/*
 * JBoss, Home of Professional Open Source
 * Copyright 2011, Red Hat, Inc. and individual contributors
 * by the @authors tag. See the copyright.txt in the distribution for a
 * full listing of individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */

package org.mobicents.protocols.ss7.m3ua.impl;

import java.io.IOException;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.spi.SelectorProvider;
import java.util.Set;

import javolution.util.FastList;

import org.mobicents.protocols.ss7.m3ua.M3UASelectionKey;
import org.mobicents.protocols.ss7.m3ua.M3UASelector;

/**
 * Implements channel multiplexer.
 * 
 * @author amit bhayani
 * @author kulikov
 */
public class M3UASelectorImpl implements M3UASelector {
	// NIO multiplexer
	protected Selector selector;
	// list used for collecting selected keys.
	private FastList<M3UASelectionKey> list = new FastList<M3UASelectionKey>();

	/**
	 * Constructs new multiplexer.
	 * 
	 * @param selector
	 *            the NIO multiplexer.
	 */
	protected M3UASelectorImpl(Selector selector) {
		this.selector = selector;
	}

	/**
	 * Static method used for constructing the multiplexer.
	 * 
	 * @return new multiplexer.
	 * @throws java.io.IOException
	 */
	public static M3UASelectorImpl open() throws IOException {
		return new M3UASelectorImpl(SelectorProvider.provider().openSelector());
	}

	/**
	 * (Non Java-doc.)
	 * 
	 * @see org.mobicents.protocols.ss7.m3ua.M3UASelector#selectNow()
	 * @throws java.io.IOException
	 */
	public FastList<M3UASelectionKey> selectNow() throws IOException {
		list.clear();
		selector.selectNow();
		Set<SelectionKey> selection = selector.selectedKeys();
		for (SelectionKey key : selection) {
//			if(!key.isValid()){
//				//Move to next key if this one is not valid
//				continue;
//			}
			try{
				if (key.isAcceptable()) {
					M3UASelectionKeyImpl k = (M3UASelectionKeyImpl) key.attachment();
					list.add(k);
				} else {
	
					if (key.isReadable()) {
						M3UASelectionKeyImpl k = (M3UASelectionKeyImpl) key.attachment();
	
						try {
							((M3UAChannelImpl) k.channel()).doRead();
						} catch (IOException ex) {
							((M3UAChannelImpl) k.channel()).ioException = ex;
						}
	
						if (k.isReadable()) {
							list.add(k);
						}
	
					}
					
					if (key.isWritable()) {
						// write....
						M3UASelectionKeyImpl k = (M3UASelectionKeyImpl) key.attachment();
	
						try {
							((M3UAChannelImpl) k.channel()).doWrite();
						} catch (IOException ex) {
							((M3UAChannelImpl) k.channel()).ioException = ex;
						}
	
						if (k.isWritable()) {
							list.add(k);
						}
					}
				}
			} catch(java.nio.channels.CancelledKeyException e){
				//Lets ignore? may be the far end closed the connection. In next iteration it will be removed anyway
			}
		}
		selection.clear();
		return list;
	}

	/**
	 * (Non Java-doc.)
	 * 
	 * @see org.mobicents.protocols.ss7.m3ua.M3UASelector#close()
	 * @throws java.io.IOException
	 */
	public void close() throws IOException {
		selector.close();
	}
}