/*
* 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 com.alibaba.jstorm.window;
import backtype.storm.task.TopologyContext;
import java.util.Collection;
import java.util.Collections;
/**
* A {@link WindowAssigner} that windows elements into windows based on the timestamp of the
* elements. Windows cannot overlap.
*/
public class TumblingEventTimeWindows<T> extends WindowAssigner<T> {
private static final long serialVersionUID = 1L;
private long size;
protected TumblingEventTimeWindows(long size) {
this.size = size;
}
@Override
public Collection<TimeWindow> assignWindows(Object element, long timestamp) {
if (timestamp > Long.MIN_VALUE) {
// Long.MIN_VALUE is currently assigned when no timestamp is present
long start = timestamp - (timestamp % size);
return Collections.singletonList(new TimeWindow(start, start + size));
} else {
throw new RuntimeException("Record has Long.MIN_VALUE timestamp (= no timestamp marker). " +
"Is the time characteristic set to 'ProcessingTime', or did you forget to call " +
"'DataStream.assignTimestampsAndWatermarks(...)'?");
}
}
public long getSize() {
return size;
}
@Override
public Trigger<T> getDefaultTrigger(TopologyContext context) {
return EventTimeTrigger.create();
}
@Override
public String toString() {
return "TumblingEventTimeWindows(" + size + ")";
}
/**
* Creates a new {@code TumblingEventTimeWindows} {@link WindowAssigner} that assigns
* elements to time windows based on the element timestamp.
*
* @param size The size of the generated windows.
* @return The time policy.
*/
public static <T> TumblingEventTimeWindows<T> of(long size) {
return new TumblingEventTimeWindows<>(size);
}
}