/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.proxy.interceptor;
import EDU.oswego.cs.dl.util.concurrent.Executor;
import org.apache.commons.proxy.Invocation;
import org.apache.commons.proxy.Interceptor;
/**
* A method interceptor that uses an {@link Executor} to execute the method invocation.
* <p/>
* <b>Note</b>: Only <em>void</em> methods can be intercepted using this class! Any attempts to intercept non-void
* methods will result in an {@link IllegalArgumentException}. If the proxy interfaces include non-void methods, try
* using a {@link FilteredInterceptor} along with a
* {@link org.apache.commons.proxy.interceptor.filter.ReturnTypeFilter} to wrap an instance of this class.
*
* <p>
* <b>Dependencies</b>:
* <ul>
* <li>Concurrent API version 1.3.4 or greater</li>
* </ul>
* </p>
* @author James Carman
* @since 1.0
*/
public class ExecutorInterceptor implements Interceptor
{
private final Executor executor;
public ExecutorInterceptor( Executor executor )
{
this.executor = executor;
}
public Object intercept( final Invocation invocation ) throws Throwable
{
if( Void.TYPE.equals( invocation.getMethod().getReturnType() ) )
{
// Special case for finalize() method (should not be run in a different thread)...
if( !( invocation.getMethod().getName().equals( "finalize" ) &&
invocation.getMethod().getParameterTypes().length == 0 ) )
{
executor.execute( new Runnable()
{
public void run()
{
try
{
invocation.proceed();
}
catch( Throwable t )
{
// What to do here? I can't convey the failure back to the caller.
}
}
} );
return null;
}
else
{
return invocation.proceed();
}
}
else
{
throw new IllegalArgumentException( "Only void methods can be executed in a different thread." );
}
}
}
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