stackoverflow.com/questions/4604868/mongodb-c-sharp-safemode-official-driver Exception Handling The driver ensures that an exception will be thrown in case of something going wrong, in case of using safe mode (as said above, when not using safe mode no exception will be thrown no matter what the outcome of the operation is). As explained here https://groups.google.com/forum/?fromgroups#!topic/mongodb-user/mS6jIq5FUiM there is no need to check for any returned value from a driver method inserting data. With updates the situation is similar to any other relational database: if an update command doesn't affect any records, the call will suceed anyway (no exception thrown) and you manually have to check for something like "records affected". For MongoDB, an Update operation will return an instance of the "SafeModeResult" class, and you can verify the "DocumentsAffected" property to ensure the intended document was indeed updated. Note: Please remember that an Update method might return a null instance instead of an "SafeModeResult" instance when safe mode is not enabled. Useful Community Articles Comments about how MongoDB works and how that might affect your application: http://ethangunderson.com/blog/two-reasons-to-not-use-mongodb/ FourSquare using MongoDB had serious scalability problems: http://mashable.com/2010/10/07/mongodb-foursquare/ Is MongoDB a replacement for Memcached? http://www.quora.com/Is-MongoDB-a-good-replacement-for-Memcached/answer/Rick-Branson MongoDB Introduction, shell, when not to use, maintenance, upgrade, backups, memory, sharding, etc: http://www.markus-gattol.name/ws/mongodb.html MongoDB Collection level locking support: https://jira.mongodb.org/browse/SERVER-1240 MongoDB performance tips: http://www.quora.com/MongoDB/What-are-some-best-practices-for-optimal-performance-of-MongoDB-particularly-for-queries-that-involve-multiple-documents Lessons learned migrating from SQL Server to MongoDB: http://www.wireclub.com/development/TqnkQwQ8CxUYTVT90/read MongoDB replication performance: http://benshepheard.blogspot.com.ar/2011/01/mongodb-replication-performance.html

    Read the article

  • Generic Sorting using C# and Lambda Expression

    - by Haitham Khedre
    Download : GenericSortTester.zip I worked in this class from long time and I think it is a nice piece of code that I need to share , it might help other people searching for the same concept. this will help you to sort any collection easily without needing to write special code for each data type , however if you need special ordering you still can do it , leave a comment and I will see if I need to write another article to cover the other cases. I attached also a fully working example to make you able to see how do you will use that .     public static class GenericSorter { public static IOrderedEnumerable<T> Sort<T>(IEnumerable<T> toSort, Dictionary<string, SortingOrder> sortOptions) { IOrderedEnumerable<T> orderedList = null; foreach (KeyValuePair<string, SortingOrder> entry in sortOptions) { if (orderedList != null) { if (entry.Value == SortingOrder.Ascending) { orderedList = orderedList.ApplyOrder<T>(entry.Key, "ThenBy"); } else { orderedList = orderedList.ApplyOrder<T>(entry.Key,"ThenByDescending"); } } else { if (entry.Value == SortingOrder.Ascending) { orderedList = toSort.ApplyOrder<T>(entry.Key, "OrderBy"); } else { orderedList = toSort.ApplyOrder<T>(entry.Key, "OrderByDescending"); } } } return orderedList; } private static IOrderedEnumerable<T> ApplyOrder<T> (this IEnumerable<T> source, string property, string methodName) { ParameterExpression param = Expression.Parameter(typeof(T), "x"); Expression expr = param; foreach (string prop in property.Split('.')) { expr = Expression.PropertyOrField(expr, prop); } Type delegateType = typeof(Func<,>).MakeGenericType(typeof(T), expr.Type); LambdaExpression lambda = Expression.Lambda(delegateType, expr, param); MethodInfo mi = typeof(Enumerable).GetMethods().Single( method => method.Name == methodName && method.IsGenericMethodDefinition && method.GetGenericArguments().Length == 2 && method.GetParameters().Length == 2) .MakeGenericMethod(typeof(T), expr.Type); return (IOrderedEnumerable<T>)mi.Invoke (null, new object[] { source, lambda.Compile() }); } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }

    Read the article

  • Organizational characteristics that impact the selection of Development Methodology concepts applied to a project

    Based on my experience, no one really follows a specific methodology exactly as it is formally designed. In fact, the key concepts of a few methodologies are usually combined to form a hybrid methodology for each project based on the current organizational makeup and the project need/requirements to be accomplished. Organizational characteristics that impact the selection of methodology concepts applied to a project. Prior subject knowledge pertaining to a project can be critical when deciding on what methodology or combination of methodologies to apply to a project. For example, if a project is very straight forward, and the development staff has experience in developing  that are similar, then the waterfall method could possibly be the best choice because little to no research is needed  in order to complete the project tasks and there is very little need for changes to occur.  On the other hand, if the development staff has limited subject knowledge or the requirements/specification of the project could possibly change as the project progresses then the use of spiral, iterative, incremental, agile, or any combination would be preferred. The previous methodologies used by an organization typically do not change much from project to project unless the needs of a project dictate differently. For example, if the waterfall method is the preferred development methodology then most projects will be developed by the waterfall method. Depending on the time allotted to a project each day can impact the selection of a development methodology. In one example, if the staff can only devote a few hours a day to a project then the incremental methodology might be ideal because modules can be added to the final project as they are developed. On the other hand, if daily time allocation is not an issue, then a multitude of methodologies could work well for a project. Project characteristics that impact the selection of methodology concepts applied to a project. The type of project being developed can often dictate the type of methodology used for the project. Based on my experience, projects that tend to have a lot of user interaction, follow a more iterative, incremental, or agile approach typically using a prototype that develops into a final project. These methodologies desire back and forth communication between users, clients, and developers to allow for requirements to change and functionality to be enhanced. Conversely, limited interaction applications or automated services can still sometimes get away with using the waterfall or transactional approach. The timeline of a project can also force an organization to prefer a particular methodology over the rest. For instance, if the project must be completed within 24 hours, then there is very little time for discussions back and forth between clients, users and the development team. In this scenario, the waterfall method would be perfect because the only interaction with the client occurs prior to a development project to outline the system requirements, and the development team can quickly move through the software development stages in order to complete the project within the deadline. If the team had more time, then the other methodologies could also be considered because there is more time for client and users to review the project and make changes as they see fit, and/or allow for more time to review the project in order to enhance the business performance and functionality. Sometimes the client and or user involvement can dictate the selection of methodologies applied to a project. One example of this is if a client is highly motivated to get a project completed and desires to play an active part in the development process then the agile development approach would work perfectly with this client because it allows for frequent interaction between clients, users and the development team. The inverse of this situation is a client that just wants to provide the project requirements and only wants to get involved when the project is to be delivered. In this case the waterfall method would work well because there is no room for changes and no back and forth between the users, clients or the development team.

    Read the article

  • Measuring Code Quality

    - by DotNetBlues
    Several months back, I was tasked with measuring the quality of code in my organization. Foolishly, I said, "No problem." I figured that Visual Studio has a built-in code metrics tool (Analyze -> Calculate Code Metrics) and that would be a fine place to start with. I was right, but also very wrong. The Visual Studio calculates five primary metrics: Maintainability Index, Cyclomatic Complexity, Depth of Inheritance, Class Coupling, and Lines of Code. The first two are figured at the method level, the second at (primarily) the class level, and the last is a simple count. The first question any reasonable person should ask is "Which one do I look at first?" The first question any manager is going to ask is, "What one number tells me about the whole application?" My answer to both, in a way, was "Maintainability Index." Why? Because each of the other numbers represent one element of quality while MI is a composite number that includes Cyclomatic Complexity. I'd be lying if I said no consideration was given to the fact that it was abstract enough that it's harder for some surly developer (I've been known to resemble that remark) to start arguing why a high coupling or inheritance is no big deal or how complex requirements are to blame for complex code. I should also note that I don't think there is one magic bullet metric that will tell you objectively how good a code base is. There are a ton of different metrics out there, and each one was created for a specific purpose in mind and has a pet theory behind it. When you've got a group of developers who aren't accustomed to measuring code quality, picking a 0-100 scale, non-controversial metric that can be easily generated by tools you already own really isn't a bad place to start. That sort of answers the question a developer would ask, but what about the management question; how do you dashboard this stuff when Visual Studio doesn't roll up the numbers to the solution level? Since VS does roll up the MI to the project level, I thought I could just figure out what sort of weighting Microsoft used to roll method scores up to the class level and then to the namespace and project levels. I was a bit surprised by the answer: there is no weighting. That means that a class with one 1300 line method (which will score a 0 MI) and one empty constructor (which will score a 100 MI) will have an overall MI of a respectable 50. Throw in a couple of DTOs that are nothing more than getters and setters (which tend to score 95 or better) and the project ends up looking really, really healthy. The next poor bastard who has to work on the application is probably not going to be singing the praises of its maintainability, though. For the record, that 1300 line method isn't a hypothetical, either. So, what does one do with that? Well, I decided to weight the average by the Lines of Code per method. For our above example, the formula for the class's MI becomes ((1300 * 0) + (1 * 100))/1301 = .077, rounded to 0. Sounds about right. Continue the pattern for namespace, project, solution, and even multi-solution application MI scores. This can be done relatively easily by using the "export to Excel" button and running a quick formula against the data. On the short list of follow-up questions would be, "How do I improve my application's score?" That's an answer for another time, though.

    Read the article

  • Rules and advice for logging?

    - by Nick Rosencrantz
    In my organization we've put together some rules / guildelines about logging that I would like to know if you can add to or comment. We use Java but you may comment in general about loggin - rules and advice Use the correct logging level ERROR: Something has gone very wrong and need fixing immediately WARNING: The process can continue without fixing. The application should tolerate this level but the warning should always get investigated. INFO: Information that an important process is finished DEBUG. Is only used during development Make sure that you know what you're logging. Avoid that the logging influences the behavior of the application The function of the logging should be to write messages in the log. Log messages should be descriptive, clear, short and concise. There is not much use of a nonsense message when troubleshooting. Put the right properties in log4j Put in that the right method and class is written automatically. Example: Datedfile -web log4j.rootLogger=ERROR, DATEDFILE log4j.logger.org.springframework=INFO log4j.logger.waffle=ERROR log4j.logger.se.prv=INFO log4j.logger.se.prv.common.mvc=INFO log4j.logger.se.prv.omklassning=DEBUG log4j.appender.DATEDFILE=biz.minaret.log4j.DatedFileAppender log4j.appender.DATEDFILE.layout=org.apache.log4j.PatternLayout log4j.appender.DATEDFILE.layout.ConversionPattern=%d{HH:mm:ss,SSS} %-5p [%C{1}.%M] - %m%n log4j.appender.DATEDFILE.Prefix=omklassning. log4j.appender.DATEDFILE.Suffix=.log log4j.appender.DATEDFILE.Directory=//localhost/WebSphereLog/omklassning/ Log value. Please log values from the application. Log prefix. State which part of the application it is that the logging is written from, preferably with something for the project agreed prefix e.g. PANDORA_DB The amount of text. Be careful so that there is not too much logging text. It can influence the performance of the app. Loggning format: -There are several variants and methods to use with log4j but we would like a uniform use of the following format, when we log at exceptions: logger.error("PANDORA_DB2: Fel vid hämtning av frist i TP210_RAPPORTFRIST", e); In the example above it is assumed that we have set log4j properties so that it automatically write the class and the method. Always use logger and not the following: System.out.println(), System.err.println(), e.printStackTrace() If the web app uses our framework you can get very detailed error information from EJB, if using try-catch in the handler and logging according to the model above: In our project we use this conversion pattern with which method and class names are written out automatically . Here we use two different pattents for console and for datedfileappender: log4j.appender.CONSOLE.layout.ConversionPattern=%d{ABSOLUTE} %5p %c{1}:%L - %m%n log4j.appender.DATEDFILE.layout.ConversionPattern=%d [%t] %-5p %c - %m%n In both the examples above method and class wioll be written out. In the console row number will also be written our. toString() Please have a toString() for every object. EX: @Override public String toString() { StringBuilder sb = new StringBuilder(); sb.append(" DwfInformation [ "); sb.append("cc: ").append(cc); sb.append("pn: ").append(pn); sb.append("kc: ").append(kc); sb.append("numberOfPages: ").append(numberOfPages); sb.append("publicationDate: ").append(publicationDate); sb.append("version: ").append(version); sb.append(" ]"); return sb.toString(); } instead of special method which make these outputs public void printAll() { logger.info("inbet: " + getInbetInput()); logger.info("betdat: " + betdat); logger.info("betid: " + betid); logger.info("send: " + send); logger.info("appr: " + appr); logger.info("rereg: " + rereg); logger.info("NY: " + ny); logger.info("CNT: " + cnt); } So is there anything you can add, comment or find questionable with these ways of using the logging? Feel free to answer or comment even if it is not related to Java, Java and log4j is just an implementation of how this is reasoned.

    Read the article

  • Override ToString() in your Classes

    - by psheriff
    One of the reasons I love teaching is because of the questions that I get from attendees. I was giving a presentation at DevConnections and was showing a collection of Product objects. When I hovered over the variable that contained the collection, it looked like Figure 2. As you can see in the collection, I have actual product names of my videos from www.pdsa.com/videos being displayed. To get your data to appear in the data tips you must override the ToString() method in your class. To illustrate this, take the following simple Product class shown below: public class Product{  public string ProductName { get; set; }  public int ProductId { get; set; }} This class does not have an override of the ToString() method so if you create a collection of Product objects you will end up with data tips that look like Figure 1. Below is the code I used to create a collection of Product objects. I have shortened the code in this blog, but you can get the full source code for this sample by following the instructions at the bottom of this blog entry. List<Product> coll = new List<Product>();Product prod; prod = new Product()  { ProductName = "From Zero to HTML 5 in 60 Minutes",     ProductId = 1 };coll.Add(prod);prod = new Product()   { ProductName = "Architecting Applications …",     ProductId = 2 };coll.Add(prod);prod = new Product()  { ProductName = "Introduction to Windows Phone Development",    ProductId = 3 };coll.Add(prod);prod = new Product()   { ProductName = "Architecting a Business  …",     ProductId = 4 };coll.Add(prod);......   Figure 1: Class without overriding ToString() Now, go back to the Product class and add an override of the ToString() method as shown in the code listed below: public class Product{  public string ProductName { get; set; }  public int ProductId { get; set; }   public override string ToString()  {    return ProductName;  }} In this simple sample, I am just returning the ProductName property. However, you can create a whole string of information if you wish to display more data in your data tips. Just concatenate any properties you want from your class and return that string. When you now run the application and hover over the collection object you will now see something that looks like Figure 2. Figure 2: Overriding ToString() in your Class Another place the ToString() override comes in handy is if you forget to use a DisplayMemberPath in your ListBox or ComboBox. The ToString() method is called automatically when a class is bound to a list control. Summary You should always override the ToString() method in your classes as this will help you when debugging your application. Seeing relevant data immediately in the data tip without having to drill down one more layer and maybe scroll through a complete list of properties should help speed up your development process. NOTE: You can download the sample code for this article by visiting my website at http://www.pdsa.com/downloads. Select “Tips & Tricks”, then select “Override ToString” from the drop down list.  

    Read the article

  • Taking a screenshot from within a Silverlight #WP7 application

    - by Laurent Bugnion
    Often times, you want to take a screenshot of an application’s page. There can be multiple reasons. For instance, you can use this to provide an easy feedback method to beta testers. I find this super invaluable when working on integration of design in an app, and the user can take quick screenshots, attach them to an email and send them to me directly from the Windows Phone device. However, the same mechanism can also be used to provide screenshots are a feature of the app, for example if the user wants to save the current status of his application, etc. Caveats Note the following: The code requires an XNA library to save the picture to the media library. To have this, follow the steps: In your application (or class library), add a reference to Microsoft.Xna.Framework. In your code, add a “using” statement to Microsoft.Xna.Framework.Media. In the Properties folder, open WMAppManifest.xml and add the following capability: ID_CAP_MEDIALIB. The method call will fail with an exception if the device is connected to the Zune application on the PC. To avoid this, either disconnect the device when testing, or end the Zune application on the PC. While the method call will not fail on the emulator, there is no way to access the media library, so it is pretty much useless on this platform. This method only prints Silverlight elements to the output image. Other elements (such as a WebBrowser control’s content for instance) will output a black rectangle. The code public static void SaveToMediaLibrary( FrameworkElement element, string title) { try { var bmp = new WriteableBitmap(element, null); var ms = new MemoryStream(); bmp.SaveJpeg( ms, (int)element.ActualWidth, (int)element.ActualHeight, 0, 100); ms.Seek(0, SeekOrigin.Begin); var lib = new MediaLibrary(); var filePath = string.Format(title + ".jpg"); lib.SavePicture(filePath, ms); MessageBox.Show( "Saved in your media library!", "Done", MessageBoxButton.OK); } catch { MessageBox.Show( "There was an error. Please disconnect your phone from the computer before saving.", "Cannot save", MessageBoxButton.OK); } } This method can save any FrameworkElement. Typically I use it to save a whole page, but you can pass any other element to it. On line 7, we create a new WriteableBitmap. This excellent class can render a visual tree into a bitmap. Note that for even more features, you can use the great WriteableBitmapEx class library (which is open source). On lines 9 to 16, we save the WriteableBitmap to a MemoryStream. The only format supported by default is JPEG, however it is possible to convert to other formats with the ImageTools library (also open source). Lines 18 to 20 save the picture to the Windows Phone device’s media library. Using the image To retrieve the image, simply launch the Pictures library on the phone. The image will be in Saved Pictures. From here, you can share the image (by email, for instance), or synchronize it with the PC using the Zune software. Saving to other platforms It is of course possible to save to other platforms than the media library. For example, you can send the image to a web service, or save it to the isolated storage on the device. To do this, instead of using a MemoryStream, you can use any other stream (such as a web request stream, or a file stream) and save to that instead. Hopefully this code will be helpful to you! Happy coding, Laurent   Laurent Bugnion (GalaSoft) Subscribe | Twitter | Facebook | Flickr | LinkedIn

    Read the article

  • I am trying to figure out the best way to understand how to cache domain objects

    - by Brett Ryan
    I've always done this wrong, I'm sure a lot of others have too, hold a reference via a map and write through to DB etc.. I need to do this right, and I just don't know how to go about it. I know how I want my objects to be cached but not sure on how to achieve it. What complicates things is that I need to do this for a legacy system where the DB can change without notice to my application. So in the context of a web application, let's say I have a WidgetService which has several methods: Widget getWidget(); Collection<Widget> getAllWidgets(); Collection<Widget> getWidgetsByCategory(String categoryCode); Collection<Widget> getWidgetsByContainer(Integer parentContainer); Collection<Widget> getWidgetsByStatus(String status); Given this, I could decide to cache by method signature, i.e. getWidgetsByCategory("AA") would have a single cache entry, or I could cache widgets individually, which would be difficult I believe; OR, a call to any method would then first cache ALL widgets with a call to getAllWidgets() but getAllWidgets() would produce caches that match all the keys for the other method invocations. For example, take the following untested theoretical code. Collection<Widget> getAllWidgets() { Entity entity = cache.get("ALL_WIDGETS"); Collection<Widget> res; if (entity == null) { res = loadCache(); } else { res = (Collection<Widget>) entity.getValue(); } return res } Collection<Widget> loadCache() { // Get widgets from underlying DB Collection<Widget> res = db.getAllWidgets(); cache.put("ALL_WIDGETS", res); Map<String, List<Widget>> byCat = new HashMap<>(); for (Widget w : res) { // cache by different types of method calls, i.e. by category if (!byCat.containsKey(widget.getCategory()) { byCat.put(widget.getCategory(), new ArrayList<Widget>); } byCat.get(widget.getCatgory(), widget); } cacheCategories(byCat); return res; } Collection<Widget> getWidgetsByCategory(String categoryCode) { CategoryCacheKey key = new CategoryCacheKey(categoryCode); Entity ent = cache.get(key); if (entity == null) { loadCache(); } ent = cache.get(key); return ent == null ? Collections.emptyList() : (Collection<Widget>)ent.getValue(); } NOTE: I have not worked with a cache manager, the above code illustrates cache as some object that may hold caches by key/value pairs, though it's not modelled on any specific implementation. Using this I have the benefit of being able to cache all objects in the different ways they will be called with only single objects on the heap, whereas if I were to cache the method call invocation via say Spring It would (I believe) cache multiple copies of the objects. I really wish to try and understand the best ways to cache domain objects before I go down the wrong path and make it harder for myself later. I have read the documentation on the Ehcache website and found various articles of interest, but nothing to give a good solid technique. Since I'm working with an ERP system, some DB calls are very complicated, not that the DB is slow, but the business representation of the domain objects makes it very clumsy, coupled with the fact that there are actually 11 different DB's where information can be contained that this application is consolidating in a single view, this makes caching quite important.

    Read the article

  • Custom Text and Binary Payloads using WebSocket (TOTD #186)

    - by arungupta
    TOTD #185 explained how to process text and binary payloads in a WebSocket endpoint. In summary, a text payload may be received as public void receiveTextMessage(String message) {    . . . } And binary payload may be received as: public void recieveBinaryMessage(ByteBuffer message) {    . . .} As you realize, both of these methods receive the text and binary data in raw format. However you may like to receive and send the data using a POJO. This marshaling and unmarshaling can be done in the method implementation but JSR 356 API provides a cleaner way. For encoding and decoding text payload into POJO, Decoder.Text (for inbound payload) and Encoder.Text (for outbound payload) interfaces need to be implemented. A sample implementation below shows how text payload consisting of JSON structures can be encoded and decoded. public class MyMessage implements Decoder.Text<MyMessage>, Encoder.Text<MyMessage> {     private JsonObject jsonObject;    @Override    public MyMessage decode(String string) throws DecodeException {        this.jsonObject = new JsonReader(new StringReader(string)).readObject();               return this;    }     @Override    public boolean willDecode(String string) {        return true;    }     @Override    public String encode(MyMessage myMessage) throws EncodeException {        return myMessage.jsonObject.toString();    } public JsonObject getObject() { return jsonObject; }} In this implementation, the decode method decodes incoming text payload to MyMessage, the encode method encodes MyMessage for the outgoing text payload, and the willDecode method returns true or false if the message can be decoded. The encoder and decoder implementation classes need to be specified in the WebSocket endpoint as: @WebSocketEndpoint(value="/endpoint", encoders={MyMessage.class}, decoders={MyMessage.class}) public class MyEndpoint { public MyMessage receiveMessage(MyMessage message) { . . . } } Notice the updated method signature where the application is working with MyMessage instead of the raw string. Note that the encoder and decoder implementations just illustrate the point and provide no validation or exception handling. Similarly Encooder.Binary and Decoder.Binary interfaces need to be implemented for encoding and decoding binary payload. Here are some references for you: JSR 356: Java API for WebSocket - Specification (Early Draft) and Implementation (already integrated in GlassFish 4 promoted builds) TOTD #183 - Getting Started with WebSocket in GlassFish TOTD #184 - Logging WebSocket Frames using Chrome Developer Tools, Net-internals and Wireshark TOTD #185: Processing Text and Binary (Blob, ArrayBuffer, ArrayBufferView) Payload in WebSocket Subsequent blogs will discuss the following topics (not necessary in that order) ... Error handling Interface-driven WebSocket endpoint Java client API Client and Server configuration Security Subprotocols Extensions Other topics from the API

    Read the article

  • F# Objects &ndash; Integration with the other .Net Languages &ndash; Part 2

    - by MarkPearl
    So in part one of my posting I covered the real basics of object creation. Today I will hopefully dig a little deeper… My expert F# book brings up an interesting point – properties in F# are just syntactic sugar for method calls. This makes sense… for instance assume I had the following object with the property exposed called Firstname. type Person(Firstname : string, Lastname : string) = member v.Firstname = Firstname I could extend the Firstname property with the following code and everything would be hunky dory… type Person(Firstname : string, Lastname : string) = member v.Firstname = Console.WriteLine("Side Effect") Firstname   All that this would do is each time I use the property Firstname, I would see the side effect printed to the screen saying “Side Effect”. Member methods have a very similar look & feel to properties, in fact the only difference really is that you declare that parameters are being passed in. type Person(Firstname : string, Lastname : string) = member v.FullName(middleName) = Firstname + " " + middleName + " " + Lastname   In the code above, FullName requires the parameter middleName, and if viewed from another project in C# would show as a method and not a property. Precomputation Optimizations Okay, so something that is obvious once you think of it but that poses an interesting side effect of mutable value holders is pre-computation of results. All it is, is a slight difference in code but can result in quite a huge saving in performance. Basically pre-computation means you would not need to compute a value every time a method is called – but could perform the computation at the creation of the object (I hope I have got it right). In a way I battle to differentiate this from lazy evaluation but I will show an example to explain the principle. Let me try and show an example to illustrate the principle… assume the following F# module namespace myNamespace open System module myMod = let Add val1 val2 = Console.WriteLine("Compute") val1 + val2 type MathPrecompute(val1 : int, val2 : int) = let precomputedsum = Add val1 val2 member v.Sum = precomputedsum type MathNormalCompute(val1 : int, val2 : int) = member v.Sum = Add val1 val2 Now assume you have a C# console app that makes use of the objects with code similar to the following… using System; using myNamespace; namespace CSharpTest { class Program { static void Main(string[] args) { Console.WriteLine("Constructing Objects"); var myObj1 = new myMod.MathNormalCompute(10, 11); var myObj2 = new myMod.MathPrecompute(10, 11); Console.WriteLine(""); Console.WriteLine("Normal Compute Sum..."); Console.WriteLine(myObj1.Sum); Console.WriteLine(myObj1.Sum); Console.WriteLine(myObj1.Sum); Console.WriteLine(""); Console.WriteLine("Pre Compute Sum..."); Console.WriteLine(myObj2.Sum); Console.WriteLine(myObj2.Sum); Console.WriteLine(myObj2.Sum); Console.ReadKey(); } } } The output when running the console application would be as follows…. You will notice with the normal compute object that the system would call the Add function every time the method was called. With the Precompute object it only called the compute method when the object was created. Subtle, but something that could lead to major performance benefits. So… this post has gone off in a slight tangent but still related to F# objects.

    Read the article

< Previous Page | 213 214 215 216 217 218 219 220 221 222 223 224  | Next Page >