WaitFor.java
/*
* 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.tools.ant.taskdefs;
import java.util.HashMap;
import java.util.Locale;
import java.util.Map;
import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.Project;
import org.apache.tools.ant.taskdefs.condition.Condition;
import org.apache.tools.ant.taskdefs.condition.ConditionBase;
import org.apache.tools.ant.types.EnumeratedAttribute;
/**
* Wait for an external event to occur.
*
* Wait for an external process to start or to complete some
* task. This is useful with the <code>parallel</code> task to
* synchronize the execution of tests with server startup.
*
* The following attributes can be specified on a waitfor task:
* <ul>
* <li>maxwait - maximum length of time to wait before giving up</li>
* <li>maxwaitunit - The unit to be used to interpret maxwait attribute</li>
* <li>checkevery - amount of time to sleep between each check</li>
* <li>checkeveryunit - The unit to be used to interpret checkevery attribute</li>
* <li>timeoutproperty - name of a property to set if maxwait has been exceeded.</li>
* </ul>
*
* The maxwaitunit and checkeveryunit are allowed to have the following values:
* millisecond, second, minute, hour, day and week. The default is millisecond.
*
* For programmatic use/subclassing, there are two methods that may be overridden,
* <code>processSuccess</code> and <code>processTimeout</code>
* @since Ant 1.5
*
* @ant.task category="control"
*/
public class WaitFor extends ConditionBase {
/** a millisecond */
public static final long ONE_MILLISECOND = 1L;
/** a second in milliseconds */
public static final long ONE_SECOND = 1000L;
/** a minute in milliseconds */
public static final long ONE_MINUTE = ONE_SECOND * 60L;
/** an hour in milliseconds */
public static final long ONE_HOUR = ONE_MINUTE * 60L;
/** a day in milliseconds */
public static final long ONE_DAY = ONE_HOUR * 24L;
/** a week in milliseconds */
public static final long ONE_WEEK = ONE_DAY * 7L;
/** default wait time */
public static final long DEFAULT_MAX_WAIT_MILLIS = ONE_MINUTE * 3L;
/** default check time */
public static final long DEFAULT_CHECK_MILLIS = 500L;
/** default max wait time in the current unit*/
private long maxWait = DEFAULT_MAX_WAIT_MILLIS;
private long maxWaitMultiplier = ONE_MILLISECOND;
/**
* check time in the current unit
*/
private long checkEvery = DEFAULT_CHECK_MILLIS;
private long checkEveryMultiplier = ONE_MILLISECOND;
private String timeoutProperty;
/**
* Constructor, names this task "waitfor".
*/
public WaitFor() {
super("waitfor");
}
/**
* Constructor that takes the name of the task in the task name.
*
* @param taskName the name of the task.
* @since Ant 1.8
*/
public WaitFor(String taskName) {
super(taskName);
}
/**
* Set the maximum length of time to wait.
* @param time a <code>long</code> value
*/
public void setMaxWait(long time) {
maxWait = time;
}
/**
* Set the max wait time unit
* @param unit an enumerated <code>Unit</code> value
*/
public void setMaxWaitUnit(Unit unit) {
maxWaitMultiplier = unit.getMultiplier();
}
/**
* Set the time between each check
* @param time a <code>long</code> value
*/
public void setCheckEvery(long time) {
checkEvery = time;
}
/**
* Set the check every time unit
* @param unit an enumerated <code>Unit</code> value
*/
public void setCheckEveryUnit(Unit unit) {
checkEveryMultiplier = unit.getMultiplier();
}
/**
* Name the property to set after a timeout.
* @param p the property name
*/
public void setTimeoutProperty(String p) {
timeoutProperty = p;
}
/**
* Check repeatedly for the specified conditions until they become
* true or the timeout expires.
* @throws BuildException on error
*/
public void execute() throws BuildException {
if (countConditions() > 1) {
throw new BuildException(
"You must not nest more than one condition into %s",
getTaskName());
}
if (countConditions() < 1) {
throw new BuildException("You must nest a condition into %s",
getTaskName());
}
Condition c = getConditions().nextElement();
try {
long maxWaitMillis = calculateMaxWaitMillis();
long checkEveryMillis = calculateCheckEveryMillis();
long start = System.currentTimeMillis();
long end = start + maxWaitMillis;
while (System.currentTimeMillis() < end) {
if (c.eval()) {
processSuccess();
return;
}
Thread.sleep(checkEveryMillis);
}
} catch (InterruptedException e) {
log("Task " + getTaskName()
+ " interrupted, treating as timed out.");
}
processTimeout();
}
/**
* Get the check wait time, in milliseconds.
* @since Ant 1.8
* @return how long to wait between checks
*/
public long calculateCheckEveryMillis() {
return checkEvery * checkEveryMultiplier;
}
/**
* Get the maximum wait time, in milliseconds.
* @since Ant 1.8
* @return how long to wait before timing out
*/
public long calculateMaxWaitMillis() {
return maxWait * maxWaitMultiplier;
}
/**
* Actions to be taken on a successful waitfor.
* This is an override point. The base implementation does nothing.
* @since Ant1.7
*/
protected void processSuccess() {
log(getTaskName() + ": condition was met", Project.MSG_VERBOSE);
}
/**
* Actions to be taken on an unsuccessful wait.
* This is an override point. It is where the timeout processing takes place.
* The base implementation sets the timeoutproperty if there was a timeout
* and the property was defined.
* @since Ant1.7
*/
protected void processTimeout() {
log(getTaskName() + ": timeout", Project.MSG_VERBOSE);
if (timeoutProperty != null) {
getProject().setNewProperty(timeoutProperty, "true");
}
}
/**
* The enumeration of units:
* millisecond, second, minute, hour, day, week
* @todo we use timestamps in many places, why not factor this out
*/
public static class Unit extends EnumeratedAttribute {
/** millisecond string */
public static final String MILLISECOND = "millisecond";
/** second string */
public static final String SECOND = "second";
/** minute string */
public static final String MINUTE = "minute";
/** hour string */
public static final String HOUR = "hour";
/** day string */
public static final String DAY = "day";
/** week string */
public static final String WEEK = "week";
private static final String[] UNITS = {
MILLISECOND, SECOND, MINUTE, HOUR, DAY, WEEK
};
private Map<String, Long> timeTable = new HashMap<>();
/** Constructor the Unit enumerated type. */
public Unit() {
timeTable.put(MILLISECOND, Long.valueOf(1L));
timeTable.put(SECOND, Long.valueOf(ONE_SECOND));
timeTable.put(MINUTE, Long.valueOf(ONE_MINUTE));
timeTable.put(HOUR, Long.valueOf(ONE_HOUR));
timeTable.put(DAY, Long.valueOf(ONE_DAY));
timeTable.put(WEEK, Long.valueOf(ONE_WEEK));
}
/**
* Convert the value to a multipler (millisecond to unit).
* @return a multipler (a long value)
*/
public long getMultiplier() {
String key = getValue().toLowerCase(Locale.ENGLISH);
return timeTable.get(key).longValue();
}
/**
* @see EnumeratedAttribute#getValues()
* {@inheritDoc}
*/
@Override
public String[] getValues() {
return UNITS;
}
}
}