/*
* Copyright 2000-2016 Vaadin Ltd.
*
* 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 com.vaadin.client.ui;
import com.google.gwt.core.client.Scheduler.ScheduledCommand;
import com.google.gwt.user.client.Timer;
/**
* Executes the given command {@code delayMs} milliseconds after a call to
* {@link #trigger()}. Calling {@link #trigger()} again before the command has
* been executed causes the execution to be rescheduled to {@code delayMs} after
* the second call.
*
*/
public class VLazyExecutor {
private Timer timer;
private int delayMs;
private ScheduledCommand cmd;
/**
* @param delayMs
* Delay in milliseconds to wait before executing the command
* @param cmd
* The command to execute
*/
public VLazyExecutor(int delayMs, ScheduledCommand cmd) {
this.delayMs = delayMs;
this.cmd = cmd;
}
/**
* Triggers execution of the command. Each call reschedules any existing
* execution to {@link #delayMs} milliseconds from that point in time.
*/
public void trigger() {
if (timer == null) {
timer = new Timer() {
@Override
public void run() {
timer = null;
cmd.execute();
}
};
}
// Schedule automatically cancels any old schedule
timer.schedule(delayMs);
}
}