/*
 * 
 * Copyright 2004 Sun Microsystems, Inc. All Rights Reserved.
 * 
 * The contents of this file are subject to the Sun Community Source
 * License v3.0/Jini Technology Specific Attachment v 1.0 (the
 * "License"). You may not use this file except in compliance with the
 * License. You may obtain a copy of the License at
 * http://wwws.sun.com/software/jini/licensing/SCSL3_JiniTSA1.html.
 * Software distributed under the License is distributed on an "AS IS"
 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
 * the License for the specific language governing rights and limitations
 * under the License.
 * 
 * The Reference Code is Jini Technology Core Platform code, v2.0. The
 * Developer of the Reference Code is Sun Microsystems, Inc.
 * 
 * Contributor(s): Sun Microsystems, Inc.
 * 
 * The contents of this file comply with the Jini Technology Core
 * Platform Compatibility Kit, v2.0A.
 * 
 * Tester(s): Sun Microsystems, Inc.
 * 
 * Test Platform(s):
 * Java 2 SDK, Standard Edition, Version 1.4.2_03 for Solaris(TM)SPARC/x86
 * Java 2 SDK, Standard Edition, Version 1.4.2_03 for Linux (Intel x86)
 * Java 2 SDK, Standard Edition, Version 1.4.2_03 for Windows (Intel Platform)
 * 
 */

package com.sun.jini.discovery;

import java.nio.ByteBuffer;

/**
 * Factory that produces byte buffers, each corresponding to a separate
 * datagram packet to be sent.  <code>DatagramBufferFactory</code> instances
 * are passed to the encoding methods of {@link MulticastRequestEncoder} and
 * {@link MulticastAnnouncementEncoder}, which can encode data to multiple
 * datagram packets (if needed) by writing to multiple buffers obtained from
 * the factory.
 *
 * @author Sun Microsystems, Inc.
 * @since 2.0
 */
public interface DatagramBufferFactory {

    /**
     * Returns a byte buffer into which to write encoded multicast packet data.
     * The buffer encompasses all of the data for the packet to be sent: buffer
     * offset <code>0</code> corresponds to the start of packet data, and the
     * capacity of the buffer indicates the maximum packet size.  Encoding
     * methods should start writing data at the initial (non-zero) position of
     * the buffer; the final position of the buffer after the encoding method
     * has returned is used to mark the end of encoded data, which translates
     * into the actual length of the sent packet.
     *
     * @return a buffer into which to write encoded multicast packet data
     */
    ByteBuffer newBuffer();
}
