001 /**
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017 package org.apache.camel.component.jpa;
018
019 import java.util.Arrays;
020 import java.util.Collection;
021 import java.util.Map;
022 import java.util.Set;
023
024 import javax.persistence.EntityManager;
025 import javax.persistence.Query;
026
027 /**
028 * A builder of query expressions
029 *
030 * @version
031 */
032 public abstract class QueryBuilder implements QueryFactory {
033 ParameterBuilder parameterBuilder;
034
035 /**
036 * Creates a query builder using the JPA query syntax
037 *
038 * @param query JPA query language to create
039 * @return a query builder
040 */
041 public static QueryBuilder query(final String query) {
042 return new QueryBuilder() {
043 protected Query makeQueryObject(EntityManager entityManager) {
044 return entityManager.createQuery(query);
045 }
046
047 @Override
048 public String toString() {
049 return "Query: " + query + getParameterDescription();
050 }
051 };
052 }
053
054 /**
055 * Creates a named query
056 */
057 public static QueryBuilder namedQuery(final String namedQuery) {
058 return new QueryBuilder() {
059 protected Query makeQueryObject(EntityManager entityManager) {
060 return entityManager.createNamedQuery(namedQuery);
061 }
062
063 @Override
064 public String toString() {
065 return "Named: " + namedQuery + getParameterDescription();
066 }
067 };
068 }
069
070 /**
071 * Creates a native SQL query
072 */
073 public static QueryBuilder nativeQuery(final String nativeQuery) {
074 return new QueryBuilder() {
075 protected Query makeQueryObject(EntityManager entityManager) {
076 return entityManager.createNativeQuery(nativeQuery);
077 }
078
079 @Override
080 public String toString() {
081 return "NativeQuery: " + nativeQuery + getParameterDescription();
082 }
083 };
084 }
085
086 /**
087 * Creates a native SQL query with a provided resultClass
088 */
089 public static QueryBuilder nativeQuery(final String nativeQuery, final Class resultClass) {
090 return new QueryBuilder() {
091 protected Query makeQueryObject(EntityManager entityManager) {
092 return entityManager.createNativeQuery(nativeQuery, resultClass);
093 }
094
095 @Override
096 public String toString() {
097 return "NativeQuery: " + nativeQuery + " resultClass:" + resultClass + getParameterDescription();
098 }
099 };
100 }
101
102 /**
103 * Specifies the parameters to the query
104 *
105 * @param parameters the parameters to be configured on the query
106 * @return this query builder
107 */
108 public QueryBuilder parameters(Object... parameters) {
109 return parameters(Arrays.asList(parameters));
110 }
111
112 /**
113 * Specifies the parameters to the query as an ordered collection of
114 * parameters
115 *
116 * @param parameters the parameters to be configured on the query
117 * @return this query builder
118 */
119 public QueryBuilder parameters(final Collection parameters) {
120 checkNoParametersConfigured();
121 parameterBuilder = new ParameterBuilder() {
122 public void populateQuery(EntityManager entityManager, Query query) {
123 int counter = 0;
124 for (Object parameter : parameters) {
125 query.setParameter(counter++, parameter);
126 }
127 }
128
129 @Override
130 public String toString() {
131 return "Parameters: " + parameters;
132 }
133 };
134 return this;
135 }
136
137 /**
138 * Specifies the parameters to the query as a Map of key/value pairs
139 *
140 * @param parameterMap the parameters to be configured on the query
141 * @return this query builder
142 */
143 public QueryBuilder parameters(final Map<String, Object> parameterMap) {
144 checkNoParametersConfigured();
145 parameterBuilder = new ParameterBuilder() {
146 public void populateQuery(EntityManager entityManager, Query query) {
147 Set<Map.Entry<String, Object>> entries = parameterMap.entrySet();
148 for (Map.Entry<String, Object> entry : entries) {
149 query.setParameter(entry.getKey(), entry.getValue());
150 }
151 }
152
153 @Override
154 public String toString() {
155 return "Parameters: " + parameterMap;
156 }
157 };
158 return this;
159 }
160
161 protected void checkNoParametersConfigured() {
162 if (parameterBuilder != null) {
163 throw new IllegalArgumentException("Cannot add parameters to a QueryBuilder which already has parameters configured");
164 }
165 }
166
167 public Query createQuery(EntityManager entityManager) {
168 Query query = makeQueryObject(entityManager);
169 populateQuery(entityManager, query);
170 return query;
171 }
172
173 protected String getParameterDescription() {
174 if (parameterBuilder == null) {
175 return "";
176 } else {
177 return " " + parameterBuilder.toString();
178 }
179 }
180
181 protected void populateQuery(EntityManager entityManager, Query query) {
182 if (parameterBuilder != null) {
183 parameterBuilder.populateQuery(entityManager, query);
184 }
185 }
186
187 protected abstract Query makeQueryObject(EntityManager entityManager);
188
189 /**
190 * A plugin strategy to populate the query with parameters
191 */
192 protected abstract static class ParameterBuilder {
193 public abstract void populateQuery(EntityManager entityManager, Query query);
194 }
195 }