1 /* 2 * Copyright (c) 1998, 2006, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package java.sql; 27 28 /** 29 * The interface used for the custom mapping of an SQL user-defined type (UDT) to 30 * a class in the Java programming language. The class object for a class 31 * implementing the <code>SQLData</code> interface will be entered in the 32 * appropriate <code>Connection</code> object's type map along with the SQL 33 * name of the UDT for which it is a custom mapping. 34 * <P> 35 * Typically, a <code>SQLData</code> implementation 36 * will define a field for each attribute of an SQL structured type or a 37 * single field for an SQL <code>DISTINCT</code> type. When the UDT is 38 * retrieved from a data source with the <code>ResultSet.getObject</code> 39 * method, it will be mapped as an instance of this class. A programmer 40 * can operate on this class instance just as on any other object in the 41 * Java programming language and then store any changes made to it by 42 * calling the <code>PreparedStatement.setObject</code> method, 43 * which will map it back to the SQL type. 44 * <p> 45 * It is expected that the implementation of the class for a custom 46 * mapping will be done by a tool. In a typical implementation, the 47 * programmer would simply supply the name of the SQL UDT, the name of 48 * the class to which it is being mapped, and the names of the fields to 49 * which each of the attributes of the UDT is to be mapped. The tool will use 50 * this information to implement the <code>SQLData.readSQL</code> and 51 * <code>SQLData.writeSQL</code> methods. The <code>readSQL</code> method 52 * calls the appropriate <code>SQLInput</code> methods to read 53 * each attribute from an <code>SQLInput</code> object, and the 54 * <code>writeSQL</code> method calls <code>SQLOutput</code> methods 55 * to write each attribute back to the data source via an 56 * <code>SQLOutput</code> object. 57 * <P> 58 * An application programmer will not normally call <code>SQLData</code> methods 59 * directly, and the <code>SQLInput</code> and <code>SQLOutput</code> methods 60 * are called internally by <code>SQLData</code> methods, not by application code. 61 * 62 * @since 1.2 63 */ 64 public interface SQLData { 65 66 /** 67 * Returns the fully-qualified 68 * name of the SQL user-defined type that this object represents. 69 * This method is called by the JDBC driver to get the name of the 70 * UDT instance that is being mapped to this instance of 71 * <code>SQLData</code>. 72 * 73 * @return the type name that was passed to the method <code>readSQL</code> 74 * when this object was constructed and populated 75 * @exception SQLException if there is a database access error 76 * @exception SQLFeatureNotSupportedException if the JDBC driver does not support 77 * this method 78 * @since 1.2 79 */ getSQLTypeName()80 String getSQLTypeName() throws SQLException; 81 82 /** 83 * Populates this object with data read from the database. 84 * The implementation of the method must follow this protocol: 85 * <UL> 86 * <LI>It must read each of the attributes or elements of the SQL 87 * type from the given input stream. This is done 88 * by calling a method of the input stream to read each 89 * item, in the order that they appear in the SQL definition 90 * of the type. 91 * <LI>The method <code>readSQL</code> then 92 * assigns the data to appropriate fields or 93 * elements (of this or other objects). 94 * Specifically, it must call the appropriate <i>reader</i> method 95 * (<code>SQLInput.readString</code>, <code>SQLInput.readBigDecimal</code>, 96 * and so on) method(s) to do the following: 97 * for a distinct type, read its single data element; 98 * for a structured type, read a value for each attribute of the SQL type. 99 * </UL> 100 * The JDBC driver initializes the input stream with a type map 101 * before calling this method, which is used by the appropriate 102 * <code>SQLInput</code> reader method on the stream. 103 * 104 * @param stream the <code>SQLInput</code> object from which to read the data for 105 * the value that is being custom mapped 106 * @param typeName the SQL type name of the value on the data stream 107 * @exception SQLException if there is a database access error 108 * @exception SQLFeatureNotSupportedException if the JDBC driver does not support 109 * this method 110 * @see SQLInput 111 * @since 1.2 112 */ readSQL(SQLInput stream, String typeName)113 void readSQL (SQLInput stream, String typeName) throws SQLException; 114 115 /** 116 * Writes this object to the given SQL data stream, converting it back to 117 * its SQL value in the data source. 118 * The implementation of the method must follow this protocol:<BR> 119 * It must write each of the attributes of the SQL type 120 * to the given output stream. This is done by calling a 121 * method of the output stream to write each item, in the order that 122 * they appear in the SQL definition of the type. 123 * Specifically, it must call the appropriate <code>SQLOutput</code> writer 124 * method(s) (<code>writeInt</code>, <code>writeString</code>, and so on) 125 * to do the following: for a Distinct Type, write its single data element; 126 * for a Structured Type, write a value for each attribute of the SQL type. 127 * 128 * @param stream the <code>SQLOutput</code> object to which to write the data for 129 * the value that was custom mapped 130 * @exception SQLException if there is a database access error 131 * @exception SQLFeatureNotSupportedException if the JDBC driver does not support 132 * this method 133 * @see SQLOutput 134 * @since 1.2 135 */ writeSQL(SQLOutput stream)136 void writeSQL (SQLOutput stream) throws SQLException; 137 } 138