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.commons.dbutils;
018
019 import java.lang.reflect.InvocationHandler;
020 import java.lang.reflect.Proxy;
021 import java.sql.CallableStatement;
022 import java.sql.Connection;
023 import java.sql.Driver;
024 import java.sql.PreparedStatement;
025 import java.sql.ResultSet;
026 import java.sql.ResultSetMetaData;
027 import java.sql.Statement;
028
029 /**
030 * Creates proxy implementations of JDBC interfaces. This avoids
031 * incompatibilities between the JDBC 2 and JDBC 3 interfaces. This class is
032 * thread safe.
033 *
034 * @see java.lang.reflect.Proxy
035 * @see java.lang.reflect.InvocationHandler
036 */
037 public class ProxyFactory {
038
039 /**
040 * The Singleton instance of this class.
041 */
042 private static final ProxyFactory instance = new ProxyFactory();
043
044 /**
045 * Returns the Singleton instance of this class.
046 *
047 * @return singleton instance
048 */
049 public static ProxyFactory instance() {
050 return instance;
051 }
052
053 /**
054 * Protected constructor for ProxyFactory subclasses to use.
055 */
056 protected ProxyFactory() {
057 super();
058 }
059
060 /**
061 * Convenience method to generate a single-interface proxy using the handler's classloader
062 *
063 * @param <T> The type of object to proxy
064 * @param type The type of object to proxy
065 * @param handler The handler that intercepts/overrides method calls.
066 * @return proxied object
067 */
068 public <T> T newProxyInstance(Class<T> type, InvocationHandler handler) {
069 return type.cast(Proxy.newProxyInstance(handler.getClass().getClassLoader(), new Class<?>[] {type}, handler));
070 }
071
072 /**
073 * Creates a new proxy <code>CallableStatement</code> object.
074 * @param handler The handler that intercepts/overrides method calls.
075 * @return proxied CallableStatement
076 */
077 public CallableStatement createCallableStatement(InvocationHandler handler) {
078 return newProxyInstance(CallableStatement.class, handler);
079 }
080
081 /**
082 * Creates a new proxy <code>Connection</code> object.
083 * @param handler The handler that intercepts/overrides method calls.
084 * @return proxied Connection
085 */
086 public Connection createConnection(InvocationHandler handler) {
087 return newProxyInstance(Connection.class, handler);
088 }
089
090 /**
091 * Creates a new proxy <code>Driver</code> object.
092 * @param handler The handler that intercepts/overrides method calls.
093 * @return proxied Driver
094 */
095 public Driver createDriver(InvocationHandler handler) {
096 return newProxyInstance(Driver.class, handler);
097 }
098
099 /**
100 * Creates a new proxy <code>PreparedStatement</code> object.
101 * @param handler The handler that intercepts/overrides method calls.
102 * @return proxied PreparedStatement
103 */
104 public PreparedStatement createPreparedStatement(InvocationHandler handler) {
105 return newProxyInstance(PreparedStatement.class, handler);
106 }
107
108 /**
109 * Creates a new proxy <code>ResultSet</code> object.
110 * @param handler The handler that intercepts/overrides method calls.
111 * @return proxied ResultSet
112 */
113 public ResultSet createResultSet(InvocationHandler handler) {
114 return newProxyInstance(ResultSet.class, handler);
115 }
116
117 /**
118 * Creates a new proxy <code>ResultSetMetaData</code> object.
119 * @param handler The handler that intercepts/overrides method calls.
120 * @return proxied ResultSetMetaData
121 */
122 public ResultSetMetaData createResultSetMetaData(InvocationHandler handler) {
123 return newProxyInstance(ResultSetMetaData.class, handler);
124 }
125
126 /**
127 * Creates a new proxy <code>Statement</code> object.
128 * @param handler The handler that intercepts/overrides method calls.
129 * @return proxied Statement
130 */
131 public Statement createStatement(InvocationHandler handler) {
132 return newProxyInstance(Statement.class, handler);
133 }
134
135 }