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 */
017package org.apache.commons.dbutils;
018
019import java.lang.reflect.InvocationHandler;
020import java.lang.reflect.Proxy;
021import java.sql.CallableStatement;
022import java.sql.Connection;
023import java.sql.Driver;
024import java.sql.PreparedStatement;
025import java.sql.ResultSet;
026import java.sql.ResultSetMetaData;
027import 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 */
037public 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}