/**
* 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.waveprotocol.wave.client.gadget.renderer;
import static org.waveprotocol.wave.client.gadget.GadgetLog.log;
import org.waveprotocol.wave.client.scheduler.ScheduleTimer;
/**
* Implements delayed submit logic to aggregate consecutive operations. Avoids
* excessive submit requests when several changes happen within a short period
* of time.
*
*/
public class Submitter {
/**
* Defines the submit method for the submitter.
*/
public static interface SubmitTask {
/**
* Submit method.
*/
void doSubmit();
}
/** Submit delay. */
private final int timeoutMs;
/** Submit interface. */
private final SubmitTask task;
/** Waiting to submit flag. */
private boolean submitScheduled;
/**
* Constructs blip submitter object that aggregates submits that happen within
* timeoutMs time interval.
*
* @param timeoutMs time interval in milliseconds to aggregate the submit
* commands; if 0 the submit is immediate.
* @param task the submit task interface.
*/
public Submitter(int timeoutMs, SubmitTask task) {
this.task = task;
this.timeoutMs = (timeoutMs > 0) ? timeoutMs : 0;
submitScheduled = false;
}
/**
* Performs submit immediately, resets the scheduled flag, suppresses and logs
* all exceptions.
*/
public void submitImmediately() {
try {
task.doSubmit();
submitScheduled = false;
} catch (Exception e) {
// Suppress and ignore all exceptions.
log("Submit exception " + e.getMessage());
}
}
/**
* Triggers scheduled submit.
*/
public void triggerScheduledSubmit() {
submitIfScheduled();
}
/**
* Schedules submit. If timeout is greater than 0 this method either schedules
* a submit or ignores the request if submit is already scheduled.
*/
public void submit() {
if (timeoutMs == 0) {
submitImmediately();
} else {
// No synchronization issues in GWT.
if (!submitScheduled) {
submitScheduled = true;
new ScheduleTimer() {
@Override
public void run() {
submitIfScheduled();
}
}.schedule(timeoutMs);
}
}
}
/**
* Performs submit if submit is scheduled.
*/
private void submitIfScheduled() {
if (submitScheduled) {
submitImmediately();
}
}
}