ProtocolState.java

/*
 * RED5 Open Source Flash Server - http://code.google.com/p/red5/
 * 
 * Copyright 2006-2012 by respective authors (see below). All rights reserved.
 * 
 * Licensed 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 under the License.
 */

package org.red5.server.net.protocol;

/**
 * Represents current state of protocol.
 */
public class ProtocolState {
    /**
     * Session key constant.
     */
	public static final String SESSION_KEY = "protocol_state";

    /**
     * Decoding finished successfully state constant.
     */
    public static byte DECODER_OK = 0x00;

    /**
     * Deconding continues state constant.
     */
    public static byte DECODER_CONTINUE = 0x01;

    /**
     * Decoder is buffering state constant.
     */
    public static byte DECODER_BUFFER = 0x02;

    /**
     * Classes like the RTMP state object will extend this marker interface.
     */
	private int decoderBufferAmount;

    /**
     * Current decoder state, decoder is stopped by default.
     */
    private byte decoderState = DECODER_OK;
	
	/**
	 * Returns current buffer amount.
	 *
	 * @return	Buffer amount
	 */
	public int getDecoderBufferAmount() {
		return decoderBufferAmount;
	}
	
	/**
	 * Specifies buffer decoding amount
	 * 
	 * @param amount        Buffer decoding amount
	 */
	public void bufferDecoding(int amount) {
		decoderState = DECODER_BUFFER;
		decoderBufferAmount = amount;
	}
	
	/**
	 * Set decoding state as "needed to be continued".
	 */
	public void continueDecoding() {
		decoderState = DECODER_CONTINUE;
	}
	
	/**
	 * Checks whether remaining buffer size is greater or equal than buffer amount and so if it makes sense to start decoding.
	 * 
	 * @param remaining		Remaining buffer size
	 * @return				<code>true</code> if there is data to decode, <code>false</code> otherwise
	 */
	public boolean canStartDecoding(int remaining) {
		if (remaining >= decoderBufferAmount) {
			return true;
		} else {
			return false;
		}
	}
	
	/**
	 * Starts decoding. Sets state to "ready" and clears buffer amount.
	 */
	public void startDecoding() {
		decoderState = DECODER_OK;
		decoderBufferAmount = 0;
	}
	
	/**
	 * Checks whether decoding is complete.
	 *
	 * @return	<code>true</code> if decoding has finished, <code>false</code> otherwise
	 */
	public boolean hasDecodedObject() {
		return (decoderState == DECODER_OK);
	}
	
	/**
	 * Checks whether decoding process can be continued.
	 *
	 * @return	<code>true</code> if decoding can be continued, <code>false</code> otherwise
	 */
	public boolean canContinueDecoding() {
		return (decoderState != DECODER_BUFFER);
	}

}