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package com.sun.enterprise.web.ara;
import com.sun.enterprise.web.connector.grizzly.LinkedListPipeline;
import com.sun.enterprise.web.connector.grizzly.StreamAlgorithm;
import com.sun.enterprise.web.connector.grizzly.Task;
import com.sun.enterprise.web.connector.grizzly.TaskEvent;
import com.sun.enterprise.web.connector.grizzly.TaskListener;
import com.sun.enterprise.web.ara.algorithms.ContextRootAlgorithm;
import com.sun.enterprise.web.connector.grizzly.ConcurrentQueue;
import com.sun.enterprise.web.connector.grizzly.WorkerThreadImpl;
import java.util.Queue;
/**
* Customized <code>Pipeline</code> which wrap the original <code>Task</code>
* instance with an instance of <code>IsolatedTask</code>
*
* @author Jeanfrancois Arcand
*/
public class IsolationPipeline extends LinkedListPipeline
implements TaskListener{
private final static String ALGORITHM_CLASS =
"com.sun.enterprise.web.ara.algorithm";
private final static String RULE_EXECUTOR_CLASS =
"com.sun.enterprise.web.ara.ruleExecutor";
/**
* Cache instance of <code>IsolatedTask</code>
*/
private Queue<IsolatedTask> isolatedTasks;
// ------------------------------------------------------ Constructor ---/
public IsolationPipeline(){
}
/**
* Initialize this pipeline by first initializing its parent, and then by
* creating the caches and the rule executor engine.
*/
@Override
public void initPipeline(){
// 1. first, init this pipeline.
super.initPipeline();
// 2. Create cache
isolatedTasks = new ConcurrentQueue<IsolatedTask>("IsolationPipeline.isolatedTasks");
// 3. Cache IsolatedTask
for (int i=0; i < maxThreads; i++){
isolatedTasks.offer(newIsolatedTask());
}
}
/**
* Create new <code>WorkerThreadImpl</code>. This method must be invoked
* from a synchronized block.
*/
@Override
protected void increaseWorkerThread(int increment, boolean startThread){
WorkerThreadImpl workerThread;
if (threadCount >= minThreads) return;
maxThreads = maxThreads - minThreads;
for (int i=0; i < minThreads; i++){
workerThread = new WorkerThreadImpl(this,
name + "WorkerThread-" + port + "-" + i);
workerThread.setPriority(priority);
if (startThread)
workerThread.start();
workerThreads[i] = workerThread;
threadCount++;
}
}
/**
* Execute the wrapped <code>Task</code>
*/
@Override
public void addTask(Task task) {
// SSL not yet supported.
if (task.getType() == Task.READ_TASK){
super.addTask(wrap(task));
} else {
super.addTask(task);
}
}
/**
* Wrap the current <code>Task</code> using an <code>IsolatedTask</code>
*/
private Task wrap(Task task){
IsolatedTask isolatedTask = isolatedTasks.poll();
if ( isolatedTask == null){
isolatedTask = newIsolatedTask();
}
isolatedTask.wrap(task);
return isolatedTask;
}
/**
* Create a new <code>IsolatedTask</code>
*/
private IsolatedTask newIsolatedTask(){
IsolatedTask task = new IsolatedTask();
task.setAlgorithm(newAlgorithm());
task.setRulesExecutor(newRulesExecutor());
task.addTaskListener(this);
task.pipeline = this;
return task;
}
/**
* Create a new <code>StreamAlgorithm</code>.
*/
private StreamAlgorithm newAlgorithm(){
return (StreamAlgorithm)loadInstance(ALGORITHM_CLASS);
}
/**
* Create the new <code>RulesExecutor</code>
*/
private RulesExecutor newRulesExecutor(){
return (IsolationRulesExecutor)loadInstance(RULE_EXECUTOR_CLASS);
}
// ----------------------------------------------- Task Listener ---------//
public void taskStarted(TaskEvent event) {
; // Do nothing.
}
/**
* Return the <code>IsolatedTask</code> to the pool.
*/
public void taskEvent(TaskEvent event) {
if ( event.getStatus() == TaskEvent.COMPLETED)
isolatedTasks.offer((IsolatedTask)event.attachement());
}
// ----------------------------------------------- Util ------------------//
/**
* Instanciate a class based on a property.
*/
private Object loadInstance(String property){
Class className = null;
try{
className = Class.forName(property);
return className.newInstance();
} catch (ClassNotFoundException ex){
} catch (InstantiationException ex){
} catch (IllegalAccessException ex){
}
// Default
if ( property.equals(ALGORITHM_CLASS)){
return new ContextRootAlgorithm();
} else if ( property.equals(RULE_EXECUTOR_CLASS)){
return new IsolationRulesExecutor();
}
throw new IllegalStateException();
}
}