| 1 | /* |
| 2 | * Copyright 2006-2007 the original author or authors. |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | package org.springframework.batch.item.support; |
| 18 | |
| 19 | import java.util.List; |
| 20 | |
| 21 | import org.springframework.batch.item.ItemProcessor; |
| 22 | import org.springframework.beans.factory.InitializingBean; |
| 23 | import org.springframework.util.Assert; |
| 24 | |
| 25 | /** |
| 26 | * Composite {@link ItemProcessor} that passes the item through a sequence of |
| 27 | * injected <code>ItemTransformer</code>s (return value of previous |
| 28 | * transformation is the entry value of the next).<br/> |
| 29 | * <br/> |
| 30 | * |
| 31 | * Note the user is responsible for injecting a chain of {@link ItemProcessor} s |
| 32 | * that conforms to declared input and output types. |
| 33 | * |
| 34 | * @author Robert Kasanicky |
| 35 | */ |
| 36 | public class CompositeItemProcessor<I, O> implements ItemProcessor<I, O>, InitializingBean { |
| 37 | |
| 38 | private List<ItemProcessor<Object, Object>> delegates; |
| 39 | |
| 40 | @SuppressWarnings("unchecked") |
| 41 | public O process(I item) throws Exception { |
| 42 | Object result = item; |
| 43 | |
| 44 | for (ItemProcessor<Object, Object> delegate : delegates) { |
| 45 | if (result == null) { |
| 46 | return null; |
| 47 | } |
| 48 | result = delegate.process(result); |
| 49 | } |
| 50 | return (O) result; |
| 51 | } |
| 52 | |
| 53 | public void afterPropertiesSet() throws Exception { |
| 54 | Assert.notNull(delegates, "The 'delgates' may not be null"); |
| 55 | Assert.notEmpty(delegates, "The 'delgates' may not be empty"); |
| 56 | } |
| 57 | |
| 58 | public void setDelegates(List<ItemProcessor<Object, Object>> delegates) { |
| 59 | this.delegates = delegates; |
| 60 | } |
| 61 | |
| 62 | } |