/*
* Copyright 2010 Google 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://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 elemental.util;
import static elemental.client.Browser.getWindow;
import elemental.html.Window;
import elemental.dom.TimeoutHandler;
/**
* A simplified, browser-safe timer class. This class serves the same purpose as
* java.util.Timer, but is simplified because of the single-threaded
* environment.
*
* To schedule a timer, simply create a subclass of it (overriding {@link #run})
* and call {@link #schedule} or {@link #scheduleRepeating}.
*/
public abstract class Timer {
private boolean isRepeating;
private int timerId;
/**
* Cancels this timer.
*/
public void cancel() {
if (isRepeating) {
getWindow().clearInterval(timerId);
} else {
getWindow().clearTimeout(timerId);
}
}
/**
* This method will be called when a timer fires. Override it to implement the
* timer's logic.
*/
public abstract void run();
/**
* Schedules a timer to elapse in the future.
*
* @param delayMillis how long to wait before the timer elapses, in
* milliseconds
*/
public void schedule(int delayMillis) {
if (delayMillis <= 0) {
throw new IllegalArgumentException("must be positive");
}
cancel();
isRepeating = false;
timerId = getWindow().setTimeout(new TimeoutHandler() {
@Override
public void onTimeoutHandler() {
run();
}
}, delayMillis);
}
/**
* Schedules a timer that elapses repeatedly.
*
* @param periodMillis how long to wait before the timer elapses, in
* milliseconds, between each repetition
*/
public void scheduleRepeating(int periodMillis) {
if (periodMillis <= 0) {
throw new IllegalArgumentException("must be positive");
}
cancel();
isRepeating = true;
timerId = getWindow().setInterval(new TimeoutHandler() {
@Override
public void onTimeoutHandler() {
run();
}
}, periodMillis);
}
}