host.anzo.simon.codec.messages.AbstractMessage Maven / Gradle / Ivy

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/*
 * Copyright (C) 2008 Alexander Christian . All rights reserved.
 *
 * This file is part of SIMON.
 *
 *   SIMON is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, either version 3 of the License, or
 *   (at your option) any later version.
 *
 *   SIMON 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 General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with SIMON.  If not, see .
 */
package host.anzo.simon.codec.messages;

import host.anzo.simon.Statics;

import java.io.Serializable;

/**
 * A base message for SIMON protocol messages.
 * Error messages are not being sent via the errorMsg field:
 * In case of a problems reading a message, the responsible decoder class will
 * inject the error message, so that the ProcessMessageRunnable can react on
 * that error accordingly.
 *
 * @author ACHR
 */
public abstract class AbstractMessage implements Serializable {

	/**
	 *
	 */
	private static final long serialVersionUID = 1L;
	private byte msgType = -1;
	private int sequence = -1;
	private String errorMsg = Statics.NO_ERROR;

	/**
	 * Returns the error message. Contains {@link Statics#NO_ERROR} if no error is present.
	 *
	 * @return the errorMsg
	 */
	public String getErrorMsg() {
		return errorMsg;
	}

	/**
	 * Sets the error message related to this message
	 *
	 * @param errorMsg the errorMsg to set
	 */
	public void setErrorMsg(String errorMsg) {
		this.errorMsg = errorMsg;
	}

	/**
	 * Returns whether this message has an error or not
	 *
	 * @return true, if error is present, false if not
	 */
	public boolean hasError() {
		// if errorMsg is 'nul', then a empty error message was set,
		// which signals an error without a message.
		return (errorMsg == null || !errorMsg.equals(Statics.NO_ERROR));
	}

	/**
	 * Creates a new message decoder
	 *
	 * @param msgType specifies a unique ID for the type of message
	 */
	protected AbstractMessage(byte msgType) {
		this.msgType = msgType;
	}

	/**
	 * Returns the message type as described by {@link SimonMessageConstants}
	 *
	 * @return the msgType
	 */
	public byte getMsgType() {
		return msgType;
	}

	/**
	 * Returns, guess what, the sequence id of the message
	 *
	 * @return the sequence
	 */
	public int getSequence() {
		return sequence;
	}

	/**
	 * Stores the sequence id in the message
	 *
	 * @param sequence the sequence to set
	 */
	public void setSequence(int sequence) {
		this.sequence = sequence;
	}
}