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• Problem connecting to Hsqldb via Hibernate when running a Eclipse GWT project.

  - by Toby

  Hi, I'm trying to run a simple GWT project where I'm trying to do a simple persitence via hibernate to a HSQLDB database. The database I'm using I have been using for at least 2 years with several osgi applications without any problems. So all I done is reused the same configuration and added a simple object mapping file. The problem I have is that I get a socket creation error when ever I try to persist the object with in GWT jetty. I now the database is up and running, I can telnet to it, run OSGI projects that uses the same config with out problems. This is the stack I get when running 25 [21704474@qtp-26509496-0] INFO org.hibernate.cfg.Environment - Hibernate 3.3.1.GA 30 [21704474@qtp-26509496-0] INFO org.hibernate.cfg.Environment - hibernate.properties not found 34 [21704474@qtp-26509496-0] INFO org.hibernate.cfg.Environment - Bytecode provider name : javassist 42 [21704474@qtp-26509496-0] INFO org.hibernate.cfg.Environment - using JDK 1.4 java.sql.Timestamp handling 162 [21704474@qtp-26509496-0] INFO org.hibernate.cfg.Configuration - configuring from resource: hibernate.cfg.xml 162 [21704474@qtp-26509496-0] INFO org.hibernate.cfg.Configuration - Configuration resource: hibernate.cfg.xml 268 [21704474@qtp-26509496-0] INFO org.hibernate.cfg.Configuration - Reading mappings from resource : hbm-mappings/project.hbm.xml 382 [21704474@qtp-26509496-0] INFO org.hibernate.cfg.HbmBinder - Mapping class: se.kanit.projectmgr.db.ProjectDAO - T_PROJECT 419 [21704474@qtp-26509496-0] INFO org.hibernate.cfg.Configuration - Configured SessionFactory: null 3534 [21704474@qtp-26509496-0] INFO org.hibernate.connection.DriverManagerConnectionProvider - Using Hibernate built-in connection pool (not for production use!) 3534 [21704474@qtp-26509496-0] INFO org.hibernate.connection.DriverManagerConnectionProvider - Hibernate connection pool size: 1 3534 [21704474@qtp-26509496-0] INFO org.hibernate.connection.DriverManagerConnectionProvider - autocommit mode: false 3537 [21704474@qtp-26509496-0] INFO org.hibernate.connection.DriverManagerConnectionProvider - using driver: org.hsqldb.jdbcDriver at URL: jdbc:hsqldb:hsql://localhost:1476/dirtyharry 3537 [21704474@qtp-26509496-0] INFO org.hibernate.connection.DriverManagerConnectionProvider - connection properties: {user=sa, password=****} 3594 [21704474@qtp-26509496-0] WARN org.hibernate.cfg.SettingsFactory - Could not obtain connection metadata java.sql.SQLException: socket creation error at org.hsqldb.jdbc.Util.sqlException(Unknown Source) at org.hsqldb.jdbc.jdbcConnection.(Unknown Source) at org.hsqldb.jdbcDriver.getConnection(Unknown Source) at org.hsqldb.jdbcDriver.connect(Unknown Source) at java.sql.DriverManager.getConnection(DriverManager.java:582) at java.sql.DriverManager.getConnection(DriverManager.java:154) at org.hibernate.connection.DriverManagerConnectionProvider.getConnection(DriverManagerConnectionProvider.java:133) at org.hibernate.cfg.SettingsFactory.buildSettings(SettingsFactory.java:111) at org.hibernate.cfg.Configuration.buildSettings(Configuration.java:2101) at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1325) at se.kanit.projectmgr.db.HibernateUtil.(HibernateUtil.java:24) at se.kanit.web.projectmgr.server.issues.IssuesService.addIssue(IssuesService.java:26) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at com.google.appengine.tools.development.agent.runtime.Runtime.invoke(Runtime.java:100) at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:562) at com.google.gwt.user.server.rpc.RemoteServiceServlet.processCall(RemoteServiceServlet.java:188) at com.google.gwt.user.server.rpc.RemoteServiceServlet.processPost(RemoteServiceServlet.java:224) at com.google.gwt.user.server.rpc.AbstractRemoteServiceServlet.doPost(AbstractRemoteServiceServlet.java:62) at javax.servlet.http.HttpServlet.service(HttpServlet.java:713) at javax.servlet.http.HttpServlet.service(HttpServlet.java:806) at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511) at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166) at com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(ServeBlobFilter.java:51) at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43) at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) at com.google.appengine.tools.development.StaticFileFilter.doFilter(StaticFileFilter.java:122) at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388) at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216) at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182) at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765) at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418) at com.google.apphosting.utils.jetty.DevAppEngineWebAppContext.handle(DevAppEngineWebAppContext.java:70) at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152) at com.google.appengine.tools.development.JettyContainerService$ApiProxyHandler.handle(JettyContainerService.java:349) at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152) at org.mortbay.jetty.Server.handle(Server.java:326) at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542) at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:938) at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:755) at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:218) at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404) at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:409) at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582) 3626 [21704474@qtp-26509496-0] INFO org.hibernate.dialect.Dialect - Using dialect: org.hibernate.dialect.HSQLDialect 3640 [21704474@qtp-26509496-0] INFO org.hibernate.transaction.TransactionFactoryFactory - Using default transaction strategy (direct JDBC transactions) 3644 [21704474@qtp-26509496-0] INFO org.hibernate.transaction.TransactionManagerLookupFactory - No TransactionManagerLookup configured (in JTA environment, use of read-write or transactional second-level cache is not recommended) 3644 [21704474@qtp-26509496-0] INFO org.hibernate.cfg.SettingsFactory - Automatic flush during beforeCompletion(): disabled 3644 [21704474@qtp-26509496-0] INFO org.hibernate.cfg.SettingsFactory - Automatic session close at end of transaction: disabled 3645 [21704474@qtp-26509496-0] INFO org.hibernate.cfg.SettingsFactory - Scrollable result sets: disabled 3645 [21704474@qtp-26509496-0] INFO org.hibernate.cfg.SettingsFactory - JDBC3 getGeneratedKeys(): disabled 3645 [21704474@qtp-26509496-0] INFO org.hibernate.cfg.SettingsFactory - Connection release mode: auto 3646 [21704474@qtp-26509496-0] INFO org.hibernate.cfg.SettingsFactory - Default batch fetch size: 1 3646 [21704474@qtp-26509496-0] INFO org.hibernate.cfg.SettingsFactory - Generate SQL with comments: disabled 3646 [21704474@qtp-26509496-0] INFO org.hibernate.cfg.SettingsFactory - Order SQL updates by primary key: disabled 3646 [21704474@qtp-26509496-0] INFO org.hibernate.cfg.SettingsFactory - Order SQL inserts for batching: disabled 3646 [21704474@qtp-26509496-0] INFO org.hibernate.cfg.SettingsFactory - Query translator: org.hibernate.hql.ast.ASTQueryTranslatorFactory 3651 [21704474@qtp-26509496-0] INFO org.hibernate.hql.ast.ASTQueryTranslatorFactory - Using ASTQueryTranslatorFactory 3651 [21704474@qtp-26509496-0] INFO org.hibernate.cfg.SettingsFactory - Query language substitutions: {} 3652 [21704474@qtp-26509496-0] INFO org.hibernate.cfg.SettingsFactory - JPA-QL strict compliance: disabled 3652 [21704474@qtp-26509496-0] INFO org.hibernate.cfg.SettingsFactory - Second-level cache: enabled 3652 [21704474@qtp-26509496-0] INFO org.hibernate.cfg.SettingsFactory - Query cache: disabled 3664 [21704474@qtp-26509496-0] INFO org.hibernate.cfg.SettingsFactory - Cache region factory : org.hibernate.cache.impl.bridge.RegionFactoryCacheProviderBridge 3665 [21704474@qtp-26509496-0] INFO org.hibernate.cache.impl.bridge.RegionFactoryCacheProviderBridge - Cache provider: org.hibernate.cache.NoCacheProvider 3666 [21704474@qtp-26509496-0] INFO org.hibernate.cfg.SettingsFactory - Optimize cache for minimal puts: disabled 3666 [21704474@qtp-26509496-0] INFO org.hibernate.cfg.SettingsFactory - Structured second-level cache entries: disabled 3678 [21704474@qtp-26509496-0] INFO org.hibernate.cfg.SettingsFactory - Statistics: disabled 3678 [21704474@qtp-26509496-0] INFO org.hibernate.cfg.SettingsFactory - Deleted entity synthetic identifier rollback: disabled 3678 [21704474@qtp-26509496-0] INFO org.hibernate.cfg.SettingsFactory - Default entity-mode: pojo 3679 [21704474@qtp-26509496-0] INFO org.hibernate.cfg.SettingsFactory - Named query checking : enabled 3775 [21704474@qtp-26509496-0] INFO org.hibernate.impl.SessionFactoryImpl - building session factory 4155 [21704474@qtp-26509496-0] INFO org.hibernate.impl.SessionFactoryObjectFactory - Not binding factory to JNDI, no JNDI name configured 4170 [21704474@qtp-26509496-0] INFO org.hibernate.tool.hbm2ddl.SchemaUpdate - Running hbm2ddl schema update 4170 [21704474@qtp-26509496-0] INFO org.hibernate.tool.hbm2ddl.SchemaUpdate - fetching database metadata 4171 [21704474@qtp-26509496-0] ERROR org.hibernate.tool.hbm2ddl.SchemaUpdate - could not get database metadata java.sql.SQLException: socket creation error at org.hsqldb.jdbc.Util.sqlException(Unknown Source) at org.hsqldb.jdbc.jdbcConnection.(Unknown Source) at org.hsqldb.jdbcDriver.getConnection(Unknown Source) at org.hsqldb.jdbcDriver.connect(Unknown Source) at java.sql.DriverManager.getConnection(DriverManager.java:582) at java.sql.DriverManager.getConnection(DriverManager.java:154) at org.hibernate.connection.DriverManagerConnectionProvider.getConnection(DriverManagerConnectionProvider.java:133) at org.hibernate.tool.hbm2ddl.SuppliedConnectionProviderConnectionHelper.prepare(SuppliedConnectionProviderConnectionHelper.java:51) at org.hibernate.tool.hbm2ddl.SchemaUpdate.execute(SchemaUpdate.java:168) at org.hibernate.impl.SessionFactoryImpl.(SessionFactoryImpl.java:346) at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1327) at se.kanit.projectmgr.db.HibernateUtil.(HibernateUtil.java:24) at se.kanit.web.projectmgr.server.issues.IssuesService.addIssue(IssuesService.java:26) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at com.google.appengine.tools.development.agent.runtime.Runtime.invoke(Runtime.java:100) at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:562) at com.google.gwt.user.server.rpc.RemoteServiceServlet.processCall(RemoteServiceServlet.java:188) at com.google.gwt.user.server.rpc.RemoteServiceServlet.processPost(RemoteServiceServlet.java:224) at com.google.gwt.user.server.rpc.AbstractRemoteServiceServlet.doPost(AbstractRemoteServiceServlet.java:62) at javax.servlet.http.HttpServlet.service(HttpServlet.java:713) at javax.servlet.http.HttpServlet.service(HttpServlet.java:806) at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511) at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166) at com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(ServeBlobFilter.java:51) at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43) at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) at com.google.appengine.tools.development.StaticFileFilter.doFilter(StaticFileFilter.java:122) at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388) at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216) at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182) at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765) at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418) at com.google.apphosting.utils.jetty.DevAppEngineWebAppContext.handle(DevAppEngineWebAppContext.java:70) at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152) at com.google.appengine.tools.development.JettyContainerService$ApiProxyHandler.handle(JettyContainerService.java:349) at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152) at org.mortbay.jetty.Server.handle(Server.java:326) at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542) at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:938) at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:755) at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:218) at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404) at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:409) at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582) 4172 [21704474@qtp-26509496-0] ERROR org.hibernate.tool.hbm2ddl.SchemaUpdate - could not complete schema update java.sql.SQLException: socket creation error at org.hsqldb.jdbc.Util.sqlException(Unknown Source) at org.hsqldb.jdbc.jdbcConnection.(Unknown Source) at org.hsqldb.jdbcDriver.getConnection(Unknown Source) at org.hsqldb.jdbcDriver.connect(Unknown Source) at java.sql.DriverManager.getConnection(DriverManager.java:582) at java.sql.DriverManager.getConnection(DriverManager.java:154) at org.hibernate.connection.DriverManagerConnectionProvider.getConnection(DriverManagerConnectionProvider.java:133) at org.hibernate.tool.hbm2ddl.SuppliedConnectionProviderConnectionHelper.prepare(SuppliedConnectionProviderConnectionHelper.java:51) at org.hibernate.tool.hbm2ddl.SchemaUpdate.execute(SchemaUpdate.java:168) at org.hibernate.impl.SessionFactoryImpl.(SessionFactoryImpl.java:346) at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1327) at se.kanit.projectmgr.db.HibernateUtil.(HibernateUtil.java:24) at se.kanit.web.projectmgr.server.issues.IssuesService.addIssue(IssuesService.java:26) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at com.google.appengine.tools.development.agent.runtime.Runtime.invoke(Runtime.java:100) at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:562) at com.google.gwt.user.server.rpc.RemoteServiceServlet.processCall(RemoteServiceServlet.java:188) at com.google.gwt.user.server.rpc.RemoteServiceServlet.processPost(RemoteServiceServlet.java:224) at com.google.gwt.user.server.rpc.AbstractRemoteServiceServlet.doPost(AbstractRemoteServiceServlet.java:62) at javax.servlet.http.HttpServlet.service(HttpServlet.java:713) at javax.servlet.http.HttpServlet.service(HttpServlet.java:806) at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511) at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166) at com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(ServeBlobFilter.java:51) at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43) at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) at com.google.appengine.tools.development.StaticFileFilter.doFilter(StaticFileFilter.java:122) at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388) at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216) at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182) at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765) at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418) at com.google.apphosting.utils.jetty.DevAppEngineWebAppContext.handle(DevAppEngineWebAppContext.java:70) at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152) at com.google.appengine.tools.development.JettyContainerService$ApiProxyHandler.handle(JettyContainerService.java:349) at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152) at org.mortbay.jetty.Server.handle(Server.java:326) at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542) at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:938) at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:755) at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:218) at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404) at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:409) at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582) 4293 [21704474@qtp-26509496-0] WARN org.hibernate.util.JDBCExceptionReporter - SQL Error: -80, SQLState: 08000 4293 [21704474@qtp-26509496-0] ERROR org.hibernate.util.JDBCExceptionReporter - socket creation error Cannot open connection org.hibernate.exception.JDBCConnectionException: Cannot open connection at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:97) at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66) at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:52) at org.hibernate.jdbc.ConnectionManager.openConnection(ConnectionManager.java:449) at org.hibernate.jdbc.ConnectionManager.getConnection(ConnectionManager.java:167) at org.hibernate.jdbc.JDBCContext.connection(JDBCContext.java:142) at org.hibernate.transaction.JDBCTransaction.begin(JDBCTransaction.java:85) at org.hibernate.impl.SessionImpl.beginTransaction(SessionImpl.java:1353) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at com.google.appengine.tools.development.agent.runtime.Runtime.invoke(Runtime.java:100) at org.hibernate.context.ThreadLocalSessionContext$TransactionProtectionWrapper.invoke(ThreadLocalSessionContext.java:342) at $Proxy7.beginTransaction(Unknown Source) at se.kanit.projectmgr.db.HibernateUtil.saveOrUpdate(HibernateUtil.java:115) at se.kanit.web.projectmgr.server.issues.IssuesService.addIssue(IssuesService.java:26) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at com.google.appengine.tools.development.agent.runtime.Runtime.invoke(Runtime.java:100) at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:562) at com.google.gwt.user.server.rpc.RemoteServiceServlet.processCall(RemoteServiceServlet.java:188) at com.google.gwt.user.server.rpc.RemoteServiceServlet.processPost(RemoteServiceServlet.java:224) at com.google.gwt.user.server.rpc.AbstractRemoteServiceServlet.doPost(AbstractRemoteServiceServlet.java:62) at javax.servlet.http.HttpServlet.service(HttpServlet.java:713) at javax.servlet.http.HttpServlet.service(HttpServlet.java:806) at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511) at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166) at com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(ServeBlobFilter.java:51) at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43) at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) at com.google.appengine.tools.development.StaticFileFilter.doFilter(StaticFileFilter.java:122) at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388) at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216) at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182) at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765) at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418) at com.google.apphosting.utils.jetty.DevAppEngineWebAppContext.handle(DevAppEngineWebAppContext.java:70) at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152) at com.google.appengine.tools.development.JettyContainerService$ApiProxyHandler.handle(JettyContainerService.java:349) at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152) at org.mortbay.jetty.Server.handle(Server.java:326) at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542) at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:938) at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:755) at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:218) at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404) at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:409) at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582) Caused by: java.sql.SQLException: socket creation error at org.hsqldb.jdbc.Util.sqlException(Unknown Source) at org.hsqldb.jdbc.jdbcConnection.(Unknown Source) at org.hsqldb.jdbcDriver.getConnection(Unknown Source) at org.hsqldb.jdbcDriver.connect(Unknown Source) at java.sql.DriverManager.getConnection(DriverManager.java:582) at java.sql.DriverManager.getConnection(DriverManager.java:154) at org.hibernate.connection.DriverManagerConnectionProvider.getConnection(DriverManagerConnectionProvider.java:133) at org.hibernate.jdbc.ConnectionManager.openConnection(ConnectionManager.java:446) ... 49 more Any tips and ideas are greatly appreciated. Cheers. Toby.

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• UIImagePickerController, UIImage, Memory and More!

  - by Itay

  I've noticed that there are many questions about how to handle UIImage objects, especially in conjunction with UIImagePickerController and then displaying it in a view (usually a UIImageView). Here is a collection of common questions and their answers. Feel free to edit and add your own. I obviously learnt all this information from somewhere too. Various forum posts, StackOverflow answers and my own experimenting brought me to all these solutions. Credit goes to those who posted some sample code that I've since used and modified. I don't remember who you all are - but hats off to you! How Do I Select An Image From the User's Images or From the Camera? You use UIImagePickerController. The documentation for the class gives a decent overview of how one would use it, and can be found here. Basically, you create an instance of the class, which is a modal view controller, display it, and set yourself (or some class) to be the delegate. Then you'll get notified when a user selects some form of media (movie or image in 3.0 on the 3GS), and you can do whatever you want. My Delegate Was Called - How Do I Get The Media? The delegate method signature is the following: - (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info; You should put a breakpoint in the debugger to see what's in the dictionary, but you use that to extract the media. For example: UIImage* image = [info objectForKey:UIImagePickerControllerOriginalImage]; There are other keys that work as well, all in the documentation. OK, I Got The Image, But It Doesn't Have Any Geolocation Data. What gives? Unfortunately, Apple decided that we're not worthy of this information. When they load the data into the UIImage, they strip it of all the EXIF/Geolocation data. Can I Get To The Original File Representing This Image on the Disk? Nope. For security purposes, you only get the UIImage. How Can I Look At The Underlying Pixels of the UIImage? Since the UIImage is immutable, you can't look at the direct pixels. However, you can make a copy. The code to this looks something like this: UIImage* image = ...; // An image NSData* pixelData = (NSData*) CGDataProviderCopyData(CGImageGetDataProvider(image.CGImage)); unsigned char* pixelBytes = (unsigned char *)[pixelData bytes]; // Take away the red pixel, assuming 32-bit RGBA for(int i = 0; i < [pixelData length]; i += 4) { pixelBytes[i] = 0; // red pixelBytes[i+1] = pixelBytes[i+1]; // green pixelBytes[i+2] = pixelBytes[i+2]; // blue pixelBytes[i+3] = pixelBytes[i+3]; // alpha } However, note that CGDataProviderCopyData provides you with an "immutable" reference to the data - meaning you can't change it (and you may get a BAD_ACCESS error if you do). Look at the next question if you want to see how you can modify the pixels. How Do I Modify The Pixels of the UIImage? The UIImage is immutable, meaning you can't change it. Apple posted a great article on how to get a copy of the pixels and modify them, and rather than copy and paste it here, you should just go read the article. Once you have the bitmap context as they mention in the article, you can do something similar to this to get a new UIImage with the modified pixels: CGImageRef ref = CGBitmapContextCreateImage(bitmap); UIImage* newImage = [UIImage imageWithCGImage:ref]; Do remember to release your references though, otherwise you're going to be leaking quite a bit of memory. After I Select 3 Images From The Camera, I Run Out Of Memory. Help! You have to remember that even though on disk these images take up only a few hundred kilobytes at most, that's because they're compressed as a PNG or JPG. When they are loaded into the UIImage, they become uncompressed. A quick over-the-envelope calculation would be: width x height x 4 = bytes in memory That's assuming 32-bit pixels. If you have 16-bit pixels (some JPGs are stored as RGBA-5551), then you'd replace the 4 with a 2. Now, images taken with the camera are 1600 x 1200 pixels, so let's do the math: 1600 x 1200 x 4 = 7,680,000 bytes = ~8 MB 8 MB is a lot, especially when you have a limit of around 24 MB for your application. That's why you run out of memory. OK, I Understand Why I Have No Memory. What Do I Do? There is never any reason to display images at their full resolution. The iPhone has a screen of 480 x 320 pixels, so you're just wasting space. If you find yourself in this situation, ask yourself the following question: Do I need the full resolution image? If the answer is yes, then you should save it to disk for later use. If the answer is no, then read the next part. Once you've decided what to do with the full-resolution image, then you need to create a smaller image to use for displaying. Many times you might even want several sizes for your image: a thumbnail, a full-size one for displaying, and the original full-resolution image. OK, I'm Hooked. How Do I Resize the Image? Unfortunately, there is no defined way how to resize an image. Also, it's important to note that when you resize it, you'll get a new image - you're not modifying the old one. There are a couple of methods to do the resizing. I'll present them both here, and explain the pros and cons of each. Method 1: Using UIKit + (UIImage*)imageWithImage:(UIImage*)image scaledToSize:(CGSize)newSize; { // Create a graphics image context UIGraphicsBeginImageContext(newSize); // Tell the old image to draw in this new context, with the desired // new size [image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)]; // Get the new image from the context UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext(); // End the context UIGraphicsEndImageContext(); // Return the new image. return newImage; } This method is very simple, and works great. It will also deal with the UIImageOrientation for you, meaning that you don't have to care whether the camera was sideways when the picture was taken. However, this method is not thread safe, and since thumbnailing is a relatively expensive operation (approximately ~2.5s on a 3G for a 1600 x 1200 pixel image), this is very much an operation you may want to do in the background, on a separate thread. Method 2: Using CoreGraphics + (UIImage*)imageWithImage:(UIImage*)sourceImage scaledToSize:(CGSize)newSize; { CGFloat targetWidth = targetSize.width; CGFloat targetHeight = targetSize.height; CGImageRef imageRef = [sourceImage CGImage]; CGBitmapInfo bitmapInfo = CGImageGetBitmapInfo(imageRef); CGColorSpaceRef colorSpaceInfo = CGImageGetColorSpace(imageRef); if (bitmapInfo == kCGImageAlphaNone) { bitmapInfo = kCGImageAlphaNoneSkipLast; } CGContextRef bitmap; if (sourceImage.imageOrientation == UIImageOrientationUp || sourceImage.imageOrientation == UIImageOrientationDown) { bitmap = CGBitmapContextCreate(NULL, targetWidth, targetHeight, CGImageGetBitsPerComponent(imageRef), CGImageGetBytesPerRow(imageRef), colorSpaceInfo, bitmapInfo); } else { bitmap = CGBitmapContextCreate(NULL, targetHeight, targetWidth, CGImageGetBitsPerComponent(imageRef), CGImageGetBytesPerRow(imageRef), colorSpaceInfo, bitmapInfo); } if (sourceImage.imageOrientation == UIImageOrientationLeft) { CGContextRotateCTM (bitmap, radians(90)); CGContextTranslateCTM (bitmap, 0, -targetHeight); } else if (sourceImage.imageOrientation == UIImageOrientationRight) { CGContextRotateCTM (bitmap, radians(-90)); CGContextTranslateCTM (bitmap, -targetWidth, 0); } else if (sourceImage.imageOrientation == UIImageOrientationUp) { // NOTHING } else if (sourceImage.imageOrientation == UIImageOrientationDown) { CGContextTranslateCTM (bitmap, targetWidth, targetHeight); CGContextRotateCTM (bitmap, radians(-180.)); } CGContextDrawImage(bitmap, CGRectMake(0, 0, targetWidth, targetHeight), imageRef); CGImageRef ref = CGBitmapContextCreateImage(bitmap); UIImage* newImage = [UIImage imageWithCGImage:ref]; CGContextRelease(bitmap); CGImageRelease(ref); return newImage; } The benefit of this method is that it is thread-safe, plus it takes care of all the small things (using correct color space and bitmap info, dealing with image orientation) that the UIKit version does. How Do I Resize and Maintain Aspect Ratio (like the AspectFill option)? It is very similar to the method above, and it looks like this: + (UIImage*)imageWithImage:(UIImage*)sourceImage scaledToSizeWithSameAspectRatio:(CGSize)targetSize; { CGSize imageSize = sourceImage.size; CGFloat width = imageSize.width; CGFloat height = imageSize.height; CGFloat targetWidth = targetSize.width; CGFloat targetHeight = targetSize.height; CGFloat scaleFactor = 0.0; CGFloat scaledWidth = targetWidth; CGFloat scaledHeight = targetHeight; CGPoint thumbnailPoint = CGPointMake(0.0,0.0); if (CGSizeEqualToSize(imageSize, targetSize) == NO) { CGFloat widthFactor = targetWidth / width; CGFloat heightFactor = targetHeight / height; if (widthFactor > heightFactor) { scaleFactor = widthFactor; // scale to fit height } else { scaleFactor = heightFactor; // scale to fit width } scaledWidth = width * scaleFactor; scaledHeight = height * scaleFactor; // center the image if (widthFactor > heightFactor) { thumbnailPoint.y = (targetHeight - scaledHeight) * 0.5; } else if (widthFactor < heightFactor) { thumbnailPoint.x = (targetWidth - scaledWidth) * 0.5; } } CGImageRef imageRef = [sourceImage CGImage]; CGBitmapInfo bitmapInfo = CGImageGetBitmapInfo(imageRef); CGColorSpaceRef colorSpaceInfo = CGImageGetColorSpace(imageRef); if (bitmapInfo == kCGImageAlphaNone) { bitmapInfo = kCGImageAlphaNoneSkipLast; } CGContextRef bitmap; if (sourceImage.imageOrientation == UIImageOrientationUp || sourceImage.imageOrientation == UIImageOrientationDown) { bitmap = CGBitmapContextCreate(NULL, targetWidth, targetHeight, CGImageGetBitsPerComponent(imageRef), CGImageGetBytesPerRow(imageRef), colorSpaceInfo, bitmapInfo); } else { bitmap = CGBitmapContextCreate(NULL, targetHeight, targetWidth, CGImageGetBitsPerComponent(imageRef), CGImageGetBytesPerRow(imageRef), colorSpaceInfo, bitmapInfo); } // In the right or left cases, we need to switch scaledWidth and scaledHeight, // and also the thumbnail point if (sourceImage.imageOrientation == UIImageOrientationLeft) { thumbnailPoint = CGPointMake(thumbnailPoint.y, thumbnailPoint.x); CGFloat oldScaledWidth = scaledWidth; scaledWidth = scaledHeight; scaledHeight = oldScaledWidth; CGContextRotateCTM (bitmap, radians(90)); CGContextTranslateCTM (bitmap, 0, -targetHeight); } else if (sourceImage.imageOrientation == UIImageOrientationRight) { thumbnailPoint = CGPointMake(thumbnailPoint.y, thumbnailPoint.x); CGFloat oldScaledWidth = scaledWidth; scaledWidth = scaledHeight; scaledHeight = oldScaledWidth; CGContextRotateCTM (bitmap, radians(-90)); CGContextTranslateCTM (bitmap, -targetWidth, 0); } else if (sourceImage.imageOrientation == UIImageOrientationUp) { // NOTHING } else if (sourceImage.imageOrientation == UIImageOrientationDown) { CGContextTranslateCTM (bitmap, targetWidth, targetHeight); CGContextRotateCTM (bitmap, radians(-180.)); } CGContextDrawImage(bitmap, CGRectMake(thumbnailPoint.x, thumbnailPoint.y, scaledWidth, scaledHeight), imageRef); CGImageRef ref = CGBitmapContextCreateImage(bitmap); UIImage* newImage = [UIImage imageWithCGImage:ref]; CGContextRelease(bitmap); CGImageRelease(ref); return newImage; } The method we employ here is to create a bitmap with the desired size, but draw an image that is actually larger, thus maintaining the aspect ratio. So We've Got Our Scaled Images - How Do I Save Them To Disk? This is pretty simple. Remember that we want to save a compressed version to disk, and not the uncompressed pixels. Apple provides two functions that help us with this (documentation is here): NSData* UIImagePNGRepresentation(UIImage *image); NSData* UIImageJPEGRepresentation (UIImage *image, CGFloat compressionQuality); And if you want to use them, you'd do something like: UIImage* myThumbnail = ...; // Get some image NSData* imageData = UIImagePNGRepresentation(myThumbnail); Now we're ready to save it to disk, which is the final step (say into the documents directory): // Give a name to the file NSString* imageName = @"MyImage.png"; // Now, we have to find the documents directory so we can save it // Note that you might want to save it elsewhere, like the cache directory, // or something similar. NSArray* paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); NSString* documentsDirectory = [paths objectAtIndex:0]; // Now we get the full path to the file NSString* fullPathToFile = [documentsDirectory stringByAppendingPathComponent:imageName]; // and then we write it out [imageData writeToFile:fullPathToFile atomically:NO]; You would repeat this for every version of the image you have. How Do I Load These Images Back Into Memory? Just look at the various UIImage initialization methods, such as +imageWithContentsOfFile: in the Apple documentation.

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• Can someone help me with this Java Chess game please?

  - by Chris Edwards

  Hey guys, Please can someone have a look at this code and let me know whether I am on the right track with the "check_somefigure_move"s and the "check_black/white_promotion"s please? And also any other help you can give would be greatly appreciated! Thanks! P.S. I know the code is not the best implementation, but its a template I have to follow :( Code: class Moves { private final Board B; private boolean regular; public Moves(final Board b) { B = b; regular = regular_position(); } public boolean get_regular_position() { return regular; } public void set_regular_position(final boolean new_reg) { regular = new_reg; } // checking whether B represents a "normal" position or not; // if not, then only simple checks regarding move-correctness should // be performed, only checking the direct characteristics of the figure // moved; // checks whether there is exactly one king of each colour, there are // no more figures than promotions allow, and there are no pawns on the // first or last rank; public boolean regular_position() { int[] counts = new int[256]; for (char file = 'a'; file <= 'h'; ++file) for (char rank = '1'; rank <= '8'; ++rank) ++counts[(int) B.get(file,rank)]; if (counts[Board.white_king] != 1 || counts[Board.black_king] != 1) return false; if (counts[Board.white_pawn] > 8 || counts[Board.black_pawn] > 8) return false; int count_w_promotions = 0; count_w_promotions += Math.max(counts[Board.white_queen]-1,0); count_w_promotions += Math.max(counts[Board.white_rook]-2,0); count_w_promotions += Math.max(counts[Board.white_bishop]-2,0); count_w_promotions += Math.max(counts[Board.white_knight]-2,0); if (count_w_promotions > 8 - counts[Board.white_pawn]) return false; int count_b_promotions = 0; count_b_promotions += Math.max(counts[Board.black_queen]-1,0); count_b_promotions += Math.max(counts[Board.black_rook]-2,0); count_b_promotions += Math.max(counts[Board.black_bishop]-2,0); count_b_promotions += Math.max(counts[Board.black_knight]-2,0); if (count_b_promotions > 8 - counts[Board.black_pawn]) return false; for (char file = 'a'; file <= 'h'; ++file) { final char fig1 = B.get(file,'1'); if (fig1 == Board.white_pawn || fig1 == Board.black_pawn) return false; final char fig8 = B.get(file,'8'); if (fig8 == Board.white_pawn || fig8 == Board.black_pawn) return false; } return true; } public boolean check_normal_white_move(final char file0, final char rank0, final char file1, final char rank1) { if (! Board.is_valid_white_figure(B.get(file0,rank0))) return false; if (! B.is_empty(file1,rank1) && ! Board.is_valid_black_figure(B.get(file1,rank1))) return false; if (B.get_active_colour() != 'w') return false; if (! check_move_simple(file0,rank0,file1,rank1)) return false; if (! regular) return true; final Board test_board = new Board(B); test_board.normal_white_move_0(file0,rank0,file1,rank1); final Moves test_move = new Moves(test_board); final char[] king_pos = test_move.white_king_position(); assert(king_pos.length == 2); return test_move.black_not_attacking(king_pos[0],king_pos[1]); } public boolean check_normal_black_move(final char file0, final char rank0, final char file1, final char rank1) { // ADDED THE CHECK NORMAL BLACK MOVE BASED ON THE CHECK NORMAL WHITE MOVE if (! Board.is_valid_black_figure(B.get(file0,rank0))) return false; if (! B.is_empty(file1,rank1) && ! Board.is_valid_white_figure(B.get(file1,rank1))) return false; if (B.get_active_colour() != 'b') return false; if (! check_move_simple(file0,rank0,file1,rank1)) return false; if (! regular) return true; final Board test_board = new Board(B); test_board.normal_black_move_0(file0,rank0,file1,rank1); final Moves test_move = new Moves(test_board); final char[] king_pos = test_move.black_king_position(); assert(king_pos.length == 2); return test_move.white_not_attacking(king_pos[0],king_pos[1]); } // for checking a normal move by just applying the move-rules private boolean check_move_simple(final char file0, final char rank0, final char file1, final char rank1) { final char fig = B.get(file0,rank0); if (fig == Board.white_king || fig == Board.black_king) return check_king_move(file0,rank0,file1,rank1); if (fig == Board.white_queen || fig == Board.black_queen) return check_queen_move(file0,rank0,file1,rank1); if (fig == Board.white_rook || fig == Board.black_rook) return check_rook_move(file0,rank0,file1,rank1); if (fig == Board.white_bishop || fig == Board.black_bishop) return check_bishop_move(file0,rank0,file1,rank1); if (fig == Board.white_knight || fig == Board.black_knight) return check_knight_move(file0,rank0,file1,rank1); if (fig == Board.white_pawn) return check_white_pawn_move(file0,rank0,file1,rank1); else return check_black_pawn_move(file0,rank0,file1,rank1); } private boolean check_king_move(final char file0, final char rank0, final char file1, final char rank1) { // ADDED KING MOVE int fileChange = file0 - file1; int rankChange = rank0 - rank1; return fileChange <= 1 && fileChange >= -1 && rankChange <= 1 && rankChange >= -1; } private boolean check_queen_move(final char file0, final char rank0, final char file1, final char rank1) { // ADDED QUEEN MOVE int fileChange = file0 - file1; int rankChange = rank0 - rank1; return fileChange <=8 && fileChange >= -8 && rankChange <= 8 && rankChange >= -8; } private boolean check_rook_move(final char file0, final char rank0, final char file1, final char rank1) { // ADDED ROOK MOVE int fileChange = file0 - file1; int rankChange = rank0 - rank1; return fileChange <=8 || fileChange >= -8 || rankChange <= 8 || rankChange >= -8; } private boolean check_bishop_move(final char file0, final char rank0, final char file1, final char rank1) { // ADDED BISHOP MOVE int fileChange = file0 - file1; int rankChange = rank0 - rank1; return fileChange <= 8 && rankChange <= 8 || fileChange <= 8 && rankChange >= -8 || fileChange >= -8 && rankChange >= -8 || fileChange >= -8 && rankChange <= 8; } private boolean check_knight_move(final char file0, final char rank0, final char file1, final char rank1) { // ADDED KNIGHT MOVE int fileChange = file0 - file1; int rankChange = rank0 - rank1; /* IS THIS THE CORRECT WAY? * return fileChange <= 1 && rankChange <= 2 || fileChange <= 1 && rankChange >= -2 || fileChange <= 2 && rankChange <= 1 || fileChange <= 2 && rankChange >= -1 || fileChange >= -1 && rankChange <= 2 || fileChange >= -1 && rankChange >= -2 || fileChange >= -2 && rankChange <= 1 || fileChange >= -2 && rankChange >= -1;*/ // OR IS THIS? return fileChange <= 1 || fileChange >= -1 || fileChange <= 2 || fileChange >= -2 && rankChange <= 1 || rankChange >= - 1 || rankChange <= 2 || rankChange >= -2; } private boolean check_white_pawn_move(final char file0, final char rank0, final char file1, final char rank1) { // ADDED PAWN MOVE int fileChange = file0 - file1; int rankChange = rank0 - rank1; return fileChange == 0 && rankChange <= 1; } private boolean check_black_pawn_move(final char file0, final char rank0, final char file1, final char rank1) { // ADDED PAWN MOVE int fileChange = file0 - file1; int rankChange = rank0 - rank1; return fileChange == 0 && rankChange >= -1; } public boolean check_white_kingside_castling() { // only demonstration code: final char c = B.get_white_castling(); if (c == '-' || c == 'q') return false; if (B.get_active_colour() == 'b') return false; if (B.get('e','1') != 'K') return false; if (! black_not_attacking('e','1')) return false; if (! free_white('f','1')) return false; // XXX return true; } public boolean check_white_queenside_castling() { // only demonstration code: final char c = B.get_white_castling(); if (c == '-' || c == 'k') return false; if (B.get_active_colour() == 'b') return false; // ADDED BASED ON KINGSIDE CASTLING if (B.get('e','1') != 'Q') return false; if (! black_not_attacking('e','1')) return false; if (! free_white('f','1')) return false; // XXX return true; } public boolean check_black_kingside_castling() { // only demonstration code: final char c = B.get_black_castling(); if (c == '-' || c == 'q') return false; if (B.get_active_colour() == 'w') return false; // ADDED BASED ON CHECK WHITE if (B.get('e','8') != 'K') return false; if (! black_not_attacking('e','8')) return false; if (! free_white('f','8')) return false; // XXX return true; } public boolean check_black_queenside_castling() { // only demonstration code: final char c = B.get_black_castling(); if (c == '-' || c == 'k') return false; if (B.get_active_colour() == 'w') return false; // ADDED BASED ON KINGSIDE CASTLING if (B.get('e','8') != 'Q') return false; if (! black_not_attacking('e','8')) return false; if (! free_white('f','8')) return false; // XXX return true; } public boolean check_white_promotion(final char pawn_file, final char figure) { // XXX // ADDED CHECKING FOR CORRECT FIGURE AND POSITION - ALTHOUGH IT SEEMS AS THOUGH // PAWN_FILE SHOULD BE PAWN_RANK, AS IT IS THE REACHING OF THE END RANK THAT // CAUSES PROMOTION OF A PAWN, NOT FILE if (figure == P && pawn_file == 8) { return true; } else return false; } public boolean check_black_promotion(final char pawn_file, final char figure) { // XXX // ADDED CHECKING FOR CORRECT FIGURE AND POSITION if (figure == p && pawn_file == 1) { return true; } else return false; } // checks whether black doesn't attack the field: public boolean black_not_attacking(final char file, final char rank) { // XXX return true; } public boolean free_white(final char file, final char rank) { // XXX return black_not_attacking(file,rank) && B.is_empty(file,rank); } // checks whether white doesn't attack the field: public boolean white_not_attacking(final char file, final char rank) { // XXX return true; } public boolean free_black(final char file, final char rank) { // XXX return white_not_attacking(file,rank) && B.is_empty(file,rank); } public char[] white_king_position() { for (char file = 'a'; file <= 'h'; ++file) for (char rank = '1'; rank <= '8'; ++rank) if (B.get(file,rank) == Board.white_king) { char[] result = new char[2]; result[0] = file; result[1] = rank; return result; } return new char[0]; } public char[] black_king_position() { for (char file = 'a'; file <= 'h'; ++file) for (char rank = '1'; rank <= '8'; ++rank) if (B.get(file,rank) == Board.black_king) { char[] result = new char[2]; result[0] = file; result[1] = rank; return result; } return new char[0]; } public static void main(final String[] args) { // checking regular_position { Moves m = new Moves(new Board()); assert(m.regular_position()); m = new Moves(new Board("8/8/8/8/8/8/8/8 w - - 0 1")); assert(!m.regular_position()); m = new Moves(new Board("KK6/8/8/8/8/8/8/8 w - - 0 1")); assert(!m.regular_position()); m = new Moves(new Board("kk6/8/8/8/8/8/8/8 w - - 0 1")); assert(!m.regular_position()); m = new Moves(new Board("Kk6/8/8/8/8/8/8/8 w - - 0 1")); assert(m.regular_position()); m = new Moves(new Board("Kk6/qqqqqqqq/QQQQQQQQ/Q7/q7/rrbbnn2/RRBBNN2/8 w - - 0 1")); assert(m.regular_position()); m = new Moves(new Board("Kk6/qqqqqqqq/QQQQQQQQ/Q7/q7/rrbbnn2/RRBBNN2/n7 w - - 0 1")); assert(!m.regular_position()); m = new Moves(new Board("Kk6/qqqqqqqq/QQQQQQQQ/Q7/q7/rrbbnn2/RRBBNN2/N7 w - - 0 1")); m = new Moves(new Board("Kk6/qqqqqqqq/QQQQQQQQ/Q7/q7/rrbbnn2/RRBBNN2/b7 w - - 0 1")); assert(!m.regular_position()); m = new Moves(new Board("Kk6/qqqqqqqq/QQQQQQQQ/Q7/q7/rrbbnn2/RRBBNN2/B7 w - - 0 1")); m = new Moves(new Board("Kk6/qqqqqqqq/QQQQQQQQ/Q7/q7/rrbbnn2/RRBBNN2/r7 w - - 0 1")); assert(!m.regular_position()); m = new Moves(new Board("Kk6/qqqqqqqq/QQQQQQQQ/Q7/q7/rrbbnn2/RRBBNN2/R7 w - - 0 1")); m = new Moves(new Board("Kk6/qqqqqqqq/QQQQQQQQ/Q7/q7/rrbbnn2/RRBBNN2/q7 w - - 0 1")); assert(!m.regular_position()); m = new Moves(new Board("Kk6/qqqqqqqq/QQQQQQQQ/Q7/q7/rrbbnn2/RRBBNN2/Q7 w - - 0 1")); assert(!m.regular_position()); m = new Moves(new Board("Kkp5/8/8/8/8/8/8/8 w - - 0 1")); assert(!m.regular_position()); m = new Moves(new Board("KkP5/8/8/8/8/8/8/8 w - - 0 1")); assert(!m.regular_position()); m = new Moves(new Board("Kk6/8/8/8/8/8/8/7p w - - 0 1")); assert(!m.regular_position()); m = new Moves(new Board("Kk6/8/8/8/8/8/8/7P w - - 0 1")); assert(!m.regular_position()); } // checking check_white/black_king/queenside_castling { Moves m = new Moves(new Board("4k2r/8/8/8/8/8/8/4K2R w Kk - 0 1")); assert(!m.check_white_kingside_castling()); assert(!m.check_black_kingside_castling()); assert(!m.check_white_queenside_castling()); assert(!m.check_black_queenside_castling()); m = new Moves(new Board("4k2r/8/8/8/8/8/8/4K2R b Kk - 0 1")); assert(!m.check_white_kingside_castling()); assert(!m.check_black_kingside_castling()); assert(!m.check_white_queenside_castling()); assert(!m.check_black_queenside_castling()); m = new Moves(new Board("4k2r/4pppp/8/8/8/8/4PPPP/4K2R w KQkq - 0 1")); assert(m.check_white_kingside_castling()); assert(!m.check_black_kingside_castling()); assert(!m.check_white_queenside_castling()); assert(!m.check_black_queenside_castling()); m = new Moves(new Board("4k2r/4pppp/8/8/8/8/4PPPP/4K2R b KQkq - 0 1")); assert(!m.check_white_kingside_castling()); assert(m.check_black_kingside_castling()); assert(!m.check_white_queenside_castling()); assert(!m.check_black_queenside_castling()); m = new Moves(new Board("r3k3/8/8/8/8/8/8/R3K3 w Qq - 0 1")); assert(!m.check_white_kingside_castling()); assert(!m.check_black_kingside_castling()); assert(!m.check_white_queenside_castling()); assert(!m.check_black_queenside_castling()); m = new Moves(new Board("r3k3/8/8/8/8/8/8/R3K3 b Qq - 0 1")); assert(!m.check_white_kingside_castling()); assert(!m.check_black_kingside_castling()); assert(!m.check_white_queenside_castling()); assert(!m.check_black_queenside_castling()); m = new Moves(new Board("r3k3/p7/8/8/8/8/8/R3K3 w Qq - 0 1")); assert(!m.check_white_kingside_castling()); assert(!m.check_black_kingside_castling()); assert(m.check_white_queenside_castling()); assert(!m.check_black_queenside_castling()); m = new Moves(new Board("r3k3/p7/8/8/8/8/8/R3K3 b Qq - 0 1")); assert(!m.check_white_kingside_castling()); assert(!m.check_black_kingside_castling()); assert(!m.check_white_queenside_castling()); assert(m.check_black_queenside_castling()); m = new Moves(new Board("r3k3/p7/8/8/8/n7/8/R3K3 w Qq - 0 1")); assert(!m.check_white_kingside_castling()); assert(!m.check_black_kingside_castling()); assert(!m.check_white_queenside_castling()); assert(!m.check_black_queenside_castling()); m = new Moves(new Board("r3k3/p7/B7/8/8/8/8/R3K3 b Qq - 0 1")); assert(!m.check_white_kingside_castling()); assert(!m.check_black_kingside_castling()); assert(!m.check_white_queenside_castling()); assert(!m.check_black_queenside_castling()); // XXX } } }

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• Failed to Install Xdebug

  - by burnt1ce

  've registered xdebug in php.ini (as per http://xdebug.org/docs/install) but it's not showing up when i run "php -m" or when i get a test page to run "phpinfo()". I've just installed the latest version of XAMPP. I've used both "zend_extention" and "zend_extention_ts" to specify the path of the xdebug dll. I ensured that my apache server restarted and used the latest change of my php.ini by executing "httpd -k restart". Can anyone provide any suggestions in getting xdebug to show up? Here are the contents of my php.ini file. [PHP] ;;;;;;;;;;;;;;;;;;; ; About php.ini ; ;;;;;;;;;;;;;;;;;;; ; PHP's initialization file, generally called php.ini, is responsible for ; configuring many of the aspects of PHP's behavior. ; PHP attempts to find and load this configuration from a number of locations. ; The following is a summary of its search order: ; 1. SAPI module specific location. ; 2. The PHPRC environment variable. (As of PHP 5.2.0) ; 3. A number of predefined registry keys on Windows (As of PHP 5.2.0) ; 4. Current working directory (except CLI) ; 5. The web server's directory (for SAPI modules), or directory of PHP ; (otherwise in Windows) ; 6. The directory from the --with-config-file-path compile time option, or the ; Windows directory (C:\windows or C:\winnt) ; See the PHP docs for more specific information. ; http://php.net/configuration.file ; The syntax of the file is extremely simple. Whitespace and Lines ; beginning with a semicolon are silently ignored (as you probably guessed). ; Section headers (e.g. [Foo]) are also silently ignored, even though ; they might mean something in the future. ; Directives following the section heading [PATH=/www/mysite] only ; apply to PHP files in the /www/mysite directory. Directives ; following the section heading [HOST=www.example.com] only apply to ; PHP files served from www.example.com. Directives set in these ; special sections cannot be overridden by user-defined INI files or ; at runtime. Currently, [PATH=] and [HOST=] sections only work under ; CGI/FastCGI. ; http://php.net/ini.sections ; Directives are specified using the following syntax: ; directive = value ; Directive names are *case sensitive* - foo=bar is different from FOO=bar. ; Directives are variables used to configure PHP or PHP extensions. ; There is no name validation. If PHP can't find an expected ; directive because it is not set or is mistyped, a default value will be used. ; The value can be a string, a number, a PHP constant (e.g. E_ALL or M_PI), one ; of the INI constants (On, Off, True, False, Yes, No and None) or an expression ; (e.g. E_ALL & ~E_NOTICE), a quoted string ("bar"), or a reference to a ; previously set variable or directive (e.g. ${foo}) ; Expressions in the INI file are limited to bitwise operators and parentheses: ; | bitwise OR ; ^ bitwise XOR ; & bitwise AND ; ~ bitwise NOT ; ! boolean NOT ; Boolean flags can be turned on using the values 1, On, True or Yes. ; They can be turned off using the values 0, Off, False or No. ; An empty string can be denoted by simply not writing anything after the equal ; sign, or by using the None keyword: ; foo = ; sets foo to an empty string ; foo = None ; sets foo to an empty string ; foo = "None" ; sets foo to the string 'None' ; If you use constants in your value, and these constants belong to a ; dynamically loaded extension (either a PHP extension or a Zend extension), ; you may only use these constants *after* the line that loads the extension. ;;;;;;;;;;;;;;;;;;; ; About this file ; ;;;;;;;;;;;;;;;;;;; ; PHP comes packaged with two INI files. One that is recommended to be used ; in production environments and one that is recommended to be used in ; development environments. ; php.ini-production contains settings which hold security, performance and ; best practices at its core. But please be aware, these settings may break ; compatibility with older or less security conscience applications. We ; recommending using the production ini in production and testing environments. ; php.ini-development is very similar to its production variant, except it's ; much more verbose when it comes to errors. We recommending using the ; development version only in development environments as errors shown to ; application users can inadvertently leak otherwise secure information. ;;;;;;;;;;;;;;;;;;; ; Quick Reference ; ;;;;;;;;;;;;;;;;;;; ; The following are all the settings which are different in either the production ; or development versions of the INIs with respect to PHP's default behavior. ; Please see the actual settings later in the document for more details as to why ; we recommend these changes in PHP's behavior. ; allow_call_time_pass_reference ; Default Value: On ; Development Value: Off ; Production Value: Off ; display_errors ; Default Value: On ; Development Value: On ; Production Value: Off ; display_startup_errors ; Default Value: Off ; Development Value: On ; Production Value: Off ; error_reporting ; Default Value: E_ALL & ~E_NOTICE ; Development Value: E_ALL | E_STRICT ; Production Value: E_ALL & ~E_DEPRECATED ; html_errors ; Default Value: On ; Development Value: On ; Production value: Off ; log_errors ; Default Value: Off ; Development Value: On ; Production Value: On ; magic_quotes_gpc ; Default Value: On ; Development Value: Off ; Production Value: Off ; max_input_time ; Default Value: -1 (Unlimited) ; Development Value: 60 (60 seconds) ; Production Value: 60 (60 seconds) ; output_buffering ; Default Value: Off ; Development Value: 4096 ; Production Value: 4096 ; register_argc_argv ; Default Value: On ; Development Value: Off ; Production Value: Off ; register_long_arrays ; Default Value: On ; Development Value: Off ; Production Value: Off ; request_order ; Default Value: None ; Development Value: "GP" ; Production Value: "GP" ; session.bug_compat_42 ; Default Value: On ; Development Value: On ; Production Value: Off ; session.bug_compat_warn ; Default Value: On ; Development Value: On ; Production Value: Off ; session.gc_divisor ; Default Value: 100 ; Development Value: 1000 ; Production Value: 1000 ; session.hash_bits_per_character ; Default Value: 4 ; Development Value: 5 ; Production Value: 5 ; short_open_tag ; Default Value: On ; Development Value: Off ; Production Value: Off ; track_errors ; Default Value: Off ; Development Value: On ; Production Value: Off ; url_rewriter.tags ; Default Value: "a=href,area=href,frame=src,form=,fieldset=" ; Development Value: "a=href,area=href,frame=src,input=src,form=fakeentry" ; Production Value: "a=href,area=href,frame=src,input=src,form=fakeentry" ; variables_order ; Default Value: "EGPCS" ; Development Value: "GPCS" ; Production Value: "GPCS" ;;;;;;;;;;;;;;;;;;;; ; php.ini Options ; ;;;;;;;;;;;;;;;;;;;; ; Name for user-defined php.ini (.htaccess) files. Default is ".user.ini" ;user_ini.filename = ".user.ini" ; To disable this feature set this option to empty value ;user_ini.filename = ; TTL for user-defined php.ini files (time-to-live) in seconds. Default is 300 seconds (5 minutes) ;user_ini.cache_ttl = 300 ;;;;;;;;;;;;;;;;;;;; ; Language Options ; ;;;;;;;;;;;;;;;;;;;; ; Enable the PHP scripting language engine under Apache. ; http://php.net/engine engine = On ; This directive determines whether or not PHP will recognize code between ; <? and ?> tags as PHP source which should be processed as such. It's been ; recommended for several years that you not use the short tag "short cut" and ; instead to use the full <?php and ?> tag combination. With the wide spread use ; of XML and use of these tags by other languages, the server can become easily ; confused and end up parsing the wrong code in the wrong context. But because ; this short cut has been a feature for such a long time, it's currently still ; supported for backwards compatibility, but we recommend you don't use them. ; Default Value: On ; Development Value: Off ; Production Value: Off ; http://php.net/short-open-tag short_open_tag = Off ; Allow ASP-style <% %> tags. ; http://php.net/asp-tags asp_tags = Off ; The number of significant digits displayed in floating point numbers. ; http://php.net/precision precision = 14 ; Enforce year 2000 compliance (will cause problems with non-compliant browsers) ; http://php.net/y2k-compliance y2k_compliance = On ; Output buffering is a mechanism for controlling how much output data ; (excluding headers and cookies) PHP should keep internally before pushing that ; data to the client. If your application's output exceeds this setting, PHP ; will send that data in chunks of roughly the size you specify. ; Turning on this setting and managing its maximum buffer size can yield some ; interesting side-effects depending on your application and web server. ; You may be able to send headers and cookies after you've already sent output ; through print or echo. You also may see performance benefits if your server is ; emitting less packets due to buffered output versus PHP streaming the output ; as it gets it. On production servers, 4096 bytes is a good setting for performance ; reasons. ; Note: Output buffering can also be controlled via Output Buffering Control ; functions. ; Possible Values: ; On = Enabled and buffer is unlimited. (Use with caution) ; Off = Disabled ; Integer = Enables the buffer and sets its maximum size in bytes. ; Note: This directive is hardcoded to Off for the CLI SAPI ; Default Value: Off ; Development Value: 4096 ; Production Value: 4096 ; http://php.net/output-buffering output_buffering = Off ; You can redirect all of the output of your scripts to a function. For ; example, if you set output_handler to "mb_output_handler", character ; encoding will be transparently converted to the specified encoding. ; Setting any output handler automatically turns on output buffering. ; Note: People who wrote portable scripts should not depend on this ini ; directive. Instead, explicitly set the output handler using ob_start(). ; Using this ini directive may cause problems unless you know what script ; is doing. ; Note: You cannot use both "mb_output_handler" with "ob_iconv_handler" ; and you cannot use both "ob_gzhandler" and "zlib.output_compression". ; Note: output_handler must be empty if this is set 'On' !!!! ; Instead you must use zlib.output_handler. ; http://php.net/output-handler ;output_handler = ; Transparent output compression using the zlib library ; Valid values for this option are 'off', 'on', or a specific buffer size ; to be used for compression (default is 4KB) ; Note: Resulting chunk size may vary due to nature of compression. PHP ; outputs chunks that are few hundreds bytes each as a result of ; compression. If you prefer a larger chunk size for better ; performance, enable output_buffering in addition. ; Note: You need to use zlib.output_handler instead of the standard ; output_handler, or otherwise the output will be corrupted. ; http://php.net/zlib.output-compression zlib.output_compression = Off ; http://php.net/zlib.output-compression-level ;zlib.output_compression_level = -1 ; You cannot specify additional output handlers if zlib.output_compression ; is activated here. This setting does the same as output_handler but in ; a different order. ; http://php.net/zlib.output-handler ;zlib.output_handler = ; Implicit flush tells PHP to tell the output layer to flush itself ; automatically after every output block. This is equivalent to calling the ; PHP function flush() after each and every call to print() or echo() and each ; and every HTML block. Turning this option on has serious performance ; implications and is generally recommended for debugging purposes only. ; http://php.net/implicit-flush ; Note: This directive is hardcoded to On for the CLI SAPI implicit_flush = Off ; The unserialize callback function will be called (with the undefined class' ; name as parameter), if the unserializer finds an undefined class ; which should be instantiated. A warning appears if the specified function is ; not defined, or if the function doesn't include/implement the missing class. ; So only set this entry, if you really want to implement such a ; callback-function. unserialize_callback_func = ; When floats & doubles are serialized store serialize_precision significant ; digits after the floating point. The default value ensures that when floats ; are decoded with unserialize, the data will remain the same. serialize_precision = 100 ; This directive allows you to enable and disable warnings which PHP will issue ; if you pass a value by reference at function call time. Passing values by ; reference at function call time is a deprecated feature which will be removed ; from PHP at some point in the near future. The acceptable method for passing a ; value by reference to a function is by declaring the reference in the functions ; definition, not at call time. This directive does not disable this feature, it ; only determines whether PHP will warn you about it or not. These warnings ; should enabled in development environments only. ; Default Value: On (Suppress warnings) ; Development Value: Off (Issue warnings) ; Production Value: Off (Issue warnings) ; http://php.net/allow-call-time-pass-reference allow_call_time_pass_reference = On ; Safe Mode ; http://php.net/safe-mode safe_mode = Off ; By default, Safe Mode does a UID compare check when ; opening files. If you want to relax this to a GID compare, ; then turn on safe_mode_gid. ; http://php.net/safe-mode-gid safe_mode_gid = Off ; When safe_mode is on, UID/GID checks are bypassed when ; including files from this directory and its subdirectories. ; (directory must also be in include_path or full path must ; be used when including) ; http://php.net/safe-mode-include-dir safe_mode_include_dir = ; When safe_mode is on, only executables located in the safe_mode_exec_dir ; will be allowed to be executed via the exec family of functions. ; http://php.net/safe-mode-exec-dir safe_mode_exec_dir = ; Setting certain environment variables may be a potential security breach. ; This directive contains a comma-delimited list of prefixes. In Safe Mode, ; the user may only alter environment variables whose names begin with the ; prefixes supplied here. By default, users will only be able to set ; environment variables that begin with PHP_ (e.g. PHP_FOO=BAR). ; Note: If this directive is empty, PHP will let the user modify ANY ; environment variable! ; http://php.net/safe-mode-allowed-env-vars safe_mode_allowed_env_vars = PHP_ ; This directive contains a comma-delimited list of environment variables that ; the end user won't be able to change using putenv(). These variables will be ; protected even if safe_mode_allowed_env_vars is set to allow to change them. ; http://php.net/safe-mode-protected-env-vars safe_mode_protected_env_vars = LD_LIBRARY_PATH ; open_basedir, if set, limits all file operations to the defined directory ; and below. This directive makes most sense if used in a per-directory ; or per-virtualhost web server configuration file. This directive is ; *NOT* affected by whether Safe Mode is turned On or Off. ; http://php.net/open-basedir ;open_basedir = ; This directive allows you to disable certain functions for security reasons. ; It receives a comma-delimited list of function names. This directive is ; *NOT* affected by whether Safe Mode is turned On or Off. ; http://php.net/disable-functions disable_functions = ; This directive allows you to disable certain classes for security reasons. ; It receives a comma-delimited list of class names. This directive is ; *NOT* affected by whether Safe Mode is turned On or Off. ; http://php.net/disable-classes disable_classes = ; Colors for Syntax Highlighting mode. Anything that's acceptable in ; <span style="color: ???????"> would work. ; http://php.net/syntax-highlighting ;highlight.string = #DD0000 ;highlight.comment = #FF9900 ;highlight.keyword = #007700 ;highlight.bg = #FFFFFF ;highlight.default = #0000BB ;highlight.html = #000000 ; If enabled, the request will be allowed to complete even if the user aborts ; the request. Consider enabling it if executing long requests, which may end up ; being interrupted by the user or a browser timing out. PHP's default behavior ; is to disable this feature. ; http://php.net/ignore-user-abort ;ignore_user_abort = On ; Determines the size of the realpath cache to be used by PHP. This value should ; be increased on systems where PHP opens many files to reflect the quantity of ; the file operations performed. ; http://php.net/realpath-cache-size ;realpath_cache_size = 16k ; Duration of time, in seconds for which to cache realpath information for a given ; file or directory. For systems with rarely changing files, consider increasing this ; value. ; http://php.net/realpath-cache-ttl ;realpath_cache_ttl = 120 ;;;;;;;;;;;;;;;;; ; Miscellaneous ; ;;;;;;;;;;;;;;;;; ; Decides whether PHP may expose the fact that it is installed on the server ; (e.g. by adding its signature to the Web server header). It is no security ; threat in any way, but it makes it possible to determine whether you use PHP ; on your server or not. ; http://php.net/expose-php expose_php = On ;;;;;;;;;;;;;;;;;;; ; Resource Limits ; ;;;;;;;;;;;;;;;;;;; ; Maximum execution time of each script, in seconds ; http://php.net/max-execution-time ; Note: This directive is hardcoded to 0 for the CLI SAPI max_execution_time = 60 ; Maximum amount of time each script may spend parsing request data. It's a good ; idea to limit this time on productions servers in order to eliminate unexpectedly ; long running scripts. ; Note: This directive is hardcoded to -1 for the CLI SAPI ; Default Value: -1 (Unlimited) ; Development Value: 60 (60 seconds) ; Production Value: 60 (60 seconds) ; http://php.net/max-input-time max_input_time = 60 ; Maximum input variable nesting level ; http://php.net/max-input-nesting-level ;max_input_nesting_level = 64 ; Maximum amount of memory a script may consume (128MB) ; http://php.net/memory-limit memory_limit = 128M ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; Error handling and logging ; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; This directive informs PHP of which errors, warnings and notices you would like ; it to take action for. The recommended way of setting values for this ; directive is through the use of the error level constants and bitwise ; operators. The error level constants are below here for convenience as well as ; some common settings and their meanings. ; By default, PHP is set to take action on all errors, notices and warnings EXCEPT ; those related to E_NOTICE and E_STRICT, which together cover best practices and ; recommended coding standards in PHP. For performance reasons, this is the ; recommend error reporting setting. Your production server shouldn't be wasting ; resources complaining about best practices and coding standards. That's what ; development servers and development settings are for. ; Note: The php.ini-development file has this setting as E_ALL | E_STRICT. This ; means it pretty much reports everything which is exactly what you want during ; development and early testing. ; ; Error Level Constants: ; E_ALL - All errors and warnings (includes E_STRICT as of PHP 6.0.0) ; E_ERROR - fatal run-time errors ; E_RECOVERABLE_ERROR - almost fatal run-time errors ; E_WARNING - run-time warnings (non-fatal errors) ; E_PARSE - compile-time parse errors ; E_NOTICE - run-time notices (these are warnings which often result ; from a bug in your code, but it's possible that it was ; intentional (e.g., using an uninitialized variable and ; relying on the fact it's automatically initialized to an ; empty string) ; E_STRICT - run-time notices, enable to have PHP suggest changes ; to your code which will ensure the best interoperability ; and forward compatibility of your code ; E_CORE_ERROR - fatal errors that occur during PHP's initial startup ; E_CORE_WARNING - warnings (non-fatal errors) that occur during PHP's ; initial startup ; E_COMPILE_ERROR - fatal compile-time errors ; E_COMPILE_WARNING - compile-time warnings (non-fatal errors) ; E_USER_ERROR - user-generated error message ; E_USER_WARNING - user-generated warning message ; E_USER_NOTICE - user-generated notice message ; E_DEPRECATED - warn about code that will not work in future versions ; of PHP ; E_USER_DEPRECATED - user-generated deprecation warnings ; ; Common Values: ; E_ALL & ~E_NOTICE (Show all errors, except for notices and coding standards warnings.) ; E_ALL & ~E_NOTICE | E_STRICT (Show all errors, except for notices) ; E_COMPILE_ERROR|E_RECOVERABLE_ERROR|E_ERROR|E_CORE_ERROR (Show only errors) ; E_ALL | E_STRICT (Show all errors, warnings and notices including coding standards.) ; Default Value: E_ALL & ~E_NOTICE ; Development Value: E_ALL | E_STRICT ; Production Value: E_ALL & ~E_DEPRECATED ; http://php.net/error-reporting error_reporting = E_ALL & ~E_NOTICE & ~E_DEPRECATED ; This directive controls whether or not and where PHP will output errors, ; notices and warnings too. Error output is very useful during development, but ; it could be very dangerous in production environments. Depending on the code ; which is triggering the error, sensitive information could potentially leak ; out of your application such as database usernames and passwords or worse. ; It's recommended that errors be logged on production servers rather than ; having the errors sent to STDOUT. ; Possible Values: ; Off = Do not display any errors ; stderr = Display errors to STDERR (affects only CGI/CLI binaries!) ; On or stdout = Display errors to STDOUT ; Default Value: On ; Development Value: On ; Production Value: Off ; http://php.net/display-errors display_errors = On ; The display of errors which occur during PHP's startup sequence are handled ; separately from display_errors. PHP's default behavior is to suppress those ; errors from clients. Turning the display of startup errors on can be useful in ; debugging configuration problems. But, it's strongly recommended that you ; leave this setting off on production servers. ; Default Value: Off ; Development Value: On ; Production Value: Off ; http://php.net/display-startup-errors display_startup_errors = On ; Besides displaying errors, PHP can also log errors to locations such as a ; server-specific log, STDERR, or a location specified by the error_log ; directive found below. While errors should not be displayed on productions ; servers they should still be monitored and logging is a great way to do that. ; Default Value: Off ; Development Value: On ; Production Value: On ; http://php.net/log-errors log_errors = Off ; Set maximum length of log_errors. In error_log information about the source is ; added. The default is 1024 and 0 allows to not apply any maximum length at all. ; http://php.net/log-errors-max-len log_errors_max_len = 1024 ; Do not log repeated messages. Repeated errors must occur in same file on same ; line unless ignore_repeated_source is set true. ; http://php.net/ignore-repeated-errors ignore_repeated_errors = Off ; Ignore source of message when ignoring repeated messages. When this setting ; is On you will not log errors with repeated messages from different files or ; source lines. ; http://php.net/ignore-repeated-source ignore_repeated_source = Off ; If this parameter is set to Off, then memory leaks will not be shown (on ; stdout or in the log). This has only effect in a debug compile, and if ; error reporting includes E_WARNING in the allowed list ; http://php.net/report-memleaks report_memleaks = On ; This setting is on by default. ;report_zend_debug = 0 ; Store the last error/warning message in $php_errormsg (boolean). Setting this value ; to On can assist in debugging and is appropriate for development servers. It should ; however be disabled on production servers. ; Default Value: Off ; Development Value: On ; Production Value: Off ; http://php.net/track-errors track_errors = Off ; Turn off normal error reporting and emit XML-RPC error XML ; http://php.net/xmlrpc-errors ;xmlrpc_errors = 0 ; An XML-RPC faultCode ;xmlrpc_error_number = 0 ; When PHP displays or logs an error, it has the capability of inserting html ; links to documentation related to that error. This directive controls whether ; those HTML links appear in error messages or not. For performance and security ; reasons, it's recommended you disable this on production servers. ; Note: This directive is hardcoded to Off for the CLI SAPI ; Default Value: On ; Development Value: On ; Production value: Off ; http://php.net/html-errors html_errors = On ; If html_errors is set On PHP produces clickable error messages that direct ; to a page describing the error or function causing the error in detail. ; You can download a copy of the PHP manual from http://php.net/docs ; and change docref_root to the base URL of your local copy including the ; leading '/'. You must also specify the file extension being used including ; the dot. PHP's default behavior is to leave these settings empty. ; Note: Never use this feature for production boxes. ; http://php.net/docref-root ; Examples ;docref_root = "/phpmanual/" ; http://php.net/docref-ext ;docref_ext = .html ; String to output before an error message. PHP's default behavior is to leave ; this setting blank. ; http://php.net/error-prepend-string ; Example: ;error_prepend_string = "<font color=#ff0000>" ; String to output after an error message. PHP's default behavior is to leave ; this setting blank. ; http://php.net/error-append-string ; Example: ;error_append_string = "</font>" ; Log errors to specified file. PHP's default behavior is to leave this value ; empty. ; http://php.net/error-log ; Example: ;error_log = php_errors.log ; Log errors to syslog (Event Log on NT, not valid in Windows 95). ;error_log = syslog ;error_log = "C:\xampp\apache\logs\php_error.log" ;;;;;;;;;;;;;;;;; ; Data Handling ; ;;;;;;;;;;;;;;;;; ; Note - track_vars is ALWAYS enabled ; The separator used in PHP generated URLs to separate arguments. ; PHP's default setting is "&". ; http://php.net/arg-separator.output ; Example: arg_separator.output = "&amp;" ; List of separator(s) used by PHP to parse input URLs into variables. ; PHP's default setting is "&

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• What are good design practices when working with Entity Framework

  - by AD

  This will apply mostly for an asp.net application where the data is not accessed via soa. Meaning that you get access to the objects loaded from the framework, not Transfer Objects, although some recommendation still apply. This is a community post, so please add to it as you see fit. Applies to: Entity Framework 1.0 shipped with Visual Studio 2008 sp1. Why pick EF in the first place? Considering it is a young technology with plenty of problems (see below), it may be a hard sell to get on the EF bandwagon for your project. However, it is the technology Microsoft is pushing (at the expense of Linq2Sql, which is a subset of EF). In addition, you may not be satisfied with NHibernate or other solutions out there. Whatever the reasons, there are people out there (including me) working with EF and life is not bad.make you think. EF and inheritance The first big subject is inheritance. EF does support mapping for inherited classes that are persisted in 2 ways: table per class and table the hierarchy. The modeling is easy and there are no programming issues with that part. (The following applies to table per class model as I don't have experience with table per hierarchy, which is, anyway, limited.) The real problem comes when you are trying to run queries that include one or many objects that are part of an inheritance tree: the generated sql is incredibly awful, takes a long time to get parsed by the EF and takes a long time to execute as well. This is a real show stopper. Enough that EF should probably not be used with inheritance or as little as possible. Here is an example of how bad it was. My EF model had ~30 classes, ~10 of which were part of an inheritance tree. On running a query to get one item from the Base class, something as simple as Base.Get(id), the generated SQL was over 50,000 characters. Then when you are trying to return some Associations, it degenerates even more, going as far as throwing SQL exceptions about not being able to query more than 256 tables at once. Ok, this is bad, EF concept is to allow you to create your object structure without (or with as little as possible) consideration on the actual database implementation of your table. It completely fails at this. So, recommendations? Avoid inheritance if you can, the performance will be so much better. Use it sparingly where you have to. In my opinion, this makes EF a glorified sql-generation tool for querying, but there are still advantages to using it. And ways to implement mechanism that are similar to inheritance. Bypassing inheritance with Interfaces First thing to know with trying to get some kind of inheritance going with EF is that you cannot assign a non-EF-modeled class a base class. Don't even try it, it will get overwritten by the modeler. So what to do? You can use interfaces to enforce that classes implement some functionality. For example here is a IEntity interface that allow you to define Associations between EF entities where you don't know at design time what the type of the entity would be. public enum EntityTypes{ Unknown = -1, Dog = 0, Cat } public interface IEntity { int EntityID { get; } string Name { get; } Type EntityType { get; } } public partial class Dog : IEntity { // implement EntityID and Name which could actually be fields // from your EF model Type EntityType{ get{ return EntityTypes.Dog; } } } Using this IEntity, you can then work with undefined associations in other classes // lets take a class that you defined in your model. // that class has a mapping to the columns: PetID, PetType public partial class Person { public IEntity GetPet() { return IEntityController.Get(PetID,PetType); } } which makes use of some extension functions: public class IEntityController { static public IEntity Get(int id, EntityTypes type) { switch (type) { case EntityTypes.Dog: return Dog.Get(id); case EntityTypes.Cat: return Cat.Get(id); default: throw new Exception("Invalid EntityType"); } } } Not as neat as having plain inheritance, particularly considering you have to store the PetType in an extra database field, but considering the performance gains, I would not look back. It also cannot model one-to-many, many-to-many relationship, but with creative uses of 'Union' it could be made to work. Finally, it creates the side effet of loading data in a property/function of the object, which you need to be careful about. Using a clear naming convention like GetXYZ() helps in that regards. Compiled Queries Entity Framework performance is not as good as direct database access with ADO (obviously) or Linq2SQL. There are ways to improve it however, one of which is compiling your queries. The performance of a compiled query is similar to Linq2Sql. What is a compiled query? It is simply a query for which you tell the framework to keep the parsed tree in memory so it doesn't need to be regenerated the next time you run it. So the next run, you will save the time it takes to parse the tree. Do not discount that as it is a very costly operation that gets even worse with more complex queries. There are 2 ways to compile a query: creating an ObjectQuery with EntitySQL and using CompiledQuery.Compile() function. (Note that by using an EntityDataSource in your page, you will in fact be using ObjectQuery with EntitySQL, so that gets compiled and cached). An aside here in case you don't know what EntitySQL is. It is a string-based way of writing queries against the EF. Here is an example: "select value dog from Entities.DogSet as dog where dog.ID = @ID". The syntax is pretty similar to SQL syntax. You can also do pretty complex object manipulation, which is well explained [here][1]. Ok, so here is how to do it using ObjectQuery< string query = "select value dog " + "from Entities.DogSet as dog " + "where dog.ID = @ID"; ObjectQuery<Dog> oQuery = new ObjectQuery<Dog>(query, EntityContext.Instance)); oQuery.Parameters.Add(new ObjectParameter("ID", id)); oQuery.EnablePlanCaching = true; return oQuery.FirstOrDefault(); The first time you run this query, the framework will generate the expression tree and keep it in memory. So the next time it gets executed, you will save on that costly step. In that example EnablePlanCaching = true, which is unnecessary since that is the default option. The other way to compile a query for later use is the CompiledQuery.Compile method. This uses a delegate: static readonly Func<Entities, int, Dog> query_GetDog = CompiledQuery.Compile<Entities, int, Dog>((ctx, id) => ctx.DogSet.FirstOrDefault(it => it.ID == id)); or using linq static readonly Func<Entities, int, Dog> query_GetDog = CompiledQuery.Compile<Entities, int, Dog>((ctx, id) => (from dog in ctx.DogSet where dog.ID == id select dog).FirstOrDefault()); to call the query: query_GetDog.Invoke( YourContext, id ); The advantage of CompiledQuery is that the syntax of your query is checked at compile time, where as EntitySQL is not. However, there are other consideration... Includes Lets say you want to have the data for the dog owner to be returned by the query to avoid making 2 calls to the database. Easy to do, right? EntitySQL string query = "select value dog " + "from Entities.DogSet as dog " + "where dog.ID = @ID"; ObjectQuery<Dog> oQuery = new ObjectQuery<Dog>(query, EntityContext.Instance)).Include("Owner"); oQuery.Parameters.Add(new ObjectParameter("ID", id)); oQuery.EnablePlanCaching = true; return oQuery.FirstOrDefault(); CompiledQuery static readonly Func<Entities, int, Dog> query_GetDog = CompiledQuery.Compile<Entities, int, Dog>((ctx, id) => (from dog in ctx.DogSet.Include("Owner") where dog.ID == id select dog).FirstOrDefault()); Now, what if you want to have the Include parametrized? What I mean is that you want to have a single Get() function that is called from different pages that care about different relationships for the dog. One cares about the Owner, another about his FavoriteFood, another about his FavotireToy and so on. Basicly, you want to tell the query which associations to load. It is easy to do with EntitySQL public Dog Get(int id, string include) { string query = "select value dog " + "from Entities.DogSet as dog " + "where dog.ID = @ID"; ObjectQuery<Dog> oQuery = new ObjectQuery<Dog>(query, EntityContext.Instance)) .IncludeMany(include); oQuery.Parameters.Add(new ObjectParameter("ID", id)); oQuery.EnablePlanCaching = true; return oQuery.FirstOrDefault(); } The include simply uses the passed string. Easy enough. Note that it is possible to improve on the Include(string) function (that accepts only a single path) with an IncludeMany(string) that will let you pass a string of comma-separated associations to load. Look further in the extension section for this function. If we try to do it with CompiledQuery however, we run into numerous problems: The obvious static readonly Func<Entities, int, string, Dog> query_GetDog = CompiledQuery.Compile<Entities, int, string, Dog>((ctx, id, include) => (from dog in ctx.DogSet.Include(include) where dog.ID == id select dog).FirstOrDefault()); will choke when called with: query_GetDog.Invoke( YourContext, id, "Owner,FavoriteFood" ); Because, as mentionned above, Include() only wants to see a single path in the string and here we are giving it 2: "Owner" and "FavoriteFood" (which is not to be confused with "Owner.FavoriteFood"!). Then, let's use IncludeMany(), which is an extension function static readonly Func<Entities, int, string, Dog> query_GetDog = CompiledQuery.Compile<Entities, int, string, Dog>((ctx, id, include) => (from dog in ctx.DogSet.IncludeMany(include) where dog.ID == id select dog).FirstOrDefault()); Wrong again, this time it is because the EF cannot parse IncludeMany because it is not part of the functions that is recognizes: it is an extension. Ok, so you want to pass an arbitrary number of paths to your function and Includes() only takes a single one. What to do? You could decide that you will never ever need more than, say 20 Includes, and pass each separated strings in a struct to CompiledQuery. But now the query looks like this: from dog in ctx.DogSet.Include(include1).Include(include2).Include(include3) .Include(include4).Include(include5).Include(include6) .[...].Include(include19).Include(include20) where dog.ID == id select dog which is awful as well. Ok, then, but wait a minute. Can't we return an ObjectQuery< with CompiledQuery? Then set the includes on that? Well, that what I would have thought so as well: static readonly Func<Entities, int, ObjectQuery<Dog>> query_GetDog = CompiledQuery.Compile<Entities, int, string, ObjectQuery<Dog>>((ctx, id) => (ObjectQuery<Dog>)(from dog in ctx.DogSet where dog.ID == id select dog)); public Dog GetDog( int id, string include ) { ObjectQuery<Dog> oQuery = query_GetDog(id); oQuery = oQuery.IncludeMany(include); return oQuery.FirstOrDefault; } That should have worked, except that when you call IncludeMany (or Include, Where, OrderBy...) you invalidate the cached compiled query because it is an entirely new one now! So, the expression tree needs to be reparsed and you get that performance hit again. So what is the solution? You simply cannot use CompiledQueries with parametrized Includes. Use EntitySQL instead. This doesn't mean that there aren't uses for CompiledQueries. It is great for localized queries that will always be called in the same context. Ideally CompiledQuery should always be used because the syntax is checked at compile time, but due to limitation, that's not possible. An example of use would be: you may want to have a page that queries which two dogs have the same favorite food, which is a bit narrow for a BusinessLayer function, so you put it in your page and know exactly what type of includes are required. Passing more than 3 parameters to a CompiledQuery Func is limited to 5 parameters, of which the last one is the return type and the first one is your Entities object from the model. So that leaves you with 3 parameters. A pitance, but it can be improved on very easily. public struct MyParams { public string param1; public int param2; public DateTime param3; } static readonly Func<Entities, MyParams, IEnumerable<Dog>> query_GetDog = CompiledQuery.Compile<Entities, MyParams, IEnumerable<Dog>>((ctx, myParams) => from dog in ctx.DogSet where dog.Age == myParams.param2 && dog.Name == myParams.param1 and dog.BirthDate > myParams.param3 select dog); public List<Dog> GetSomeDogs( int age, string Name, DateTime birthDate ) { MyParams myParams = new MyParams(); myParams.param1 = name; myParams.param2 = age; myParams.param3 = birthDate; return query_GetDog(YourContext,myParams).ToList(); } Return Types (this does not apply to EntitySQL queries as they aren't compiled at the same time during execution as the CompiledQuery method) Working with Linq, you usually don't force the execution of the query until the very last moment, in case some other functions downstream wants to change the query in some way: static readonly Func<Entities, int, string, IEnumerable<Dog>> query_GetDog = CompiledQuery.Compile<Entities, int, string, IEnumerable<Dog>>((ctx, age, name) => from dog in ctx.DogSet where dog.Age == age && dog.Name == name select dog); public IEnumerable<Dog> GetSomeDogs( int age, string name ) { return query_GetDog(YourContext,age,name); } public void DataBindStuff() { IEnumerable<Dog> dogs = GetSomeDogs(4,"Bud"); // but I want the dogs ordered by BirthDate gridView.DataSource = dogs.OrderBy( it => it.BirthDate ); } What is going to happen here? By still playing with the original ObjectQuery (that is the actual return type of the Linq statement, which implements IEnumerable), it will invalidate the compiled query and be force to re-parse. So, the rule of thumb is to return a List< of objects instead. static readonly Func<Entities, int, string, IEnumerable<Dog>> query_GetDog = CompiledQuery.Compile<Entities, int, string, IEnumerable<Dog>>((ctx, age, name) => from dog in ctx.DogSet where dog.Age == age && dog.Name == name select dog); public List<Dog> GetSomeDogs( int age, string name ) { return query_GetDog(YourContext,age,name).ToList(); //<== change here } public void DataBindStuff() { List<Dog> dogs = GetSomeDogs(4,"Bud"); // but I want the dogs ordered by BirthDate gridView.DataSource = dogs.OrderBy( it => it.BirthDate ); } When you call ToList(), the query gets executed as per the compiled query and then, later, the OrderBy is executed against the objects in memory. It may be a little bit slower, but I'm not even sure. One sure thing is that you have no worries about mis-handling the ObjectQuery and invalidating the compiled query plan. Once again, that is not a blanket statement. ToList() is a defensive programming trick, but if you have a valid reason not to use ToList(), go ahead. There are many cases in which you would want to refine the query before executing it. Performance What is the performance impact of compiling a query? It can actually be fairly large. A rule of thumb is that compiling and caching the query for reuse takes at least double the time of simply executing it without caching. For complex queries (read inherirante), I have seen upwards to 10 seconds. So, the first time a pre-compiled query gets called, you get a performance hit. After that first hit, performance is noticeably better than the same non-pre-compiled query. Practically the same as Linq2Sql When you load a page with pre-compiled queries the first time you will get a hit. It will load in maybe 5-15 seconds (obviously more than one pre-compiled queries will end up being called), while subsequent loads will take less than 300ms. Dramatic difference, and it is up to you to decide if it is ok for your first user to take a hit or you want a script to call your pages to force a compilation of the queries. Can this query be cached? { Dog dog = from dog in YourContext.DogSet where dog.ID == id select dog; } No, ad-hoc Linq queries are not cached and you will incur the cost of generating the tree every single time you call it. Parametrized Queries Most search capabilities involve heavily parametrized queries. There are even libraries available that will let you build a parametrized query out of lamba expressions. The problem is that you cannot use pre-compiled queries with those. One way around that is to map out all the possible criteria in the query and flag which one you want to use: public struct MyParams { public string name; public bool checkName; public int age; public bool checkAge; } static readonly Func<Entities, MyParams, IEnumerable<Dog>> query_GetDog = CompiledQuery.Compile<Entities, MyParams, IEnumerable<Dog>>((ctx, myParams) => from dog in ctx.DogSet where (myParams.checkAge == true && dog.Age == myParams.age) && (myParams.checkName == true && dog.Name == myParams.name ) select dog); protected List<Dog> GetSomeDogs() { MyParams myParams = new MyParams(); myParams.name = "Bud"; myParams.checkName = true; myParams.age = 0; myParams.checkAge = false; return query_GetDog(YourContext,myParams).ToList(); } The advantage here is that you get all the benifits of a pre-compiled quert. The disadvantages are that you most likely will end up with a where clause that is pretty difficult to maintain, that you will incur a bigger penalty for pre-compiling the query and that each query you run is not as efficient as it could be (particularly with joins thrown in). Another way is to build an EntitySQL query piece by piece, like we all did with SQL. protected List<Dod> GetSomeDogs( string name, int age) { string query = "select value dog from Entities.DogSet where 1 = 1 "; if( !String.IsNullOrEmpty(name) ) query = query + " and dog.Name == @Name "; if( age > 0 ) query = query + " and dog.Age == @Age "; ObjectQuery<Dog> oQuery = new ObjectQuery<Dog>( query, YourContext ); if( !String.IsNullOrEmpty(name) ) oQuery.Parameters.Add( new ObjectParameter( "Name", name ) ); if( age > 0 ) oQuery.Parameters.Add( new ObjectParameter( "Age", age ) ); return oQuery.ToList(); } Here the problems are: - there is no syntax checking during compilation - each different combination of parameters generate a different query which will need to be pre-compiled when it is first run. In this case, there are only 4 different possible queries (no params, age-only, name-only and both params), but you can see that there can be way more with a normal world search. - Noone likes to concatenate strings! Another option is to query a large subset of the data and then narrow it down in memory. This is particularly useful if you are working with a definite subset of the data, like all the dogs in a city. You know there are a lot but you also know there aren't that many... so your CityDog search page can load all the dogs for the city in memory, which is a single pre-compiled query and then refine the results protected List<Dod> GetSomeDogs( string name, int age, string city) { string query = "select value dog from Entities.DogSet where dog.Owner.Address.City == @City "; ObjectQuery<Dog> oQuery = new ObjectQuery<Dog>( query, YourContext ); oQuery.Parameters.Add( new ObjectParameter( "City", city ) ); List<Dog> dogs = oQuery.ToList(); if( !String.IsNullOrEmpty(name) ) dogs = dogs.Where( it => it.Name == name ); if( age > 0 ) dogs = dogs.Where( it => it.Age == age ); return dogs; } It is particularly useful when you start displaying all the data then allow for filtering. Problems: - Could lead to serious data transfer if you are not careful about your subset. - You can only filter on the data that you returned. It means that if you don't return the Dog.Owner association, you will not be able to filter on the Dog.Owner.Name So what is the best solution? There isn't any. You need to pick the solution that works best for you and your problem: - Use lambda-based query building when you don't care about pre-compiling your queries. - Use fully-defined pre-compiled Linq query when your object structure is not too complex. - Use EntitySQL/string concatenation when the structure could be complex and when the possible number of different resulting queries are small (which means fewer pre-compilation hits). - Use in-memory filtering when you are working with a smallish subset of the data or when you had to fetch all of the data on the data at first anyway (if the performance is fine with all the data, then filtering in memory will not cause any time to be spent in the db). Singleton access The best way to deal with your context and entities accross all your pages is to use the singleton pattern: public sealed class YourContext { private const string instanceKey = "On3GoModelKey"; YourContext(){} public static YourEntities Instance { get { HttpContext context = HttpContext.Current; if( context == null ) return Nested.instance; if (context.Items[instanceKey] == null) { On3GoEntities entity = new On3GoEntities(); context.Items[instanceKey] = entity; } return (YourEntities)context.Items[instanceKey]; } } class Nested { // Explicit static constructor to tell C# compiler // not to mark type as beforefieldinit static Nested() { } internal static readonly YourEntities instance = new YourEntities(); } } NoTracking, is it worth it? When executing a query, you can tell the framework to track the objects it will return or not. What does it mean? With tracking enabled (the default option), the framework will track what is going on with the object (has it been modified? Created? Deleted?) and will also link objects together, when further queries are made from the database, which is what is of interest here. For example, lets assume that Dog with ID == 2 has an owner which ID == 10. Dog dog = (from dog in YourContext.DogSet where dog.ID == 2 select dog).FirstOrDefault(); //dog.OwnerReference.IsLoaded == false; Person owner = (from o in YourContext.PersonSet where o.ID == 10 select dog).FirstOrDefault(); //dog.OwnerReference.IsLoaded == true; If we were to do the same with no tracking, the result would be different. ObjectQuery<Dog> oDogQuery = (ObjectQuery<Dog>) (from dog in YourContext.DogSet where dog.ID == 2 select dog); oDogQuery.MergeOption = MergeOption.NoTracking; Dog dog = oDogQuery.FirstOrDefault(); //dog.OwnerReference.IsLoaded == false; ObjectQuery<Person> oPersonQuery = (ObjectQuery<Person>) (from o in YourContext.PersonSet where o.ID == 10 select o); oPersonQuery.MergeOption = MergeOption.NoTracking; Owner owner = oPersonQuery.FirstOrDefault(); //dog.OwnerReference.IsLoaded == false; Tracking is very useful and in a perfect world without performance issue, it would always be on. But in this world, there is a price for it, in terms of performance. So, should you use NoTracking to speed things up? It depends on what you are planning to use the data for. Is there any chance that the data your query with NoTracking can be used to make update/insert/delete in the database? If so, don't use NoTracking because associations are not tracked and will causes exceptions to be thrown. In a page where there are absolutly no updates to the database, you can use NoTracking. Mixing tracking and NoTracking is possible, but it requires you to be extra careful with updates/inserts/deletes. The problem is that if you mix then you risk having the framework trying to Attach() a NoTracking object to the context where another copy of the same object exist with tracking on. Basicly, what I am saying is that Dog dog1 = (from dog in YourContext.DogSet where dog.ID == 2).FirstOrDefault(); ObjectQuery<Dog> oDogQuery = (ObjectQuery<Dog>) (from dog in YourContext.DogSet where dog.ID == 2 select dog); oDogQuery.MergeOption = MergeOption.NoTracking; Dog dog2 = oDogQuery.FirstOrDefault(); dog1 and dog2 are 2 different objects, one tracked and one not. Using the detached object in an update/insert will force an Attach() that will say "Wait a minute, I do already have an object here with the same database key. Fail". And when you Attach() one object, all of its hierarchy gets attached as well, causing problems everywhere. Be extra careful. How much faster is it with NoTracking It depends on the queries. Some are much more succeptible to tracking than other. I don't have a fast an easy rule for it, but it helps. So I should use NoTracking everywhere then? Not exactly. There are some advantages to tracking object. The first one is that the object is cached, so subsequent call for that object will not hit the database. That cache is only valid for the lifetime of the YourEntities object, which, if you use the singleton code above, is the same as the page lifetime. One page request == one YourEntity object. So for multiple calls for the same object, it will load only once per page request. (Other caching mechanism could extend that). What happens when you are using NoTracking and try to load the same object multiple times? The database will be queried each time, so there is an impact there. How often do/should you call for the same object during a single page request? As little as possible of course, but it does happens. Also remember the piece above about having the associations connected automatically for your? You don't have that with NoTracking, so if you load your data in multiple batches, you will not have a link to between them: ObjectQuery<Dog> oDogQuery = (ObjectQuery<Dog>)(from dog in YourContext.DogSet select dog); oDogQuery.MergeOption = MergeOption.NoTracking; List<Dog> dogs = oDogQuery.ToList(); ObjectQuery<Person> oPersonQuery = (ObjectQuery<Person>)(from o in YourContext.PersonSet select o); oPersonQuery.MergeOption = MergeOption.NoTracking; List<Person> owners = oPersonQuery.ToList(); In this case, no dog will have its .Owner property set. Some things to keep in mind when you are trying to optimize the performance. No lazy loading, what am I to do? This can be seen as a blessing in disguise. Of course it is annoying to load everything manually. However, it decreases the number of calls to the db and forces you to think about when you should load data. The more you can load in one database call the better. That was always true, but it is enforced now with this 'feature' of EF. Of course, you can call if( !ObjectReference.IsLoaded ) ObjectReference.Load(); if you want to, but a better practice is to force the framework to load the objects you know you will need in one shot. This is where the discussion about parametrized Includes begins to make sense. Lets say you have you Dog object public class Dog { public Dog Get(int id) { return YourContext.DogSet.FirstOrDefault(it => it.ID == id ); } } This is the type of function you work with all the time. It gets called from all over the place and once you have that Dog object, you will do very different things to it in different functions. First, it should be pre-compiled, because you will call that very often. Second, each different pages will want to have access to a different subset of the Dog data. Some will want the Owner, some the FavoriteToy, etc. Of course, you could call Load() for each reference you need anytime you need one. But that will generate a call to the database each time. Bad idea. So instead, each page will ask for the data it wants to see when it first request for the Dog object: static public Dog Get(int id) { return GetDog(entity,"");} static public Dog Get(int id, string includePath) { string query = "select value o " + " from YourEntities.DogSet as o " +

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