| /* |
| * Copyright (c) 2005, 2013, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package java.sql; |
| |
| /** |
| * Interface for JDBC classes which provide the ability to retrieve the delegate instance when the instance |
| * in question is in fact a proxy class. |
| * <p> |
| * The wrapper pattern is employed by many JDBC driver implementations to provide extensions beyond |
| * the traditional JDBC API that are specific to a data source. Developers may wish to gain access to |
| * these resources that are wrapped (the delegates) as proxy class instances representing the |
| * the actual resources. This interface describes a standard mechanism to access |
| * these wrapped resources |
| * represented by their proxy, to permit direct access to the resource delegates. |
| * |
| * @since 1.6 |
| */ |
| |
| public interface Wrapper { |
| |
| /** |
| * Returns an object that implements the given interface to allow access to |
| * non-standard methods, or standard methods not exposed by the proxy. |
| * |
| * If the receiver implements the interface then the result is the receiver |
| * or a proxy for the receiver. If the receiver is a wrapper |
| * and the wrapped object implements the interface then the result is the |
| * wrapped object or a proxy for the wrapped object. Otherwise return the |
| * the result of calling <code>unwrap</code> recursively on the wrapped object |
| * or a proxy for that result. If the receiver is not a |
| * wrapper and does not implement the interface, then an <code>SQLException</code> is thrown. |
| * |
| * @param <T> the type of the class modeled by this Class object |
| * @param iface A Class defining an interface that the result must implement. |
| * @return an object that implements the interface. May be a proxy for the actual implementing object. |
| * @throws java.sql.SQLException If no object found that implements the interface |
| * @since 1.6 |
| */ |
| <T> T unwrap(java.lang.Class<T> iface) throws java.sql.SQLException; |
| |
| /** |
| * Returns true if this either implements the interface argument or is directly or indirectly a wrapper |
| * for an object that does. Returns false otherwise. If this implements the interface then return true, |
| * else if this is a wrapper then return the result of recursively calling <code>isWrapperFor</code> on the wrapped |
| * object. If this does not implement the interface and is not a wrapper, return false. |
| * This method should be implemented as a low-cost operation compared to <code>unwrap</code> so that |
| * callers can use this method to avoid expensive <code>unwrap</code> calls that may fail. If this method |
| * returns true then calling <code>unwrap</code> with the same argument should succeed. |
| * |
| * @param iface a Class defining an interface. |
| * @return true if this implements the interface or directly or indirectly wraps an object that does. |
| * @throws java.sql.SQLException if an error occurs while determining whether this is a wrapper |
| * for an object with the given interface. |
| * @since 1.6 |
| */ |
| boolean isWrapperFor(java.lang.Class<?> iface) throws java.sql.SQLException; |
| |
| } |