/**
* Copyright 2010 JBoss Inc
*
* Licensed 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.drools.concurrent;
import java.io.Externalizable;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.LinkedBlockingQueue;
import org.drools.WorkingMemory;
/**
* The CommandExecutor is a Producer/Consumer style classes that provides a queue of Commands
* in a LinkedBlockingQueue. This the run() method loops for continously until shutdown() is
* called.
*
*/
public class CommandExecutor implements Runnable, Externalizable {
private static final long serialVersionUID = 510l;
private WorkingMemory workingMemory;
private BlockingQueue queue;
private volatile boolean run;
public CommandExecutor() {
}
public CommandExecutor(WorkingMemory workingMemory) {
this.workingMemory = workingMemory;
this.queue = new LinkedBlockingQueue();
}
public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
workingMemory = (WorkingMemory)in.readObject();
queue = (BlockingQueue)in.readObject();
run = in.readBoolean();
}
public void writeExternal(ObjectOutput out) throws IOException {
out.writeObject(workingMemory);
out.writeObject(queue);
out.writeBoolean(run);
}
/**
* Allows the looping run() method to execute.
*
*/
public void shutdown() {
this.run = false;
}
/**
* Submit a Command for execution
*
* @param command
*
* @return
* return the Future
*/
public Future submit(Command command) {
this.queue.offer( command );
// we know our commands also implement Future
return (Future) command;
}
public void run() {
this.run = true;
while (this.run) {
try {
Command executor = ( Command ) this.queue.take();
executor.execute( this.workingMemory );
} catch(InterruptedException e) {
return;
}
}
}
}