001/*
002 * Copyright 2006-2007 the original author or authors.
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 *      https://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 */
016
017package org.springframework.batch.item.support;
018
019import java.util.ArrayList;
020import java.util.List;
021
022import org.springframework.aop.support.AopUtils;
023import org.springframework.batch.item.ItemReader;
024
025/**
026 * An {@link ItemReader} that pulls data from a list. Useful for testing.
027 * 
028 * @author Dave Syer
029 * 
030 */
031public class ListItemReader<T> implements ItemReader<T> {
032
033        private List<T> list;
034
035        public ListItemReader(List<T> list) {
036                // If it is a proxy we assume it knows how to deal with its own state.
037                // (It's probably transaction aware.)
038                if (AopUtils.isAopProxy(list)) {
039                        this.list = list;
040                }
041                else {
042                        this.list = new ArrayList<T>(list);
043                }
044        }
045
046    @Override
047        public T read() {
048                if (!list.isEmpty()) {
049                        return list.remove(0);
050                }
051                return null;
052        }
053
054}