/*
 * 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.wayang.spark.compiler;

import org.apache.spark.api.java.function.FlatMapFunction;

import java.util.Iterator;

/**
 * Wraps a {@link java.util.function.Function} as a {@link FlatMapFunction}.
 */
public class FlatMapFunctionAdapter<InputType, OutputType> implements FlatMapFunction<InputType, OutputType> {

    private java.util.function.Function<InputType, Iterable<OutputType>> function;

    public FlatMapFunctionAdapter(java.util.function.Function<InputType, Iterable<OutputType>> function) {
        this.function = function;
    }

    @Override
    public Iterator<OutputType> call(InputType dataQuantum) throws Exception {
        return this.function.apply(dataQuantum).iterator();
    }
}