Java tutorial
/* * Copyright (c) 1998, 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; /** * An input stream that contains a stream of values representing an * instance of an SQL structured type or an SQL distinct type. * This interface, used only for custom mapping, is used by the driver * behind the scenes, and a programmer never directly invokes * <code>SQLInput</code> methods. The <i>reader</i> methods * (<code>readLong</code>, <code>readBytes</code>, and so on) * provide a way for an implementation of the <code>SQLData</code> * interface to read the values in an <code>SQLInput</code> object. * And as described in <code>SQLData</code>, calls to reader methods must * be made in the order that their corresponding attributes appear in the * SQL definition of the type. * The method <code>wasNull</code> is used to determine whether * the last value read was SQL <code>NULL</code>. * <P>When the method <code>getObject</code> is called with an * object of a class implementing the interface <code>SQLData</code>, * the JDBC driver calls the method <code>SQLData.getSQLType</code> * to determine the SQL type of the user-defined type (UDT) * being custom mapped. The driver * creates an instance of <code>SQLInput</code>, populating it with the * attributes of the UDT. The driver then passes the input * stream to the method <code>SQLData.readSQL</code>, which in turn * calls the <code>SQLInput</code> reader methods * in its implementation for reading the * attributes from the input stream. * @since 1.2 */ public interface SQLInput { //================================================================ // Methods for reading attributes from the stream of SQL data. // These methods correspond to the column-accessor methods of // java.sql.ResultSet. //================================================================ /** * Reads the next attribute in the stream and returns it as a <code>String</code> * in the Java programming language. * * @return the attribute; if the value is SQL <code>NULL</code>, returns <code>null</code> * @exception SQLException if a database access error occurs * @exception SQLFeatureNotSupportedException if the JDBC driver does not support * this method * @since 1.2 */ String readString() throws SQLException; /** * Reads the next attribute in the stream and returns it as a <code>boolean</code> * in the Java programming language. * * @return the attribute; if the value is SQL <code>NULL</code>, returns <code>false</code> * @exception SQLException if a database access error occurs * @exception SQLFeatureNotSupportedException if the JDBC driver does not support * this method * @since 1.2 */ boolean readBoolean() throws SQLException; /** * Reads the next attribute in the stream and returns it as a <code>byte</code> * in the Java programming language. * * @return the attribute; if the value is SQL <code>NULL</code>, returns <code>0</code> * @exception SQLException if a database access error occurs * @exception SQLFeatureNotSupportedException if the JDBC driver does not support * this method * @since 1.2 */ byte readByte() throws SQLException; /** * Reads the next attribute in the stream and returns it as a <code>short</code> * in the Java programming language. * * @return the attribute; if the value is SQL <code>NULL</code>, returns <code>0</code> * @exception SQLException if a database access error occurs * @exception SQLFeatureNotSupportedException if the JDBC driver does not support * this method * @since 1.2 */ short readShort() throws SQLException; /** * Reads the next attribute in the stream and returns it as an <code>int</code> * in the Java programming language. * * @return the attribute; if the value is SQL <code>NULL</code>, returns <code>0</code> * @exception SQLException if a database access error occurs * @exception SQLFeatureNotSupportedException if the JDBC driver does not support * this method * @since 1.2 */ int readInt() throws SQLException; /** * Reads the next attribute in the stream and returns it as a <code>long</code> * in the Java programming language. * * @return the attribute; if the value is SQL <code>NULL</code>, returns <code>0</code> * @exception SQLException if a database access error occurs * @exception SQLFeatureNotSupportedException if the JDBC driver does not support * this method * @since 1.2 */ long readLong() throws SQLException; /** * Reads the next attribute in the stream and returns it as a <code>float</code> * in the Java programming language. * * @return the attribute; if the value is SQL <code>NULL</code>, returns <code>0</code> * @exception SQLException if a database access error occurs * @exception SQLFeatureNotSupportedException if the JDBC driver does not support * this method * @since 1.2 */ float readFloat() throws SQLException; /** * Reads the next attribute in the stream and returns it as a <code>double</code> * in the Java programming language. * * @return the attribute; if the value is SQL <code>NULL</code>, returns <code>0</code> * @exception SQLException if a database access error occurs * @exception SQLFeatureNotSupportedException if the JDBC driver does not support * this method * @since 1.2 */ double readDouble() throws SQLException; /** * Reads the next attribute in the stream and returns it as a <code>java.math.BigDecimal</code> * object in the Java programming language. * * @return the attribute; if the value is SQL <code>NULL</code>, returns <code>null</code> * @exception SQLException if a database access error occurs * @exception SQLFeatureNotSupportedException if the JDBC driver does not support * this method * @since 1.2 */ java.math.BigDecimal readBigDecimal() throws SQLException; /** * Reads the next attribute in the stream and returns it as an array of bytes * in the Java programming language. * * @return the attribute; if the value is SQL <code>NULL</code>, returns <code>null</code> * @exception SQLException if a database access error occurs * @exception SQLFeatureNotSupportedException if the JDBC driver does not support * this method * @since 1.2 */ byte[] readBytes() throws SQLException; /** * Reads the next attribute in the stream and returns it as a <code>java.sql.Date</code> object. * * @return the attribute; if the value is SQL <code>NULL</code>, returns <code>null</code> * @exception SQLException if a database access error occurs * @exception SQLFeatureNotSupportedException if the JDBC driver does not support * this method * @since 1.2 */ java.sql.Date readDate() throws SQLException; /** * Reads the next attribute in the stream and returns it as a <code>java.sql.Time</code> object. * * @return the attribute; if the value is SQL <code>NULL</code>, returns <code>null</code> * @exception SQLException if a database access error occurs * @exception SQLFeatureNotSupportedException if the JDBC driver does not support * this method * @since 1.2 */ java.sql.Time readTime() throws SQLException; /** * Reads the next attribute in the stream and returns it as a <code>java.sql.Timestamp</code> object. * * @return the attribute; if the value is SQL <code>NULL</code>, returns <code>null</code> * @exception SQLException if a database access error occurs * @exception SQLFeatureNotSupportedException if the JDBC driver does not support * this method * @since 1.2 */ java.sql.Timestamp readTimestamp() throws SQLException; /** * Reads the next attribute in the stream and returns it as a stream of Unicode characters. * * @return the attribute; if the value is SQL <code>NULL</code>, returns <code>null</code> * @exception SQLException if a database access error occurs * @exception SQLFeatureNotSupportedException if the JDBC driver does not support * this method * @since 1.2 */ java.io.Reader readCharacterStream() throws SQLException; /** * Reads the next attribute in the stream and returns it as a stream of ASCII characters. * * @return the attribute; if the value is SQL <code>NULL</code>, returns <code>null</code> * @exception SQLException if a database access error occurs * @exception SQLFeatureNotSupportedException if the JDBC driver does not support * this method * @since 1.2 */ java.io.InputStream readAsciiStream() throws SQLException; /** * Reads the next attribute in the stream and returns it as a stream of uninterpreted * bytes. * * @return the attribute; if the value is SQL <code>NULL</code>, returns <code>null</code> * @exception SQLException if a database access error occurs * @exception SQLFeatureNotSupportedException if the JDBC driver does not support * this method * @since 1.2 */ java.io.InputStream readBinaryStream() throws SQLException; //================================================================ // Methods for reading items of SQL user-defined types from the stream. //================================================================ /** * Reads the datum at the head of the stream and returns it as an * <code>Object</code> in the Java programming language. The * actual type of the object returned is determined by the default type * mapping, and any customizations present in this stream's type map. * * <P>A type map is registered with the stream by the JDBC driver before the * stream is passed to the application. * * <P>When the datum at the head of the stream is an SQL <code>NULL</code>, * the method returns <code>null</code>. If the datum is an SQL structured or distinct * type, it determines the SQL type of the datum at the head of the stream. * If the stream's type map has an entry for that SQL type, the driver * constructs an object of the appropriate class and calls the method * <code>SQLData.readSQL</code> on that object, which reads additional data from the * stream, using the protocol described for that method. * * @return the datum at the head of the stream as an <code>Object</code> in the * Java programming language;<code>null</code> if the datum is SQL <code>NULL</code> * @exception SQLException if a database access error occurs * @exception SQLFeatureNotSupportedException if the JDBC driver does not support * this method * @since 1.2 */ Object readObject() throws SQLException; /** * Reads an SQL <code>REF</code> value from the stream and returns it as a * <code>Ref</code> object in the Java programming language. * * @return a <code>Ref</code> object representing the SQL <code>REF</code> value * at the head of the stream; <code>null</code> if the value read is * SQL <code>NULL</code> * @exception SQLException if a database access error occurs * @exception SQLFeatureNotSupportedException if the JDBC driver does not support * this method * @since 1.2 */ Ref readRef() throws SQLException; /** * Reads an SQL <code>BLOB</code> value from the stream and returns it as a * <code>Blob</code> object in the Java programming language. * * @return a <code>Blob</code> object representing data of the SQL <code>BLOB</code> value * at the head of the stream; <code>null</code> if the value read is * SQL <code>NULL</code> * @exception SQLException if a database access error occurs * @exception SQLFeatureNotSupportedException if the JDBC driver does not support * this method * @since 1.2 */ Blob readBlob() throws SQLException; /** * Reads an SQL <code>CLOB</code> value from the stream and returns it as a * <code>Clob</code> object in the Java programming language. * * @return a <code>Clob</code> object representing data of the SQL <code>CLOB</code> value * at the head of the stream; <code>null</code> if the value read is * SQL <code>NULL</code> * @exception SQLException if a database access error occurs * @exception SQLFeatureNotSupportedException if the JDBC driver does not support * this method * @since 1.2 */ Clob readClob() throws SQLException; /** * Reads an SQL <code>ARRAY</code> value from the stream and returns it as an * <code>Array</code> object in the Java programming language. * * @return an <code>Array</code> object representing data of the SQL * <code>ARRAY</code> value at the head of the stream; <code>null</code> * if the value read is SQL <code>NULL</code> * @exception SQLException if a database access error occurs * @exception SQLFeatureNotSupportedException if the JDBC driver does not support * this method * @since 1.2 */ Array readArray() throws SQLException; /** * Retrieves whether the last value read was SQL <code>NULL</code>. * * @return <code>true</code> if the most recently read SQL value was SQL * <code>NULL</code>; <code>false</code> otherwise * @exception SQLException if a database access error occurs * * @exception SQLFeatureNotSupportedException if the JDBC driver does not support * this method * @since 1.2 */ boolean wasNull() throws SQLException; //---------------------------- JDBC 3.0 ------------------------- /** * Reads an SQL <code>DATALINK</code> value from the stream and returns it as a * <code>java.net.URL</code> object in the Java programming language. * * @return a <code>java.net.URL</code> object. * @exception SQLException if a database access error occurs, * or if a URL is malformed * @exception SQLFeatureNotSupportedException if the JDBC driver does not support * this method * @since 1.4 */ java.net.URL readURL() throws SQLException; //---------------------------- JDBC 4.0 ------------------------- /** * Reads an SQL <code>NCLOB</code> value from the stream and returns it as a * <code>NClob</code> object in the Java programming language. * * @return a <code>NClob</code> object representing data of the SQL <code>NCLOB</code> value * at the head of the stream; <code>null</code> if the value read is * SQL <code>NULL</code> * @exception SQLException if a database access error occurs * @exception SQLFeatureNotSupportedException if the JDBC driver does not support * this method * @since 1.6 */ NClob readNClob() throws SQLException; /** * Reads the next attribute in the stream and returns it as a <code>String</code> * in the Java programming language. It is intended for use when * accessing <code>NCHAR</code>,<code>NVARCHAR</code> * and <code>LONGNVARCHAR</code> columns. * * @return the attribute; if the value is SQL <code>NULL</code>, returns <code>null</code> * @exception SQLException if a database access error occurs * @exception SQLFeatureNotSupportedException if the JDBC driver does not support * this method * @since 1.6 */ String readNString() throws SQLException; /** * Reads an SQL <code>XML</code> value from the stream and returns it as a * <code>SQLXML</code> object in the Java programming language. * * @return a <code>SQLXML</code> object representing data of the SQL <code>XML</code> value * at the head of the stream; <code>null</code> if the value read is * SQL <code>NULL</code> * @exception SQLException if a database access error occurs * @exception SQLFeatureNotSupportedException if the JDBC driver does not support * this method * @since 1.6 */ SQLXML readSQLXML() throws SQLException; /** * Reads an SQL <code>ROWID</code> value from the stream and returns it as a * <code>RowId</code> object in the Java programming language. * * @return a <code>RowId</code> object representing data of the SQL <code>ROWID</code> value * at the head of the stream; <code>null</code> if the value read is * SQL <code>NULL</code> * @exception SQLException if a database access error occurs * @exception SQLFeatureNotSupportedException if the JDBC driver does not support * this method * @since 1.6 */ RowId readRowId() throws SQLException; //--------------------------JDBC 4.2 ----------------------------- /** * Reads the next attribute in the stream and returns it as an * {@code Object} in the Java programming language. The * actual type of the object returned is determined by the specified * Java data type, and any customizations present in this * stream's type map. * * <P>A type map is registered with the stream by the JDBC driver before the * stream is passed to the application. * * <P>When the attribute at the head of the stream is an SQL {@code NULL} * the method returns {@code null}. If the attribute is an SQL * structured or distinct * type, it determines the SQL type of the attribute at the head of the stream. * If the stream's type map has an entry for that SQL type, the driver * constructs an object of the appropriate class and calls the method * {@code SQLData.readSQL} on that object, which reads additional data from the * stream, using the protocol described for that method. *<p> * The default implementation will throw {@code SQLFeatureNotSupportedException} * * @param <T> the type of the class modeled by this Class object * @param type Class representing the Java data type to convert the attribute to. * @return the attribute at the head of the stream as an {@code Object} in the * Java programming language;{@code null} if the attribute is SQL {@code NULL} * @exception SQLException if a database access error occurs * @exception SQLFeatureNotSupportedException if the JDBC driver does not support * this method * @since 1.8 */ default <T> T readObject(Class<T> type) throws SQLException { throw new SQLFeatureNotSupportedException(); } }