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; 026import org.springframework.lang.Nullable; 027 028/** 029 * The standard implementation of the {@link KeyHolder} interface, to be used for 030 * holding auto-generated keys (as potentially returned by JDBC insert statements). 031 * 032 * <p>Create an instance of this class for each insert operation, and pass it 033 * to the corresponding {@link org.springframework.jdbc.core.JdbcTemplate} or 034 * {@link org.springframework.jdbc.object.SqlUpdate} methods. 035 * 036 * @author Thomas Risberg 037 * @author Juergen Hoeller 038 * @since 1.1 039 */ 040public class GeneratedKeyHolder implements KeyHolder { 041 042 private final List<Map<String, Object>> keyList; 043 044 045 /** 046 * Create a new GeneratedKeyHolder with a default list. 047 */ 048 public GeneratedKeyHolder() { 049 this.keyList = new LinkedList<>(); 050 } 051 052 /** 053 * Create a new GeneratedKeyHolder with a given list. 054 * @param keyList a list to hold maps of keys 055 */ 056 public GeneratedKeyHolder(List<Map<String, Object>> keyList) { 057 this.keyList = keyList; 058 } 059 060 061 @Override 062 @Nullable 063 public Number getKey() throws InvalidDataAccessApiUsageException, DataRetrievalFailureException { 064 if (this.keyList.isEmpty()) { 065 return null; 066 } 067 if (this.keyList.size() > 1 || this.keyList.get(0).size() > 1) { 068 throw new InvalidDataAccessApiUsageException( 069 "The getKey method should only be used when a single key is returned. " + 070 "The current key entry contains multiple keys: " + this.keyList); 071 } 072 Iterator<Object> keyIter = this.keyList.get(0).values().iterator(); 073 if (keyIter.hasNext()) { 074 Object key = keyIter.next(); 075 if (!(key instanceof Number)) { 076 throw new DataRetrievalFailureException( 077 "The generated key is not of a supported numeric type. " + 078 "Unable to cast [" + (key != null ? key.getClass().getName() : null) + 079 "] to [" + Number.class.getName() + "]"); 080 } 081 return (Number) key; 082 } 083 else { 084 throw new DataRetrievalFailureException("Unable to retrieve the generated key. " + 085 "Check that the table has an identity column enabled."); 086 } 087 } 088 089 @Override 090 @Nullable 091 public Map<String, Object> getKeys() throws InvalidDataAccessApiUsageException { 092 if (this.keyList.isEmpty()) { 093 return null; 094 } 095 if (this.keyList.size() > 1) { 096 throw new InvalidDataAccessApiUsageException( 097 "The getKeys method should only be used when keys for a single row are returned. " + 098 "The current key list contains keys for multiple rows: " + this.keyList); 099 } 100 return this.keyList.get(0); 101 } 102 103 @Override 104 public List<Map<String, Object>> getKeyList() { 105 return this.keyList; 106 } 107 108}