偶也研究OSGi

偶也开始研究OSGi了，这东西真不错。不过官方的OSGi标准包太大了，前两天偶根据规范实现了其Module Layer部分并根据大家提到的一些不足，增加了自定义ClassPath和NativeCode的功能，这下应该可以用在基于Spring的 Webapp上了～

不多说了，看看测试代码吧：

java 代码

public   class  TFramework  extends  TestCase {

   private  Framework framework;

   public   void  setUp() {
    framework =  new  Framework();
    framework.addFrameworkListener( new  IFrameworkListener() {
       public   void  frameworkEvent(IFrameworkEvent event) {
         if  (event.getMessage() !=  null ) {
          System.out.println(event.getMessage());
        }
         if  (event.getThrowable() !=  null ) {
          event.getThrowable().printStackTrace();
        }
      }
    });
  }

   public   void  tearDown() {
    framework =  null ;
    System.out.println();
  }

   public   void  testBundle()  throws  Exception {

    framework.addClassPath( "C:\\osgi\\ws\\commons-logging.jar" );
    framework.addLibraryPath( "C:\\osgi\\os" );

     // ----------------------------------------------
     // Bundle-SymbolicName: com.yipsilon.osgi.test
     // Bundle-Version: 1.0.0.20061212
     // Bundle-NativeCode: swt-gdip-win32-3235.dll,swt-awt-win32-3235.dll,swt-wgl-win32-3235.dll,swt-win32-3235.dll
     // Bundle-Activator: com.yipsilon.osgi.test.Activator
     // Export-Package: com.yipsilon.osgi.test
     // Import-Package: org.apache.commons.logging
     // Bundle-ClassPath: swt.3.2.1.v3235.jar
     // ----------------------------------------------

    framework.installBundle( "C:\\osgi\\test.jar" );

    ClassLoader cl = framework.getClassLoader();

    URL explicitURL = cl.getResource( "com/yipsilon/osgi/test/Test.class" );
    URL implicitURL = cl.getResource( "com/yipsilon/osgi/test1/Hello.class" );
    URL externalURL = cl.getResource( "org/apache/commons/logging/LogFactory.class" );

    System.out.println( "implicitURL: "  + (implicitURL !=  null ));   // Returns true
    System.out.println( "explicitURL: "  + (explicitURL !=  null ));  // Returns true
    System.out.println( "externalURL: "  + (externalURL !=  null ));  // Returns true

    Class explicitClass = cl.loadClass( "com.yipsilon.osgi.test.Test" );
    Class implicitClass = cl.loadClass( "com.yipsilon.osgi.test1.Hello" );
    Class externalClass = cl.loadClass( "org.apache.commons.logging.LogFactory" );

    System.out.println( "implicitClass: "  + (implicitClass !=  null ));  // Returns false
    System.out.println( "explicitClass: "  + (explicitClass !=  null ));  // Returns true
    System.out.println( "externalClass: "  + (externalClass !=  null ));  // Returns true
  }
}

看完了知道这东西该怎么用了吧... 嘿嘿！！

不过要真正实现Webapp功能，还需要加一些东西，这些稍后我会开发出来～～进度的快慢全凭偶的空闲时间的多少... faint

PS：怎么附件加不进去呐？？才1.5MB而已....

 

 

 

继“偶也研究OSGi了之一 ”之后不到12小时，偶又开始发博了，大家检查一下内容质量如何～

这次，在上次的示例基础上，展示一下MINI OSGi的一些基本特性。还是刚才的代码（有少许变化）：

PS：为了简化代码，省略了所有的注释，代码结构还算不错，一般可以看懂～

java 代码

public   class  TFramework  extends  TestCase {

   private  Framework framework;

   public   void  setUp() {
    framework =  new  Framework();
    framework.addFrameworkListener( new  IFrameworkListener() {
       public   void  frameworkEvent(IFrameworkEvent event) {
         if  (event.getType() != IFrameworkEvent.TYPE.DEBUG && event.getMessage() !=  null ) {
          System.out.println(event.getMessage());
        }
         if  (event.getThrowable() !=  null ) {
          event.getThrowable().printStackTrace();
        }
      }
    });
    framework.addBundleListener( new  ISynchronousBundleListener(){
       public   void  bundleChanged(IBundleEvent event) {
        IBundle bundle = event.getBundle();
        System.out.println( "Bundle(SymbolicName:"  + bundle.getSymbolicName() +  ") state is changed to "  + event.getType().name());
      }

    });
  }

   public   void  tearDown() {
    framework =  null ;
  }

   public   void  testBundle()  throws  Exception {
    framework.addClassPath( "C:\\osgi\\lib" );
    framework.addClassPath( "C:\\osgi\\lib\\commons-logging.jar" );
    IBundle[] bundle = framework.installBundles( "C:\\osgi" );
    bundle[ 0 ].start();
  }
}

看到了吧，这里使用Bundle对象了～看看Bundle所对应的Activator类吧：

java 代码

public   class  Activator  implements  IBundleActivator{

   public   void  start(IBundleContext context)  throws  Exception {
    System.out.println( "Test.start("  + context +  ")" );
  }

   public   void  stop(IBundleContext context)  throws  Exception {
    System.out.println( "Test.stop("  + context +  ")" );
  }
}

"C:\osgi"目录下有一个叫 test.jar 的bundle包，MANIFEST.MF文件内容为：

Bundle-SymbolicName: com.yipsilon.osgi.test
Bundle-Version: 1.0.0.20061212
Bundle-NativeCode: swt-gdip-win32-3235.dll,swt-awt-win32-3235.dll,swt-wgl-win32-3235.dll,swt-win32-3235.dll
Bundle-Activator: com.yipsilon.osgi.test.Activator
Export-Package: com.yipsilon.osgi.test
Import-Package: org.apache.commons.logging
Bundle-ClassPath: swt.3.2.1.v3235.jar

其中 test.jar 的文件结构为：

test.jar
│  swt-awt-win32-3235.dll
│  swt-gdip-win32-3235.dll
│  swt-wgl-win32-3235.dll
│  swt-win32-3235.dll
│  swt.3.2.1.v3235.jar
│
├─com
│  └─yipsilon
│      └─osgi
│          ├─test
│          │      Activator.java
│          │      Test.java
│          │
│          └─test1
│                  ApplicationWindow.java
│                  Hello.java
│
└─META-INF
        MANIFEST.MF

使用JUnit3运行TFramework后，后台打印出：

01. Bundle(SymbolicName:com.yipsilon.osgi.test) state is changed to INSTALLED
02. Bundle(SymbolicName:com.yipsilon.osgi.test) state is changed to RESOLVED
03. Bundle(SymbolicName:com.yipsilon.osgi.test) state is changed to STARTING
04. Test.start(com.yipsilon.osgi.BundleContext@14a9972)
05. Bundle(SymbolicName:com.yipsilon.osgi.test) state is changed to STARTED
06. Bundle(SymbolicName:com.yipsilon.osgi.test) state is changed to STOPPING
07. Test.stop(com.yipsilon.osgi.BundleContext@14a9972)
08. Bundle(SymbolicName:com.yipsilon.osgi.test) state is changed to STOPPED
09. Bundle(SymbolicName:com.yipsilon.osgi.test) state is changed to UNINSTALLED

目前，MINI OSGI已经实现了import-package和require-bundle的resolve检查（也就是输出第2行的执行结果）。

我使用了addShutdownHook来在系统退出时释放所有没有卸载的bundle资源，以防止内存泄漏（第6－9行就是自动释放的输出）。

目前Module Layer部分还没有完全实现MANIFEST属性条件的判断，我觉得那个东西太复杂，大多数情况也用不上（至少以我现在的项目来说），所以先搁置一下。其他重要的功能就剩下update()方法了。HOHO～～