ActiveMQ example source code file (DNSState.java)

This example ActiveMQ source code file (DNSState.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - ActiveMQ tags/keywords

announcing_1, arraylist, arraylist, canceled, comparable, dnsstate, dnsstate, log, logger, logging, probing_1, probing_1, probing_2, probing_3, string, string, util

The ActiveMQ DNSState.java source code

/**
 * Copyright 2003-2005 Arthur van Hoff, Rick Blair
 *
 * 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 under the License.
 */
package org.apache.activemq.jmdns;

import java.util.ArrayList;
import java.util.logging.Logger;

/**
 * DNSState defines the possible states for services registered with JmDNS.
 *
 * @author Werner Randelshofer, Rick Blair
 * @version 1.0  May 23, 2004  Created.
 */
public class DNSState implements Comparable
{
    private static Logger logger = Logger.getLogger(DNSState.class.toString());

    private final String name;

    /**
     * Ordinal of next state to be created.
     */
    private static int nextOrdinal = 0;
    /**
     * Assign an ordinal to this state.
     */
    private final int ordinal = nextOrdinal++;
    /**
     * Logical sequence of states.
     * The sequence is consistent with the ordinal of a state.
     * This is used for advancing through states.
     */
    private final static ArrayList sequence = new ArrayList();

    private DNSState(String name)
    {
        this.name = name;
        sequence.add(this);
    }

    public final String toString()
    {
        return name;
    }

    public static final DNSState PROBING_1 = new DNSState("probing 1");
    public static final DNSState PROBING_2 = new DNSState("probing 2");
    public static final DNSState PROBING_3 = new DNSState("probing 3");
    public static final DNSState ANNOUNCING_1 = new DNSState("announcing 1");
    public static final DNSState ANNOUNCING_2 = new DNSState("announcing 2");
    public static final DNSState ANNOUNCED = new DNSState("announced");
    public static final DNSState CANCELED = new DNSState("canceled");

    /**
     * Returns the next advanced state.
     * In general, this advances one step in the following sequence: PROBING_1,
     * PROBING_2, PROBING_3, ANNOUNCING_1, ANNOUNCING_2, ANNOUNCED.
     * Does not advance for ANNOUNCED and CANCELED state.
     */
    public final DNSState advance()
    {
        return (isProbing() || isAnnouncing()) ? (DNSState) sequence.get(ordinal + 1) : this;
    }

    /**
     * Returns to the next reverted state.
     * All states except CANCELED revert to PROBING_1.
     * Status CANCELED does not revert.
     */
    public final DNSState revert()
    {
        return (this == CANCELED) ? this : PROBING_1;
    }

    /**
     * Returns true, if this is a probing state.
     */
    public boolean isProbing()
    {
        return compareTo(PROBING_1) >= 0 && compareTo(PROBING_3) <= 0;
    }

    /**
     * Returns true, if this is an announcing state.
     */
    public boolean isAnnouncing()
    {
        return compareTo(ANNOUNCING_1) >= 0 && compareTo(ANNOUNCING_2) <= 0;
    }

    /**
     * Returns true, if this is an announced state.
     */
    public boolean isAnnounced()
    {
        return compareTo(ANNOUNCED) == 0;
    }

    /**
     * Compares two states.
     * The states compare as follows:
     * PROBING_1 < PROBING_2 < PROBING_3 < ANNOUNCING_1 <
     * ANNOUNCING_2 < RESPONDING < ANNOUNCED < CANCELED.
     */
    public int compareTo(Object o)
    {
        return ordinal - ((DNSState) o).ordinal;
    }
}