1/*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements.  See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License.  You may obtain a copy of the License at
8 *
9 *     http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18package java.sql;
19
20/**
21 * This class is an actual usage of the wrapper pattern for JDBC classes.
22 * Developers can get the delegate instance when the instance may be a proxy
23 * class.
24 *
25 * @since 1.6
26 */
27public interface Wrapper {
28
29    /**
30     * Returns an object that implements the given interface. If the caller is
31     * not a wrapper, a SQLException will be thrown.
32     *
33     * @param iface -
34     *            the class that defines the interface
35     * @return - an object that implements the interface
36     * @throws SQLException -
37     *             if there is no object implementing the specific interface
38     */
39    <T> T unwrap(Class<T> iface) throws SQLException;
40
41    /**
42     * If the caller is a wrapper of the class or implements the given
43     * interface, the methods return false and vice versa.
44     *
45     * @param iface -
46     *            the class that defines the interface
47     * @return - true if the instance implements the interface
48     * @throws SQLException -
49     *             when an error occurs when judges the object
50     */
51    boolean isWrapperFor(Class<?> iface) throws SQLException;
52}
53