RefreshTimer.java

/*
 * Copyright 2008-2012 Amazon Technologies, Inc. 
 *
 * 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://aws.amazon.com/apache2.0
 *
 * This file 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.amazonaws.eclipse.ec2.ui.views.instances;

import org.eclipse.swt.widgets.Display;

import com.amazonaws.eclipse.core.ui.IRefreshable;

/**
 * Timer responsible for controlling when a specified control is refreshed.
 */
public class RefreshTimer implements Runnable {
	/** The default period (in milliseconds) between refreshes */
	public static final int DEFAULT_TIMER_PERIOD = 60 * 1000;
	
	/** The control that this timer is responsible for refreshing */
	private final IRefreshable control;

	/** The period (in milliseconds) between refreshes */
	private int refreshPeriodInMilliseconds;

	/**
	 * Creates a new RefreshTimer ready to refresh the specified control
	 * with the default period. Note that once a RefreshTimer has been
	 * created, it needs to be explicitly started before it will start
	 * refreshing the specified control.
	 * 
	 * @param control
	 *            The control this timer is responsible for refreshing.
	 */
	public RefreshTimer(IRefreshable control) {
		this(control, DEFAULT_TIMER_PERIOD);
	}

	/**
	 * Creates a new RefreshTimer ready to refresh the specified control
	 * with the specified period. Note that a RefreshTimer has been
	 * created, it needs to be explicitly started before it will start
	 * refreshing the specified control.
	 * 
	 * @param control
	 *            The control this timer is responsible for refreshing.
	 * @param refreshPeriodInMilliseconds
	 *            The period between refreshes, in milliseconds.
	 */
	public RefreshTimer(IRefreshable control, int refreshPeriodInMilliseconds) {
		this.control = control;
		this.refreshPeriodInMilliseconds = refreshPeriodInMilliseconds;
	}
	
	/* (non-Javadoc)
	 * @see java.lang.Runnable#run()
	 */
	public void run() {
		control.refreshData();
		
		startTimer();
	}

	/**
	 * Sets the period, in milliseconds, between refreshes.
	 * 
	 * @param refreshPeriodInMilliseconds
	 *            The period, in milliseconds, between refreshes.
	 */
	public void setRefreshPeriod(int refreshPeriodInMilliseconds) {
		this.refreshPeriodInMilliseconds = refreshPeriodInMilliseconds;
		
		startTimer();
	}
	
	/**
	 * Starts this refresh timer.
	 */
	public void startTimer() {
		Display.getDefault().timerExec(refreshPeriodInMilliseconds, this);
	}
	
	/**
	 * Stops this refresh timer.
	 */
	public void stopTimer() {
		Display.getDefault().timerExec(-1, this);
	}
	
}