Java tutorial
/* * 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, * 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; 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; }