org.apache.flink.streaming.api.functions.windowing.delta.extractor.FieldFromArray Maven / Gradle / Ivy
/*
* 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.functions.windowing.delta.extractor;
import org.apache.flink.annotation.Internal;
import java.lang.reflect.Array;
/**
* Extracts a single field out of an array.
*
* @param The type of the extracted field.
*/
@Internal
public class FieldFromArray implements Extractor {
private static final long serialVersionUID = -5161386546695574359L;
private int fieldId = 0;
/** Extracts the first field (id 0) from the array. */
public FieldFromArray() {
// noting to do => will use default 0
}
/**
* Extracts the field with the given id from the array.
*
* @param fieldId The id of the field which will be extracted from the array.
*/
public FieldFromArray(int fieldId) {
this.fieldId = fieldId;
}
@SuppressWarnings("unchecked")
@Override
public OUT extract(Object in) {
return (OUT) Array.get(in, fieldId);
}
}