001/*
002 * Copyright 2002-2012 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.dao.support;
018
019import java.util.ArrayList;
020import java.util.List;
021
022import org.springframework.dao.DataAccessException;
023import org.springframework.util.Assert;
024
025/**
026 * Implementation of {@link PersistenceExceptionTranslator} that supports chaining,
027 * allowing the addition of PersistenceExceptionTranslator instances in order.
028 * Returns {@code non-null} on the first (if any) match.
029 *
030 * @author Rod Johnson
031 * @author Juergen Hoeller
032 * @since 2.0
033 */
034public class ChainedPersistenceExceptionTranslator implements PersistenceExceptionTranslator {
035
036        /** List of PersistenceExceptionTranslators */
037        private final List<PersistenceExceptionTranslator> delegates = new ArrayList<PersistenceExceptionTranslator>(4);
038
039
040        /**
041         * Add a PersistenceExceptionTranslator to the chained delegate list.
042         */
043        public final void addDelegate(PersistenceExceptionTranslator pet) {
044                Assert.notNull(pet, "PersistenceExceptionTranslator must not be null");
045                this.delegates.add(pet);
046        }
047
048        /**
049         * Return all registered PersistenceExceptionTranslator delegates (as array).
050         */
051        public final PersistenceExceptionTranslator[] getDelegates() {
052                return this.delegates.toArray(new PersistenceExceptionTranslator[this.delegates.size()]);
053        }
054
055
056        @Override
057        public DataAccessException translateExceptionIfPossible(RuntimeException ex) {
058                for (PersistenceExceptionTranslator pet : this.delegates) {
059                        DataAccessException translatedDex = pet.translateExceptionIfPossible(ex);
060                        if (translatedDex != null) {
061                                return translatedDex;
062                        }
063                }
064                return null;
065        }
066
067}