leosimons 2003/08/21 14:27:08
Modified: magic/impl/src/java/org/apache/avalon/magic/impl
Avalon2PicoAdapter.java
Log:
more docs
Revision Changes Path
1.4 +56 -8
avalon-sandbox/magic/impl/src/java/org/apache/avalon/magic/impl/Avalon2PicoAdapter.java
Index: Avalon2PicoAdapter.java
===================================================================
RCS file:
/home/cvs/avalon-sandbox/magic/impl/src/java/org/apache/avalon/magic/impl/Avalon2PicoAdapter.java,v
retrieving revision 1.3
retrieving revision 1.4
diff -u -r1.3 -r1.4
--- Avalon2PicoAdapter.java 21 Aug 2003 21:13:51 -0000 1.3
+++ Avalon2PicoAdapter.java 21 Aug 2003 21:27:07 -0000 1.4
@@ -124,9 +124,57 @@
*
* Yes, indeed, this allows you to deploy any PicoContainer-compatible
* component into an existing avalon container! This class can also be
- * used by avalon containers internally to automagicallly support
+ * used by avalon containers internally to automagically support
* PicoContainer-compatible components.
*
+ * Performance notes: since this class depends on extensive reflection
+ * during component creation, it is signifcantly more expensive (an order
+ * of magnitude, often) to instantiate a component this way (as opposed
+ * to a container with native pico support). Also, since the component
+ * remains JDK-proxied even after initialization, there is a rather harsh
+ * performance hit that may not be acceptable. However, since many avalon
+ * containers already do proxying anyway, doing proxying by extension or
+ * encapsulation of this class results in very little perfomance decrease.
+ * Example:
+ *
+ * <pre>
+ * public class MyContainerProxy extends Avalon2PicoAdapter
+ * {
+ * MyContainerProxy( Class targetClass )
+ * {
+ * super( targetClass );
+ * }
+ * public static Object getProxy( Class targetClass )
+ * {
+ * // all interfaces implemented by the class,
+ * // and all lifecycle interfaces implemented
+ * // by the handler
+ * Class[] intf = targetClass.getInterfaces();
+ * List i = new ArrayList( Arrays.asList(intf) );
+ * i.add( LogEnabled.class );
+ * i.add( Serviceable.class );
+ * i.add( Contextualizable.class );
+ * i.add( Configurable.class );
+ * i.add( Initializable.class );
+ * intf = (Class[])i.toArray( new Class[i.size()] );
+ *
+ * return Proxy.newProxyInstance(
+ * targetClass.getClassLoader(),
+ * intf,
+ * new MyContainerProxy( targetClass ) );
+ * }
+ *
+ * public Object invoke( Object proxy, Method method, Object[] args )
+ * throws Throwable
+ * {
+ * if(!initialized)
+ * return super.invoke( proxy, method, args );
+ *
+ * [do your thing here]
+ * }
+ * }
+ * </pre>
+ *
* @version $Id$
*/
public class Avalon2PicoAdapter implements InvocationHandler
@@ -134,8 +182,8 @@
// ----------------------------------------------------------------------
// Properties
// ----------------------------------------------------------------------
- private boolean initialized = false;
- private boolean badstate = false;
+ protected boolean initialized = false;
+ protected boolean badstate = false;
private Class m_targetClass;
private Object m_target;
@@ -233,7 +281,7 @@
// Constructors
// ----------------------------------------------------------------------
- Avalon2PicoAdapter( Class target )
+ protected Avalon2PicoAdapter( Class target )
{
setTargetClass( target );
}
@@ -322,10 +370,10 @@
public Object invoke( Object proxy, Method method, Object[] args )
throws Throwable
{
- if(badstate)
- throw new IllegalStateException( "Initialization did not complete
without errors!" );
if(initialized)
return method.invoke( m_target, args );
+ if(badstate)
+ throw new IllegalStateException( "Initialization did not complete
without errors!" );
if( ENABLE_LOGGING.equals( method ) )
{
@@ -364,7 +412,7 @@
if( m_target == null )
throw new IllegalStateException( "You need to call initialize() first!"
);
- return method.invoke( m_target, args );
+ return method.invoke( m_target, args ); // will never actually be called
}
protected void createInstance()
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