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package com.sun.enterprise.web.connector.grizzly.comet;
import com.sun.enterprise.web.connector.grizzly.SelectorThread;
import com.sun.enterprise.web.connector.grizzly.NioProvider;
import java.io.IOException;
import java.nio.channels.CancelledKeyException;
import java.nio.channels.SelectableChannel;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.SocketChannel;
import java.util.Iterator;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
* NIO <code>Selector</code> allowing <code>CometHandler</code> to receive
* non-blocking requests bytes during request polling.
*
* @author Jeanfrancois Arcand
*/
public class CometSelector {
/**
* The <code>CometEngine</code> singleton
*/
protected CometEngine cometEngine;
/**
* The <code>java.nio.channels.Selector</code>
*/
private Selector selector;
/**
* Logger.
*/
private Logger logger = SelectorThread.logger();
/**
* The list of <code>SelectionKey</code> to register with the
* <code>Selector</code>
*/
private ConcurrentHashMap<SelectionKey,CometTask> keysToRegister
= new ConcurrentHashMap<SelectionKey,CometTask>();
/**
* New <code>CometSelector</code>
* @param cometEngine The <code>CometEngine</code> singleton
*/
public CometSelector(CometEngine cometEngine) {
this.cometEngine = cometEngine;
}
/**
* Start the <code>java.nio.channels.Selector</code> running on its
* Thread.
*/
public void start(){
new Thread("CometSelector"){
{
setDaemon(true);
}
public void run(){
try{
selector = Selector.open();
} catch(IOException ex){
// Most probably a fd leak.
logger.log(Level.SEVERE,"CometSelector.open()",ex);
return;
}
while (true){
SelectionKey key = null;
Set readyKeys;
Iterator<SelectionKey> iterator;
int selectorState = 0;
try{
selectorState = 0;
try{
selectorState = selector.select(1000);
} catch (CancelledKeyException ex){
;
}
readyKeys = selector.selectedKeys();
iterator = readyKeys.iterator();
CometTask cometTask;
while (iterator.hasNext()) {
key = iterator.next();
iterator.remove();
if (key.isValid()) {
cometTask = (CometTask)key.attachment();
if (key.isReadable()){
key.interestOps(key.interestOps()
& (~SelectionKey.OP_READ));
cometTask.upcoming_op =
CometTask.OP_EVENT.READ;
}
if (key.isWritable()){
key.interestOps(key.interestOps()
& (~SelectionKey.OP_WRITE));
cometTask.upcoming_op =
CometTask.OP_EVENT.WRITE;
}
if (cometTask.getSelectionKey().attachment() == null){
cometTask.execute();
} else {
key.cancel();
}
} else {
cancelKey(key);
}
}
Iterator<SelectionKey> keys =
keysToRegister.keySet().iterator();
/**
* The mainKey is the SelectionKey returned by the
* Selector used in the SelectorThread class.
*/
SelectionKey mainKey;
SocketChannel channel;
while (keys.hasNext()){
mainKey = keys.next();
channel = (SocketChannel)mainKey.channel();
if (mainKey.isValid() && channel.isOpen()) {
key = channel
.register(selector,SelectionKey.OP_READ);
cometTask = keysToRegister.remove(mainKey);
cometTask.setCometKey(key);
key.attach(cometTask);
keys.remove();
}
}
expireIdleKeys();
if (selectorState <= 0){
selector.selectedKeys().clear();
}
} catch (Throwable t){
if (key != null){
try{
cancelKey(key);
} catch (Throwable t2){
logger.log(Level.SEVERE,"CometSelector",t2);
}
}
if (selectorState <= 0){
selector.selectedKeys().clear();
}
logger.log(Level.SEVERE,"CometSelector",t);
}
}
}
}.start();
}
/**
* Expires registered <code>SelectionKey</code>. If a
* <code>SelectionKey</code> is expired, the request will be resumed and the
* HTTP request will complete,
*/
protected void expireIdleKeys(){
Set<SelectionKey> readyKeys = selector.keys();
if (readyKeys.isEmpty()){
return;
}
long current = System.currentTimeMillis();
Iterator<SelectionKey> iterator = readyKeys.iterator();
SelectionKey key;
while (iterator.hasNext()) {
key = iterator.next();
CometTask cometTask = (CometTask)key.attachment();
if (cometTask == null) return;
long expire = cometTask.getExpireTime();
if (current - expire >= cometTask.getExpirationDelay()) {
cancelKey(key);
}
/**
* The connection has been resumed since the timeout is
* re-attached to the SelectionKey so cancel the Comet key.
*/
if (cometTask.getSelectionKey() != null
&& cometTask.getSelectionKey().attachment() instanceof Long){
key.cancel();
cometEngine.interrupt(key);
}
}
}
/**
* Cancel a <code>SelectionKey</code>, and delegate the request
* polling interruption to the <code>CometEngine</code>
* @param key the expired <code>SelectionKey</code>
*/
protected synchronized void cancelKey(SelectionKey key){
if (!key.isValid()) return;
try{
CometTask cometTask = (CometTask)key.attachment();
if (cometTask != null){
SelectorThread st = cometTask.getSelectorThread();
SelectionKey mainKey = cometTask.getSelectionKey();
cometTask.getCometContext().interrupt(mainKey);
cometEngine.interrupt(key);
st.cancelKey(mainKey);
} else {
cometEngine.interrupt(key);
}
} catch (Throwable t) {
logger.log(Level.SEVERE,"CometSelector",t);
} finally {
key.attach(null);
}
key.cancel();
}
/**
* Register the <code>SelectionKey/code> to the <code>Selector</code>. We
* cannot register the <code>SelectionKey/code> directy on the
* <code>Selector</code> because there is a deadlock in the VM (see bug XXX).
*/
public void registerKey(SelectionKey key, CometTask cometTask){
cometTask.setExpireTime(System.currentTimeMillis());
keysToRegister.put(key, cometTask);
selector.wakeup();
}
/**
* Wakes up the <code>java.nio.channels.Selector</code>
*/
public void wakeup(){
selector.wakeup();
}
/**
* Return the SelectionKey associated with this channel.
*/
public SelectionKey cometKeyFor(SelectableChannel channel){
NioProvider nioP = NioProvider.getProvider();
if (nioP == null) {
return channel.keyFor(selector);
} else {
return nioP.keyFor(channel, selector);
}
}
}
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