org.apache.flink.table.runtime.sort.LimitOperator Maven / Gradle / Ivy
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* 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.table.runtime.sort;
import org.apache.flink.streaming.api.operators.OneInputStreamOperator;
import org.apache.flink.streaming.runtime.streamrecord.StreamRecord;
import org.apache.flink.table.dataformat.BaseRow;
import org.apache.flink.table.runtime.AbstractStreamOperatorWithMetrics;
import org.apache.flink.table.runtime.util.StreamRecordCollector;
import org.apache.flink.util.Collector;
/**
* Operator for limit.
* TODO support stopEarly.
*/
public class LimitOperator extends AbstractStreamOperatorWithMetrics
implements OneInputStreamOperator {
private final boolean isGlobal;
private final long limitStart;
private final long limitEnd;
private transient Collector collector;
private transient int count = 0;
public LimitOperator(boolean isGlobal, long limitStart, long limitEnd) {
this.isGlobal = isGlobal;
this.limitStart = limitStart;
this.limitEnd = limitEnd;
}
@Override
public void open() throws Exception {
super.open();
this.collector = new StreamRecordCollector<>(output);
}
@Override
public void processElement(StreamRecord element) throws Exception {
if (count < limitEnd) {
count++;
if (!isGlobal || count > limitStart) {
collector.collect(element.getValue());
}
}
}
@Override
public void endInput() throws Exception {
}
}