Blob


1   /*
2    * @(#)Blob.java    1.28 03/12/19
3    *
4    * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
5    * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
6    */
7   
8   package java.sql;
9    
10  /**
11   * The representation (mapping) in
12   * the Java<sup><font size=-2>TM</font></sup> programming
13   * language of an SQL 
14   * <code>BLOB</code> value.  An SQL <code>BLOB</code> is a built-in type 
15   * that stores a Binary Large Object as a column value in a row of 
16   * a database table. By default drivers implement <code>Blob</code> using
17   * an SQL <code>locator(BLOB)</code>, which means that a
18   * <code>Blob</code> object contains a logical pointer to the
19   * SQL <code>BLOB</code> data rather than the data itself.
20   * A <code>Blob</code> object is valid for the duration of the
21   * transaction in which is was created.
22   * 
23   * <P>Methods in the interfaces {@link ResultSet}, 
24   * {@link CallableStatement}, and {@link PreparedStatement}, such as
25   * <code>getBlob</code> and <code>setBlob</code> allow a programmer to 
26   * access an SQL <code>BLOB</code> value.
27   * The <code>Blob</code> interface provides methods for getting the
28   * length of an SQL <code>BLOB</code> (Binary Large Object) value,
29   * for materializing a <code>BLOB</code> value on the client, and for
30   * determining the position of a pattern of bytes within a 
31   * <code>BLOB</code> value. In addition, this interface has methods for updating
32   * a <code>BLOB</code> value.
33   *
34   * @since 1.2
35   */
36  
37  public interface Blob {
38  
39    /**
40     * Returns the number of bytes in the <code>BLOB</code> value
41     * designated by this <code>Blob</code> object.
42     * @return length of the <code>BLOB</code> in bytes
43     * @exception SQLException if there is an error accessing the
44     * length of the <code>BLOB</code>
45     * @since 1.2
46     */
47    long length() throws SQLException  ;
48  
49    /**
50     * Retrieves all or part of the <code>BLOB</code>
51     * value that this <code>Blob</code> object represents, as an array of
52     * bytes.  This <code>byte</code> array contains up to <code>length</code> 
53     * consecutive bytes starting at position <code>pos</code>.
54     *
55     * @param pos the ordinal position of the first byte in the 
56     *        <code>BLOB</code> value to be extracted; the first byte is at
57     *        position 1
58     * @param length the number of consecutive bytes to be copied
59     * @return a byte array containing up to <code>length</code> 
60     *         consecutive bytes from the <code>BLOB</code> value designated
61     *         by this <code>Blob</code> object, starting with the
62     *         byte at position <code>pos</code>
63     * @exception SQLException if there is an error accessing the
64     *            <code>BLOB</code> value
65     * @see #setBytes
66     * @since 1.2
67     */
68    byte[] getBytes(long pos, int length) throws SQLException  ; 
69  
70    /**
71     * Retrieves the <code>BLOB</code> value designated by this
72     * <code>Blob</code> instance as a stream.
73     *
74     * @return a stream containing the <code>BLOB</code> data
75     * @exception SQLException if there is an error accessing the
76     *            <code>BLOB</code> value
77     * @see #setBinaryStream
78     * @since 1.2
79     */
80    java.io.InputStream   getBinaryStream () throws SQLException  ;
81  
82    /** 
83     * Retrieves the byte position at which the specified byte array
84     * <code>pattern</code> begins within the <code>BLOB</code>
85     * value that this <code>Blob</code> object represents.  The
86     * search for <code>pattern</code> begins at position
87     * <code>start</code>.  
88     *
89     * @param pattern the byte array for which to search
90     * @param start the position at which to begin searching; the
91     *        first position is 1
92     * @return the position at which the pattern appears, else -1
93     * @exception SQLException if there is an error accessing the 
94     * <code>BLOB</code>
95     * @since 1.2
96     */
97    long position(byte pattern[], long start) throws SQLException  ;
98  
99    /** 
100    * Retrieves the byte position in the <code>BLOB</code> value
101    * designated by this <code>Blob</code> object at which 
102    * <code>pattern</code> begins.  The search begins at position
103    * <code>start</code>.
104    *
105    * @param pattern the <code>Blob</code> object designating
106    * the <code>BLOB</code> value for which to search
107    * @param start the position in the <code>BLOB</code> value
108    *        at which to begin searching; the first position is 1
109    * @return the position at which the pattern begins, else -1
110    * @exception SQLException if there is an error accessing the
111    *            <code>BLOB</code> value
112    * @since 1.2
113    */
114   long position(Blob   pattern, long start) throws SQLException  ;
115 
116     // -------------------------- JDBC 3.0 -----------------------------------
117 
118     /**
119      * Writes the given array of bytes to the <code>BLOB</code> value that
120      * this <code>Blob</code> object represents, starting at position 
121      * <code>pos</code>, and returns the number of bytes written.
122      *
123      * @param pos the position in the <code>BLOB</code> object at which
124      *        to start writing
125      * @param bytes the array of bytes to be written to the <code>BLOB</code>
126      *        value that this <code>Blob</code> object represents
127      * @return the number of bytes written
128      * @exception SQLException if there is an error accessing the
129      *            <code>BLOB</code> value
130      * @see #getBytes
131      * @since 1.4
132      */
133     int setBytes(long pos, byte[] bytes) throws SQLException  ;
134 
135     /**
136      * Writes all or part of the given <code>byte</code> array to the
137      * <code>BLOB</code> value that this <code>Blob</code> object represents
138      * and returns the number of bytes written.
139      * Writing starts at position <code>pos</code> in the <code>BLOB</code>
140      * value; <code>len</code> bytes from the given byte array are written.
141      *
142      * @param pos the position in the <code>BLOB</code> object at which
143      *        to start writing
144      * @param bytes the array of bytes to be written to this <code>BLOB</code>
145      *        object
146      * @param offset the offset into the array <code>bytes</code> at which
147      *        to start reading the bytes to be set
148      * @param len the number of bytes to be written to the <code>BLOB</code>
149      *        value from the array of bytes <code>bytes</code>
150      * @return the number of bytes written
151      * @exception SQLException if there is an error accessing the
152      *            <code>BLOB</code> value
153      * @see #getBytes
154      * @since 1.4
155      */
156     int setBytes(long pos, byte[] bytes, int offset, int len) throws SQLException  ;
157 
158     /**
159      * Retrieves a stream that can be used to write to the <code>BLOB</code> 
160      * value that this <code>Blob</code> object represents.  The stream begins
161      * at position <code>pos</code>.
162      *
163      * @param pos the position in the <code>BLOB</code> value at which
164      *        to start writing
165      * @return a <code>java.io.OutputStream</code> object to which data can 
166      *         be written
167      * @exception SQLException if there is an error accessing the
168      *            <code>BLOB</code> value
169      * @see #getBinaryStream
170      * @since 1.4
171      */
172     java.io.OutputStream   setBinaryStream(long pos) throws SQLException  ;
173 
174     /**
175      * Truncates the <code>BLOB</code> value that this <code>Blob</code>
176      * object represents to be <code>len</code> bytes in length.
177      *
178      * @param len the length, in bytes, to which the <code>BLOB</code> value
179      *        that this <code>Blob</code> object represents should be truncated
180      * @exception SQLException if there is an error accessing the
181      *            <code>BLOB</code> value
182      * @since 1.4
183      */
184     void truncate(long len) throws SQLException  ;
185 
186 }
187 
188 
189
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