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package com.sun.enterprise.web.connector.grizzly.async;
import com.sun.enterprise.web.connector.grizzly.AsyncExecutor;
import com.sun.enterprise.web.connector.grizzly.AsyncFilter;
import com.sun.enterprise.web.connector.grizzly.AsyncHandler;
import com.sun.enterprise.web.connector.grizzly.AsyncTask;
import com.sun.enterprise.web.connector.grizzly.ProcessorTask;
import com.sun.enterprise.web.connector.grizzly.SelectorThread;
import java.util.ArrayList;
import java.util.StringTokenizer;
import java.util.logging.Level;
/**
* Default implementation of the <code>AsyncExecutor</code>. This class will
* execute a <code>ProcessorTask</code> asynchronously, by interrupting the
* process based on the logic defined in its associated <code>AsyncFilter</code>
* If no <code>AsyncFilter</code> are defined, the <code>ProcessorTask</code>
* will not be interrupted and executed synchronously.
*
* @author Jeanfrancois Arcand
*/
public class DefaultAsyncExecutor implements AsyncExecutor{
private final static String ASYNC_FILTER =
"com.sun.enterprise.web.connector.grizzly.asyncFilters";
/**
* The <code>AsyncTask</code> used to wrap the
* <code>ProcessorTask</code>
*/
private AsyncTask asyncProcessorTask;
/**
* The associated <code>ProcessorTask</code>
*/
private ProcessorTask processorTask;
/**
* The <code>AsyncFilter</code> to execute asynchronous operations on
* a <code>ProcessorTask</code>.
*/
private static String[] sharedAsyncFilters = null;;
/**
* The <code>AsyncFilter</code> to execute asynchronous operations on
* a <code>ProcessorTask</code>.
*/
private ArrayList<AsyncFilter> asyncFilters =
new ArrayList<AsyncFilter>();
/**
* Do we need to invoke filters?
*/
private boolean invokeFilter = true;
/**
* Loads filters implementation.
*/
static {
loadFilters();
}
/**
* The <code>AsyncHandler</code> associated with this object.
*/
private AsyncHandler asyncHandler;
// --------------------------------------------------------------------- //
public DefaultAsyncExecutor(){
init();
}
private void init(){
if (sharedAsyncFilters != null){
for (String filterName: sharedAsyncFilters){
asyncFilters.add(loadInstance(filterName));
}
}
}
// ------------------------------------------------Asynchrounous Execution --/
/**
* Pre-execute a <code>ProcessorTask</code> by parsing the request
* line.
*/
public boolean preExecute() throws Exception{
processorTask = asyncProcessorTask.getProcessorTask();
if ( processorTask == null ){
throw new IllegalStateException("Null ProcessorTask");
}
processorTask.preProcess();
processorTask.parseRequest();
return true;
}
/**
* Interrupt the <code>ProcessorTask</code> if <code>AsyncFilter</code>
* has been defined.
* @return true if the execution can continue, false if delayed.
*/
public boolean interrupt() throws Exception{
if ( asyncFilters == null || asyncFilters.size() == 0 ) {
execute();
return false;
} else {
asyncHandler.addToInterruptedQueue(asyncProcessorTask);
return invokeFilters();
}
}
/**
* Interrupt the <code>ProcessorTask</code> if <code>AsyncFilter</code>
* has been defined.
* @return true if the execution can continue, false if delayed.
*/
public boolean execute() throws Exception{
processorTask.invokeAdapter();
return true;
}
/**
* Invoke the <code>AsyncFilter</code>
*/
private boolean invokeFilters(){
boolean continueExec = true;
for (AsyncFilter asf: asyncFilters){
continueExec = asf.doFilter(this);
if ( !continueExec ){
break;
}
}
return continueExec;
}
/**
* Post-execute the <code>ProcessorTask</code> by preparing the response,
* flushing the response and then close or keep-alive the connection.
*/
public boolean postExecute() throws Exception{
processorTask.postResponse();
processorTask.postProcess();
processorTask.terminateProcess();
// De-reference so under stress we don't have a simili leak.
processorTask = null;
return false;
}
/**
* Set the <code>AsyncTask</code>.
*/
public void setAsyncTask(AsyncTask asyncProcessorTask){
this.asyncProcessorTask = asyncProcessorTask;
}
/**
* Return <code>AsyncTask</code>.
*/
public AsyncTask getAsyncTask(){
return asyncProcessorTask;
}
// --------------------------------------------------------- Util --------//
/**
* Load the list of <code>AsynchFilter</code>.
*/
protected static void loadFilters(){
if ( System.getProperty(ASYNC_FILTER) != null){
StringTokenizer st = new StringTokenizer(
System.getProperty(ASYNC_FILTER),",");
sharedAsyncFilters = new String[st.countTokens()];
int i = 0;
while (st.hasMoreTokens()){
sharedAsyncFilters[i++] = st.nextToken();
}
}
}
/**
* Instanciate a class based on a property.
*/
private static AsyncFilter loadInstance(String property){
Class className = null;
try{
className = Class.forName(property);
return (AsyncFilter)className.newInstance();
} catch (ClassNotFoundException ex){
SelectorThread.logger().log(Level.WARNING,ex.getMessage(),ex);
} catch (InstantiationException ex){
SelectorThread.logger().log(Level.WARNING,ex.getMessage(),ex);
} catch (IllegalAccessException ex){
SelectorThread.logger().log(Level.WARNING,ex.getMessage(),ex);
}
return null;
}
/**
* Add an <code>AsyncFilter</code>
*/
public void addAsyncFilter(AsyncFilter asyncFilter) {
asyncFilters.add(asyncFilter);
}
/**
* Remove an <code>AsyncFilter</code>
*/
public boolean removeAsyncFilter(AsyncFilter asyncFilter) {
return asyncFilters.remove(asyncFilter);
}
/**
* Get the <code>AsyncHandler</code> who drive the asynchronous process.
*/
public AsyncHandler getAsyncHandler() {
return asyncHandler;
}
/**
* Set the <code>AsyncHandler</code> who drive the asynchronous process.
*/
public void setAsyncHandler(AsyncHandler asyncHandler) {
this.asyncHandler = asyncHandler;
}
}
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