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  • Tomcat 6: Access Control Exception?

    - by iftrue
    I'm trying to setup a tomcat6 server, and I'm trying to match another setup someone else established. However, my deployment (default Ubuntu install) uses a policy.d/ directory structure, and the established server just uses a catalina.policy file. I've tried setting every entry in policy.d to match the given catalina.policy, but I still get the following stacktrace on boot (from localhost log). I have two questions, then. First, how do I get tomcat to use a single poilcy file, rather than the directory structure presented by policy.d/? Secondly, why, when I specify all files to use the same policy, do I still get the stack trace below? Stack trace: SEVERE: Servlet /myapp threw load() exception java.security.AccessControlException: access denied (java.lang.RuntimePermission accessClassInPackage.org.apache.jasper) at java.security.AccessControlContext.checkPermission(AccessControlContext.java:342) at java.security.AccessController.checkPermission(AccessController.java:553) at java.lang.SecurityManager.checkPermission(SecurityManager.java:549) at java.lang.SecurityManager.checkPackageAccess(SecurityManager.java:1529) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:291) at java.lang.ClassLoader.loadClass(ClassLoader.java:264) at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1314) at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1245) at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:332) at org.apache.jasper.servlet.JspServlet.init(JspServlet.java:100) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:616) at org.apache.catalina.security.SecurityUtil$1.run(SecurityUtil.java:244) at java.security.AccessController.doPrivileged(Native Method) at javax.security.auth.Subject.doAsPrivileged(Subject.java:537) at org.apache.catalina.security.SecurityUtil.execute(SecurityUtil.java:276) at org.apache.catalina.security.SecurityUtil.doAsPrivilege(SecurityUtil.java:162) at org.apache.catalina.security.SecurityUtil.doAsPrivilege(SecurityUtil.java:115) at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1166) at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:992) at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:4058) at org.apache.catalina.core.StandardContext.start(StandardContext.java:4367) at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:791) at org.apache.catalina.core.ContainerBase.access$000(ContainerBase.java:123) at org.apache.catalina.core.ContainerBase$PrivilegedAddChild.run(ContainerBase.java:145) at java.security.AccessController.doPrivileged(Native Method) at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:769) at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:525) at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:978) at org.apache.catalina.startup.HostConfig.deployDirectories(HostConfig.java:941) at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:499) at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1201) at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:318) at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117) at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1053) at org.apache.catalina.core.StandardHost.start(StandardHost.java:719) at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1045) at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:443) at org.apache.catalina.core.StandardService.start(StandardService.java:516) at org.apache.catalina.core.StandardServer.start(StandardServer.java:710) at org.apache.catalina.startup.Catalina.start(Catalina.java:578) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:616) at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:288) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:616) at org.apache.commons.daemon.support.DaemonLoader.start(DaemonLoader.java:177) Policy.d grant codeBase "file:${java.home}/lib/-" { permission java.security.AllPermission; }; // These permissions apply to all shared system extensions grant codeBase "file:${java.home}/jre/lib/ext/-" { permission java.security.AllPermission; }; // These permissions apply to javac when ${java.home] points at $JAVA_HOME/jre grant codeBase "file:${java.home}/../lib/-" { permission java.security.AllPermission; }; // These permissions apply to all shared system extensions when // ${java.home} points at $JAVA_HOME/jre grant codeBase "file:${java.home}/lib/ext/-" { permission java.security.AllPermission; }; // ========== CATALINA CODE PERMISSIONS ======================================= // These permissions apply to the daemon code grant codeBase "file:${catalina.home}/bin/commons-daemon.jar" { permission java.security.AllPermission; }; // These permissions apply to the logging API grant codeBase "file:${catalina.home}/bin/tomcat-juli.jar" { permission java.util.PropertyPermission "java.util.logging.config.class", "read"; permission java.util.PropertyPermission "java.util.logging.config.file", "read"; permission java.io.FilePermission "${java.home}${file.separator}lib${file.separator}logging.properties", "read"; permission java.lang.RuntimePermission "shutdownHooks"; permission java.io.FilePermission "${catalina.base}${file.separator}conf${file.separator}logging.properties", "read"; permission java.util.PropertyPermission "catalina.base", "read"; permission java.util.logging.LoggingPermission "control"; permission java.io.FilePermission "${catalina.base}${file.separator}logs", "read, write"; permission java.io.FilePermission "${catalina.base}${file.separator}logs${file.separator}*", "read, write"; permission java.lang.RuntimePermission "getClassLoader"; // To enable per context logging configuration, permit read access to the appropriate file. // Be sure that the logging configuration is secure before enabling such access // eg for the examples web application: // permission java.io.FilePermission "${catalina.base}${file.separator}webapps${file.separator}examples${file.separator}WEB-INF${file.separator}classes${file.separator}logging.properties", "read"; }; // These permissions apply to the server startup code grant codeBase "file:${catalina.home}/bin/bootstrap.jar" { permission java.security.AllPermission; }; // These permissions apply to the servlet API classes // and those that are shared across all class loaders // located in the "lib" directory grant codeBase "file:${catalina.home}/lib/-" { permission java.security.AllPermission; }; // ========== WEB APPLICATION PERMISSIONS ===================================== // These permissions are granted by default to all web applications // In addition, a web application will be given a read FilePermission // and JndiPermission for all files and directories in its document root. grant { // Required for JNDI lookup of named JDBC DataSource's and // javamail named MimePart DataSource used to send mail permission java.util.PropertyPermission "java.home", "read"; permission java.util.PropertyPermission "java.naming.*", "read"; permission java.util.PropertyPermission "javax.sql.*", "read"; // OS Specific properties to allow read access permission java.util.PropertyPermission "os.name", "read"; permission java.util.PropertyPermission "os.version", "read"; permission java.util.PropertyPermission "os.arch", "read"; permission java.util.PropertyPermission "file.separator", "read"; permission java.util.PropertyPermission "path.separator", "read"; permission java.util.PropertyPermission "line.separator", "read"; // JVM properties to allow read access permission java.util.PropertyPermission "java.version", "read"; permission java.util.PropertyPermission "java.vendor", "read"; permission java.util.PropertyPermission "java.vendor.url", "read"; permission java.util.PropertyPermission "java.class.version", "read"; permission java.util.PropertyPermission "java.specification.version", "read"; permission java.util.PropertyPermission "java.specification.vendor", "read"; permission java.util.PropertyPermission "java.specification.name", "read"; permission java.util.PropertyPermission "java.vm.specification.version", "read"; permission java.util.PropertyPermission "java.vm.specification.vendor", "read"; permission java.util.PropertyPermission "java.vm.specification.name", "read"; permission java.util.PropertyPermission "java.vm.version", "read"; permission java.util.PropertyPermission "java.vm.vendor", "read"; permission java.util.PropertyPermission "java.vm.name", "read"; // Required for OpenJMX permission java.lang.RuntimePermission "getAttribute"; // Allow read of JAXP compliant XML parser debug permission java.util.PropertyPermission "jaxp.debug", "read"; // Precompiled JSPs need access to this package. permission java.lang.RuntimePermission "accessClassInPackage.org.apache.jasper.runtime"; permission java.lang.RuntimePermission "accessClassInPackage.org.apache.jasper.runtime.*"; // Precompiled JSPs need access to this system property. permission java.util.PropertyPermission "org.apache.jasper.runtime.BodyContentImpl.LIMIT_BUFFER", "read"; };

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  • WPF Lookless Control Events

    - by Scott
    I have the following class: public class LooklessControl : Control { public List<int> IntList { get; private set; } public int CurrentInt { get; private set; } private int _index = 0; static LooklessControl() { DefaultStyleKeyProperty.OverrideMetadata(typeof(LooklessControl), new FrameworkPropertyMetadata(typeof(LooklessControl))); } public LooklessControl() { IntList = new List<int>(); for (int i = 0; i < 10; i++) { IntList.Add(i); } CurrentInt = IntList[_index]; } public static readonly RoutedCommand NextItemCommand = new RoutedCommand("NextItemCommand", typeof(LooklessControl)); private void ExecutedNextItemCommand(object sender, ExecutedRoutedEventArgs e) { NextItemHandler(); } private void CanExecuteNextItemCommand(object sender, CanExecuteRoutedEventArgs e) { e.CanExecute = true; } public static readonly RoutedCommand PrevItemCommand = new RoutedCommand("PrevItemCommand", typeof(LooklessControl)); private void ExecutedPrevItemCommand(ExecutedRoutedEventArgs e) { PrevItemHandler(); } private void CanExecutePrevItemCommand(object sender, CanExecuteRoutedEventArgs e) { e.CanExecute = true; } public static readonly RoutedEvent NextItemEvent = EventManager.RegisterRoutedEvent("NextItemEvent", RoutingStrategy.Bubble, typeof(RoutedEventHandler), typeof(LooklessControl)); public event RoutedEventHandler NextItem { add { AddHandler(NextItemEvent, value); } remove { RemoveHandler(NextItemEvent, value); } } private void RaiseNextItemEvent() { RoutedEventArgs args = new RoutedEventArgs(LooklessControl.NextItemEvent); RaiseEvent(args); } public static readonly RoutedEvent PrevItemEvent = EventManager.RegisterRoutedEvent("PrevItemEvent", RoutingStrategy.Bubble, typeof(RoutedEventHandler), typeof(LooklessControl)); public event RoutedEventHandler PrevItem { add { AddHandler(PrevItemEvent, value); } remove { RemoveHandler(PrevItemEvent, value); } } private void RaisePrevItemEvent() { RoutedEventArgs args = new RoutedEventArgs(LooklessControl.PrevItemEvent); RaiseEvent(args); } private void NextItemHandler() { _index++; if (_index == IntList.Count) { _index = 0; } CurrentInt = IntList[_index]; RaiseNextItemEvent(); } private void PrevItemHandler() { _index--; if (_index == 0) { _index = IntList.Count - 1; } CurrentInt = IntList[_index]; RaisePrevItemEvent(); } } The class has a default style, in Generic.xaml, that looks like this: <Style x:Key="{x:Type local:LooklessControl}" TargetType="{x:Type local:LooklessControl}"> <Setter Property="Height" Value="200"/> <Setter Property="Width" Value="90"/> <Setter Property="Template"> <Setter.Value> <ControlTemplate TargetType="{x:Type local:LooklessControl}"> <Border BorderBrush="Black" BorderThickness="1" Padding="2"> <Grid> <Grid.RowDefinitions> <RowDefinition Height="20"/> <RowDefinition Height="*"/> </Grid.RowDefinitions> <Rectangle Grid.Row="0" Fill="LightGray"/> <Rectangle Grid.Row="1" Fill="Gainsboro"/> <Grid Grid.Row="0"> <Grid.ColumnDefinitions> <ColumnDefinition Width="10"/> <ColumnDefinition Width="*"/> <ColumnDefinition Width="10"/> </Grid.ColumnDefinitions> <Path Grid.Column="0" x:Name="pathLeftArrow" Data="M0,0.5 L1,1 1,0Z" Width="6" Height="14" Stretch="Fill" HorizontalAlignment="Center" Fill="SlateBlue"/> <TextBlock Grid.Column="1" Name="textBlock" Text="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=CurrentInt}" HorizontalAlignment="Center" VerticalAlignment="Center" FontFamily="Junction" FontSize="13"/> <Path Grid.Column="2" x:Name="pathRightArrow" Data="M0,0 L1,0.5 0,1Z" Width="6" Height="14" Stretch="Fill" HorizontalAlignment="Center" Fill="SlateBlue"/> </Grid> <ListBox Grid.Row="1" HorizontalContentAlignment="Center" VerticalContentAlignment="Center" Background="Transparent" ItemsSource="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=IntList}"/> </Grid> </Border> </ControlTemplate> </Setter.Value> </Setter> </Style> How do I make it so that when the user clicks on pathLeftArrow it fires LooklessControl.PrevItemCommand, or or they click on pathRightArrow and it fires LooklessControl.NextItemCommand, or they click on an item in the ListBox and LooklessControl is notified of the newly selected item? In other words, without adding x:Class to the top of Generic.xaml and thus creating a code-behind file for it, which I assume you wouldn't want to do, how do you handle events for elements in your xaml that don't have a Command property (which is just about everything other than a Button)? Should LooklessControl have it's own XAML file (much like what you get when you create a new UserControl) associated with it that Generic.xaml just pulls in as a MergedDictionar as its default template? Or is there some other acknowledged way to do what I'm trying to do?

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  • Why is Java EE 6 better than Spring ?

    - by arungupta
    Java EE 6 was released over 2 years ago and now there are 14 compliant application servers. In all my talks around the world, a question that is frequently asked is Why should I use Java EE 6 instead of Spring ? There are already several blogs covering that topic: Java EE wins over Spring by Bill Burke Why will I use Java EE instead of Spring in new Enterprise Java projects in 2012 ? by Kai Waehner (more discussion on TSS) Spring to Java EE migration (Part 1 and 2, 3 and 4 coming as well) by David Heffelfinger Spring to Java EE - A Migration Experience by Lincoln Baxter Migrating Spring to Java EE 6 by Bert Ertman and Paul Bakker at NLJUG Moving from Spring to Java EE 6 - The Age of Frameworks is Over at TSS Java EE vs Spring Shootout by Rohit Kelapure and Reza Rehman at JavaOne 2011 Java EE 6 and the Ewoks by Murat Yener Definite excuse to avoid Spring forever - Bert Ertman and Arun Gupta I will try to share my perspective in this blog. First of all, I'd like to start with a note: Thank you Spring framework for filling the interim gap and providing functionality that is now included in the mainstream Java EE 6 application servers. The Java EE platform has evolved over the years learning from frameworks like Spring and provides all the functionality to build an enterprise application. Thank you very much Spring framework! While Spring was revolutionary in its time and is still very popular and quite main stream in the same way Struts was circa 2003, it really is last generation's framework - some people are even calling it legacy. However my theory is "code is king". So my approach is to build/take a simple Hello World CRUD application in Java EE 6 and Spring and compare the deployable artifacts. I started looking at the official tutorial Developing a Spring Framework MVC Application Step-by-Step but it is using the older version 2.5. I wasn't able to find any updated version in the current 3.1 release. Next, I downloaded Spring Tool Suite and thought that would provide some template samples to get started. A least a quick search did not show any handy tutorials - either video or text-based. So I searched and found a link to their SVN repository at src.springframework.org/svn/spring-samples/. I tried the "mvc-basic" sample and the generated WAR file was 4.43 MB. While it was named a "basic" sample it seemed to come with 19 different libraries bundled but it was what I could find: ./WEB-INF/lib/aopalliance-1.0.jar./WEB-INF/lib/hibernate-validator-4.1.0.Final.jar./WEB-INF/lib/jcl-over-slf4j-1.6.1.jar./WEB-INF/lib/joda-time-1.6.2.jar./WEB-INF/lib/joda-time-jsptags-1.0.2.jar./WEB-INF/lib/jstl-1.2.jar./WEB-INF/lib/log4j-1.2.16.jar./WEB-INF/lib/slf4j-api-1.6.1.jar./WEB-INF/lib/slf4j-log4j12-1.6.1.jar./WEB-INF/lib/spring-aop-3.0.5.RELEASE.jar./WEB-INF/lib/spring-asm-3.0.5.RELEASE.jar./WEB-INF/lib/spring-beans-3.0.5.RELEASE.jar./WEB-INF/lib/spring-context-3.0.5.RELEASE.jar./WEB-INF/lib/spring-context-support-3.0.5.RELEASE.jar./WEB-INF/lib/spring-core-3.0.5.RELEASE.jar./WEB-INF/lib/spring-expression-3.0.5.RELEASE.jar./WEB-INF/lib/spring-web-3.0.5.RELEASE.jar./WEB-INF/lib/spring-webmvc-3.0.5.RELEASE.jar./WEB-INF/lib/validation-api-1.0.0.GA.jar And it is not even using any database! The app deployed fine on GlassFish 3.1.2 but the "@Controller Example" link did not work as it was missing the context root. With a bit of tweaking I could deploy the application and assume that the account got created because no error was displayed in the browser or server log. Next I generated the WAR for "mvc-ajax" and the 5.1 MB WAR had 20 JARs (1 removed, 2 added): ./WEB-INF/lib/aopalliance-1.0.jar./WEB-INF/lib/hibernate-validator-4.1.0.Final.jar./WEB-INF/lib/jackson-core-asl-1.6.4.jar./WEB-INF/lib/jackson-mapper-asl-1.6.4.jar./WEB-INF/lib/jcl-over-slf4j-1.6.1.jar./WEB-INF/lib/joda-time-1.6.2.jar./WEB-INF/lib/jstl-1.2.jar./WEB-INF/lib/log4j-1.2.16.jar./WEB-INF/lib/slf4j-api-1.6.1.jar./WEB-INF/lib/slf4j-log4j12-1.6.1.jar./WEB-INF/lib/spring-aop-3.0.5.RELEASE.jar./WEB-INF/lib/spring-asm-3.0.5.RELEASE.jar./WEB-INF/lib/spring-beans-3.0.5.RELEASE.jar./WEB-INF/lib/spring-context-3.0.5.RELEASE.jar./WEB-INF/lib/spring-context-support-3.0.5.RELEASE.jar./WEB-INF/lib/spring-core-3.0.5.RELEASE.jar./WEB-INF/lib/spring-expression-3.0.5.RELEASE.jar./WEB-INF/lib/spring-web-3.0.5.RELEASE.jar./WEB-INF/lib/spring-webmvc-3.0.5.RELEASE.jar./WEB-INF/lib/validation-api-1.0.0.GA.jar 2 more JARs for just doing Ajax. Anyway, deploying this application gave the following error: Caused by: java.lang.NoSuchMethodError: org.codehaus.jackson.map.SerializationConfig.<init>(Lorg/codehaus/jackson/map/ClassIntrospector;Lorg/codehaus/jackson/map/AnnotationIntrospector;Lorg/codehaus/jackson/map/introspect/VisibilityChecker;Lorg/codehaus/jackson/map/jsontype/SubtypeResolver;)V    at org.springframework.samples.mvc.ajax.json.ConversionServiceAwareObjectMapper.<init>(ConversionServiceAwareObjectMapper.java:20)    at org.springframework.samples.mvc.ajax.json.JacksonConversionServiceConfigurer.postProcessAfterInitialization(JacksonConversionServiceConfigurer.java:40)    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsAfterInitialization(AbstractAutowireCapableBeanFactory.java:407) Seems like some incorrect repos in the "pom.xml". Next one is "mvc-showcase" and the 6.49 MB WAR now has 28 JARs as shown below: ./WEB-INF/lib/aopalliance-1.0.jar./WEB-INF/lib/aspectjrt-1.6.10.jar./WEB-INF/lib/commons-fileupload-1.2.2.jar./WEB-INF/lib/commons-io-2.0.1.jar./WEB-INF/lib/el-api-2.2.jar./WEB-INF/lib/hibernate-validator-4.1.0.Final.jar./WEB-INF/lib/jackson-core-asl-1.8.1.jar./WEB-INF/lib/jackson-mapper-asl-1.8.1.jar./WEB-INF/lib/javax.inject-1.jar./WEB-INF/lib/jcl-over-slf4j-1.6.1.jar./WEB-INF/lib/jdom-1.0.jar./WEB-INF/lib/joda-time-1.6.2.jar./WEB-INF/lib/jstl-api-1.2.jar./WEB-INF/lib/jstl-impl-1.2.jar./WEB-INF/lib/log4j-1.2.16.jar./WEB-INF/lib/rome-1.0.0.jar./WEB-INF/lib/slf4j-api-1.6.1.jar./WEB-INF/lib/slf4j-log4j12-1.6.1.jar./WEB-INF/lib/spring-aop-3.1.0.RELEASE.jar./WEB-INF/lib/spring-asm-3.1.0.RELEASE.jar./WEB-INF/lib/spring-beans-3.1.0.RELEASE.jar./WEB-INF/lib/spring-context-3.1.0.RELEASE.jar./WEB-INF/lib/spring-context-support-3.1.0.RELEASE.jar./WEB-INF/lib/spring-core-3.1.0.RELEASE.jar./WEB-INF/lib/spring-expression-3.1.0.RELEASE.jar./WEB-INF/lib/spring-web-3.1.0.RELEASE.jar./WEB-INF/lib/spring-webmvc-3.1.0.RELEASE.jar./WEB-INF/lib/validation-api-1.0.0.GA.jar The app at least deployed and showed results this time. But still no database! Next I tried building "jpetstore" and got the error: [ERROR] Failed to execute goal on project org.springframework.samples.jpetstore:Could not resolve dependencies for project org.springframework.samples:org.springframework.samples.jpetstore:war:1.0.0-SNAPSHOT: Failed to collect dependencies for [commons-fileupload:commons-fileupload:jar:1.2.1 (compile), org.apache.struts:com.springsource.org.apache.struts:jar:1.2.9 (compile), javax.xml.rpc:com.springsource.javax.xml.rpc:jar:1.1.0 (compile), org.apache.commons:com.springsource.org.apache.commons.dbcp:jar:1.2.2.osgi (compile), commons-io:commons-io:jar:1.3.2 (compile), hsqldb:hsqldb:jar:1.8.0.7 (compile), org.apache.tiles:tiles-core:jar:2.2.0 (compile), org.apache.tiles:tiles-jsp:jar:2.2.0 (compile), org.tuckey:urlrewritefilter:jar:3.1.0 (compile), org.springframework:spring-webmvc:jar:3.0.0.BUILD-SNAPSHOT (compile), org.springframework:spring-orm:jar:3.0.0.BUILD-SNAPSHOT (compile), org.springframework:spring-context-support:jar:3.0.0.BUILD-SNAPSHOT (compile), org.springframework.webflow:spring-js:jar:2.0.7.RELEASE (compile), org.apache.ibatis:com.springsource.com.ibatis:jar:2.3.4.726 (runtime), com.caucho:com.springsource.com.caucho:jar:3.2.1 (compile), org.apache.axis:com.springsource.org.apache.axis:jar:1.4.0 (compile), javax.wsdl:com.springsource.javax.wsdl:jar:1.6.1 (compile), javax.servlet:jstl:jar:1.2 (runtime), org.aspectj:aspectjweaver:jar:1.6.5 (compile), javax.servlet:servlet-api:jar:2.5 (provided), javax.servlet.jsp:jsp-api:jar:2.1 (provided), junit:junit:jar:4.6 (test)]: Failed to read artifact descriptor for org.springframework:spring-webmvc:jar:3.0.0.BUILD-SNAPSHOT: Could not transfer artifact org.springframework:spring-webmvc:pom:3.0.0.BUILD-SNAPSHOT from/to JBoss repository (http://repository.jboss.com/maven2): Access denied to: http://repository.jboss.com/maven2/org/springframework/spring-webmvc/3.0.0.BUILD-SNAPSHOT/spring-webmvc-3.0.0.BUILD-SNAPSHOT.pom It appears the sample is broken - maybe I was pulling from the wrong repository - would be great if someone were to point me at a good target to use here. With a 50% hit on samples in this repository, I started searching through numerous blogs, most of which have either outdated information (using XML-heavy Spring 2.5), some piece of configuration (which is a typical "feature" of Spring) is missing, or too much complexity in the sample. I finally found this blog that worked like a charm. This blog creates a trivial Spring MVC 3 application using Hibernate and MySQL. This application performs CRUD operations on a single table in a database using typical Spring technologies.  I downloaded the sample code from the blog, deployed it on GlassFish 3.1.2 and could CRUD the "person" entity. The source code for this application can be downloaded here. More details on the application statistics below. And then I built a similar CRUD application in Java EE 6 using NetBeans wizards in a couple of minutes. The source code for the application can be downloaded here and the WAR here. The Spring Source Tool Suite may also offer similar wizard-driven capabilities but this blog focus primarily on comparing the runtimes. The lack of STS tutorials was slightly disappointing as well. NetBeans however has tons of text-based and video tutorials and tons of material even by the community. One more bit on the download size of tools bundle ... NetBeans 7.1.1 "All" is 211 MB (which includes GlassFish and Tomcat) Spring Tool Suite  2.9.0 is 347 MB (~ 65% bigger) This blog is not about the tooling comparison so back to the Java EE 6 version of the application .... In order to run the Java EE version on GlassFish, copy the MySQL Connector/J to glassfish3/glassfish/domains/domain1/lib/ext directory and create a JDBC connection pool and JDBC resource as: ./bin/asadmin create-jdbc-connection-pool --datasourceclassname \\ com.mysql.jdbc.jdbc2.optional.MysqlDataSource --restype \\ javax.sql.DataSource --property \\ portNumber=3306:user=mysql:password=mysql:databaseName=mydatabase \\ myConnectionPool ./bin/asadmin create-jdbc-resource --connectionpoolid myConnectionPool jdbc/myDataSource I generated WARs for the two projects and the table below highlights some differences between them: Java EE 6 Spring WAR File Size 0.021030 MB 10.87 MB (~516x) Number of files 20 53 (> 2.5x) Bundled libraries 0 36 Total size of libraries 0 12.1 MB XML files 3 5 LoC in XML files 50 (11 + 15 + 24) 129 (27 + 46 + 16 + 11 + 19) (~ 2.5x) Total .properties files 1 Bundle.properties 2 spring.properties, log4j.properties Cold Deploy 5,339 ms 11,724 ms Second Deploy 481 ms 6,261 ms Third Deploy 528 ms 5,484 ms Fourth Deploy 484 ms 5,576 ms Runtime memory ~73 MB ~101 MB Some points worth highlighting from the table ... 516x WAR file, 10x deployment time - With 12.1 MB of libraries (for a very basic application) bundled in your application, the WAR file size and the deployment time will naturally go higher. The WAR file for Spring-based application is 516x bigger and the deployment time is double during the first deployment and ~ 10x during subsequent deployments. The Java EE 6 application is fully portable and will run on any Java EE 6 compliant application server. 36 libraries in the WAR - There are 14 Java EE 6 compliant application servers today. Each of those servers provide all the functionality like transactions, dependency injection, security, persistence, etc typically required of an enterprise or web application. There is no need to bundle 36 libraries worth 12.1 MB for a trivial CRUD application. These 14 compliant application servers provide all the functionality baked in. Now you can also deploy these libraries in the container but then you don't get the "portability" offered by Spring in that case. Does your typical Spring deployment actually do that ? 3x LoC in XML - The number of XML files is about 1.6x and the LoC is ~ 2.5x. So much XML seems circa 2003 when the Java language had no annotations. The XML files can be further reduced, e.g. faces-config.xml can be replaced without providing i18n, but I just want to compare stock applications. Memory usage - Both the applications were deployed on default GlassFish 3.1.2 installation and any additional memory consumed as part of deployment/access was attributed to the application. This is by no means scientific but at least provides an initial ballpark. This area definitely needs more investigation. Another table that compares typical Java EE 6 compliant application servers and the custom-stack created for a Spring application ... Java EE 6 Spring Web Container ? 53 MB (tcServer 2.6.3 Developer Edition) Security ? 12 MB (Spring Security 3.1.0) Persistence ? 6.3 MB (Hibernate 4.1.0, required) Dependency Injection ? 5.3 MB (Framework) Web Services ? 796 KB (Spring WS 2.0.4) Messaging ? 3.4 MB (RabbitMQ Server 2.7.1) 936 KB (Java client 936) OSGi ? 1.3 MB (Spring OSGi 1.2.1) GlassFish and WebLogic (starting at 33 MB) 83.3 MB There are differentiating factors on both the stacks. But most of the functionality like security, persistence, and dependency injection is baked in a Java EE 6 compliant application server but needs to be individually managed and patched for a Spring application. This very quickly leads to a "stack explosion". The Java EE 6 servers are tested extensively on a variety of platforms in different combinations whereas a Spring application developer is responsible for testing with different JDKs, Operating Systems, Versions, Patches, etc. Oracle has both the leading OSS lightweight server with GlassFish and the leading enterprise Java server with WebLogic Server, both Java EE 6 and both with lightweight deployment options. The Web Container offered as part of a Java EE 6 application server not only deploys your enterprise Java applications but also provide operational management, diagnostics, and mission-critical capabilities required by your applications. The Java EE 6 platform also introduced the Web Profile which is a subset of the specifications from the entire platform. It is targeted at developers of modern web applications offering a reasonably complete stack, composed of standard APIs, and is capable out-of-the-box of addressing the needs of a large class of Web applications. As your applications grow, the stack can grow to the full Java EE 6 platform. The GlassFish Server Web Profile starting at 33MB (smaller than just the non-standard tcServer) provides most of the functionality typically required by a web application. WebLogic provides battle-tested functionality for a high throughput, low latency, and enterprise grade web application. No individual managing or patching, all tested and commercially supported for you! Note that VMWare does have a server, tcServer, but it is non-standard and not even certified to the level of the standard Web Profile most customers expect these days. Customers who choose this risk proprietary lock-in since VMWare does not seem to want to formally certify with either Java EE 6 Enterprise Platform or with Java EE 6 Web Profile but of course it would be great if they were to join the community and help their customers reduce the risk of deploying on VMWare software. Some more points to help you decide choose between Java EE 6 and Spring ... Freedom to choose container - There are 14 Java EE 6 compliant application servers today, with a variety of open source and commercial offerings. A Java EE 6 application can be deployed on any of those containers. So if you deployed your application on GlassFish today and would like to scale up with your demands then you can deploy the same application to WebLogic. And because of the portability of a Java EE 6 application, you can even take it a different vendor altogether. Spring requires a runtime which could be any of these app servers as well. But why use Spring when all the required functionality is already baked into the application server itself ? Spring also has a different definition of portability where they claim to bundle all the libraries in the WAR file and move to any application server. But we saw earlier how bloated that archive could be. The equivalent features in Spring runtime offerings (mainly tcServer) are not all open source, not as mature, and often require manual assembly.  Vendor choice - The Java EE 6 platform is created using the Java Community Process where all the big players like Oracle, IBM, RedHat, and Apache are conritbuting to make the platform successful. Each application server provides the basic Java EE 6 platform compliance and has its own competitive offerings. This allows you to choose an application server for deploying your Java EE 6 applications. If you are not happy with the support or feature of one vendor then you can move your application to a different vendor because of the portability promise offered by the platform. Spring is a set of products from a single company, one price book, one support organization, one sustaining organization, one sales organization, etc. If any of those cause a customer headache, where do you go ? Java EE, backed by multiple vendors, is a safer bet for those that are risk averse. Production support - With Spring, typically you need to get support from two vendors - VMWare and the container provider. With Java EE 6, all of this is typically provided by one vendor. For example, Oracle offers commercial support from systems, operating systems, JDK, application server, and applications on top of them. VMWare certainly offers complete production support but do you really want to put all your eggs in one basket ? Do you really use tcServer ? ;-) Maintainability - With Spring, you are likely building your own distribution with multiple JAR files, integrating, patching, versioning, etc of all those components. Spring's claim is that multiple JAR files allow you to go à la carte and pick the latest versions of different components. But who is responsible for testing whether all these versions work together ? Yep, you got it, its YOU! If something does not work, who patches and maintains the JARs ? Of course, you! Commercial support for such a configuration ? On your own! The Java EE application servers manage all of this for you and provide a well-tested and commercially supported bundle. While it is always good to realize that there is something new and improved that updates and replaces older frameworks like Spring, the good news is not only does a Java EE 6 container offer what is described here, most also will let you deploy and run your Spring applications on them while you go through an upgrade to a more modern architecture. End result, you get the best of both worlds - keeping your legacy investment but moving to a more agile, lightweight world of Java EE 6. A message to the Spring lovers ... The complexity in J2EE 1.2, 1.3, and 1.4 led to the genesis of Spring but that was in 2004. This is 2012 and the name has changed to "Java EE 6" :-) There are tons of improvements in the Java EE platform to make it easy-to-use and powerful. Some examples: Adding @Stateless on a POJO makes it an EJB EJBs can be packaged in a WAR with no special packaging or deployment descriptors "web.xml" and "faces-config.xml" are optional in most of the common cases Typesafe dependency injection is now part of the Java EE platform Add @Path on a POJO allows you to publish it as a RESTful resource EJBs can be used as backing beans for Facelets-driven JSF pages providing full MVC Java EE 6 WARs are known to be kilobytes in size and deployed in milliseconds Tons of other simplifications in the platform and application servers So if you moved away from J2EE to Spring many years ago and have not looked at Java EE 6 (which has been out since Dec 2009) then you should definitely try it out. Just be at least aware of what other alternatives are available instead of restricting yourself to one stack. Here are some workshops and screencasts worth trying: screencast #37 shows how to build an end-to-end application using NetBeans screencast #36 builds the same application using Eclipse javaee-lab-feb2012.pdf is a 3-4 hours self-paced hands-on workshop that guides you to build a comprehensive Java EE 6 application using NetBeans Each city generally has a "spring cleanup" program every year. It allows you to clean up the mess from your house. For your software projects, you don't need to wait for an annual event, just get started and reduce the technical debt now! Move away from your legacy Spring-based applications to a lighter and more modern approach of building enterprise Java applications using Java EE 6. Watch this beautiful presentation that explains how to migrate from Spring -> Java EE 6: List of files in the Java EE 6 project: ./index.xhtml./META-INF./person./person/Create.xhtml./person/Edit.xhtml./person/List.xhtml./person/View.xhtml./resources./resources/css./resources/css/jsfcrud.css./template.xhtml./WEB-INF./WEB-INF/classes./WEB-INF/classes/Bundle.properties./WEB-INF/classes/META-INF./WEB-INF/classes/META-INF/persistence.xml./WEB-INF/classes/org./WEB-INF/classes/org/javaee./WEB-INF/classes/org/javaee/javaeemysql./WEB-INF/classes/org/javaee/javaeemysql/AbstractFacade.class./WEB-INF/classes/org/javaee/javaeemysql/Person.class./WEB-INF/classes/org/javaee/javaeemysql/Person_.class./WEB-INF/classes/org/javaee/javaeemysql/PersonController$1.class./WEB-INF/classes/org/javaee/javaeemysql/PersonController$PersonControllerConverter.class./WEB-INF/classes/org/javaee/javaeemysql/PersonController.class./WEB-INF/classes/org/javaee/javaeemysql/PersonFacade.class./WEB-INF/classes/org/javaee/javaeemysql/util./WEB-INF/classes/org/javaee/javaeemysql/util/JsfUtil.class./WEB-INF/classes/org/javaee/javaeemysql/util/PaginationHelper.class./WEB-INF/faces-config.xml./WEB-INF/web.xml List of files in the Spring 3.x project: ./META-INF ./META-INF/MANIFEST.MF./WEB-INF./WEB-INF/applicationContext.xml./WEB-INF/classes./WEB-INF/classes/log4j.properties./WEB-INF/classes/org./WEB-INF/classes/org/krams ./WEB-INF/classes/org/krams/tutorial ./WEB-INF/classes/org/krams/tutorial/controller ./WEB-INF/classes/org/krams/tutorial/controller/MainController.class ./WEB-INF/classes/org/krams/tutorial/domain ./WEB-INF/classes/org/krams/tutorial/domain/Person.class ./WEB-INF/classes/org/krams/tutorial/service ./WEB-INF/classes/org/krams/tutorial/service/PersonService.class ./WEB-INF/hibernate-context.xml ./WEB-INF/hibernate.cfg.xml ./WEB-INF/jsp ./WEB-INF/jsp/addedpage.jsp ./WEB-INF/jsp/addpage.jsp ./WEB-INF/jsp/deletedpage.jsp ./WEB-INF/jsp/editedpage.jsp ./WEB-INF/jsp/editpage.jsp ./WEB-INF/jsp/personspage.jsp ./WEB-INF/lib ./WEB-INF/lib/antlr-2.7.6.jar ./WEB-INF/lib/aopalliance-1.0.jar ./WEB-INF/lib/c3p0-0.9.1.2.jar ./WEB-INF/lib/cglib-nodep-2.2.jar ./WEB-INF/lib/commons-beanutils-1.8.3.jar ./WEB-INF/lib/commons-collections-3.2.1.jar ./WEB-INF/lib/commons-digester-2.1.jar ./WEB-INF/lib/commons-logging-1.1.1.jar ./WEB-INF/lib/dom4j-1.6.1.jar ./WEB-INF/lib/ejb3-persistence-1.0.2.GA.jar ./WEB-INF/lib/hibernate-annotations-3.4.0.GA.jar ./WEB-INF/lib/hibernate-commons-annotations-3.1.0.GA.jar ./WEB-INF/lib/hibernate-core-3.3.2.GA.jar ./WEB-INF/lib/javassist-3.7.ga.jar ./WEB-INF/lib/jstl-1.1.2.jar ./WEB-INF/lib/jta-1.1.jar ./WEB-INF/lib/junit-4.8.1.jar ./WEB-INF/lib/log4j-1.2.14.jar ./WEB-INF/lib/mysql-connector-java-5.1.14.jar ./WEB-INF/lib/persistence-api-1.0.jar ./WEB-INF/lib/slf4j-api-1.6.1.jar ./WEB-INF/lib/slf4j-log4j12-1.6.1.jar ./WEB-INF/lib/spring-aop-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-asm-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-beans-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-context-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-context-support-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-core-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-expression-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-jdbc-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-orm-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-tx-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-web-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-webmvc-3.0.5.RELEASE.jar ./WEB-INF/lib/standard-1.1.2.jar ./WEB-INF/lib/xml-apis-1.0.b2.jar ./WEB-INF/spring-servlet.xml ./WEB-INF/spring.properties ./WEB-INF/web.xml So, are you excited about Java EE 6 ? Want to get started now ? Here are some resources: Java EE 6 SDK (including runtime, samples, tutorials etc) GlassFish Server Open Source Edition 3.1.2 (Community) Oracle GlassFish Server 3.1.2 (Commercial) Java EE 6 using WebLogic 12c and NetBeans (Video) Java EE 6 with NetBeans and GlassFish (Video) Java EE with Eclipse and GlassFish (Video)

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  • Serious about Embedded: Java Embedded @ JavaOne 2012

    - by terrencebarr
    It bears repeating: More than ever, the Java platform is the best technology for many embedded use cases. Java’s platform independence, high level of functionality, security, and developer productivity address the key pain points in building embedded solutions. Transitioning from 16 to 32 bit or even 64 bit? Need to support multiple architectures and operating systems with a single code base? Want to scale on multi-core systems? Require a proven security model? Dynamically deploy and manage software on your devices? Cut time to market by leveraging code, expertise, and tools from a large developer ecosystem? Looking for back-end services, integration, and management? The Java platform has got you covered. Java already powers around 10 billion devices worldwide, with traditional desktops and servers being only a small portion of that. And the ‘Internet of Things‘ is just really starting to explode … it is estimated that within five years, intelligent and connected embedded devices will outnumber desktops and mobile phones combined, and will generate the majority of the traffic on the Internet. Is your platform and services strategy ready for the coming disruptions and opportunities? It should come as no surprise that Oracle is keenly focused on Java for Embedded. At JavaOne 2012 San Francisco the dedicated track for Java ME, Java Card, and Embedded keeps growing, with 52 sessions, tutorials, Hands-on-Labs, and BOFs scheduled for this track alone, plus keynotes, demos, booths, and a variety of other embedded content. To further prove Oracle’s commitment, in 2012 for the first time there will be a dedicated sub-conference focused on the business aspects of embedded Java: Java Embedded @ JavaOne. This conference will run for two days in parallel to JavaOne in San Francisco, will have its own business-oriented track and content, and targets C-level executives, architects, business leaders, and decision makers. Registration and Call For Papers for Java Embedded @ JavaOne are now live. We expect a lot of interest in this new event and space is limited, so be sure to submit your paper and register soon. Hope to see you there! Cheers, – Terrence Filed under: Mobile & Embedded Tagged: ARM, Call for Papers, Embedded Java, Java Embedded, Java Embedded @ JavaOne, Java ME, Java SE Embedded, Java SE for Embedded, JavaOne San Francisco, PowerPC

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  • C#/.NET Little Wonders: The Concurrent Collections (1 of 3)

    - by James Michael Hare
    Once again we consider some of the lesser known classes and keywords of C#.  In the next few weeks, we will discuss the concurrent collections and how they have changed the face of concurrent programming. This week’s post will begin with a general introduction and discuss the ConcurrentStack<T> and ConcurrentQueue<T>.  Then in the following post we’ll discuss the ConcurrentDictionary<T> and ConcurrentBag<T>.  Finally, we shall close on the third post with a discussion of the BlockingCollection<T>. For more of the "Little Wonders" posts, see the index here. A brief history of collections In the beginning was the .NET 1.0 Framework.  And out of this framework emerged the System.Collections namespace, and it was good.  It contained all the basic things a growing programming language needs like the ArrayList and Hashtable collections.  The main problem, of course, with these original collections is that they held items of type object which means you had to be disciplined enough to use them correctly or you could end up with runtime errors if you got an object of a type you weren't expecting. Then came .NET 2.0 and generics and our world changed forever!  With generics the C# language finally got an equivalent of the very powerful C++ templates.  As such, the System.Collections.Generic was born and we got type-safe versions of all are favorite collections.  The List<T> succeeded the ArrayList and the Dictionary<TKey,TValue> succeeded the Hashtable and so on.  The new versions of the library were not only safer because they checked types at compile-time, in many cases they were more performant as well.  So much so that it's Microsoft's recommendation that the System.Collections original collections only be used for backwards compatibility. So we as developers came to know and love the generic collections and took them into our hearts and embraced them.  The problem is, thread safety in both the original collections and the generic collections can be problematic, for very different reasons. Now, if you are only doing single-threaded development you may not care – after all, no locking is required.  Even if you do have multiple threads, if a collection is “load-once, read-many” you don’t need to do anything to protect that container from multi-threaded access, as illustrated below: 1: public static class OrderTypeTranslator 2: { 3: // because this dictionary is loaded once before it is ever accessed, we don't need to synchronize 4: // multi-threaded read access 5: private static readonly Dictionary<string, char> _translator = new Dictionary<string, char> 6: { 7: {"New", 'N'}, 8: {"Update", 'U'}, 9: {"Cancel", 'X'} 10: }; 11:  12: // the only public interface into the dictionary is for reading, so inherently thread-safe 13: public static char? Translate(string orderType) 14: { 15: char charValue; 16: if (_translator.TryGetValue(orderType, out charValue)) 17: { 18: return charValue; 19: } 20:  21: return null; 22: } 23: } Unfortunately, most of our computer science problems cannot get by with just single-threaded applications or with multi-threading in a load-once manner.  Looking at  today's trends, it's clear to see that computers are not so much getting faster because of faster processor speeds -- we've nearly reached the limits we can push through with today's technologies -- but more because we're adding more cores to the boxes.  With this new hardware paradigm, it is even more important to use multi-threaded applications to take full advantage of parallel processing to achieve higher application speeds. So let's look at how to use collections in a thread-safe manner. Using historical collections in a concurrent fashion The early .NET collections (System.Collections) had a Synchronized() static method that could be used to wrap the early collections to make them completely thread-safe.  This paradigm was dropped in the generic collections (System.Collections.Generic) because having a synchronized wrapper resulted in atomic locks for all operations, which could prove overkill in many multithreading situations.  Thus the paradigm shifted to having the user of the collection specify their own locking, usually with an external object: 1: public class OrderAggregator 2: { 3: private static readonly Dictionary<string, List<Order>> _orders = new Dictionary<string, List<Order>>(); 4: private static readonly _orderLock = new object(); 5:  6: public void Add(string accountNumber, Order newOrder) 7: { 8: List<Order> ordersForAccount; 9:  10: // a complex operation like this should all be protected 11: lock (_orderLock) 12: { 13: if (!_orders.TryGetValue(accountNumber, out ordersForAccount)) 14: { 15: _orders.Add(accountNumber, ordersForAccount = new List<Order>()); 16: } 17:  18: ordersForAccount.Add(newOrder); 19: } 20: } 21: } Notice how we’re performing several operations on the dictionary under one lock.  With the Synchronized() static methods of the early collections, you wouldn’t be able to specify this level of locking (a more macro-level).  So in the generic collections, it was decided that if a user needed synchronization, they could implement their own locking scheme instead so that they could provide synchronization as needed. The need for better concurrent access to collections Here’s the problem: it’s relatively easy to write a collection that locks itself down completely for access, but anything more complex than that can be difficult and error-prone to write, and much less to make it perform efficiently!  For example, what if you have a Dictionary that has frequent reads but in-frequent updates?  Do you want to lock down the entire Dictionary for every access?  This would be overkill and would prevent concurrent reads.  In such cases you could use something like a ReaderWriterLockSlim which allows for multiple readers in a lock, and then once a writer grabs the lock it blocks all further readers until the writer is done (in a nutshell).  This is all very complex stuff to consider. Fortunately, this is where the Concurrent Collections come in.  The Parallel Computing Platform team at Microsoft went through great pains to determine how to make a set of concurrent collections that would have the best performance characteristics for general case multi-threaded use. Now, as in all things involving threading, you should always make sure you evaluate all your container options based on the particular usage scenario and the degree of parallelism you wish to acheive. This article should not be taken to understand that these collections are always supperior to the generic collections. Each fills a particular need for a particular situation. Understanding what each container is optimized for is key to the success of your application whether it be single-threaded or multi-threaded. General points to consider with the concurrent collections The MSDN points out that the concurrent collections all support the ICollection interface. However, since the collections are already synchronized, the IsSynchronized property always returns false, and SyncRoot always returns null.  Thus you should not attempt to use these properties for synchronization purposes. Note that since the concurrent collections also may have different operations than the traditional data structures you may be used to.  Now you may ask why they did this, but it was done out of necessity to keep operations safe and atomic.  For example, in order to do a Pop() on a stack you have to know the stack is non-empty, but between the time you check the stack’s IsEmpty property and then do the Pop() another thread may have come in and made the stack empty!  This is why some of the traditional operations have been changed to make them safe for concurrent use. In addition, some properties and methods in the concurrent collections achieve concurrency by creating a snapshot of the collection, which means that some operations that were traditionally O(1) may now be O(n) in the concurrent models.  I’ll try to point these out as we talk about each collection so you can be aware of any potential performance impacts.  Finally, all the concurrent containers are safe for enumeration even while being modified, but some of the containers support this in different ways (snapshot vs. dirty iteration).  Once again I’ll highlight how thread-safe enumeration works for each collection. ConcurrentStack<T>: The thread-safe LIFO container The ConcurrentStack<T> is the thread-safe counterpart to the System.Collections.Generic.Stack<T>, which as you may remember is your standard last-in-first-out container.  If you think of algorithms that favor stack usage (for example, depth-first searches of graphs and trees) then you can see how using a thread-safe stack would be of benefit. The ConcurrentStack<T> achieves thread-safe access by using System.Threading.Interlocked operations.  This means that the multi-threaded access to the stack requires no traditional locking and is very, very fast! For the most part, the ConcurrentStack<T> behaves like it’s Stack<T> counterpart with a few differences: Pop() was removed in favor of TryPop() Returns true if an item existed and was popped and false if empty. PushRange() and TryPopRange() were added Allows you to push multiple items and pop multiple items atomically. Count takes a snapshot of the stack and then counts the items. This means it is a O(n) operation, if you just want to check for an empty stack, call IsEmpty instead which is O(1). ToArray() and GetEnumerator() both also take snapshots. This means that iteration over a stack will give you a static view at the time of the call and will not reflect updates. Pushing on a ConcurrentStack<T> works just like you’d expect except for the aforementioned PushRange() method that was added to allow you to push a range of items concurrently. 1: var stack = new ConcurrentStack<string>(); 2:  3: // adding to stack is much the same as before 4: stack.Push("First"); 5:  6: // but you can also push multiple items in one atomic operation (no interleaves) 7: stack.PushRange(new [] { "Second", "Third", "Fourth" }); For looking at the top item of the stack (without removing it) the Peek() method has been removed in favor of a TryPeek().  This is because in order to do a peek the stack must be non-empty, but between the time you check for empty and the time you execute the peek the stack contents may have changed.  Thus the TryPeek() was created to be an atomic check for empty, and then peek if not empty: 1: // to look at top item of stack without removing it, can use TryPeek. 2: // Note that there is no Peek(), this is because you need to check for empty first. TryPeek does. 3: string item; 4: if (stack.TryPeek(out item)) 5: { 6: Console.WriteLine("Top item was " + item); 7: } 8: else 9: { 10: Console.WriteLine("Stack was empty."); 11: } Finally, to remove items from the stack, we have the TryPop() for single, and TryPopRange() for multiple items.  Just like the TryPeek(), these operations replace Pop() since we need to ensure atomically that the stack is non-empty before we pop from it: 1: // to remove items, use TryPop or TryPopRange to get multiple items atomically (no interleaves) 2: if (stack.TryPop(out item)) 3: { 4: Console.WriteLine("Popped " + item); 5: } 6:  7: // TryPopRange will only pop up to the number of spaces in the array, the actual number popped is returned. 8: var poppedItems = new string[2]; 9: int numPopped = stack.TryPopRange(poppedItems); 10:  11: foreach (var theItem in poppedItems.Take(numPopped)) 12: { 13: Console.WriteLine("Popped " + theItem); 14: } Finally, note that as stated before, GetEnumerator() and ToArray() gets a snapshot of the data at the time of the call.  That means if you are enumerating the stack you will get a snapshot of the stack at the time of the call.  This is illustrated below: 1: var stack = new ConcurrentStack<string>(); 2:  3: // adding to stack is much the same as before 4: stack.Push("First"); 5:  6: var results = stack.GetEnumerator(); 7:  8: // but you can also push multiple items in one atomic operation (no interleaves) 9: stack.PushRange(new [] { "Second", "Third", "Fourth" }); 10:  11: while(results.MoveNext()) 12: { 13: Console.WriteLine("Stack only has: " + results.Current); 14: } The only item that will be printed out in the above code is "First" because the snapshot was taken before the other items were added. This may sound like an issue, but it’s really for safety and is more correct.  You don’t want to enumerate a stack and have half a view of the stack before an update and half a view of the stack after an update, after all.  In addition, note that this is still thread-safe, whereas iterating through a non-concurrent collection while updating it in the old collections would cause an exception. ConcurrentQueue<T>: The thread-safe FIFO container The ConcurrentQueue<T> is the thread-safe counterpart of the System.Collections.Generic.Queue<T> class.  The concurrent queue uses an underlying list of small arrays and lock-free System.Threading.Interlocked operations on the head and tail arrays.  Once again, this allows us to do thread-safe operations without the need for heavy locks! The ConcurrentQueue<T> (like the ConcurrentStack<T>) has some departures from the non-concurrent counterpart.  Most notably: Dequeue() was removed in favor of TryDequeue(). Returns true if an item existed and was dequeued and false if empty. Count does not take a snapshot It subtracts the head and tail index to get the count.  This results overall in a O(1) complexity which is quite good.  It’s still recommended, however, that for empty checks you call IsEmpty instead of comparing Count to zero. ToArray() and GetEnumerator() both take snapshots. This means that iteration over a queue will give you a static view at the time of the call and will not reflect updates. The Enqueue() method on the ConcurrentQueue<T> works much the same as the generic Queue<T>: 1: var queue = new ConcurrentQueue<string>(); 2:  3: // adding to queue is much the same as before 4: queue.Enqueue("First"); 5: queue.Enqueue("Second"); 6: queue.Enqueue("Third"); For front item access, the TryPeek() method must be used to attempt to see the first item if the queue.  There is no Peek() method since, as you’ll remember, we can only peek on a non-empty queue, so we must have an atomic TryPeek() that checks for empty and then returns the first item if the queue is non-empty. 1: // to look at first item in queue without removing it, can use TryPeek. 2: // Note that there is no Peek(), this is because you need to check for empty first. TryPeek does. 3: string item; 4: if (queue.TryPeek(out item)) 5: { 6: Console.WriteLine("First item was " + item); 7: } 8: else 9: { 10: Console.WriteLine("Queue was empty."); 11: } Then, to remove items you use TryDequeue().  Once again this is for the same reason we have TryPeek() and not Peek(): 1: // to remove items, use TryDequeue. If queue is empty returns false. 2: if (queue.TryDequeue(out item)) 3: { 4: Console.WriteLine("Dequeued first item " + item); 5: } Just like the concurrent stack, the ConcurrentQueue<T> takes a snapshot when you call ToArray() or GetEnumerator() which means that subsequent updates to the queue will not be seen when you iterate over the results.  Thus once again the code below will only show the first item, since the other items were added after the snapshot. 1: var queue = new ConcurrentQueue<string>(); 2:  3: // adding to queue is much the same as before 4: queue.Enqueue("First"); 5:  6: var iterator = queue.GetEnumerator(); 7:  8: queue.Enqueue("Second"); 9: queue.Enqueue("Third"); 10:  11: // only shows First 12: while (iterator.MoveNext()) 13: { 14: Console.WriteLine("Dequeued item " + iterator.Current); 15: } Using collections concurrently You’ll notice in the examples above I stuck to using single-threaded examples so as to make them deterministic and the results obvious.  Of course, if we used these collections in a truly multi-threaded way the results would be less deterministic, but would still be thread-safe and with no locking on your part required! For example, say you have an order processor that takes an IEnumerable<Order> and handles each other in a multi-threaded fashion, then groups the responses together in a concurrent collection for aggregation.  This can be done easily with the TPL’s Parallel.ForEach(): 1: public static IEnumerable<OrderResult> ProcessOrders(IEnumerable<Order> orderList) 2: { 3: var proxy = new OrderProxy(); 4: var results = new ConcurrentQueue<OrderResult>(); 5:  6: // notice that we can process all these in parallel and put the results 7: // into our concurrent collection without needing any external locking! 8: Parallel.ForEach(orderList, 9: order => 10: { 11: var result = proxy.PlaceOrder(order); 12:  13: results.Enqueue(result); 14: }); 15:  16: return results; 17: } Summary Obviously, if you do not need multi-threaded safety, you don’t need to use these collections, but when you do need multi-threaded collections these are just the ticket! The plethora of features (I always think of the movie The Three Amigos when I say plethora) built into these containers and the amazing way they acheive thread-safe access in an efficient manner is wonderful to behold. Stay tuned next week where we’ll continue our discussion with the ConcurrentBag<T> and the ConcurrentDictionary<TKey,TValue>. For some excellent information on the performance of the concurrent collections and how they perform compared to a traditional brute-force locking strategy, see this wonderful whitepaper by the Microsoft Parallel Computing Platform team here.   Tweet Technorati Tags: C#,.NET,Concurrent Collections,Collections,Multi-Threading,Little Wonders,BlackRabbitCoder,James Michael Hare

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  • Imperative Programming v/s Declarative Programming v/s Functional Programming

    - by kaleidoscope
    Imperative Programming :: Imperative programming is a programming paradigm that describes computation in terms of statements that change a program state. In much the same way as the imperative mood in natural languages expresses commands to take action, imperative programs define sequences of commands for the computer to perform. The focus is on what steps the computer should take rather than what the computer will do (ex. C, C++, Java). Declarative Programming :: Declarative programming is a programming paradigm that expresses the logic of a computation without describing its control flow. It attempts to minimize or eliminate side effects by describing what the program should accomplish, rather than describing how to go about accomplishing it. The focus is on what the computer should do rather than how it should do it (ex. SQL). A  C# example of declarative v/s. imperative programming is LINQ. With imperative programming, you tell the compiler what you want to happen, step by step. For example, let's start with this collection, and choose the odd numbers: List<int> collection = new List<int> { 1, 2, 3, 4, 5 }; With imperative programming, we'd step through this, and decide what we want: List<int> results = new List<int>(); foreach(var num in collection) {     if (num % 2 != 0)           results.Add(num); } Here’s what we are doing: *Create a result collection *Step through each number in the collection *Check the number, if it's odd, add it to the results With declarative programming, on the other hand, we write the code that describes what you want, but not necessarily how to get it var results = collection.Where( num => num % 2 != 0); Here, we're saying "Give us everything where it's odd", not "Step through the collection. Check this item, if it's odd, add it to a result collection." Functional Programming :: Functional programming is a programming paradigm that treats computation as the evaluation of mathematical functions and avoids state and mutable data. It emphasizes the application of functions.Functional programming has its roots in the lambda calculus. It is a subset of declarative languages that has heavy focus on recursion. Functional programming can be a mind-bender, which is one reason why Lisp, Scheme, and Haskell have never really surpassed C, C++, Java and COBOL in commercial popularity. But there are benefits to the functional way. For one, if you can get the logic correct, functional programming requires orders of magnitude less code than imperative programming. That means fewer points of failure, less code to test, and a more productive (and, many would say, happier) programming life. As systems get bigger, this has become more and more important. To know more : http://stackoverflow.com/questions/602444/what-is-functional-declarative-and-imperative-programming http://msdn.microsoft.com/en-us/library/bb669144.aspx http://en.wikipedia.org/wiki/Imperative_programming   Technorati Tags: Ranjit,Imperative Programming,Declarative programming,Functional Programming

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  • Learn Cloud Computing – It’s Time

    - by Ben Griswold
    Last week, I gave an in-house presentation on cloud computing.  I walked through an overview of cloud computing – characteristics (on demand, elastic, fully managed by provider), why are we interested (virtualization, distributed computing, increased access to high-speed internet, weak economy), various types (public, private, virtual private cloud) and services models (IaaS, PaaS, SaaS.)  Though numerous providers have emerged in the cloud computing space, the presentation focused on Amazon, Google and Microsoft offerings and provided an overview of their platforms, costs, data tier technologies, management and security.  One of the biggest talking points was why developers should consider the cloud as part of their deployment strategy: You only have to pay for what you consume You will be well-positioned for one time event provisioning You will reap the benefits of automated growth and scalable technologies For the record: having deployed dozens of applications on various platforms over the years, pricing tends to be the biggest customer concern.  Yes, scalability is a customer consideration, too, but it comes in distant second.  Boy do I hope you’re still reading… You may be thinking, “Cloud computing is well and good and it sounds catchy, but should I bother?  After all, it’s just another technology bundle which I’m supposed to ramp up on because it’s the latest thing, right?”  Well, my clients used to be 100% reliant upon me to find adequate hosting for them.  Now I find they are often aware of cloud services and some come to me with the “possibility” that deploying to the cloud is the best solution for them.  It’s like the patient who walks into the doctor’s office with their diagnosis and treatment already in mind thanks to the handful of Internet searches they performed earlier that day.  You know what?  The customer may be correct about the cloud. It may be a perfect fit for their app.  But maybe not…  I don’t think there’s a need to learn about every technical thing under the sun, but if you are responsible for identifying hosting solutions for your customers, it is time to get up to speed on cloud computing and the various offerings (if you haven’t already.)  Here are a few references to get you going: DZone Refcardz #82 Getting Started with Cloud Computing by Daniel Rubio Wikipedia Cloud Computing – What is it? Amazon Machine Images (AMI) Google App Engine SDK Azure SDK EC2 Spot Pricing Google App Engine Team Blog Amazon EC2 Team Blog Microsoft Azure Team Blog Amazon EC2 – Cost Calculator Google App Engine – Cost and Billing Resources Microsoft Azure – Cost Calculator Larry Ellison has stated that cloud computing has been defined as "everything that we currently do" and that it will have no effect except to "change the wording on some of our ads" Oracle launches worldwide cloud-computing tour NoSQL Movement  

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  • Netbeans doesn't start, Java fatal error, unless sudo

    - by elect
    Fresh 13.10 64b Openjdk 6 is there, I just installed Netbeans 7.01 from the repo, but it doesn't work, I open then a console elect@elect-desktop:~$ netbeans # # A fatal error has been detected by the Java Runtime Environment: # # SIGSEGV (0xb) at pc=0x00007faebdf79325, pid=5251, tid=140388628424448 # # JRE version: 6.0_27-b27 # Java VM: OpenJDK 64-Bit Server VM (20.0-b12 mixed mode linux-amd64 compressed oops) # Derivative: IcedTea6 1.12.6 # Distribution: Ubuntu Saucy Salamander (development branch), package 6b27-1.12.6-1ubuntu2 # Problematic frame: # C [libgobject-2.0.so.0+0x14325] g_cclosure_marshal_BOOLEAN__BOXED_BOXEDv+0x985 # # An error report file with more information is saved as: # /home/elect/hs_err_pid5251.log [thread 140386948781824 also had an error] # # If you would like to submit a bug report, please include # instructions how to reproduce the bug and visit: # https://bugs.launchpad.net/ubuntu/+source/openjdk-6/ # /usr/share/netbeans/7.0.1/bin/../platform/lib/nbexec: line 548: 5251 Aborted (core dumped) "/usr/lib/jvm/java-6-openjdk-amd64/bin/java" -Djdk.home="/usr/lib/jvm/java-6-openjdk-amd64" -Djava.library.path=/usr/lib/jni -classpath "/usr/share/netbeans/7.0.1/platform/lib/boot.jar:/usr/share/netbeans/7.0.1/platform/lib/org-openide-modules.jar:/usr/share/netbeans/7.0.1/platform/lib/org-openide-util.jar:/usr/share/netbeans/7.0.1/platform/lib/org-openide-util-lookup.jar:/usr/lib/jvm/java-6-openjdk-amd64/lib/dt.jar:/usr/lib/jvm/java-6-openjdk-amd64/lib/tools.jar" -Dnetbeans.system_http_proxy="DIRECT" -Dnetbeans.system_http_non_proxy_hosts="" -Dnetbeans.dirs="/usr/share/netbeans/7.0.1/nb:/usr/share/netbeans/7.0.1/bin/../ergonomics:/usr/share/netbeans/7.0.1/ide:/usr/share/netbeans/7.0.1/java:/usr/share/netbeans/7.0.1/bin/../xml:/usr/share/netbeans/7.0.1/apisupport:/usr/share/netbeans/7.0.1/bin/../webcommon:/usr/share/netbeans/7.0.1/bin/../websvccommon:/usr/share/netbeans/7.0.1/bin/../enterprise:/usr/share/netbeans/7.0.1/bin/../mobility:/usr/share/netbeans/7.0.1/bin/../profiler:/usr/share/netbeans/7.0.1/bin/../ruby:/usr/share/netbeans/7.0.1/bin/../python:/usr/share/netbeans/7.0.1/bin/../php:/usr/share/netbeans/7.0.1/bin/../visualweb:/usr/share/netbeans/7.0.1/bin/../soa:/usr/share/netbeans/7.0.1/bin/../identity:/usr/share/netbeans/7.0.1/bin/../uml:/usr/share/netbeans/7.0.1/harness:/usr/share/netbeans/7.0.1/bin/../cnd:/usr/share/netbeans/7.0.1/bin/../dlight:/usr/share/netbeans/7.0.1/bin/../groovy:/usr/share/netbeans/7.0.1/bin/../extra:/usr/share/netbeans/7.0.1/bin/../javafx:/usr/share/netbeans/7.0.1/bin/../javacard:" -Dnetbeans.home="/usr/share/netbeans/7.0.1/platform" '-Dnetbeans.importclass=org.netbeans.upgrade.AutoUpgrade' '-Dnetbeans.accept_license_class=org.netbeans.license.AcceptLicense' '-XX:MaxPermSize=384m' '-Xmx768m' '-client' '-Xss2m' '-Xms32m' '-XX:PermSize=32m' '-Dapple.laf.useScreenMenuBar=true' '-Dapple.awt.graphics.UseQuartz=true' '-Dsun.java2d.noddraw=true' '-Dsun.java2d.pmoffscreen=false' -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath="/home/elect/.netbeans/7.0/var/log/heapdump.hprof" org.netbeans.Main --userdir "/home/elect/.netbeans/7.0" "--branding" "nb" 0<&0 Looking around, the second answer, here Vigintas Labakojis, points out something regarding permission, I just try sudo netbeans, it works.. Then I look for the ~/.cache/netbeans/ I dont have, I have instead ~/.netbeans/ Then I run his commands on those folder, it doesn't work.. It must be something else, do you have any idea? In any case, my log /home/elect/hs_err_pid5251.log is here

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  • SQL SERVER – Importance of User Without Login – T-SQL Demo Script

    - by pinaldave
    Earlier I wrote a blog post about SQL SERVER – Importance of User Without Login and my friend and SQL Expert Vinod Kumar has written excellent follow up blog post about Contained Databases inside SQL Server 2012. Now lots of people asked me if I can also explain the same concept again so here is the small demonstration for it. Let me show you how login without user can help. Before we continue on this subject I strongly recommend that you read my earlier blog post here. In following demo I am going to demonstrate following situation. Login using the System Admin account Create a user without login Checking Access Impersonate the user without login Checking Access Revert Impersonation Give Permission to user without login Impersonate the user without login Checking Access Revert Impersonation Clean up USE [AdventureWorks2012] GO -- Step 1 : Login using the SA -- Step 2 : Create Login Less User CREATE USER [testguest] 9ITHOUT LOGIN WITH DEFAULT_SCHEMA=[dbo] GO -- Step 3 : Checking access to Tables SELECT * FROM sys.tables; -- Step 4 : Changing the execution contest EXECUTE AS USER   = 'testguest'; GO -- Step 5 : Checking access to Tables SELECT * FROM sys.tables; GO -- Step 6 : Reverting Permissions REVERT; -- Step 7 : Giving more Permissions to testguest user GRANT SELECT ON [dbo].[ErrorLog] TO [testguest]; GRANT SELECT ON [dbo].[DatabaseLog] TO [testguest]; GO -- Step 8 : Changing the execution contest EXECUTE AS USER   = 'testguest'; GO -- Step 9 : Checking access to Tables SELECT * FROM sys.tables; GO -- Step 10 : Reverting Permissions REVERT; GO -- Step 11: Clean up DROP USER [testguest]Step 3 GO Here is the step 9 we will be able to notice that how a user without login gets access to some of the data/object which we gave permission. What I am going to prove with this example? Well there can be different rights with different account. Once the login is authenticated it makes sense for impersonating a user with only necessary permissions to be used for further operation. Again this is very basic and fundamental example. There are lots of more points to be discussed as we go in future posts. Just do not take this blog post as a template and implement everything as it is. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Security, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • Silverlight Cream for April 03, 2010 -- #829

    - by Dave Campbell
    In this Issue: Scott Marlowe, Nokola, SilverLaw, Brad Abrams, Jeff Wilcox, Jesse Liberty, Alexey Zakharov, ondrejsv, Ward Bell, and David Anson. Shoutouts: Bart Czernicki has a post up about the latest with HTML5: HTML 5 is Born Old - Quake in HTML 5 I was sent a link to shoebox360 a while back and had to sign up to see the Silverlight use, but it does work very nice. I like the panoramic carousel in the viewer: shoebox360 Jeff Handley has a post up on RIA Services - Documentation Guidance and Community Samples... the team is looking for feedback from all of us Shawn Wildermuth posted his My MIX Talks' Source Code Laurent Bugnion posted his Sample code and slides for my TechDays10 (Belgium) talks From SilverlightCream.com: Silverlight to WCF Cross Domain SecurityException Scott Marlowe wrote an article about an often-encountered security exception having to do with cross-domain policies. He details the problem, the response, the solution, and yet another problem/solution associated... good stuff, Scott! Simple Functions for HTML Interop You've seen Nokola's graphic work... how about some HTML Interop from him? He's exposing the code he uses in his work. New Video: ChildWindow Styling - Silverlight 3 SilverLaw has a new video tutorial on Silerlight 3 ChildWindow Styling up - in German - but the video is language-agnostic :) Silverlight 4 + RIA Services - Ready for Business: Exposing WCF (SOAP\WSDL) Services Brad Abrams' continuation in his RIA series is this one demonstrating exposing RIA Services as a Soap\WSDL service Silverlight 4: New parser implementation. New parser features. Jeff Wilcox has a post up highlighting some of the new features in Silverlight 4 such as a new parser implementation with new XAML features. New Video Series – Getting Started With Silverlight Jesse Liberty is starting a new video tutorial series that's going to build out to be a "complete survey of Silverlight programming". The first two are in this post and are Getting Started and Adding Controls to a Silverlight App... looks like good material, Jesse, and all the source is there for the taking as well. Silverlight layout hack: Centered content with fixed maxwidth Alexey Zakharov has a quick tip up on creating centered content with fixed maxwidth. He calls it a dirty trick... looks like code to me :) Silverlight DataForm’s autogenerated fields send empty strings to database ondrejsv points up a problem he had with the Toolkit's DataForm, and his solution to it... with code for all of us following along behind :) DevForce Extensibility With MEF InheritedExport Ward Bell has a post up describing how they got DevForce MEF'd up, and looks like a good post to get you all excited about MEF as well... lots of external links and good info. Tip: Read-only custom DependencyProperties don't exist in Silverlight, but can be closely approximated David Anson's latest Tip is about Read-only custom DependencyProperties in Silverlight -- which strictly is not possible, but he has a code example up that gets close. Stay in the 'Light! Twitter SilverlightNews | Twitter WynApse | WynApse.com | Tagged Posts | SilverlightCream Join me @ SilverlightCream | Phoenix Silverlight User Group Technorati Tags: Silverlight    Silverlight 3    Silverlight 4    Windows Phone MIX10

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  • Facebook Sponsored Results: Is It Getting Results?

    - by Mike Stiles
    Social marketers who like to focus on the paid aspect of the paid/earned hybrid Facebook represents may want to keep themselves aware of how the network’s new Sponsored Results ad product is performing. The ads, which appear when a user conducts a search from the Facebook search bar, have only been around a week or so. But the first statistics coming out of them are not bad. Marketer Nanigans says click-through rates on the Sponsored Results have been nearly 23 times better than regular Facebook ads. Some click-through rates have even gone over 3%. Just to give you some perspective, a TechCrunch article points out that’s the same kind of click-through rates that were being enjoyed during the go-go dot com boom of the 90’s. The average across the Internet in its entirety is now somewhere around .3% on a good day, so a 3% number should be enough to raise an eyebrow. Plus the cost-per-click price is turning up 78% lower than regular Facebook ads, so that should raise the other eyebrow. Marketers have gotten pretty used to being able to buy ads against certain keywords. Most any digital property worth its salt that sells ads offers this, and so does Facebook with its Sponsored Results product. But the unique prize Facebook brings to the table is the ability to also buy based on demographic and interest information gleaned from Facebook user profiles. With almost 950 million logging in, this is exactly the kind of leveraging of those users conventional wisdom says is necessary for Facebook to deliver on its amazing potential. So how does the Facebook user fit into this? Notorious for finding out exactly where sponsored marketing messages are appearing and training their eyeballs to avoid those areas, will the Facebook user reject these Sponsored Results? Well, Facebook may have found an area in addition to the News Feed where paid elements can’t be avoided and will be tolerated. If users want to read their News Feed, and they do, they’re going to see sponsored posts. Likewise, if they want to search for friends or Pages, and they do, they’re going to see Sponsored Results. The paid results are clearly marked as such. As long as their organic search results are not tainted or compromised, they will continue using search. But something more is going on. The early click-through rate numbers say not only do users not mind seeing these Sponsored Results, they’re finding them relevant enough to click on. And once they click, they seem to be liking what they find, with a reported 14% higher install rate than Marketplace Ads. It’s early, and obviously the jury is still out. But this is a new social paid marketing opportunity that’s well worth keeping an eye on, and that may wind up hitting the trifecta of being effective for the platform, the consumer, and the marketer.

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  • Internet Protocol Suite: Transition Control Protocol (TCP) vs. User Datagram Protocol (UDP)

    How do we communicate over the Internet?  How is data transferred from one machine to another? These types of act ivies can only be done by using one of two Internet protocols currently. The collection of Internet Protocol consists of the Transition Control Protocol (TCP) and the User Datagram Protocol (UDP).  Both protocols are used to send data between two network end points, however they both have very distinct ways of transporting data from one endpoint to another. If transmission speed and reliability is the primary concern when trying to transfer data between two network endpoints then TCP is the proper choice. When a device attempts to send data to another endpoint using TCP it creates a direct connection between both devices until the transmission has completed. The direct connection between both devices ensures the reliability of the transmission due to the fact that no intermediate devices are needed to transfer the data. Due to the fact that both devices have to continuously poll the connection until transmission has completed increases the resources needed to perform the transmission. An example of this type of direct communication can be seen when a teacher tells a students to do their homework. The teacher is talking directly to the students in order to communicate that the homework needs to be done.  Students can then ask questions about the assignment to ensure that they have received the proper instructions for the assignment. UDP is a less resource intensive approach to sending data between to network endpoints. When a device uses UDP to send data across a network, the data is broken up and repackaged with the destination address. The sending device then releases the data packages to the network, but cannot ensure when or if the receiving device will actually get the data.  The sending device depends on other devices on the network to forward the data packages to the destination devices in order to complete the transmission. As you can tell this type of transmission is less resource intensive because not connection polling is needed,  but should not be used for transmitting data with speed or reliability requirements. This is due to the fact that the sending device can not ensure that the transmission is received.  An example of this type of communication can be seen when a teacher tells a student that they would like to speak with their parents. The teacher is relying on the student to complete the transmission to the parents, and the teacher has no guarantee that the student will actually inform the parents about the request. Both TCP and UPD are invaluable when attempting to send data across a network, but depending on the situation one protocol may be better than the other. Before deciding on which protocol to use an evaluation for transmission speed, reliability, latency, and overhead must be completed in order to define the best protocol for the situation.  

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  • DevConnections jQuery Session Slides and Samples posted

    - by Rick Strahl
    I’ve posted all of my slides and samples from the DevConnections VS 2010 Launch event last week in Vegas. All three sessions are contained in a single zip file which contains all slide decks and samples in one place: www.west-wind.com/files/conferences/jquery.zip There were 3 separate sessions: Using jQuery with ASP.NET Starting with an overview of jQuery client features via many short and fun examples, you'll find out about core features like the power of selectors to select document elements, manipulate these elements with jQuery's wrapped set methods in a browser independent way, how to hook up and handle events easily and generally apply concepts of unobtrusive JavaScript principles to client scripting. The session also covers AJAX interaction between jQuery and the .NET server side code using several different approaches including sending HTML and JSON data and how to avoid user interface duplication by using client side templating. This session relies heavily on live examples and walk-throughs. jQuery Extensibility and Integration with ASP.NET Server Controls One of the great strengths of the jQuery Javascript framework is its simple, yet powerful extensibility model that has resulted in an explosion of plug-ins available for jQuery. You need it - chances are there's a plug-in for it! In this session we'll look at a few plug-ins to demonstrate the power of the jQuery plug-in model before diving in and creating our own custom jQuery plug-ins. We'll look at how to create a plug-in from scratch as well as discussing when it makes sense to do so. Once you have a plug-in it can also be useful to integrate it more seamlessly with ASP.NET by creating server controls that coordinate both server side and jQuery client side behavior. I'll demonstrate a host of custom components that utilize a combination of client side jQuery functionality and server side ASP.NET server controls that provide smooth integration in the user interface development process. This topic focuses on component development both for pure client side plug-ins and mixed mode controls. jQuery Tips and Tricks This session was kind of a last minute substitution for an ASP.NET AJAX talk. Nothing too radical here :-), but I focused on things that have been most productive for myself. Look at the slide deck for individual points and some of the specific samples.   It was interesting to see that unlike in previous conferences this time around all the session were fairly packed – interest in jQuery is definitely getting more pronounced especially with microsoft’s recent announcement of focusing on jQuery integration rather than continuing on the path of ASP.NET AJAX – which is a welcome change. Most of the samples also use the West Wind Web & Ajax Toolkit and the support tools contained within it – a snapshot version of the toolkit is included in the samples download. Specicifically a number of the samples use functionality in the ww.jquery.js support file which contains a fairly large set of plug-ins and helper functionality – most of these pieces while contained in the single file are self-contained and can be lifted out of this file (several people asked). Hopefully you'll find something useful in these slides and samples.© Rick Strahl, West Wind Technologies, 2005-2010Posted in ASP.NET  jQuery  

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  • Silverlight Cream for March 10, 2010 -- #810

    - by Dave Campbell
    In this Issue: Andrea Boschin, Jeremy Likness(-2-), Andrew Veresov, Nokola, SilverLaw, Gill Cleeren, Jim Wightman and Jeremy Likness, Viktor Larsson(-2-), and Walter Ferrari. Shoutouts: Viktor Larsson has a post up about Silverlight Market Penetration ... hope to meet you at MIX10, Viktor! Gergely Orosz has posted the Slides and code for the presentation “An Introduction to Silverlight” It appears that if I miss a day, I can pretty much do an all-submittal post :) From SilverlightCream.com: Writing an AsyncLoader to enqueue long running operations Andrea Boschin has a tutorial on SilverlightShow where he's building up an asynch service to deal with a long-running app on the server. MVVM with MEF in Silverlight: Video Tutorial Jeremy Likness has a video tutorial up for helping beginners wire up MVVM and MEF to Silverlight. Source code for the app in the video is downloadable. MVVM with MEF in Silverlight Video Tutorial Part 2: Plugins and Metadata In part 2, Jeremy Likness redesigns the app using metadata to turn the shapes into objects, and then show how easy it is to add a new plugin... and the source for the app is downloadable. Binding a Converter Parameter Andrew Veresov has a nice code-filled solution up for those times that you need to bind a ConverterParameter value. EasyPainter: Lion Hair styling Nokola has not been idle with Easy Painter... now he's added "Lion Hair" to the list of stylings you can apply... guess if you want to change someone's 'mane' ... sorry! Twisting Navigation - Silverlight 3 SilverLaw has another control up - a "Twisting Navigation" control... very cool :) ... and since I'm behind the curve, he already has an update in the Expression Gallery as noted in his post, and a video tutorial on implementing it in an application... and if you understand German, turn up the sound :) Uploading and downloading images using a WCF service with Silverlight Gill Cleeren has a tutorial up at SilverlightShow on uploading and downloading images using WCF Services in Silverlight New Windows Phone 7 Community Developer Hub Jim Wightman and Jeremy Likness have a very cool Silverlight page up where you can paste the URL of your XAP in and have it display in a "Windows 7 Series Phone" ... and that's all I'm saying about that. XAML Transformation 101 Viktor Larsson is discussing Transforms in XAML and has a nice tutorial up that is easily the beginning of a carousel... you may also want to check out his other posts... I'm adding him to my list. Silverlight 4 Webcam Demo In this post, Viktor Larsson has a tutorial up for using the WebCam. This is from a beginner perspective, so if you haven't jumped in, now's a good time. How to extend Bing Maps Silverlight with an elevation profile graph - Part 1 Walter Ferrari has a post up at SilverlightShow discussing extensions to BingMaps such as creating routes using GeoCoding and Route Services plus drawing lines on the maps and getting coordinates of the points. Stay in the 'Light! Twitter SilverlightNews | Twitter WynApse | WynApse.com | Tagged Posts | SilverlightCream Join me @ SilverlightCream | Phoenix Silverlight User Group Technorati Tags: Silverlight    Silverlight 3    Silverlight 4    MIX10

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  • Silverlight Cream for December 28, 2010 -- #1017

    - by Dave Campbell
    In this Issue: Davide Zordan, Alex Golesh, Michael S. Scherotter, Andrej Tozon, Alex Knight, Jeff Blankenburg(-2-), Jeremy Likness, and Laurent Bugnion. Above the Fold: Silverlight: "My “What’s new in Silverlight 4 demo” app" Andrej Tozon WP7: "Taking a screenshot from within a Silverlight #WP7 application" Laurent Bugnion Expression Blend: "PathListBox: getting started" Alex Knight Shoutouts: If you haven't seen this SurfCube app demo on YouTube yet... check it out now: SurfCube V1.0 Windows Phone 7 Browser Want to get a free WP7 class from Shawn Wildermuth? Check this out: Webinar: Writing your first Windows Phone 7 Application Koen Zwikstra announed the next preview of his great tool: Silverlight Spy Preview 2 From SilverlightCream.com: Using the Multi-Touch Behavior in a Windows Phone 7 Multi-Page application Davide Zordan has a post up responding to questions he receives about multi-touch on WP7 in applications spanning more than one page. Silverlight for Windows Phone 7 Quick Tip: Fix missing icons while using DatePicker/TimePicker controls Alex Golesh discusses the use of the DatePicker control from the WP7 toolkit and found an unpleasant surprise associated with the Done/Cancel icons in the ApplicationBar, and has a solution for us. Updated SMF Thumbnail Scrubbing Sample Code Michael S. Scherotter has a post up about an update he's done to Silverlight 4 of code that allows thumbnail views of a video while 'scrubbing' ... don't know what that is? read the post :) My “What’s new in Silverlight 4 demo” app Andrej Tozon admits he's a little behind with this post, but as he points out, it might be a good time to review Silverlight 4 features, on the eve of 5. PathListBox: getting started One half the Knight team -- Alex Knight this time, has the first post of a series on the PathListBox up ... some real Expression Blend goodness. What I Learned in WP7 – Issue #9 Two more from Jeff Blankenburg today, in his number 9, he starts off demonstrating passing data between pages when navigating and fnishes up with some excellent info for submitting apps to the marketplace. What I Learned in WP7 – #Issue 10 Jeff Blankenburg's number 10 elaborates on the query string data he discussed in number 9. Using Sterling in Windows Phone 7 Applications Who better than the author?? Jeremy Likness has an end-to-end WP7/Sterling app up on his blog... begin with downloading Sterling, discuss what's needed to support Tombstoning, even custom serialization. Taking a screenshot from within a Silverlight #WP7 application Laurent Bugnion has a post up describing something people have been looking for: getting a screenshot of a WP7 application's page. Stay in the 'Light! Twitter SilverlightNews | Twitter WynApse | WynApse.com | Tagged Posts | SilverlightCream Join me @ SilverlightCream | Phoenix Silverlight User Group Technorati Tags: Silverlight    Silverlight 3    Silverlight 4    Windows Phone MIX10

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  • Silverlight Cream for April 04, 2010 -- #830

    - by Dave Campbell
    In this Issue: Michael Washington, Hassan, David Anson, Jeff Wilcox, UK Application Development Consulting, Davide Zordan, Victor Gaudioso, Anoop Madhusudanan, Phil Middlemiss, and Laurent Bugnion. Shoutouts: Josh Smith has a good-read post up: Design-time data is still data Shawn Hargreaves reported his MIX demo released From SilverlightCream.com: Silverlight MVVM: Enabling Design-Time Data in Expression Blend When Using Web Services Michael Washington has a tutorial up on MVVM and using a web service to get design-time data that works in Blend also... lots of information and screenshots. WP7 Transition Animation Hassan has a new WP7 tutorial up that demonstrates playing media and adding transition animation between pages. Tip: For a truly read-only custom DependencyProperty in Silverlight, use a read-only CLR property instead David Anson's latest tip is in response to comments on his previous post and details one by Dr. WPF who points out that a read-only DependencyProperty doesn't actually need to be a DependencyProperty as long as the class implements INotifyPropertyChanged. Template parts and custom controls (quick tip) Jeff Wilcox has posted a set of tips and recommendations to use when developing control development in Silverlight ... this is a post to bookmark. Flexible Data Template Support in Silverlight The UK Application Development Consulting details a 'problem' in Silverlight that doesn't exist in WPF and that is data templates that vary by type... and discusses a way around it. Multi-Touch enabling Silverlight Simon using Blend behaviors and the Surface sample for Silverlight Davide Zordan brought Multi-Touch to the Silverlight Simon game on CodePlex using Blend Behaviors. New Video Tutorial: How to Use a Behavior to Fire Methods from Objects in Styles Victor Gaudioso has a video tutorial up responding to a question from a developer. He demonstrates development of a Behavior that can be attached to objects in or out of Styles that allows you to specify what Method they need to fire. Creating a Silverlight Client for @shanselman ’s Nerd Dinner, using oData and Bing Maps Anoop Madhusudanan took Scott Hanselman's post on an OData API for StackOverflow, and has created a Silverlight client for Nerd Dinner, including BingMaps. A Chrome and Glass Theme - Part 2 Phil Middlemiss has the next part of his Chrome and Glass Theme up. In this one he creates a very nice chrome-look button with visual state changes. MVVM Light Toolkit V3 SP1 for Windows Phone 7 Laurent Bugnion has released a new version of MVVM Light for WP7. Included is an installation manual and information about what was changed. Stay in the 'Light! Twitter SilverlightNews | Twitter WynApse | WynApse.com | Tagged Posts | SilverlightCream Join me @ SilverlightCream | Phoenix Silverlight User Group Technorati Tags: Silverlight    Silverlight 3    Silverlight 4    Windows Phone MIX10

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  • Oracle ADF Core Functionality Now Available for Free - Presenting Oracle ADF Essentials

    - by Shay Shmeltzer
    Normal 0 false false false EN-US X-NONE HE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Calibri","sans-serif"; mso-bidi-font-family:Arial;} We are happy to announce the new Oracle ADF Essentials - a free to develop and deploy version of the core technologies at the base of Oracle ADF – Oracle’s strategic development framework that was used, among other things, to build the new generation of the enterprise Oracle Fusion Applications. This release is aligned with the new Oracle JDeveloper 11.1.2.3 version that we released today. Oracle ADF Essentials enables developers to use the following free: Oracle ADF Faces Rich Client components –over 150 JSF 2.0 components that include extensive charting and data visualization components, supports skinning, internalization, accessibility and touch gestures and providing advanced Ajax, windowing, drag and drop and other UI capabilities in a declarative way. Oracle ADF Controller – an extension on top of the JSF controller providing complete process flow definition and enabling advanced reusability of flows inside page’s regions. Oracle ADF Binding – a declarative way to bind various business services to JSF user interfaces eliminating tedious managed-beans coding. Oracle ADF Business Components – a declarative layer for building Java based business services on top of relational databases. The main goal of Oracle ADF Essentials is to bring the benefits of Oracle ADF to a broader community of developers. If you are already using Oracle ADF, a key new functionality for you would be the ability to deploy your application on GlassFish. Several other interesting points: We provide instructions for deployment of Oracle ADF Essentials on GlassFish and officially support this platform for Oracle ADF Essentials deployment. Developers can choose to use the whole Oracle ADF Essentials, or just pieces of the technology. Visual development for Oracle ADF Essentials is provided in Oracle JDeveloper. Eclipse support via Oracle Enterprise for Eclipse (OEPE) is also planned. Want to learn more? Here is a quick overview and development demo of Oracle ADF Essentials For more visit the Oracle ADF Essentials page on OTN

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  • “Cloud Integration in Minutes” – True or False?

    - by Bruce Tierney
    The short answer is “yes”. Connecting on-premise and cloud applications “in minutes” is true…provided you only consider the connectivity subset of integration and have a small number of cloud integration touch points. At the recent Gartner AADI conference, 230 attendees filled up the Oracle session to get a more comprehensive answer to this question. During the session, titled “Simplifying Integration – The Cloud & Mobile Pre-requisite”, Oracle’s Tim Hall described cloud connectivity and then, equally importantly, the other essential and sometimes overlooked aspects of integration required to ensure a long term application and service integration strategy. To understand the challenges and opportunities faced by cloud integration, the session started off with a slide that describes how connectivity can quickly transition from simplicity to complexity as the number of applications and service vendor instances grows: Increased complexity puts increased demand on the integration platform As companies expand from on-premise applications into a hybrid on-premise/cloud infrastructure with support for mobile, cloud, and social, there is a new sense of urgency to implement a unified and comprehensive service integration platform. Without getting this unified platform in place, companies face increased complexity and cost managing a growing patchwork of niche integration toolsets as well as the disparate standards mandated by each SaaS vendor as shown in the image below: dddddddddddddddddddd Incomplete and overlapping offerings from a patchwork of niche vendors Also at Gartner AADI, Oracle SOA Suite customer Geeta Pyne, Director of Middleware at BMC presented their successful strategy on how BMC efficiently manages their cloud integration despite disparate requirements from each vendor. From one of Geeta’s slide: Interfaces are dictated by SaaS vendors; wide variety (SOAP, REST, Socket, HTTP/POX, SFTP); Flexibility of Oracle Service Bus/SOA Suite helps to support Every vendor has their way to handle Security; WS-Security, Custom Header; Support in Oracle Service Bus helps to adhere to disparate requirements At BMC, the flexibility of Oracle Service Bus and Oracle SOA Suite allowed them to support the wide variation in the functional requirements as mandated by their SaaS vendors. In contrast to the patchwork platform approach of escalating complexity from overlapping SaaS toolkits, Oracle’s strategy is to provide a unified platform to support disparate requirements from your SaaS vendors, on-premise apps, legacy apps, and more. Furthermore, Oracle SOA Suite includes the many aspects of comprehensive integration beyond basic connectivity including orchestration, analytics (BAM, events…), service virtualization and more in a single unified interface. Oracle SOA Suite – Unified and comprehensive To summarize, yes you can achieve “cloud integration in minutes” when considering the connectivity subset of integration but be sure to look for ways to simplify as you consider a more comprehensive view of integration beyond basic connectivity such as service virtualization, management, event processing and more. And finally, be sure your integration platform has the deep flexibility to handle the requirements of all your future SaaS applications…many of which are unknown to you now.

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  • Cloud Application Management for Platforms

    - by user756764
    Today Oracle, along with CloudBees, Cloudsoft, Huawei, Rackspace, Red Hat, and Software AG, published the Cloud Application Management for Platforms (CAMP) specification. This spec deals with application management in the context of PaaS. It defines a model (consisting of a set resources and their relationships), a REST-based API for manipulating that model, and a packaging format for getting applications (and their attendant metadata) into and out of the platform. My colleague, Mark Carlson, has already provided an excellent writeup on the spec here. The following, additional points bear emphasizing: CAMP is language, framework and platform neutral; it should be equally applicable to the task of deploying and managing Ruby on Rails applications as Java/Spring applications (as Node.js applications, etc.) CAMP only covers the interactions between a Cloud Consumer and a Cloud Provider (using the definitions of these terms provided in the NIST Cloud Computing Reference Architecture). The internal APIs used by the Cloud Provider to, for example, deploy additional platform services (e.g. a new message queuing service) are out of CAMP's scope. CAMP supports the management of the entire lifecycle of the application (e.g. start/stop, suspend/resume, etc.) not just the deployment of the components that make up the application. Complexity is the antithesis of interoperability. One of CAMP's goals is to be as broadly interoperable as possible. To this end, the authors of CAMP tried to "make things as simple as possible, but no simpler". For example, JSON is the only serialization format used in the spec (although Providers can extend this to support additional serialization formats such as XML). It remains to be seen whether we can preserve this simplicity as the spec is processed by OASIS. So far, those who have indicated an interest in collaborating on the spec seem to be of a like mind with regards to the need for simplicity. The flip side to simplicity is the knowledge that you undoubtedly missed something that is important to someone. To make up for this, CAMP is designed to be extensible. The idea is to ship what we know will work, allow implementers to extend the spec, then re-factor the spec to incorporate the most popular extensions. Anyone interested in this effort, particularly those of you using PaaS-level services, is encouraged to join the forthcoming OASIS TC. As you may have noticed, CAMP is a bit of a departure from some of the more monolithic management standards that have preceded it. The idea is to develop simple, discrete standards targeted to address specific interoperability and portability problems and tie these standards together with common patterns based on REST and HATEOAS. I'm excited to see how this idea plays out.

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  • Oracle Coherence 3.5 : Create Internet-scale applications using Oracle's high-performance data grid

    - by frederic.michiara
    Oracle Coherence Coherence provides replicated and distributed (partitioned) data management and caching services on top of a reliable, highly scalable peer-to-peer clustering protocol. Coherence has no single points of failure; it automatically and transparently fails over and redistributes its clustered data management services when a server becomes inoperative or is disconnected from the network. When a new server is added, or when a failed server is restarted, it automatically joins the cluster and Coherence fails back services to it, transparently redistributing the cluster load. Coherence includes network-level fault tolerance features and transparent soft re-start capability to enable servers to self-heal. For the ones looking at an easy reading and first good approach to Oracle Coherence, I would recommend reading the following book : Overview of Oracle Coherence 3.5 Build scalable web sites and Enterprise applications using a market-leading data grid product Design and implement your domain objects to work most effectively with Coherence and apply Domain Driven Designs (DDD) to Coherence applications Leverage Coherence events and continuous queries to provide real-time updates to client applications Successfully integrate various persistence technologies, such as JDBC, Hibernate, or TopLink, with Coherence Filled with numerous examples that provide best practice guidance, and a number of classes you can readily reuse within your own applications This book is targeted to Architects and developers, and as in our team we're more about Solutions Architects than developers I found interest in this book as it help to understand better Oracle Coherence and its value. The only point I may not agree with the authors is that Oracle Coherence is not an alternative to Oracle RAC in providing High Availability, but combining both Oracle RAC and Oracle Coherence will help Architects and Customers to reach higher level of service and high-availability. This book is available on https://www.packtpub.com/oracle-coherence-3-5/book Need to find out about Table of contents : https://www.packtpub.com/toc/oracle-coherence-35-table-contents Discover a sample chapter : https://www.packtpub.com/sites/default/files/6125_Oracle%20Coherence_SampleChapter.pdf Read also articles from the Authors on http://www.packtpub.com/ : Working with Aggregators in Oracle Coherence 3.5 Working with Value Extractors and Simplifying Queries in Oracle Coherence 3.5 Querying the Data Grid in Coherence 3.5: Obtaining Query Results and Using Indexes Installing Coherence 3.5 and Accessing the Data Grid: Part 1 Installing Coherence 3.5 and Accessing the Data Grid: Part 2 For more information on Oracle Coherence : What Oracle Coherence Can Do for You... : http://www.oracle.com/technology/products/coherence/coherencedatagrid/coherence_solutions.html Oracle Coherence on OTN : http://www.oracle.com/technology/products/coherence/index.html Oracle Coherence Knowledge Base : http://coherence.oracle.com/display/COH/Oracle+Coherence+Knowledge+Base+Home

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  • Subterranean IL: Filter exception handlers

    - by Simon Cooper
    Filter handlers are the second type of exception handler that aren't accessible from C#. Unlike the other handler types, which have defined conditions for when the handlers execute, filter lets you use custom logic to determine whether the handler should be run. However, similar to a catch block, the filter block does not get run if control flow exits the block without throwing an exception. Introducing filter blocks An example of a filter block in IL is the following: .try { // try block } filter { // filter block endfilter }{ // filter handler } or, in v1 syntax, TryStart: // try block TryEnd: FilterStart: // filter block HandlerStart: // filter handler HandlerEnd: .try TryStart to TryEnd filter FilterStart handler HandlerStart to HandlerEnd In the v1 syntax there is no end label specified for the filter block. This is because the filter block must come immediately before the filter handler; the end of the filter block is the start of the filter handler. The filter block indicates to the CLR whether the filter handler should be executed using a boolean value on the stack when the endfilter instruction is run; true/non-zero if it is to be executed, false/zero if it isn't. At the start of the filter block, and the corresponding filter handler, a reference to the exception thrown is pushed onto the stack as a raw object (you have to manually cast to System.Exception). The allowed IL inside a filter block is tightly controlled; you aren't allowed branches outside the block, rethrow instructions, and other exception handling clauses. You can, however, use call and callvirt instructions to call other methods. Filter block logic To demonstrate filter block logic, in this example I'm filtering on whether there's a particular key in the Data dictionary of the thrown exception: .try { // try block } filter { // Filter starts with exception object on stack // C# code: ((Exception)e).Data.Contains("MyExceptionDataKey") // only execute handler if Contains returns true castclass [mscorlib]System.Exception callvirt instance class [mscorlib]System.Collections.IDictionary [mscorlib]System.Exception::get_Data() ldstr "MyExceptionDataKey" callvirt instance bool [mscorlib]System.Collections.IDictionary::Contains(object) endfilter }{ // filter handler // Also starts off with exception object on stack callvirt instance string [mscorlib]System.Object::ToString() call void [mscorlib]System.Console::WriteLine(string) } Conclusion Filter exception handlers are another exception handler type that isn't accessible from C#, however, just like fault handlers, the behaviour can be replicated using a normal catch block: try { // try block } catch (Exception e) { if (!FilterLogic(e)) throw; // handler logic } So, it's not that great a loss, but it's still annoying that this functionality isn't directly accessible. Well, every feature starts off with minus 100 points, so it's understandable why something like this didn't make it into the C# compiler ahead of a different feature.

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  • How to Write an E-Book

    A few days ago my attention was drawn to a tweet spat between Karl Seguin and Scott Hanselman around the relaunch of ASP.NET and the title element in HTML. Tempest in a teapot of course, but worthwhile as I did some googling on Karl and found his blog at codebetter.com. From there it was a short jump to his free e-book, The Foundations of Programming. This short book is distinguished by its orientation, opinionated, its tone, mentoring and its honesty, which is refreshing. In Foundations, Karl covers what he considers the basics of programming and good design, including test driven development, dependency injection and domain driven design. Karl is opinionated, as the topics suggest, and doesnt bother to pretend that he doesnt think what hes suggesting is the better way, not just another way. He is aligned with ALT.NET, and gives an excellent overview of what that means; an overview more enlightening than the ALT.NET site. ALT.NET has its critics, but presenting a strong opinion grabbed my attention as a reader. It is a short walk from opinionated to hectoring,  but Karl held my attention without insulting me. He takes the time to explain, with examples, from the ground up, the problems that test driven development and dependency injection solve. So for dependency injection he builds it up from no DI, to a hand crafted approach, to a full fledged DI framework. This approach is more persuasive than just proscriptive and engaged me as the reader to follow along with his train of thought. Foundations is not as pedantic as I am making it sound. The final ingredient in Karls mix is honesty. He acknowledges that sometimes unit testing does cost more up front and take more time. He admits that sometimes he designs something a certain way just to be testable. He also warns that focusing too much on DI and loose coupling can lead to the poor design you are trying to avoid. These points add depth to his argument as I could tell hes speaking from experience, with some hard won lessons. I enjoyed The Foundations of Programming. When I was done with it, I was amazed how much I got a lot out of its 80 some pages. It is a rarity to come across something worthwhile that is longer then a tweet, but shorter than a tome these days. Well done Karl.   -- Relevant Links -- The now titled and newly relaunched page in question: http://www.asp.net/ The pleasantly confusing ALT.NET homepage: http://altdotnet.org/ A longer review, with details, chapter listings and all that important stuff: http://accidentaltechnologist.com/book-reviews/book-review-foundations-of-programming-by-karl-seguin/Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • Innovation and the Role of Social Media

    - by Brian Dirking
    A very interesting post by Andy Mulholland of CAP Gemini this week – “The CIO is trapped between the CEO wanting innovation and the CFO needing compliance” – had many interesting points: “A successful move in one area won’t be recognized and rapidly implemented in other areas to multiply the benefits, or worse unsuccessful ideas will get repeated adding to the cost and time wasted. That’s where the need to really address the combination of social networking, collaboration, knowledge management and business information is required.” Without communicating what works and what doesn’t, the innovations of our organization may be lost, and the failures repeated. That makes sense. If you liked Andy Mulholland’s blog post, you need to hear Howard Beader’s presentation at Enterprise 2.0 Conference on innovation and the role of social media. (Howard will be speaking in the Market Leaders Session at 1 PM on Wednesday June 22nd). Some of the thoughts Howard will share include: • Innovation is more than just ideas, it’s getting ideas to market, and removing the obstacles that stand in the way • Innovation is about parallel processing – you can’t remove the obstacles one by one because you will get to market too late • Innovation can be about product innovation, but it can also be about process innovation This brings us to Andy’s second issue he raises: "..the need for integration with, and visibility of, processes to understand exactly how the enterprise functions and delivers on its policies…" Andy goes on to talk about this from the perspective of compliance and the CFO’s concerns. And it’s true: innovation can come both in product innovation, but also internal process innovation. And process innovation can have as much impact as product innovation.  New supply chain models can disrupt an industry overnight. Many people ignore process innovation as a benefit of social business, because it is perceived as a bottom line rather than top line impact. But it can actually impact your top line by changing your entire business model. Oracle WebCenter sits at this crossroads between product innovation and process innovation, enabling you to drive go-to-market innovations through internal social media tools, removing obstacles in parallel, and also providing you deep insight into your processes so you can identify bottlenecks and realize whole new ways of doing business. Learn more about how at the Enterprise 2.0 Conference, where Oracle will be in booth #213 showing Oracle WebCenter and Oracle Fusion Applications.

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  • Cloud Computing : publication du volet 3 du Syntec Numérique

    - by Eric Bezille
    Une vision client/fournisseur réunie autour d'une ébauche de cadre contractuel Lors de la Cloud Computing World Expo qui se tenait au CNIT la semaine dernière, j'ai assisté à la présentation du nouveau volet du Syntec numérique sur le Cloud Computing et les "nouveaux modèles" induits : modèles économiques, contrats, relations clients-fournisseurs, organisation de la DSI. L'originalité de ce livre blanc vis à vis de ceux déjà existants dans le domaine est de s'être attaché à regrouper l'ensemble des acteurs clients (au travers du CRIP) et fournisseurs, autour d'un cadre de formalisation contractuel, en s'appuyant sur le modèle e-SCM. Accélération du passage en fournisseur de Services et fin d'une IT en silos ? Si le Cloud Computing permet d'accélérer le passage de l'IT en fournisseur de services (dans la suite d'ITIL v3), il met également en exergue le challenge pour les DSI d'un modèle en rupture nécessitant des compétences transverses permettant de garantir les qualités attendues d'un service de Cloud Computing : déploiement en mode "self-service" à la demande, accès standardisé au travers du réseau,  gestion de groupes de ressources partagées,  service "élastique" : que l'on peut faire croitre ou diminuer rapidement en fonction de la demande mesurable On comprendra bien ici, que le Cloud Computing va bien au delà de la simple virtualisation de serveurs. Comme le décrit fort justement Constantin Gonzales dans son blog ("Three Enterprise Principles for Building Clouds"), l'important réside dans le respect du standard de l'interface d'accès au service. Ensuite, la façon dont il est réalisé (dans le nuage), est de la charge et de la responsabilité du fournisseur. A lui d'optimiser au mieux pour être compétitif, tout en garantissant les niveaux de services attendus. Pour le fournisseur de service, bien entendu, il faut maîtriser cette implémentation qui repose essentiellement sur l'intégration et l'automatisation des couches et composants nécessaires... dans la durée... avec la prise en charge des évolutions de chacun des éléments. Pour le client, il faut toujours s'assurer de la réversibilité de la solution au travers du respect des standards... Point également abordé dans le livre blanc du Syntec, qui rappelle les points d'attention et fait un état des lieux de l'avancement des standards autour du Cloud Computing. En vous souhaitant une bonne lecture...

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  • Build Mobile App for E-Business Suite Using SOA Suite and ADF Mobile

    - by Michelle Kimihira
    With the upcoming release of Oracle ADF Mobile, I caught up with Srikant Subramaniam, Senior Principal Product Manager, Oracle Fusion Middleware post OpenWorld to learn about the cool hands-on lab at OpenWorld.  For those of you who missed it, you will want to keep reading... Author: Srikant Subramaniam, Senior Principal Product Manager,Oracle Fusion Middleware Oracle ADF Mobile enables rapid and declarative development of native on-device mobile applications. These native applications provide a richer experience for smart devices users running Apple iOS or other mobile platforms. Oracle ADF Mobile protects Oracle customers from technology shifts by adopting a metadata-based development framework that enables developer to develop one app (using Oracle JDeveloper), and deploy to multiple device platforms (starting with iOS and Android).  Oracle ADF Mobile also enables IT organizations to leverage existing expertise in web-based and Java development by adopting a hybrid application architecture that brings together HTML5, Java, and device native container: HTML5 allows developer to deliver device-native user experiences while maintaining portability across different platforms Java allows developers to create modules to support business logic and data services Native container provides integration into device services such as camera, contacts, etc All these technologies are packaged into a development framework that supports declarative application development through Oracle JDeveloper. ADF Mobile also provides out of box integratoin with key Fusion Middleware components, such as SOA Suite and Business Process Management (BPM). Oracle Fusion Middleware provides the necessary infrastructure to extend business processes and services to the mobile device -- enabling the mobile user to participate in human tasks – without the additional “mobile middleware” layer. When coupled with Oracle SOA Suite, this combination can execute business transactions on Oracle E-Business Suite (or any Oracle Application). Demo Use Case: Mobile E-Business Suite (iExpense) Approvals Using an employee expense approval scenario, we illustrate how to use Oracle Fusion Middleware and Oracle ADF Mobile to build application extensions that integrate intelligently with Oracle Applications (For example, E-Business Suite). Building these extensions using Oracle Fusion middleware and ADF makes modifications simple, quick to implement, and easy to maintain/upgrade. As described earlier, this approach also extends Fusion Middleware to mobile users without the additional "Mobile Middleware" layer. The approver is presented with a list of expense reports that have been submitted for approval. These expense reports are retrieved from the backend E-Business Suite and displayed on the mobile device. Approval (or rejection) of the expense report kicks off the workflow in E-Business Suite and takes it to completion. The demo also shows how to integrate with native device services such as email, contacts, BI dashboards as well as a prebuilt PDF viewer (this is especially useful in the expense approval scenario, as there is often a need for the approver to access the submitted receipts). Summary Oracle recommends Fusion Middleware as the application integration platform to deliver critical enterprise data and processes to mobile applications.  Pre-built connectors between Fusion Middleware and Applications greatly accelerates the integration process.  Instead of building individual integration points between mobile applications and individual enterprise applications, Oracle Fusion Middleware enables IT organizations to leverage a common platform to support both desktop and mobile application.  Additional Information Product Information on Oracle.com: Oracle Fusion Middleware Follow us on Twitter and Facebook Subscribe to our regular Fusion Middleware Newsletter

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