jdk/src/share/classes/java/sql/SQLData.java
changeset 2 90ce3da70b43
child 5506 202f599c92aa
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/java/sql/SQLData.java	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,137 @@
+/*
+ * Copyright 1998-2006 Sun Microsystems, Inc.  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.  Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+package java.sql;
+
+/**
+ * The interface used for the custom mapping of an SQL user-defined type (UDT) to
+ * a class in the Java programming language. The class object for a class
+ * implementing the <code>SQLData</code> interface will be entered in the
+ * appropriate <code>Connection</code> object's type map along with the SQL
+ * name of the UDT for which it is a custom mapping.
+ * <P>
+ * Typically, a <code>SQLData</code> implementation
+ * will define a field for each attribute of an SQL structured type or a
+ * single field for an SQL <code>DISTINCT</code> type. When the UDT is
+ * retrieved from a data source with the <code>ResultSet.getObject</code>
+ * method, it will be mapped as an instance of this class.  A programmer
+ * can operate on this class instance just as on any other object in the
+ * Java programming language and then store any changes made to it by
+ * calling the <code>PreparedStatement.setObject</code> method,
+ * which will map it back to the SQL type.
+ * <p>
+ * It is expected that the implementation of the class for a custom
+ * mapping will be done by a tool.  In a typical implementation, the
+ * programmer would simply supply the name of the SQL UDT, the name of
+ * the class to which it is being mapped, and the names of the fields to
+ * which each of the attributes of the UDT is to be mapped.  The tool will use
+ * this information to implement the <code>SQLData.readSQL</code> and
+ * <code>SQLData.writeSQL</code> methods.  The <code>readSQL</code> method
+ * calls the appropriate <code>SQLInput</code> methods to read
+ * each attribute from an <code>SQLInput</code> object, and the
+ * <code>writeSQL</code> method calls <code>SQLOutput</code> methods
+ * to write each attribute back to the data source via an
+ * <code>SQLOutput</code> object.
+ * <P>
+ * An application programmer will not normally call <code>SQLData</code> methods
+ * directly, and the <code>SQLInput</code> and <code>SQLOutput</code> methods
+ * are called internally by <code>SQLData</code> methods, not by application code.
+ *
+ * @since 1.2
+ */
+public interface SQLData {
+
+ /**
+  * Returns the fully-qualified
+  * name of the SQL user-defined type that this object represents.
+  * This method is called by the JDBC driver to get the name of the
+  * UDT instance that is being mapped to this instance of
+  * <code>SQLData</code>.
+  *
+  * @return the type name that was passed to the method <code>readSQL</code>
+  *            when this object was constructed and populated
+  * @exception SQLException if there is a database access error
+  * @exception SQLFeatureNotSupportedException if the JDBC driver does not support
+  * this method
+  * @since 1.2
+  */
+  String getSQLTypeName() throws SQLException;
+
+ /**
+  * Populates this object with data read from the database.
+  * The implementation of the method must follow this protocol:
+  * <UL>
+  * <LI>It must read each of the attributes or elements of the SQL
+  * type  from the given input stream.  This is done
+  * by calling a method of the input stream to read each
+  * item, in the order that they appear in the SQL definition
+  * of the type.
+  * <LI>The method <code>readSQL</code> then
+  * assigns the data to appropriate fields or
+  * elements (of this or other objects).
+  * Specifically, it must call the appropriate <i>reader</i> method
+  * (<code>SQLInput.readString</code>, <code>SQLInput.readBigDecimal</code>,
+  * and so on) method(s) to do the following:
+  * for a distinct type, read its single data element;
+  * for a structured type, read a value for each attribute of the SQL type.
+  * </UL>
+  * The JDBC driver initializes the input stream with a type map
+  * before calling this method, which is used by the appropriate
+  * <code>SQLInput</code> reader method on the stream.
+  *
+  * @param stream the <code>SQLInput</code> object from which to read the data for
+  * the value that is being custom mapped
+  * @param typeName the SQL type name of the value on the data stream
+  * @exception SQLException if there is a database access error
+  * @exception SQLFeatureNotSupportedException if the JDBC driver does not support
+  * this method
+  * @see SQLInput
+  * @since 1.2
+  */
+  void readSQL (SQLInput stream, String typeName) throws SQLException;
+
+  /**
+  * Writes this object to the given SQL data stream, converting it back to
+  * its SQL value in the data source.
+  * The implementation of the method must follow this protocol:<BR>
+  * It must write each of the attributes of the SQL type
+  * to the given output stream.  This is done by calling a
+  * method of the output stream to write each item, in the order that
+  * they appear in the SQL definition of the type.
+  * Specifically, it must call the appropriate <code>SQLOutput</code> writer
+  * method(s) (<code>writeInt</code>, <code>writeString</code>, and so on)
+  * to do the following: for a Distinct Type, write its single data element;
+  * for a Structured Type, write a value for each attribute of the SQL type.
+  *
+  * @param stream the <code>SQLOutput</code> object to which to write the data for
+  * the value that was custom mapped
+  * @exception SQLException if there is a database access error
+  * @exception SQLFeatureNotSupportedException if the JDBC driver does not support
+  * this method
+  * @see SQLOutput
+  * @since 1.2
+  */
+  void writeSQL (SQLOutput stream) throws SQLException;
+}