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 * Copyright (c) 1998, 2014, 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,

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 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 */

package java.sql;

import java.io.Reader;

/**

 * The mapping in the Java™ programming language

 * for the SQL {@code CLOB} type.

 * An SQL {@code CLOB} is a built-in type

 * that stores a Character Large Object as a column value in a row of

 * a database table.

 * By default drivers implement a {@code Clob} object using an SQL

 * {@code locator(CLOB)}, which means that a {@code Clob} object

 * contains a logical pointer to the SQL {@code CLOB} data rather than

 * the data itself. A {@code Clob} object is valid for the duration

 * of the transaction in which it was created.

 * <P>The {@code Clob} interface provides methods for getting the

 * length of an SQL {@code CLOB} (Character Large Object) value,

 * for materializing a {@code CLOB} value on the client, and for

 * searching for a substring or {@code CLOB} object within a

 * {@code CLOB} value.

 * Methods in the interfaces {@link ResultSet},

 * {@link CallableStatement}, and {@link PreparedStatement}, such as

 * {@code getClob} and {@code setClob} allow a programmer to

 * access an SQL {@code CLOB} value.  In addition, this interface

 * has methods for updating a {@code CLOB} value.

 * <p>

 * All methods on the {@code Clob} interface must be

 * fully implemented if the JDBC driver supports the data type.

 *

 * @since 1.2

 */

public interface Clob {

  /**

   * Retrieves the number of characters

   * in the {@code CLOB} value

   * designated by this {@code Clob} object.

   *

   * @return length of the {@code CLOB} in characters

   * @exception SQLException if there is an error accessing the

   *            length of the {@code CLOB} value

   * @exception SQLFeatureNotSupportedException if the JDBC driver

   *            does not support this method

   * @since 1.2

   */

  long length() throws SQLException;

  /**

   * Retrieves a copy of the specified substring

   * in the {@code CLOB} value

   * designated by this {@code Clob} object.

   * The substring begins at position

   * {@code pos} and has up to {@code length} consecutive

   * characters.

   *

   * @param pos the first character of the substring to be extracted.

   *        The first character is at position 1.

   * @param length the number of consecutive characters to be copied;

   *        the value for length must be 0 or greater

   * @return a {@code String} that is the specified substring in

   *         the {@code CLOB} value designated by this {@code Clob} object

   * @exception SQLException if there is an error accessing the

   *            {@code CLOB} value; if pos is less than 1 or length is

   *            less than 0

   * @exception SQLFeatureNotSupportedException if the JDBC driver

   *            does not support this method

   * @since 1.2

   */

  String getSubString(long pos, int length) throws SQLException;

  /**

   * Retrieves the {@code CLOB} value designated by this {@code Clob}

   * object as a {@code java.io.Reader} object (or as a stream of

   * characters).

   *

   * @return a {@code java.io.Reader} object containing the

   *         {@code CLOB} data

   * @exception SQLException if there is an error accessing the

   *            {@code CLOB} value

   * @exception SQLFeatureNotSupportedException if the JDBC driver

   *            does not support this method

   * @see #setCharacterStream

   * @since 1.2

   */

  java.io.Reader getCharacterStream() throws SQLException;

  /**

   * Retrieves the {@code CLOB} value designated by this {@code Clob}

   * object as an ascii stream.

   *

   * @return a {@code java.io.InputStream} object containing the

   *         {@code CLOB} data

   * @exception SQLException if there is an error accessing the

   *            {@code CLOB} value

   * @exception SQLFeatureNotSupportedException if the JDBC driver

   *            does not support this method

   * @see #setAsciiStream

   * @since 1.2

   */

  java.io.InputStream getAsciiStream() throws SQLException;

  /**

   * Retrieves the character position at which the specified substring

   * {@code searchstr} appears in the SQL {@code CLOB} value

   * represented by this {@code Clob} object.  The search

   * begins at position {@code start}.

   *

   * @param searchstr the substring for which to search

   * @param start the position at which to begin searching;

   *        the first position is 1

   * @return the position at which the substring appears or -1 if it is not

   *         present; the first position is 1

   * @exception SQLException if there is an error accessing the

   *            {@code CLOB} value or if pos is less than 1

   * @exception SQLFeatureNotSupportedException if the JDBC driver

   *            does not support this method

   * @since 1.2

   */

  long position(String searchstr, long start) throws SQLException;

  /**

   * Retrieves the character position at which the specified

   * {@code Clob} object {@code searchstr} appears in this

   * {@code Clob} object.  The search begins at position

   * {@code start}.

   *

   * @param searchstr the {@code Clob} object for which to search

   * @param start the position at which to begin searching; the first

   *              position is 1

   * @return the position at which the {@code Clob} object appears

   *         or -1 if it is not present; the first position is 1

   * @exception SQLException if there is an error accessing the

   *            {@code CLOB} value or if start is less than 1

   * @exception SQLFeatureNotSupportedException if the JDBC driver

   *            does not support this method

   * @since 1.2

   */

  long position(Clob searchstr, long start) throws SQLException;

    //---------------------------- jdbc 3.0 -----------------------------------

    /**

     * Writes the given Java {@code String} to the {@code CLOB}

     * value that this {@code Clob} object designates at the position

     * {@code pos}. The string will overwrite the existing characters

     * in the {@code Clob} object starting at the position

     * {@code pos}.  If the end of the {@code Clob} value is reached

     * while writing the given string, then the length of the {@code Clob}

     * value will be increased to accommodate the extra characters.

     * <p>

     * <b>Note:</b> If the value specified for {@code pos}

     * is greater than the length+1 of the {@code CLOB} value then the

     * behavior is undefined. Some JDBC drivers may throw an

     * {@code SQLException} while other drivers may support this

     * operation.

     *

     * @param pos the position at which to start writing to the {@code CLOB}

     *        value that this {@code Clob} object represents;

     *        the first position is 1.

     * @param str the string to be written to the {@code CLOB}

     *        value that this {@code Clob} designates

     * @return the number of characters written

     * @exception SQLException if there is an error accessing the

     *            {@code CLOB} value or if pos is less than 1

     *

     * @exception SQLFeatureNotSupportedException if the JDBC driver

     *            does not support this method

     * @since 1.4

     */

    int setString(long pos, String str) throws SQLException;

    /**

     * Writes {@code len} characters of {@code str}, starting

     * at character {@code offset}, to the {@code CLOB} value

     * that this {@code Clob} represents.

     * The string will overwrite the existing characters

     * in the {@code Clob} object starting at the position

     * {@code pos}.  If the end of the {@code Clob} value is reached

     * while writing the given string, then the length of the {@code Clob}

     * value will be increased to accommodate the extra characters.

     * <p>

     * <b>Note:</b> If the value specified for {@code pos}

     * is greater than the length+1 of the {@code CLOB} value then the

     * behavior is undefined. Some JDBC drivers may throw an

     * {@code SQLException} while other drivers may support this

     * operation.

     *

     * @param pos the position at which to start writing to this

     *        {@code CLOB} object; The first position  is 1

     * @param str the string to be written to the {@code CLOB}

     *        value that this {@code Clob} object represents

     * @param offset the offset into {@code str} to start reading

     *        the characters to be written

     * @param len the number of characters to be written

     * @return the number of characters written

     * @exception SQLException if there is an error accessing the

     *            {@code CLOB} value or if pos is less than 1

     *

     * @exception SQLFeatureNotSupportedException if the JDBC driver

     *            does not support this method

     * @since 1.4

     */

    int setString(long pos, String str, int offset, int len) throws SQLException;

    /**

     * Retrieves a stream to be used to write Ascii characters to the

     * {@code CLOB} value that this {@code Clob} object represents,

     * starting at position {@code pos}.  Characters written to the stream

     * will overwrite the existing characters

     * in the {@code Clob} object starting at the position

     * {@code pos}.  If the end of the {@code Clob} value is reached

     * while writing characters to the stream, then the length of the {@code Clob}

     * value will be increased to accommodate the extra characters.

     * <p>

     * <b>Note:</b> If the value specified for {@code pos}

     * is greater than the length+1 of the {@code CLOB} value then the

     * behavior is undefined. Some JDBC drivers may throw an

     * {@code SQLException} while other drivers may support this

     * operation.

     *

     * @param pos the position at which to start writing to this

     *        {@code CLOB} object; The first position is 1

     * @return the stream to which ASCII encoded characters can be written

     * @exception SQLException if there is an error accessing the

     *            {@code CLOB} value or if pos is less than 1

     * @exception SQLFeatureNotSupportedException if the JDBC driver

     *            does not support this method

     * @see #getAsciiStream

     *

     * @since 1.4

     */

    java.io.OutputStream setAsciiStream(long pos) throws SQLException;

    /**

     * Retrieves a stream to be used to write a stream of Unicode characters

     * to the {@code CLOB} value that this {@code Clob} object

     * represents, at position {@code pos}. Characters written to the stream

     * will overwrite the existing characters

     * in the {@code Clob} object starting at the position

     * {@code pos}.  If the end of the {@code Clob} value is reached

     * while writing characters to the stream, then the length of the {@code Clob}

     * value will be increased to accommodate the extra characters.

     * <p>

     * <b>Note:</b> If the value specified for {@code pos}

     * is greater than the length+1 of the {@code CLOB} value then the

     * behavior is undefined. Some JDBC drivers may throw an

     * {@code SQLException} while other drivers may support this

     * operation.

     *

     * @param  pos the position at which to start writing to the

     *        {@code CLOB} value; The first position is 1

     *

     * @return a stream to which Unicode encoded characters can be written

     * @exception SQLException if there is an error accessing the

     *            {@code CLOB} value or if pos is less than 1

     * @exception SQLFeatureNotSupportedException if the JDBC driver

     *            does not support this method

     * @see #getCharacterStream

     *

     * @since 1.4

     */

    java.io.Writer setCharacterStream(long pos) throws SQLException;

    /**

     * Truncates the {@code CLOB} value that this {@code Clob}

     * designates to have a length of {@code len}

     * characters.

     * <p>

     * <b>Note:</b> If the value specified for {@code pos}

     * is greater than the length+1 of the {@code CLOB} value then the

     * behavior is undefined. Some JDBC drivers may throw an

     * {@code SQLException} while other drivers may support this

     * operation.

     *

     * @param len the length, in characters, to which the {@code CLOB} value

     *        should be truncated

     * @exception SQLException if there is an error accessing the

     *            {@code CLOB} value or if len is less than 0

     *

     * @exception SQLFeatureNotSupportedException if the JDBC driver

     *            does not support this method

     * @since 1.4

     */

    void truncate(long len) throws SQLException;

    /**

     * This method releases the resources that the {@code Clob} object

     * holds.  The object is invalid once the {@code free} method

     * is called.

     * <p>

     * After {@code free} has been called, any attempt to invoke a

     * method other than {@code free} will result in a {@code SQLException}

     * being thrown.  If {@code free} is called multiple times, the subsequent

     * calls to {@code free} are treated as a no-op.

     *

     * @throws SQLException if an error occurs releasing

     *         the Clob's resources

     *

     * @exception SQLFeatureNotSupportedException if the JDBC driver

     *            does not support this method

     * @since 1.6

     */

    void free() throws SQLException;

    /**

     * Returns a {@code Reader} object that contains

     * a partial {@code Clob} value, starting with the character

     * specified by pos, which is length characters in length.

     *

     * @param pos the offset to the first character of the partial value to

     * be retrieved.  The first character in the Clob is at position 1.

     * @param length the length in characters of the partial value to be retrieved.

     * @return {@code Reader} through which

     *         the partial {@code Clob} value can be read.

     * @throws SQLException if pos is less than 1;

     *         or if pos is greater than the number of characters

     *         in the {@code Clob};

     *         or if pos + length is greater than the number of

     *         characters in the {@code Clob}

     *

     * @exception SQLFeatureNotSupportedException if the JDBC driver

     *            does not support this method

     * @since 1.6

     */

    Reader getCharacterStream(long pos, long length) throws SQLException;

}