SlowLinkSimulator.java

/*
*Copyright (c) 2005-2010, WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
*
*WSO2 Inc. 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.wso2.carbon.automation.test.utils.tcpmon.client;

/**
 * class to simulate slow connections by slowing down the system
 */
class SlowLinkSimulator {

	private int delayBytes;

	private int delayTime;

	private int currentBytes;

	private int totalBytes;

	/**
	 * construct
	 *
	 * @param delayBytes bytes per delay; set to 0 for no delay
	 * @param delayTime  delay time per delay in milliseconds
	 */
	public SlowLinkSimulator(int delayBytes, int delayTime) {
		this.delayBytes = delayBytes;
		this.delayTime = delayTime;
	}

	/**
	 * construct by copying delay bytes and time, but not current
	 * count of bytes
	 *
	 * @param that source of data
	 */
	public SlowLinkSimulator(SlowLinkSimulator that) {
		this.delayBytes = that.delayBytes;
		this.delayTime = that.delayTime;
	}

	/**
	 * how many bytes have gone past?
	 *
	 * @return integer
	 */
	public int getTotalBytes() {
		return totalBytes;
	}

	/**
	 * log #of bytes pumped. Will pause when necessary. This method is not
	 * synchronized
	 *
	 * @param bytes
	 */
	public void pump(int bytes) {
		totalBytes += bytes;
		if (delayBytes == 0) {

			// when not delaying, we are just a byte counter
			return;
		}
		currentBytes += bytes;
		if (currentBytes > delayBytes) {

			// we have overshot. lets find out how far
			int delaysize = currentBytes / delayBytes;
			long delay = delaysize * (long) delayTime;

			// move byte counter down to the remainder of bytes
			currentBytes = currentBytes % delayBytes;

			// now wait
			try {
				Thread.sleep(delay);
			} catch (InterruptedException e) {
				// ignore the exception
			}
		}
	}

	/**
	 * get the current byte count
	 *
	 * @return integer
	 */
	public int getCurrentBytes() {
		return currentBytes;
	}

	/**
	 * set the current byte count
	 *
	 * @param currentBytes current Bytes
	 */
	public void setCurrentBytes(int currentBytes) {
		this.currentBytes = currentBytes;
	}
}