1 /*

     2  * Copyright 1998-2006 Sun Microsystems, Inc.  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.  Sun designates this

     8  * particular file as subject to the "Classpath" exception as provided

     9  * by Sun 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

    18  * 2 along with this work; if not, write to the Free Software Foundation,

    19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    20  *

    21  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

    22  * CA 95054 USA or visit www.sun.com if you need additional information or

    23  * have any questions.

    24  */

    25 

    26 package java.sql;

    27 

    28 import 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 

    58 public 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 }