/**
* EasyBeans
* Copyright (C) 2006 Bull S.A.S.
* Contact: easybeans@ow2.org
*
* This library 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 any later version.
*
* This library 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 library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
* USA
*
* --------------------------------------------------------------------------
* $Id: AbsMessage.java 5369 2010-02-24 14:58:19Z benoitf $
* --------------------------------------------------------------------------
*/
package org.ow2.easybeans.component.smartclient.message;
import java.io.UnsupportedEncodingException;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.CharacterCodingException;
import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;
import org.ow2.easybeans.component.smartclient.api.Message;
import org.ow2.easybeans.component.smartclient.api.ProtocolConstants;
/**
* Abstract class that needs to be used for every message that are exchanged between client and endpoint.
* @author Florent Benoit
*
*/
public abstract class AbsMessage implements Message {
/**
* Gets a message to send.
* @return the bytebuffer to send
*/
public ByteBuffer getMessage() {
ByteBuffer subMessage = getSubMessage();
// compute length
int length = HEADER_SIZE;
if (subMessage != null) {
length += subMessage.capacity();
}
// Create ByteBuffer
ByteBuffer byteBuffer = ByteBuffer.allocate(length);
// Append header
byteBuffer.put(ProtocolConstants.PROTOCOL_VERSION);
byteBuffer.put(getOpCode());
if (subMessage != null) {
byteBuffer.putInt(subMessage.capacity());
}
// append inner message (go to position 0 first)
if (subMessage != null) {
subMessage.position(0);
byteBuffer.put(subMessage);
}
// reset our position
byteBuffer.position(0);
// return buffer
return byteBuffer;
}
/**
* Gets the OpCode of this message.
* @return the operation code.
*/
public abstract byte getOpCode();
/**
* Gets the content of this message (only this part, not the header).
* @return the content of this message.
*/
public abstract ByteBuffer getSubMessage();
/**
* Encode the given string into a bytebuffer.
* @param str the given string
* @return a bytebuffer with UTF-8 encoded string
*/
protected ByteBuffer encode(final String str) {
byte[] bytes = null;
try {
bytes = str.getBytes("UTF-8");
} catch (UnsupportedEncodingException e) {
throw new IllegalArgumentException("Invalid Encoding scheme", e);
}
ByteBuffer buffer = ByteBuffer.allocate(bytes.length);
buffer.put(bytes);
return buffer;
}
/**
* Decode the string encoded in the bytebuffer in UTF-8 format.
* @param buffer the given buffer to analyze.
* @return the decoded string
*/
protected String decode(final ByteBuffer buffer) {
Charset charset = Charset.forName("UTF-8");
CharsetDecoder charsetDecoder = charset.newDecoder();
CharBuffer charBuffer = null;
try {
charBuffer = charsetDecoder.decode(buffer);
} catch (CharacterCodingException e) {
throw new IllegalStateException("Invalid characted encoding", e);
}
return charBuffer.toString();
}
}