001/**
002 * Copyright (C) 2006-2020 Talend Inc. - www.talend.com
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016package org.talend.sdk.component.api.base;
017
018import java.util.Iterator;
019import java.util.function.Supplier;
020
021import lombok.RequiredArgsConstructor;
022
023// helper class to implement {@link @Producer}
024// using a buffer
025@RequiredArgsConstructor
026public class BufferizedProducerSupport<T> {
027
028    private final Supplier<Iterator<T>> supplier;
029
030    private Iterator<T> current;
031
032    public T next() {
033        if (current == null || !current.hasNext()) {
034            current = supplier.get();
035        }
036        return current != null && current.hasNext() ? current.next() : null;
037    }
038}