001 /* 002 // $Id: OlapWrapper.java 229 2009-05-08 19:11:29Z jhyde $ 003 // This software is subject to the terms of the Eclipse Public License v1.0 004 // Agreement, available at the following URL: 005 // http://www.eclipse.org/legal/epl-v10.html. 006 // Copyright (C) 2007-2008 Julian Hyde 007 // All Rights Reserved. 008 // You must accept the terms of that agreement to use this software. 009 */ 010 package org.olap4j; 011 012 import java.sql.SQLException; 013 014 /** 015 * Interface for olap4j classes which provide the ability to retrieve the 016 * delegate instance when the instance in question is in fact a proxy class. 017 * 018 * <p><code>OlapWrapper</code> duplicates the functionality of the 019 * <code>java.sql.Wrapper</code> interface (introduced in JDBC 4.0), making 020 * this functionality available to olap4j clients running in a JDBC 3.0 021 * environment. For code which will run only on JDBC 4.0 and later, Wrapper can 022 * be used, and OlapWrapper can be ignored.</p> 023 * 024 * <p>In JDBC 3.0 (JDK 1.5) and earlier, the <code>OlapWrapper</code> interface 025 * is used to convert a JDBC class to the corresponding olap4j class. For 026 * instance, write 027 * 028 * <blockquote> 029 * <pre> 030 * import java.sql.Connection; 031 * import java.sql.DriverManager; 032 * import org.olap4j.OlapConnection; 033 * import org.olap4j.OlapWrapper; 034 * 035 * Connection connection = DriverManager.getConnection("jdbc: ..."); 036 * OlapWrapper wrapper = (OlapWrapper) connection; 037 * OlapConnection olapConnection = wrapper.unwrap(OlapConnection.class); 038 * </pre> 039 * </blockquote> 040 * 041 * to create a JDBC 3.0 connection and convert it to an olap4j connection. 042 * 043 * <p>In JDBC 4.0 (JDK 1.6) and later, you don't need to use this class. All of 044 * the key JDBC classes implement <code>java.sql.Wrapper</code> interface, so 045 * you can use its <code>isWrapper</code> and <code>unwrap</code> methods 046 * without casting. For instance, write 047 * 048 * <blockquote> 049 * <pre> 050 * import java.sql.Connection; 051 * import java.sql.DriverManager; 052 * import org.olap4j.OlapConnection; 053 * 054 * Connection connection = DriverManager.getConnection("jdbc: ..."); 055 * OlapConnection olapConnection = connection.unwrap(OlapConnection.class); 056 * </pre> 057 * </blockquote> 058 * 059 * to create a JDBC 4.0 connection and convert it to an olap4j connection. 060 * 061 * @author jhyde 062 * @version $Id: OlapWrapper.java 229 2009-05-08 19:11:29Z jhyde $ 063 * @since Jun 14, 2007 064 */ 065 public interface OlapWrapper { 066 // duplicate method from java.sql.Wrapper (JDBC 4.0), so method is available 067 // in JDBC 3.0 068 <T> T unwrap(Class<T> iface) throws SQLException; 069 070 // duplicate method from java.sql.Wrapper (JDBC 4.0), so method is available 071 // in JDBC 3.0 072 boolean isWrapperFor(Class<?> iface) throws SQLException; 073 } 074 075 // End OlapWrapper.java