001/*
002 * Copyright 2002-2018 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.jdbc.support;
018
019import java.util.Iterator;
020import java.util.LinkedList;
021import java.util.List;
022import java.util.Map;
023
024import org.springframework.dao.DataRetrievalFailureException;
025import org.springframework.dao.InvalidDataAccessApiUsageException;
026
027/**
028 * The standard implementation of the {@link KeyHolder} interface, to be used for
029 * holding auto-generated keys (as potentially returned by JDBC insert statements).
030 *
031 * <p>Create an instance of this class for each insert operation, and pass it
032 * to the corresponding {@link org.springframework.jdbc.core.JdbcTemplate} or
033 * {@link org.springframework.jdbc.object.SqlUpdate} methods.
034 *
035 * @author Thomas Risberg
036 * @author Juergen Hoeller
037 * @since 1.1
038 */
039public class GeneratedKeyHolder implements KeyHolder {
040
041        private final List<Map<String, Object>> keyList;
042
043
044        /**
045         * Create a new GeneratedKeyHolder with a default list.
046         */
047        public GeneratedKeyHolder() {
048                this.keyList = new LinkedList<Map<String, Object>>();
049        }
050
051        /**
052         * Create a new GeneratedKeyHolder with a given list.
053         * @param keyList a list to hold maps of keys
054         */
055        public GeneratedKeyHolder(List<Map<String, Object>> keyList) {
056                this.keyList = keyList;
057        }
058
059
060        @Override
061        public Number getKey() throws InvalidDataAccessApiUsageException, DataRetrievalFailureException {
062                if (this.keyList.isEmpty()) {
063                        return null;
064                }
065                if (this.keyList.size() > 1 || this.keyList.get(0).size() > 1) {
066                        throw new InvalidDataAccessApiUsageException(
067                                        "The getKey method should only be used when a single key is returned.  " +
068                                        "The current key entry contains multiple keys: " + this.keyList);
069                }
070                Iterator<Object> keyIter = this.keyList.get(0).values().iterator();
071                if (keyIter.hasNext()) {
072                        Object key = keyIter.next();
073                        if (!(key instanceof Number)) {
074                                throw new DataRetrievalFailureException(
075                                                "The generated key is not of a supported numeric type. " +
076                                                "Unable to cast [" + (key != null ? key.getClass().getName() : null) +
077                                                "] to [" + Number.class.getName() + "]");
078                        }
079                        return (Number) key;
080                }
081                else {
082                        throw new DataRetrievalFailureException("Unable to retrieve the generated key. " +
083                                        "Check that the table has an identity column enabled.");
084                }
085        }
086
087        @Override
088        public Map<String, Object> getKeys() throws InvalidDataAccessApiUsageException {
089                if (this.keyList.isEmpty()) {
090                        return null;
091                }
092                if (this.keyList.size() > 1) {
093                        throw new InvalidDataAccessApiUsageException(
094                                        "The getKeys method should only be used when keys for a single row are returned.  " +
095                                        "The current key list contains keys for multiple rows: " + this.keyList);
096                }
097                return this.keyList.get(0);
098        }
099
100        @Override
101        public List<Map<String, Object>> getKeyList() {
102                return this.keyList;
103        }
104
105}