HRTimer.java Source code

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Here is the source code for HRTimer.java

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/**
 * Copyright (c) 2006 Richard Rodgers
 *
 * 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 com.monad.homerun.util;

import java.util.Timer;
import java.util.TimerTask;

/**
 * HRTimer is a simple system-wide timer facility using a singleton Timer,
 * with additional instrumentation.
 */

public class HRTimer {
    // the singleton instance
    private static HRTimer instance = null;

    // the timer instance
    private Timer hrTimer = null;

    // task counters
    private int numRepeatTasks = 0;

    private int numOneOffTasks = 0;

    // private constructor
    private HRTimer() {
        hrTimer = new Timer(true);
    }

    /**
     * Resturns an instance of an HRTimer
     * 
     * @return timer
     *         the timer instance
     */
    public static synchronized HRTimer getInstance() {
        if (instance == null) {
            instance = new HRTimer();
        }
        return instance;
    }

    /**
     * Adds a repeating task to the timer
     * 
     * @param task
     *        the timer task to add
     * @param period
     *        the time interval between task executions 
     */
    public void addTask(TimerTask task, long period) {
        ++numRepeatTasks;
        hrTimer.schedule(task, 0L, period);
    }

    /**
     * Adds a task to be executed only once
     * 
     * @param task
     *        the task to perform
     * @param delay
     *        initial time interval before execution
     */
    public void addOneOffTask(TimerTask task, long delay) {
        ++numOneOffTasks;
        hrTimer.schedule(task, delay);
    }

    /**
     * Adds a repeating task with an initial delay
     * 
     * @param task
     *        the task to add
     * @param delay
     *        the intial delay before first execution
     * @param period
     *        the interval between task executions
     */
    public void addDelayedTask(TimerTask task, long delay, long period) {
        ++numRepeatTasks;
        hrTimer.schedule(task, delay, period);
    }

    /**
     * Cancels a regsitered task
     * 
     * @param task
     *        the task to be cancelled
     */
    public void cancelTask(TimerTask task) {
        --numRepeatTasks;
        task.cancel();
    }

    /**
     * Returns the number of active tasks
     * 
     * @return num
     *         the number of current tasks
     */
    public int getNumTasks() {
        return numRepeatTasks + numOneOffTasks;
    }

    /**
     * Returns the current number of repeatable tasks
     * 
     * @return num
     *         the number of repreatable tasks
     */
    public int getNumRepeatTasks() {
        return numRepeatTasks;
    }

    /**
     * Returns the current number of non-repeatable tasks
     * 
     * @return num
     *         the number of non-repreatable tasks
     */
    public int getNumOneOffTasks() {
        return numOneOffTasks;
    }
}