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 * 
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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
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package com.sun.star.comp.connections;


import com.sun.star.comp.loader.FactoryHelper;

import com.sun.star.connection.XConnection;

import com.sun.star.lang.XMultiServiceFactory;
import com.sun.star.lang.XSingleServiceFactory;

import com.sun.star.registry.XRegistryKey;

/**
 * The PipedConnection is a component that implements the
 * <code>XConnection</code> Interface.
 * It is useful for <code>Thread</code> communication
 * in one Process.
 * <p>
 * @version 	$Revision: 1.3 $ $ $Date: 2008-04-11 11:09:30 $
 * @author 	    Kay Ramme
 * @see         com.sun.star.connections.XConnection
 * @see         com.sun.star.loader.JavaLoader
 * @since       UDK1.0
 */
public class PipedConnection implements XConnection {
	/**
	 * When set to true, enables various debugging output.
	 */
	public static final boolean DEBUG = false;

	/**
	 * The name of the service, the <code>JavaLoader</code> acceses this through reflection.
	 */
    static private final String __serviceName = "com.sun.star.connection.PipedConnection";

	/**
	 * Gives a factory for creating the service.
	 * This method is called by the <code>JavaLoader</code>
	 * <p>
	 * @return  returns a <code>XSingleServiceFactory</code> for creating the component
	 * @param   implName     the name of the implementation for which a service is desired
	 * @param   multiFactory the service manager to be uses if needed
	 * @param   regKey       the registryKey
	 * @see                  com.sun.star.comp.loader.JavaLoader
	 */
	public static XSingleServiceFactory __getServiceFactory(String implName, 
														  XMultiServiceFactory multiFactory, 
														  XRegistryKey regKey)
	{
		XSingleServiceFactory xSingleServiceFactory = null;

	    if (implName.equals(PipedConnection.class.getName()) )
	        xSingleServiceFactory = FactoryHelper.getServiceFactory(PipedConnection.class,
																	__serviceName,
																	multiFactory, 
																	regKey);
	    
	    return xSingleServiceFactory;
	}

	/**
	 * The amount of time in milliseconds, to wait to
	 * see check the buffers.
	 */
	protected static final int __waitTime = 10000;

	protected byte			   _buffer[] = new byte[4096];
	protected int			   _in, 
							   _out;
	protected boolean		   _closed;
	protected PipedConnection  _otherSide;

	/**
	 * Constructs a new <code>PipedConnection</code>, sees if there 
	 * is an other side, which it should be connected to.
	 * <p>
	 * @param    args   Another side could be in index 0.
	 */
	public PipedConnection(Object args[]) throws com.sun.star.uno.RuntimeException {
		if (DEBUG) System.err.println("##### " + getClass().getName() + " - instantiated");

		_otherSide = (args.length == 1) ? (PipedConnection)args[0] : null;
		if(_otherSide != null) {
			if(_otherSide == this) 
				throw new RuntimeException("can not connect to myself");

			_otherSide._otherSide = this;
		}
	}

	/**
	 * This is a private method, used to cummunicate 
	 * internal in the pipe.
	 */
	private synchronized void receive(byte aData[]) throws com.sun.star.io.IOException {
		int bytesWritten = 0;

		if(DEBUG) System.err.println("##### PipedConnection.receive - bytes:" + aData.length + " at:" + _out);

		while(bytesWritten < aData.length) {
			// wait until it is not full anymore
			while(_out == (_in - 1) || (_in == 0 && _out == _buffer.length - 1)) {
				try {
					notify(); // the buffer is full, signal it

					wait(__waitTime);
				}
				catch(InterruptedException interruptedException) {
					throw new com.sun.star.io.IOException(interruptedException.toString());
				}
			}

			if(_closed) throw new com.sun.star.io.IOException("connection has been closed");

			int bytes  ;

			if(_out < _in) {
				bytes = Math.min(aData.length - bytesWritten, _in - _out - 1);

				System.arraycopy(aData, bytesWritten, _buffer, _out, bytes);
			}
			else {
				if(_in > 0){
					bytes = Math.min(aData.length - bytesWritten, _buffer.length - _out);
				}
				else {
					bytes = Math.min(aData.length - bytesWritten, _buffer.length - _out - 1);
				}
				
				System.arraycopy(aData, bytesWritten, _buffer, _out, bytes);
			}

			bytesWritten += bytes;
			_out += bytes;
			if(_out >= _buffer.length)
				_out = 0;
		}
	}

	/**
	 * Read the required number of bytes.
	 * <p>
	 * @return   the number of bytes read
	 * @param    aReadBytes   the outparameter, where the bytes have to be placed
	 * @param    nBytesToRead the number of bytes to read
     * @see       com.sun.star.connections.XConnection#read
	 */
    public synchronized int read(/*OUT*/byte[][] aReadBytes, int nBytesToRead) throws com.sun.star.io.IOException, com.sun.star.uno.RuntimeException {
		aReadBytes[0] = new byte[nBytesToRead];

		if(DEBUG) System.err.println("##### PipedConnection.read - bytes:" + nBytesToRead + " at:" + _in);

		// loop while not all bytes read or when closed but there is still data
		while(nBytesToRead > 0 && (_in != _out || !_closed)) {
			while(_in == _out && !_closed) {
				try {
					notify(); // the buffer is empty, signal it

					wait(__waitTime); // we wait for data or for the pipe to be closed
				}
				catch(InterruptedException interruptedException) {
					throw new com.sun.star.io.IOException(interruptedException.toString());
				}
			}

			if(_in < _out) {
				int bytes = Math.min(nBytesToRead, _out - _in);

				System.arraycopy(_buffer, _in, aReadBytes[0], aReadBytes[0].length - nBytesToRead, bytes);

				nBytesToRead -= bytes;
				_in += bytes;
			}
			else if(_in > _out) {
				int bytes = Math.min(nBytesToRead, _buffer.length - _in);

				System.arraycopy(_buffer, _in, aReadBytes[0], aReadBytes[0].length - nBytesToRead, bytes);

				nBytesToRead -= bytes;
				_in += bytes;
				if(_in >= _buffer.length)
					_in = 0;
			}
		}

		if(nBytesToRead > 0) { // not all bytes read
			byte tmp[] = new byte[aReadBytes[0].length - nBytesToRead];
			System.arraycopy(aReadBytes[0], 0, tmp, 0, tmp.length);

			aReadBytes[0] = tmp;
		}

		return aReadBytes[0].length;
	}

	/**
	 * Write bytes.
	 * <p>
	 * @param    aData the bytes to write
     * @see       com.sun.star.connections.XConnection#write
	 */
    public void write(byte aData[]) throws com.sun.star.io.IOException, com.sun.star.uno.RuntimeException {
		_otherSide.receive(aData);
	}

	/**
	 * Flushes the buffer, notifies if necessary the other side that new data has arrived.
	 * <p>
     * @see       com.sun.star.connections.XConnection#flush
	 */
    public void flush() throws com.sun.star.io.IOException, com.sun.star.uno.RuntimeException {
		synchronized(_otherSide) {
			_otherSide.notify();
		}
	}

	/**
	 * Closes the pipe.
	 * <p>
     * @see       com.sun.star.connections.XConnection#closed
	 */
    public synchronized void close() throws com.sun.star.io.IOException, com.sun.star.uno.RuntimeException {
		if(!_closed) {
			_closed = true;
			
			_otherSide.close();

			notify();
		}
	}

	/**
	 * Gives a description of this pipe.
	 * <p>
	 * @return  the description
     * @see       com.sun.star.connections.XConnection#getDescription
	 */
    public String getDescription() throws com.sun.star.uno.RuntimeException {
		return getClass().getName();
	}

}