138 lines
6.4 KiB
Java
138 lines
6.4 KiB
Java
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/*
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* Copyright (c) 1998, 2006, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Oracle designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Oracle in the LICENSE file that accompanied this code.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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package java.sql;
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/**
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* The interface used for the custom mapping of an SQL user-defined type (UDT) to
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* a class in the Java programming language. The class object for a class
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* implementing the <code>SQLData</code> interface will be entered in the
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* appropriate <code>Connection</code> object's type map along with the SQL
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* name of the UDT for which it is a custom mapping.
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* <P>
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* Typically, a <code>SQLData</code> implementation
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* will define a field for each attribute of an SQL structured type or a
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* single field for an SQL <code>DISTINCT</code> type. When the UDT is
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* retrieved from a data source with the <code>ResultSet.getObject</code>
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* method, it will be mapped as an instance of this class. A programmer
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* can operate on this class instance just as on any other object in the
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* Java programming language and then store any changes made to it by
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* calling the <code>PreparedStatement.setObject</code> method,
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* which will map it back to the SQL type.
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* <p>
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* It is expected that the implementation of the class for a custom
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* mapping will be done by a tool. In a typical implementation, the
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* programmer would simply supply the name of the SQL UDT, the name of
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* the class to which it is being mapped, and the names of the fields to
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* which each of the attributes of the UDT is to be mapped. The tool will use
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* this information to implement the <code>SQLData.readSQL</code> and
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* <code>SQLData.writeSQL</code> methods. The <code>readSQL</code> method
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* calls the appropriate <code>SQLInput</code> methods to read
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* each attribute from an <code>SQLInput</code> object, and the
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* <code>writeSQL</code> method calls <code>SQLOutput</code> methods
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* to write each attribute back to the data source via an
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* <code>SQLOutput</code> object.
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* <P>
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* An application programmer will not normally call <code>SQLData</code> methods
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* directly, and the <code>SQLInput</code> and <code>SQLOutput</code> methods
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* are called internally by <code>SQLData</code> methods, not by application code.
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*
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* @since 1.2
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*/
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public interface SQLData {
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/**
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* Returns the fully-qualified
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* name of the SQL user-defined type that this object represents.
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* This method is called by the JDBC driver to get the name of the
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* UDT instance that is being mapped to this instance of
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* <code>SQLData</code>.
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*
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* @return the type name that was passed to the method <code>readSQL</code>
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* when this object was constructed and populated
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* @exception SQLException if there is a database access error
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* @exception SQLFeatureNotSupportedException if the JDBC driver does not support
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* this method
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* @since 1.2
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*/
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String getSQLTypeName() throws SQLException;
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/**
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* Populates this object with data read from the database.
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* The implementation of the method must follow this protocol:
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* <UL>
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* <LI>It must read each of the attributes or elements of the SQL
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* type from the given input stream. This is done
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* by calling a method of the input stream to read each
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* item, in the order that they appear in the SQL definition
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* of the type.
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* <LI>The method <code>readSQL</code> then
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* assigns the data to appropriate fields or
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* elements (of this or other objects).
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* Specifically, it must call the appropriate <i>reader</i> method
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* (<code>SQLInput.readString</code>, <code>SQLInput.readBigDecimal</code>,
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* and so on) method(s) to do the following:
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* for a distinct type, read its single data element;
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* for a structured type, read a value for each attribute of the SQL type.
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* </UL>
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* The JDBC driver initializes the input stream with a type map
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* before calling this method, which is used by the appropriate
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* <code>SQLInput</code> reader method on the stream.
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*
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* @param stream the <code>SQLInput</code> object from which to read the data for
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* the value that is being custom mapped
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* @param typeName the SQL type name of the value on the data stream
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* @exception SQLException if there is a database access error
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* @exception SQLFeatureNotSupportedException if the JDBC driver does not support
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* this method
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* @see SQLInput
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* @since 1.2
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*/
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void readSQL (SQLInput stream, String typeName) throws SQLException;
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/**
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* Writes this object to the given SQL data stream, converting it back to
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* its SQL value in the data source.
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* The implementation of the method must follow this protocol:<BR>
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* It must write each of the attributes of the SQL type
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* to the given output stream. This is done by calling a
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* method of the output stream to write each item, in the order that
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* they appear in the SQL definition of the type.
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* Specifically, it must call the appropriate <code>SQLOutput</code> writer
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* method(s) (<code>writeInt</code>, <code>writeString</code>, and so on)
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* to do the following: for a Distinct Type, write its single data element;
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* for a Structured Type, write a value for each attribute of the SQL type.
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*
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* @param stream the <code>SQLOutput</code> object to which to write the data for
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* the value that was custom mapped
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* @exception SQLException if there is a database access error
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* @exception SQLFeatureNotSupportedException if the JDBC driver does not support
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* this method
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* @see SQLOutput
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* @since 1.2
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*/
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void writeSQL (SQLOutput stream) throws SQLException;
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}
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