/*
* 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 java.lang.reflect.Array;
import org.apache.flink.annotation.Internal;
/**
* Extracts multiple fields from an array and puts them into a new array of the
* specified type.
*
* @param <OUT>
* The type of the output array. If out is set to String, the output
* of the extractor will be a String[]. If it is set to String[] the
* output will be String[][].
*/
@Internal
public class FieldsFromArray<OUT> implements Extractor<Object, OUT[]> {
private static final long serialVersionUID = 8075055384516397670L;
private int[] order;
private Class<OUT> clazz;
/**
* Extracts multiple fields from an array and puts them in the given order
* into a new array of the specified type.
*
* @param clazz
* the Class object representing the component type of the new
* array
* @param indexes
* The indexes of the fields to be extracted. Any order is
* possible, but not more than 255 fields due to limitations in
* {@link Array#newInstance(Class, int...)}.
*/
public FieldsFromArray(Class<OUT> clazz, int... indexes) {
this.order = indexes;
this.clazz = clazz;
}
@SuppressWarnings("unchecked")
@Override
public OUT[] extract(Object in) {
OUT[] output = (OUT[]) Array.newInstance(clazz, order.length);
for (int i = 0; i < order.length; i++) {
output[i] = (OUT) Array.get(in, this.order[i]);
}
return output;
}
}