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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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5 * This code is free software; you can redistribute it and/or modify it
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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).
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24 */
25
26package java.sql;
27
28import java.io.Reader;
29
30/**
31 * The mapping in the Java™ programming language
32 * for the SQL {@code CLOB} type.
33 * An SQL {@code CLOB} 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} object using an SQL
37 * {@code locator(CLOB)}, which means that a {@code Clob} object
38 * contains a logical pointer to the SQL {@code CLOB} data rather than
39 * the data itself. A {@code Clob} object is valid for the duration
40 * of the transaction in which it was created.
41 * <P>The {@code Clob} interface provides methods for getting the
42 * length of an SQL {@code CLOB} (Character Large Object) value,
43 * for materializing a {@code CLOB} value on the client, and for
44 * searching for a substring or {@code CLOB} object within a
45 * {@code CLOB} value.
46 * Methods in the interfaces {@link ResultSet},
47 * {@link CallableStatement}, and {@link PreparedStatement}, such as
48 * {@code getClob} and {@code setClob} allow a programmer to
49 * access an SQL {@code CLOB} value.  In addition, this interface
50 * has methods for updating a {@code CLOB} value.
51 * <p>
52 * All methods on the {@code Clob} interface must be
53 * fully implemented if the 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} value
63   * designated by this {@code Clob} object.
64   *
65   * @return length of the {@code CLOB} in characters
66   * @exception SQLException if there is an error accessing the
67   *            length of the {@code CLOB} value
68   * @exception SQLFeatureNotSupportedException if the JDBC driver
69   *            does not support 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} value
77   * designated by this {@code Clob} object.
78   * The substring begins at position
79   * {@code pos} and has up to {@code length} 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} that is the specified substring in
87   *         the {@code CLOB} value designated by this {@code Clob} object
88   * @exception SQLException if there is an error accessing the
89   *            {@code CLOB} value; if pos is less than 1 or length is
90   *            less than 0
91   * @exception SQLFeatureNotSupportedException if the JDBC driver
92   *            does not support this method
93   * @since 1.2
94   */
95  String getSubString(long pos, int length) throws SQLException;
96
97  /**
98   * Retrieves the {@code CLOB} value designated by this {@code Clob}
99   * object as a {@code java.io.Reader} object (or as a stream of
100   * characters).
101   *
102   * @return a {@code java.io.Reader} object containing the
103   *         {@code CLOB} data
104   * @exception SQLException if there is an error accessing the
105   *            {@code CLOB} value
106   * @exception SQLFeatureNotSupportedException if the JDBC driver
107   *            does not support this method
108   * @see #setCharacterStream
109   * @since 1.2
110   */
111  java.io.Reader getCharacterStream() throws SQLException;
112
113  /**
114   * Retrieves the {@code CLOB} value designated by this {@code Clob}
115   * object as an ascii stream.
116   *
117   * @return a {@code java.io.InputStream} object containing the
118   *         {@code CLOB} data
119   * @exception SQLException if there is an error accessing the
120   *            {@code CLOB} value
121   * @exception SQLFeatureNotSupportedException if the JDBC driver
122   *            does not support 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} appears in the SQL {@code CLOB} value
131   * represented by this {@code Clob} object.  The search
132   * begins at position {@code start}.
133   *
134   * @param searchstr the substring for which to search
135   * @param start the position at which to begin searching;
136   *        the first position 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} value or if pos is less than 1
141   * @exception SQLFeatureNotSupportedException if the JDBC driver
142   *            does not support 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} object {@code searchstr} appears in this
150   * {@code Clob} object.  The search begins at position
151   * {@code start}.
152   *
153   * @param searchstr the {@code Clob} 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} 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} value or if start is less than 1
160   * @exception SQLFeatureNotSupportedException if the JDBC driver
161   *            does not support 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} to the {@code CLOB}
170     * value that this {@code Clob} object designates at the position
171     * {@code pos}. The string will overwrite the existing characters
172     * in the {@code Clob} object starting at the position
173     * {@code pos}.  If the end of the {@code Clob} value is reached
174     * while writing the given string, then the length of the {@code Clob}
175     * value will be increased to accommodate the extra characters.
176     * <p>
177     * <b>Note:</b> If the value specified for {@code pos}
178     * is greater than the length+1 of the {@code CLOB} value then the
179     * behavior is undefined. Some JDBC drivers may throw an
180     * {@code SQLException} while other drivers may support this
181     * operation.
182     *
183     * @param pos the position at which to start writing to the {@code CLOB}
184     *        value that this {@code Clob} object represents;
185     *        the first position is 1.
186     * @param str the string to be written to the {@code CLOB}
187     *        value that this {@code Clob} designates
188     * @return the number of characters written
189     * @exception SQLException if there is an error accessing the
190     *            {@code CLOB} value or if pos is less than 1
191     *
192     * @exception SQLFeatureNotSupportedException if the JDBC driver
193     *            does not support this method
194     * @since 1.4
195     */
196    int setString(long pos, String str) throws SQLException;
197
198    /**
199     * Writes {@code len} characters of {@code str}, starting
200     * at character {@code offset}, to the {@code CLOB} value
201     * that this {@code Clob} represents.
202     * The string will overwrite the existing characters
203     * in the {@code Clob} object starting at the position
204     * {@code pos}.  If the end of the {@code Clob} value is reached
205     * while writing the given string, then the length of the {@code Clob}
206     * value will be increased to accommodate the extra characters.
207     * <p>
208     * <b>Note:</b> If the value specified for {@code pos}
209     * is greater than the length+1 of the {@code CLOB} value then the
210     * behavior is undefined. Some JDBC drivers may throw an
211     * {@code SQLException} while other drivers may support this
212     * operation.
213     *
214     * @param pos the position at which to start writing to this
215     *        {@code CLOB} object; The first position  is 1
216     * @param str the string to be written to the {@code CLOB}
217     *        value that this {@code Clob} object represents
218     * @param offset the offset into {@code str} to start reading
219     *        the characters to be written
220     * @param len the number of characters to be written
221     * @return the number of characters written
222     * @exception SQLException if there is an error accessing the
223     *            {@code CLOB} value or if pos is less than 1
224     *
225     * @exception SQLFeatureNotSupportedException if the JDBC driver
226     *            does not support this method
227     * @since 1.4
228     */
229    int setString(long pos, String str, int offset, int len) throws SQLException;
230
231    /**
232     * Retrieves a stream to be used to write Ascii characters to the
233     * {@code CLOB} value that this {@code Clob} object represents,
234     * starting at position {@code pos}.  Characters written to the stream
235     * will overwrite the existing characters
236     * in the {@code Clob} object starting at the position
237     * {@code pos}.  If the end of the {@code Clob} value is reached
238     * while writing characters to the stream, then the length of the {@code Clob}
239     * value will be increased to accommodate the extra characters.
240     * <p>
241     * <b>Note:</b> If the value specified for {@code pos}
242     * is greater than the length+1 of the {@code CLOB} value then the
243     * behavior is undefined. Some JDBC drivers may throw an
244     * {@code SQLException} while other drivers may support this
245     * operation.
246     *
247     * @param pos the position at which to start writing to this
248     *        {@code CLOB} object; The first position is 1
249     * @return the stream to which ASCII encoded characters can be written
250     * @exception SQLException if there is an error accessing the
251     *            {@code CLOB} value or if pos is less than 1
252     * @exception SQLFeatureNotSupportedException if the JDBC driver
253     *            does not support this method
254     * @see #getAsciiStream
255     *
256     * @since 1.4
257     */
258    java.io.OutputStream setAsciiStream(long pos) throws SQLException;
259
260    /**
261     * Retrieves a stream to be used to write a stream of Unicode characters
262     * to the {@code CLOB} value that this {@code Clob} object
263     * represents, at position {@code pos}. Characters written to the stream
264     * will overwrite the existing characters
265     * in the {@code Clob} object starting at the position
266     * {@code pos}.  If the end of the {@code Clob} value is reached
267     * while writing characters to the stream, then the length of the {@code Clob}
268     * value will be increased to accommodate the extra characters.
269     * <p>
270     * <b>Note:</b> If the value specified for {@code pos}
271     * is greater than the length+1 of the {@code CLOB} value then the
272     * behavior is undefined. Some JDBC drivers may throw an
273     * {@code SQLException} while other drivers may support this
274     * operation.
275     *
276     * @param  pos the position at which to start writing to the
277     *        {@code CLOB} value; The first position is 1
278     *
279     * @return a stream to which Unicode encoded characters can be written
280     * @exception SQLException if there is an error accessing the
281     *            {@code CLOB} value or if pos is less than 1
282     * @exception SQLFeatureNotSupportedException if the JDBC driver
283     *            does not support this method
284     * @see #getCharacterStream
285     *
286     * @since 1.4
287     */
288    java.io.Writer setCharacterStream(long pos) throws SQLException;
289
290    /**
291     * Truncates the {@code CLOB} value that this {@code Clob}
292     * designates to have a length of {@code len}
293     * characters.
294     * <p>
295     * <b>Note:</b> If the value specified for {@code pos}
296     * is greater than the length+1 of the {@code CLOB} value then the
297     * behavior is undefined. Some JDBC drivers may throw an
298     * {@code SQLException} while other drivers may support this
299     * operation.
300     *
301     * @param len the length, in characters, to which the {@code CLOB} value
302     *        should be truncated
303     * @exception SQLException if there is an error accessing the
304     *            {@code CLOB} value or if len is less than 0
305     *
306     * @exception SQLFeatureNotSupportedException if the JDBC driver
307     *            does not support this method
308     * @since 1.4
309     */
310    void truncate(long len) throws SQLException;
311
312    /**
313     * This method releases the resources that the {@code Clob} object
314     * holds.  The object is invalid once the {@code free} method
315     * is called.
316     * <p>
317     * After {@code free} has been called, any attempt to invoke a
318     * method other than {@code free} will result in a {@code SQLException}
319     * being thrown.  If {@code free} is called multiple times, the subsequent
320     * calls to {@code free} are treated as a no-op.
321     *
322     * @throws SQLException if an error occurs releasing
323     *         the Clob's resources
324     *
325     * @exception SQLFeatureNotSupportedException if the JDBC driver
326     *            does not support this method
327     * @since 1.6
328     */
329    void free() throws SQLException;
330
331    /**
332     * Returns a {@code Reader} object that contains
333     * a partial {@code Clob} value, starting with the character
334     * specified by pos, which is length characters in length.
335     *
336     * @param pos the offset to the first character of the partial value to
337     * be retrieved.  The first character in the Clob is at position 1.
338     * @param length the length in characters of the partial value to be retrieved.
339     * @return {@code Reader} through which
340     *         the partial {@code Clob} value can be read.
341     * @throws SQLException if pos is less than 1;
342     *         or if pos is greater than the number of characters
343     *         in the {@code Clob};
344     *         or if pos + length is greater than the number of
345     *         characters in the {@code Clob}
346     *
347     * @exception SQLFeatureNotSupportedException if the JDBC driver
348     *            does not support this method
349     * @since 1.6
350     */
351    Reader getCharacterStream(long pos, long length) throws SQLException;
352
353}
354