/*
* 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.flink.streaming.api.windowing.triggers;
import org.apache.flink.annotation.PublicEvolving;
import org.apache.flink.streaming.api.windowing.windows.TimeWindow;
/**
* A {@link Trigger} that fires once the current system time passes the end of the window
* to which a pane belongs.
*/
@PublicEvolving
public class ProcessingTimeTrigger extends Trigger<Object, TimeWindow> {
private static final long serialVersionUID = 1L;
private ProcessingTimeTrigger() {}
@Override
public TriggerResult onElement(Object element, long timestamp, TimeWindow window, TriggerContext ctx) {
ctx.registerProcessingTimeTimer(window.maxTimestamp());
return TriggerResult.CONTINUE;
}
@Override
public TriggerResult onEventTime(long time, TimeWindow window, TriggerContext ctx) throws Exception {
return TriggerResult.CONTINUE;
}
@Override
public TriggerResult onProcessingTime(long time, TimeWindow window, TriggerContext ctx) {
return TriggerResult.FIRE;
}
@Override
public void clear(TimeWindow window, TriggerContext ctx) throws Exception {
ctx.deleteProcessingTimeTimer(window.maxTimestamp());
}
@Override
public boolean canMerge() {
return true;
}
@Override
public void onMerge(TimeWindow window,
OnMergeContext ctx) {
ctx.registerProcessingTimeTimer(window.maxTimestamp());
}
@Override
public String toString() {
return "ProcessingTimeTrigger()";
}
/**
* Creates a new trigger that fires once system time passes the end of the window.
*/
public static ProcessingTimeTrigger create() {
return new ProcessingTimeTrigger();
}
}