1/*
2 * Copyright (c) 1998, 2006, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
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19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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24 */
25
26package java.sql;
27
28import java.io.Reader;
29
30/**
31 * The mapping in the Java<sup><font size=-2>TM</font></sup> programming language
32 * for the SQL <code>CLOB</code> type.
33 * An SQL <code>CLOB</code> is a built-in type
34 * that stores a Character Large Object as a column value in a row of
35 * a database table.
36 * By default drivers implement a <code>Clob</code> object using an SQL
37 * <code>locator(CLOB)</code>, which means that a <code>Clob</code> object
38 * contains a logical pointer to the SQL <code>CLOB</code> data rather than
39 * the data itself. A <code>Clob</code> object is valid for the duration
40 * of the transaction in which it was created.
41 * <P>The <code>Clob</code> interface provides methods for getting the
42 * length of an SQL <code>CLOB</code> (Character Large Object) value,
43 * for materializing a <code>CLOB</code> value on the client, and for
44 * searching for a substring or <code>CLOB</code> object within a
45 * <code>CLOB</code> value.
46 * Methods in the interfaces {@link ResultSet},
47 * {@link CallableStatement}, and {@link PreparedStatement}, such as
48 * <code>getClob</code> and <code>setClob</code> allow a programmer to
49 * access an SQL <code>CLOB</code> value.  In addition, this interface
50 * has methods for updating a <code>CLOB</code> value.
51 * <p>
52 * All methods on the <code>Clob</code> interface must be fully implemented if the
53 * JDBC driver supports the data type.
54 *
55 * @since 1.2
56 */
57
58public interface Clob {
59
60  /**
61   * Retrieves the number of characters
62   * in the <code>CLOB</code> value
63   * designated by this <code>Clob</code> object.
64   *
65   * @return length of the <code>CLOB</code> in characters
66   * @exception SQLException if there is an error accessing the
67   *            length of the <code>CLOB</code> value
68   * @exception SQLFeatureNotSupportedException if the JDBC driver does not support
69   * this method
70   * @since 1.2
71   */
72  long length() throws SQLException;
73
74  /**
75   * Retrieves a copy of the specified substring
76   * in the <code>CLOB</code> value
77   * designated by this <code>Clob</code> object.
78   * The substring begins at position
79   * <code>pos</code> and has up to <code>length</code> consecutive
80   * characters.
81   *
82   * @param pos the first character of the substring to be extracted.
83   *            The first character is at position 1.
84   * @param length the number of consecutive characters to be copied;
85   * the value for length must be 0 or greater
86   * @return a <code>String</code> that is the specified substring in
87   *         the <code>CLOB</code> value designated by this <code>Clob</code> object
88   * @exception SQLException if there is an error accessing the
89   *            <code>CLOB</code> value; if pos is less than 1 or length is
90   * less than 0
91   * @exception SQLFeatureNotSupportedException if the JDBC driver does not support
92   * this method
93   * @since 1.2
94   */
95  String getSubString(long pos, int length) throws SQLException;
96
97  /**
98   * Retrieves the <code>CLOB</code> value designated by this <code>Clob</code>
99   * object as a <code>java.io.Reader</code> object (or as a stream of
100   * characters).
101   *
102   * @return a <code>java.io.Reader</code> object containing the
103   *         <code>CLOB</code> data
104   * @exception SQLException if there is an error accessing the
105   *            <code>CLOB</code> value
106   * @exception SQLFeatureNotSupportedException if the JDBC driver does not support
107   * this method
108   * @see #setCharacterStream
109   * @since 1.2
110   */
111  java.io.Reader getCharacterStream() throws SQLException;
112
113  /**
114   * Retrieves the <code>CLOB</code> value designated by this <code>Clob</code>
115   * object as an ascii stream.
116   *
117   * @return a <code>java.io.InputStream</code> object containing the
118   *         <code>CLOB</code> data
119   * @exception SQLException if there is an error accessing the
120   *            <code>CLOB</code> value
121   * @exception SQLFeatureNotSupportedException if the JDBC driver does not support
122   * this method
123   * @see #setAsciiStream
124   * @since 1.2
125   */
126  java.io.InputStream getAsciiStream() throws SQLException;
127
128  /**
129   * Retrieves the character position at which the specified substring
130   * <code>searchstr</code> appears in the SQL <code>CLOB</code> value
131   * represented by this <code>Clob</code> object.  The search
132   * begins at position <code>start</code>.
133   *
134   * @param searchstr the substring for which to search
135   * @param start the position at which to begin searching; the first position
136   *              is 1
137   * @return the position at which the substring appears or -1 if it is not
138   *         present; the first position is 1
139   * @exception SQLException if there is an error accessing the
140   *            <code>CLOB</code> value or if pos is less than 1
141   * @exception SQLFeatureNotSupportedException if the JDBC driver does not support
142   * this method
143   * @since 1.2
144   */
145  long position(String searchstr, long start) throws SQLException;
146
147  /**
148   * Retrieves the character position at which the specified
149   * <code>Clob</code> object <code>searchstr</code> appears in this
150   * <code>Clob</code> object.  The search begins at position
151   * <code>start</code>.
152   *
153   * @param searchstr the <code>Clob</code> object for which to search
154   * @param start the position at which to begin searching; the first
155   *              position is 1
156   * @return the position at which the <code>Clob</code> object appears
157   *              or -1 if it is not present; the first position is 1
158   * @exception SQLException if there is an error accessing the
159   *            <code>CLOB</code> value or if start is less than 1
160   * @exception SQLFeatureNotSupportedException if the JDBC driver does not support
161   * this method
162   * @since 1.2
163   */
164  long position(Clob searchstr, long start) throws SQLException;
165
166    //---------------------------- jdbc 3.0 -----------------------------------
167
168    /**
169     * Writes the given Java <code>String</code> to the <code>CLOB</code>
170     * value that this <code>Clob</code> object designates at the position
171     * <code>pos</code>. The string will overwrite the existing characters
172     * in the <code>Clob</code> object starting at the position
173     * <code>pos</code>.  If the end of the <code>Clob</code> value is reached
174     * while writing the given string, then the length of the <code>Clob</code>
175     * value will be increased to accomodate the extra characters.
176     * <p>
177     * <b>Note:</b> If the value specified for <code>pos</code>
178     * is greater then the length+1 of the <code>CLOB</code> value then the
179     * behavior is undefined. Some JDBC drivers may throw a
180     * <code>SQLException</code> while other drivers may support this
181     * operation.
182     *
183     * @param pos the position at which to start writing to the <code>CLOB</code>
184     *         value that this <code>Clob</code> object represents;
185     * The first position is 1
186     * @param str the string to be written to the <code>CLOB</code>
187     *        value that this <code>Clob</code> designates
188     * @return the number of characters written
189     * @exception SQLException if there is an error accessing the
190     *            <code>CLOB</code> value or if pos is less than 1
191     *
192     * @exception SQLFeatureNotSupportedException if the JDBC driver does not support
193     * this method
194     * @since 1.4
195     */
196    int setString(long pos, String str) throws SQLException;
197
198    /**
199     * Writes <code>len</code> characters of <code>str</code>, starting
200     * at character <code>offset</code>, to the <code>CLOB</code> value
201     * that this <code>Clob</code> represents.  The string will overwrite the existing characters
202     * in the <code>Clob</code> object starting at the position
203     * <code>pos</code>.  If the end of the <code>Clob</code> value is reached
204     * while writing the given string, then the length of the <code>Clob</code>
205     * value will be increased to accomodate the extra characters.
206     * <p>
207     * <b>Note:</b> If the value specified for <code>pos</code>
208     * is greater then the length+1 of the <code>CLOB</code> value then the
209     * behavior is undefined. Some JDBC drivers may throw a
210     * <code>SQLException</code> while other drivers may support this
211     * operation.
212     *
213     * @param pos the position at which to start writing to this
214     *        <code>CLOB</code> object; The first position  is 1
215     * @param str the string to be written to the <code>CLOB</code>
216     *        value that this <code>Clob</code> object represents
217     * @param offset the offset into <code>str</code> to start reading
218     *        the characters to be written
219     * @param len the number of characters to be written
220     * @return the number of characters written
221     * @exception SQLException if there is an error accessing the
222     *            <code>CLOB</code> value or if pos is less than 1
223     *
224     * @exception SQLFeatureNotSupportedException if the JDBC driver does not support
225     * this method
226     * @since 1.4
227     */
228    int setString(long pos, String str, int offset, int len) throws SQLException;
229
230    /**
231     * Retrieves a stream to be used to write Ascii characters to the
232     * <code>CLOB</code> value that this <code>Clob</code> object represents,
233     * starting at position <code>pos</code>.  Characters written to the stream
234     * will overwrite the existing characters
235     * in the <code>Clob</code> object starting at the position
236     * <code>pos</code>.  If the end of the <code>Clob</code> value is reached
237     * while writing characters to the stream, then the length of the <code>Clob</code>
238     * value will be increased to accomodate the extra characters.
239     * <p>
240     * <b>Note:</b> If the value specified for <code>pos</code>
241     * is greater then the length+1 of the <code>CLOB</code> value then the
242     * behavior is undefined. Some JDBC drivers may throw a
243     * <code>SQLException</code> while other drivers may support this
244     * operation.
245     *
246     * @param pos the position at which to start writing to this
247     *        <code>CLOB</code> object; The first position is 1
248     * @return the stream to which ASCII encoded characters can be written
249     * @exception SQLException if there is an error accessing the
250     *            <code>CLOB</code> value or if pos is less than 1
251     * @exception SQLFeatureNotSupportedException if the JDBC driver does not support
252     * this method
253     * @see #getAsciiStream
254     *
255     * @since 1.4
256     */
257    java.io.OutputStream setAsciiStream(long pos) throws SQLException;
258
259    /**
260     * Retrieves a stream to be used to write a stream of Unicode characters
261     * to the <code>CLOB</code> value that this <code>Clob</code> object
262     * represents, at position <code>pos</code>. Characters written to the stream
263     * will overwrite the existing characters
264     * in the <code>Clob</code> object starting at the position
265     * <code>pos</code>.  If the end of the <code>Clob</code> value is reached
266     * while writing characters to the stream, then the length of the <code>Clob</code>
267     * value will be increased to accomodate the extra characters.
268     * <p>
269     * <b>Note:</b> If the value specified for <code>pos</code>
270     * is greater then the length+1 of the <code>CLOB</code> value then the
271     * behavior is undefined. Some JDBC drivers may throw a
272     * <code>SQLException</code> while other drivers may support this
273     * operation.
274     *
275     * @param  pos the position at which to start writing to the
276     *        <code>CLOB</code> value; The first position is 1
277     *
278     * @return a stream to which Unicode encoded characters can be written
279     * @exception SQLException if there is an error accessing the
280     *            <code>CLOB</code> value or if pos is less than 1
281     * @exception SQLFeatureNotSupportedException if the JDBC driver does not support
282     * this method
283     * @see #getCharacterStream
284     *
285     * @since 1.4
286     */
287    java.io.Writer setCharacterStream(long pos) throws SQLException;
288
289    /**
290     * Truncates the <code>CLOB</code> value that this <code>Clob</code>
291     * designates to have a length of <code>len</code>
292     * characters.
293     * <p>
294     * <b>Note:</b> If the value specified for <code>pos</code>
295     * is greater then the length+1 of the <code>CLOB</code> value then the
296     * behavior is undefined. Some JDBC drivers may throw a
297     * <code>SQLException</code> while other drivers may support this
298     * operation.
299     *
300     * @param len the length, in characters, to which the <code>CLOB</code> value
301     *        should be truncated
302     * @exception SQLException if there is an error accessing the
303     *            <code>CLOB</code> value or if len is less than 0
304     *
305     * @exception SQLFeatureNotSupportedException if the JDBC driver does not support
306     * this method
307     * @since 1.4
308     */
309    void truncate(long len) throws SQLException;
310
311    /**
312     * This method frees the <code>Clob</code> object and releases the resources the resources
313     * that it holds.  The object is invalid once the <code>free</code> method
314     * is called.
315     * <p>
316     * After <code>free</code> has been called, any attempt to invoke a
317     * method other than <code>free</code> will result in a <code>SQLException</code>
318     * being thrown.  If <code>free</code> is called multiple times, the subsequent
319     * calls to <code>free</code> are treated as a no-op.
320     * <p>
321     * @throws SQLException if an error occurs releasing
322     * the Clob's resources
323     *
324     * @exception SQLFeatureNotSupportedException if the JDBC driver does not support
325     * this method
326     * @since 1.6
327     */
328    void free() throws SQLException;
329
330    /**
331     * Returns a <code>Reader</code> object that contains a partial <code>Clob</code> value, starting
332     * with the character specified by pos, which is length characters in length.
333     *
334     * @param pos the offset to the first character of the partial value to
335     * be retrieved.  The first character in the Clob is at position 1.
336     * @param length the length in characters of the partial value to be retrieved.
337     * @return <code>Reader</code> through which the partial <code>Clob</code> value can be read.
338     * @throws SQLException if pos is less than 1 or if pos is greater than the number of
339     * characters in the <code>Clob</code> or if pos + length is greater than the number of
340     * characters in the <code>Clob</code>
341     *
342     * @exception SQLFeatureNotSupportedException if the JDBC driver does not support
343     * this method
344     * @since 1.6
345     */
346    Reader getCharacterStream(long pos, long length) throws SQLException;
347
348}
349