/**
* NOTE: This copyright does *not* cover user programs that use HQ
* program services by normal system calls through the application
* program interfaces provided as part of the Hyperic Plug-in Development
* Kit or the Hyperic Client Development Kit - this is merely considered
* normal use of the program, and does *not* fall under the heading of
* "derived work".
*
* Copyright (C) [2009-2010], VMware, Inc.
* This file is part of HQ.
*
* HQ is free software; you can redistribute it and/or modify
* it under the terms version 2 of the GNU General Public License as
* published by the Free Software Foundation. This program 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 this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
* USA.
*
*/
package org.hyperic.util;
/**
* Utility that continuosly evaluates a specified condition at specified retry
* intervals, until either the condition is true or the specified timeout is
* reached. This utility can be used, for example, by test classes that need to
* verify the completion of some asynchronous task. It is expected that most
* instrumentation tests will use this class to verify that performance monitors
* have been asynchronously updated
*
* @author Jennifer Hickey
*
*/
public class SpinBarrier {
private long timeout = 120000l;
private long retryInterval = 250l;
private final SpinBarrierCondition condition;
/**
* Constructor that uses the default timeout and retry interval
*
* @param condition
* The condition to evaluate
*/
public SpinBarrier(SpinBarrierCondition condition) {
this.condition = condition;
}
/**
*
* @param timeout
* The amount of time, in milliseconds, to continue evaluating
* the condition if it has not been met
* @param retryInterval
* The amount of time to wait between evaluations of the
* condition
* @param condition
* The condition to evaluate
*/
public SpinBarrier(long timeout, long retryInterval, SpinBarrierCondition condition) {
this.timeout = timeout;
this.retryInterval = retryInterval;
this.condition = condition;
}
/**
* Evaluates a specified condition at specified retry intervals, until
* either the condition is true or the specified timeout is reached
*
* @return true if the condition evaluated to true before the timeout was
* reached
*/
public boolean waitFor() {
final long startTime = System.currentTimeMillis();
boolean conditionMet = false;
while (!(conditionMet) && (System.currentTimeMillis() < (startTime + timeout))) {
conditionMet = condition.evaluate();
if (conditionMet) {
continue;
}
try {
Thread.sleep(retryInterval);
} catch (InterruptedException e) {
// Ignore
}
}
return conditionMet;
}
}