001/*
002 * Copyright 2006-2013 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 */
016package org.springframework.batch.core.listener;
017
018import java.util.Iterator;
019import java.util.List;
020
021import org.springframework.batch.core.ItemReadListener;
022import org.springframework.core.Ordered;
023
024/**
025 * @author Lucas Ward
026 * @author Dave Syer
027 *
028 */
029public class CompositeItemReadListener<T> implements ItemReadListener<T> {
030
031        private OrderedComposite<ItemReadListener<? super T>> listeners = new OrderedComposite<ItemReadListener<? super T>>();
032
033        /**
034         * Public setter for the listeners.
035         *
036         * @param itemReadListeners list of {@link ItemReadListener}s to be called when read events occur.
037         */
038        public void setListeners(List<? extends ItemReadListener<? super T>> itemReadListeners) {
039                this.listeners.setItems(itemReadListeners);
040        }
041
042        /**
043         * Register additional listener.
044         *
045         * @param itemReaderListener instance of {@link ItemReadListener} to be registered.
046         */
047        public void register(ItemReadListener<? super T> itemReaderListener) {
048                listeners.add(itemReaderListener);
049        }
050
051        /**
052         * Call the registered listeners in reverse order, respecting and
053         * prioritising those that implement {@link Ordered}.
054         * @see org.springframework.batch.core.ItemReadListener#afterRead(java.lang.Object)
055         */
056        @Override
057        public void afterRead(T item) {
058                for (Iterator<ItemReadListener<? super T>> iterator = listeners.reverse(); iterator.hasNext();) {
059                        ItemReadListener<? super T> listener = iterator.next();
060                        listener.afterRead(item);
061                }
062        }
063
064        /**
065         * Call the registered listeners in order, respecting and prioritising those
066         * that implement {@link Ordered}.
067         * @see org.springframework.batch.core.ItemReadListener#beforeRead()
068         */
069        @Override
070        public void beforeRead() {
071                for (Iterator<ItemReadListener<? super T>> iterator = listeners.iterator(); iterator.hasNext();) {
072                        ItemReadListener<? super T> listener = iterator.next();
073                        listener.beforeRead();
074                }
075        }
076
077        /**
078         * Call the registered listeners in reverse order, respecting and
079         * prioritising those that implement {@link Ordered}.
080         * @see org.springframework.batch.core.ItemReadListener#onReadError(java.lang.Exception)
081         */
082        @Override
083        public void onReadError(Exception ex) {
084                for (Iterator<ItemReadListener<? super T>> iterator = listeners.reverse(); iterator.hasNext();) {
085                        ItemReadListener<? super T> listener = iterator.next();
086                        listener.onReadError(ex);
087                }
088        }
089}