Package org.apache.avalon.framework.component
Deprecated: use the interfaces in the
org.apache.avalon.framework.service
package instead.
Interfaces and implementation of the component management services
supporting container based management of componet lookup and
decommissioning.
Migration from This Package
The Avalon team has determined that the best way to remove the need for this package in projects that existed before the team deprecated the package is to use a dynamic proxy. There are two ways of defining a dynamic proxy: using JDK 1.3's dynamic proxy generation code, and using BCEL to write a special purpose proxy.
All the Avalon containers now employ this technique so that you can
confidently remove all deprecation warnings from your code by removing
the Component
interface.
The code snippet below describes how to use JDK 1.3 to create a dynamic
proxy at runtime. The method getProxy
is where the proxy
is actually created. The class ComponentInvocationHandler
takes care of handling the method calls.
/** * Get the Component wrapped in the proxy. The role must be the service * interface's fully qualified classname to work. */ public Component getProxy( String role, Object service ) throws Exception { Class serviceInterface = m_classLoader.loadClass( role ); return (Component)Proxy.newProxyInstance( m_classLoader, new Class[]{Component.class, serviceInterface}, new ComponentInvocationHandler( service ) ); } /** * Internal class to handle the wrapping with Component */ private final static class ComponentInvocationHandler implements InvocationHandler { private final Object m_delagate; public ComponentInvocationHandler( final Object delegate ) { if( null == delegate ) { throw new NullPointerException( "delegate" ); } m_delagate = delegate; } public Object invoke( final Object proxy, final Method meth, final Object[] args ) throws Throwable { try { return meth.invoke( m_delagate, args ); } catch( final InvocationTargetException ite ) { throw ite.getTargetException(); } } }
-
Interface Summary Interface Description Component This interface identifies classes that can be used asComponents
by aComposable
.ComponentManager AComponentManager
selectsComponent
s based on a role.ComponentSelector AComponentSelector
selectsComponent
s based on a hint.Composable AComposable
class is one that needs to connect to software components using a "role" abstraction, thus not depending on particular implementations but on behavioral interfaces.Recomposable Deprecated. Deprecated with no replacement. -
Class Summary Class Description DefaultComponentManager This class is a static implementation of a ComponentManager.DefaultComponentSelector This is the default implementation of the ComponentSelector.WrapperComponentManager This is aComponentManager
implementation that can wrap around aServiceManager
object effectively adapting aServiceManager
interface to aComponentManager
interface.WrapperComponentSelector This is aServiceSelector
implementation that can wrap around a legacyComponentSelector
object effectively adapting aComponentSelector
interface to aServiceSelector
interface. -
Exception Summary Exception Description ComponentException The exception thrown to indicate a problem with Components.