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; import java.io.InputStream; /** * The representation (mapping) in * the Java™ programming language of an SQL * {@code BLOB} value. An SQL {@code BLOB} is a built-in type * that stores a Binary Large Object as a column value in a row of * a database table. By default drivers implement {@code Blob} using * an SQL {@code locator(BLOB)}, which means that a * {@code Blob} object contains a logical pointer to the * SQL {@code BLOB} data rather than the data itself. * A {@code Blob} object is valid for the duration of the * transaction in which is was created. * * <P>Methods in the interfaces {@link ResultSet}, * {@link CallableStatement}, and {@link PreparedStatement}, such as * {@code getBlob} and {@code setBlob} allow a programmer to * access an SQL {@code BLOB} value. * The {@code Blob} interface provides methods for getting the * length of an SQL {@code BLOB} (Binary Large Object) value, * for materializing a {@code BLOB} value on the client, and for * determining the position of a pattern of bytes within a * {@code BLOB} value. In addition, this interface has methods for updating * a {@code BLOB} value. * <p> * All methods on the {@code Blob} interface must be fully implemented if the * JDBC driver supports the data type. * * @since 1.2 */ public interface Blob { /** * Returns the number of bytes in the {@code BLOB} value * designated by this {@code Blob} object. * * @return length of the {@code BLOB} in bytes * @exception SQLException if there is an error accessing the * length of the {@code BLOB} * @exception SQLFeatureNotSupportedException if the JDBC driver * does not support this method * @since 1.2 */ long length() throws SQLException; /** * Retrieves all or part of the {@code BLOB} * value that this {@code Blob} object represents, as an array of * bytes. This {@code byte} array contains up to {@code length} * consecutive bytes starting at position {@code pos}. * * @param pos the ordinal position of the first byte in the * {@code BLOB} value to be extracted; the first byte is at * position 1 * @param length the number of consecutive bytes to be copied; the value * for length must be 0 or greater * @return a byte array containing up to {@code length} * consecutive bytes from the {@code BLOB} value designated * by this {@code Blob} object, starting with the * byte at position {@code pos} * @exception SQLException if there is an error accessing the * {@code BLOB} value; if pos is less than 1 or length is * less than 0 * @exception SQLFeatureNotSupportedException if the JDBC driver * does not support this method * @see #setBytes * @since 1.2 */ byte[] getBytes(long pos, int length) throws SQLException; /** * Retrieves the {@code BLOB} value designated by this * {@code Blob} instance as a stream. * * @return a stream containing the {@code BLOB} data * @exception SQLException if there is an error accessing the * {@code BLOB} value * @exception SQLFeatureNotSupportedException if the JDBC driver * does not support this method * @see #setBinaryStream * @since 1.2 */ java.io.InputStream getBinaryStream() throws SQLException; /** * Retrieves the byte position at which the specified byte array * {@code pattern} begins within the {@code BLOB} * value that this {@code Blob} object represents. * The search for {@code pattern} begins at position * {@code start}. * * @param pattern the byte array for which to search * @param start the position at which to begin searching; the * first position is 1 * @return the position at which the pattern appears, else -1 * @exception SQLException if there is an error accessing the * {@code BLOB} or if start is less than 1 * @exception SQLFeatureNotSupportedException if the JDBC driver * does not support this method * @since 1.2 */ long position(byte pattern[], long start) throws SQLException; /** * Retrieves the byte position in the {@code BLOB} value * designated by this {@code Blob} object at which * {@code pattern} begins. The search begins at position * {@code start}. * * @param pattern the {@code Blob} object designating * the {@code BLOB} value for which to search * @param start the position in the {@code BLOB} value * at which to begin searching; the first position is 1 * @return the position at which the pattern begins, else -1 * @exception SQLException if there is an error accessing the * {@code BLOB} value or if start is less than 1 * @exception SQLFeatureNotSupportedException if the JDBC driver * does not support this method * @since 1.2 */ long position(Blob pattern, long start) throws SQLException; // -------------------------- JDBC 3.0 ----------------------------------- /** * Writes the given array of bytes to the {@code BLOB} value that * this {@code Blob} object represents, starting at position * {@code pos}, and returns the number of bytes written. * The array of bytes will overwrite the existing bytes * in the {@code Blob} object starting at the position * {@code pos}. If the end of the {@code Blob} value is reached * while writing the array of bytes, then the length of the {@code Blob} * value will be increased to accommodate the extra bytes. * <p> * <b>Note:</b> If the value specified for {@code pos} * is greater than the length+1 of the {@code BLOB} 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 in the {@code BLOB} object at which * to start writing; the first position is 1 * @param bytes the array of bytes to be written to the {@code BLOB} * value that this {@code Blob} object represents * @return the number of bytes written * @exception SQLException if there is an error accessing the * {@code BLOB} value or if pos is less than 1 * @exception SQLFeatureNotSupportedException if the JDBC driver * does not support this method * @see #getBytes * @since 1.4 */ int setBytes(long pos, byte[] bytes) throws SQLException; /** * Writes all or part of the given {@code byte} array to the * {@code BLOB} value that this {@code Blob} object represents * and returns the number of bytes written. * Writing starts at position {@code pos} in the {@code BLOB} * value; {@code len} bytes from the given byte array are written. * The array of bytes will overwrite the existing bytes * in the {@code Blob} object starting at the position * {@code pos}. If the end of the {@code Blob} value is reached * while writing the array of bytes, then the length of the {@code Blob} * value will be increased to accommodate the extra bytes. * <p> * <b>Note:</b> If the value specified for {@code pos} * is greater than the length+1 of the {@code BLOB} 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 in the {@code BLOB} object at which * to start writing; the first position is 1 * @param bytes the array of bytes to be written to this {@code BLOB} * object * @param offset the offset into the array {@code bytes} at which * to start reading the bytes to be set * @param len the number of bytes to be written to the {@code BLOB} * value from the array of bytes {@code bytes} * @return the number of bytes written * @exception SQLException if there is an error accessing the * {@code BLOB} value or if pos is less than 1 * @exception SQLFeatureNotSupportedException if the JDBC driver * does not support this method * @see #getBytes * @since 1.4 */ int setBytes(long pos, byte[] bytes, int offset, int len) throws SQLException; /** * Retrieves a stream that can be used to write to the {@code BLOB} * value that this {@code Blob} object represents. The stream begins * at position {@code pos}. * The bytes written to the stream will overwrite the existing bytes * in the {@code Blob} object starting at the position * {@code pos}. If the end of the {@code Blob} value is reached * while writing to the stream, then the length of the {@code Blob} * value will be increased to accommodate the extra bytes. * <p> * <b>Note:</b> If the value specified for {@code pos} * is greater than the length+1 of the {@code BLOB} 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 in the {@code BLOB} value at which * to start writing; the first position is 1 * @return a {@code java.io.OutputStream} object to which data can * be written * @exception SQLException if there is an error accessing the * {@code BLOB} value or if pos is less than 1 * @exception SQLFeatureNotSupportedException if the JDBC driver * does not support this method * @see #getBinaryStream * @since 1.4 */ java.io.OutputStream setBinaryStream(long pos) throws SQLException; /** * Truncates the {@code BLOB} value that this {@code Blob} * object represents to be {@code len} bytes in length. * <p> * <b>Note:</b> If the value specified for {@code pos} * is greater than the length+1 of the {@code BLOB} 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 bytes, to which the {@code BLOB} value * that this {@code Blob} object represents should be truncated * @exception SQLException if there is an error accessing the * {@code BLOB} 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 frees the {@code Blob} object and releases the resources that * it 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 an {@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 Blob's resources * @exception SQLFeatureNotSupportedException if the JDBC driver * does not support this method * @since 1.6 */ void free() throws SQLException; /** * Returns an {@code InputStream} object that contains * a partial {@code Blob} value, starting with the byte * specified by pos, which is length bytes in length. * * @param pos the offset to the first byte of the partial value to be * retrieved. The first byte in the {@code Blob} is at position 1. * @param length the length in bytes of the partial value to be retrieved * @return {@code InputStream} through which * the partial {@code Blob} value can be read. * @throws SQLException if pos is less than 1 or if pos is greater * than the number of bytes in the {@code Blob} or if * pos + length is greater than the number of bytes * in the {@code Blob} * * @exception SQLFeatureNotSupportedException if the JDBC driver * does not support this method * @since 1.6 */ InputStream getBinaryStream(long pos, long length) throws SQLException; }