org.apache.flink.runtime.util.RegularToMutableObjectIterator Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of flink-runtime Show documentation

The newest version!

/*
 * 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.runtime.util;

import org.apache.flink.api.common.typeutils.TypeSerializer;
import org.apache.flink.util.MutableObjectIterator;

import java.util.Iterator;

public class RegularToMutableObjectIterator implements MutableObjectIterator {

    private final Iterator iterator;

    private final TypeSerializer serializer;

    public RegularToMutableObjectIterator(Iterator iterator, TypeSerializer serializer) {
        this.iterator = iterator;
        this.serializer = serializer;
    }

    @Override
    public T next(T reuse) {
        // -----------------------------------------------------------------------------------------
        // IMPORTANT: WE NEED TO COPY INTO THE REUSE OBJECT TO SIMULATE THE MUTABLE OBJECT RUNTIME
        // -----------------------------------------------------------------------------------------
        if (this.iterator.hasNext()) {
            return this.serializer.copy(this.iterator.next(), reuse);
        } else {
            return null;
        }
    }

    @Override
    public T next() {
        if (this.iterator.hasNext()) {
            return this.iterator.next();
        } else {
            return null;
        }
    }
}