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 * 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

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 */

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();

    }

}