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package java.sql;

import java.io.Reader;

/**
 * The mapping in the Java™ programming language
 * for the SQL <code>CLOB</code> type.
 * An SQL <code>CLOB</code> is a built-in type
 * that stores a Character Large Object as a column value in a row of
 * a database table.
 * By default drivers implement a <code>Clob</code> object using an SQL
 * <code>locator(CLOB)</code>, which means that a <code>Clob</code> object
 * contains a logical pointer to the SQL <code>CLOB</code> data rather than
 * the data itself. A <code>Clob</code> object is valid for the duration
 * of the transaction in which it was created.
 * <P>The <code>Clob</code> interface provides methods for getting the
 * length of an SQL <code>CLOB</code> (Character Large Object) value,
 * for materializing a <code>CLOB</code> value on the client, and for
 * searching for a substring or <code>CLOB</code> object within a
 * <code>CLOB</code> value.
 * Methods in the interfaces {@link ResultSet},
 * {@link CallableStatement}, and {@link PreparedStatement}, such as
 * <code>getClob</code> and <code>setClob</code> allow a programmer to
 * access an SQL <code>CLOB</code> value. In addition, this interface
 * has methods for updating a <code>CLOB</code> value.
 * <p>
 * All methods on the <code>Clob</code> interface must be fully implemented if the
 * JDBC driver supports the data type.
 *
 * @since 1.2
 */

public interface Clob {

 /**
 * Retrieves the number of characters
 * in the <code>CLOB</code> value
 * designated by this <code>Clob</code> object.
 *
 * @return length of the <code>CLOB</code> in characters
 * @exception SQLException if there is an error accessing the
 * length of the <code>CLOB</code> value
 * @exception SQLFeatureNotSupportedException if the JDBC driver does not support
 * this method
 * @since 1.2
 */
 long length() throws SQLException;

 /**
 * Retrieves a copy of the specified substring
 * in the <code>CLOB</code> value
 * designated by this <code>Clob</code> object.
 * The substring begins at position
 * <code>pos</code> and has up to <code>length</code> consecutive
 * characters.
 *
 * @param pos the first character of the substring to be extracted.
 * The first character is at position 1.
 * @param length the number of consecutive characters to be copied;
 * the value for length must be 0 or greater
 * @return a <code>String</code> that is the specified substring in
 * the <code>CLOB</code> value designated by this <code>Clob</code> object
 * @exception SQLException if there is an error accessing the
 * <code>CLOB</code> value; if pos is less than 1 or length is
 * less than 0
 * @exception SQLFeatureNotSupportedException if the JDBC driver does not support
 * this method
 * @since 1.2
 */
 String getSubString(long pos, int length) throws SQLException;

 /**
 * Retrieves the <code>CLOB</code> value designated by this <code>Clob</code>
 * object as a <code>java.io.Reader</code> object (or as a stream of
 * characters).
 *
 * @return a <code>java.io.Reader</code> object containing the
 * <code>CLOB</code> data
 * @exception SQLException if there is an error accessing the
 * <code>CLOB</code> value
 * @exception SQLFeatureNotSupportedException if the JDBC driver does not support
 * this method
 * @see #setCharacterStream
 * @since 1.2
 */
 java.io.Reader getCharacterStream() throws SQLException;

 /**
 * Retrieves the <code>CLOB</code> value designated by this <code>Clob</code>
 * object as an ascii stream.
 *
 * @return a <code>java.io.InputStream</code> object containing the
 * <code>CLOB</code> data
 * @exception SQLException if there is an error accessing the
 * <code>CLOB</code> value
 * @exception SQLFeatureNotSupportedException if the JDBC driver does not support
 * this method
 * @see #setAsciiStream
 * @since 1.2
 */
 java.io.InputStream getAsciiStream() throws SQLException;

 /**
 * Retrieves the character position at which the specified substring
 * <code>searchstr</code> appears in the SQL <code>CLOB</code> value
 * represented by this <code>Clob</code> object. The search
 * begins at position <code>start</code>.
 *
 * @param searchstr the substring for which to search
 * @param start the position at which to begin searching; the first position
 * is 1
 * @return the position at which the substring appears or -1 if it is not
 * present; the first position is 1
 * @exception SQLException if there is an error accessing the
 * <code>CLOB</code> value or if pos is less than 1
 * @exception SQLFeatureNotSupportedException if the JDBC driver does not support
 * this method
 * @since 1.2
 */
 long position(String searchstr, long start) throws SQLException;

 /**
 * Retrieves the character position at which the specified
 * <code>Clob</code> object <code>searchstr</code> appears in this
 * <code>Clob</code> object. The search begins at position
 * <code>start</code>.
 *
 * @param searchstr the <code>Clob</code> object for which to search
 * @param start the position at which to begin searching; the first
 * position is 1
 * @return the position at which the <code>Clob</code> object appears
 * or -1 if it is not present; the first position is 1
 * @exception SQLException if there is an error accessing the
 * <code>CLOB</code> value or if start is less than 1
 * @exception SQLFeatureNotSupportedException if the JDBC driver does not support
 * this method
 * @since 1.2
 */
 long position(Clob searchstr, long start) throws SQLException;

 //---------------------------- jdbc 3.0 -----------------------------------

 /**
 * Writes the given Java <code>String</code> to the <code>CLOB</code>
 * value that this <code>Clob</code> object designates at the position
 * <code>pos</code>. The string will overwrite the existing characters
 * in the <code>Clob</code> object starting at the position
 * <code>pos</code>. If the end of the <code>Clob</code> value is reached
 * while writing the given string, then the length of the <code>Clob</code>
 * value will be increased to accommodate the extra characters.
 * <p>
 * <b>Note:</b> If the value specified for <code>pos</code>
 * is greater then the length+1 of the <code>CLOB</code> value then the
 * behavior is undefined. Some JDBC drivers may throw a
 * <code>SQLException</code> while other drivers may support this
 * operation.
 *
 * @param pos the position at which to start writing to the <code>CLOB</code>
 * value that this <code>Clob</code> object represents;
 * The first position is 1
 * @param str the string to be written to the <code>CLOB</code>
 * value that this <code>Clob</code> designates
 * @return the number of characters written
 * @exception SQLException if there is an error accessing the
 * <code>CLOB</code> value or if pos is less than 1
 *
 * @exception SQLFeatureNotSupportedException if the JDBC driver does not support
 * this method
 * @since 1.4
 */
 int setString(long pos, String str) throws SQLException;

 /**
 * Writes <code>len</code> characters of <code>str</code>, starting
 * at character <code>offset</code>, to the <code>CLOB</code> value
 * that this <code>Clob</code> represents. The string will overwrite the existing characters
 * in the <code>Clob</code> object starting at the position
 * <code>pos</code>. If the end of the <code>Clob</code> value is reached
 * while writing the given string, then the length of the <code>Clob</code>
 * value will be increased to accommodate the extra characters.
 * <p>
 * <b>Note:</b> If the value specified for <code>pos</code>
 * is greater then the length+1 of the <code>CLOB</code> value then the
 * behavior is undefined. Some JDBC drivers may throw a
 * <code>SQLException</code> while other drivers may support this
 * operation.
 *
 * @param pos the position at which to start writing to this
 * <code>CLOB</code> object; The first position is 1
 * @param str the string to be written to the <code>CLOB</code>
 * value that this <code>Clob</code> object represents
 * @param offset the offset into <code>str</code> to start reading
 * the characters to be written
 * @param len the number of characters to be written
 * @return the number of characters written
 * @exception SQLException if there is an error accessing the
 * <code>CLOB</code> value or if pos is less than 1
 *
 * @exception SQLFeatureNotSupportedException if the JDBC driver does not support
 * this method
 * @since 1.4
 */
 int setString(long pos, String str, int offset, int len) throws SQLException;

 /**
 * Retrieves a stream to be used to write Ascii characters to the
 * <code>CLOB</code> value that this <code>Clob</code> object represents,
 * starting at position <code>pos</code>. Characters written to the stream
 * will overwrite the existing characters
 * in the <code>Clob</code> object starting at the position
 * <code>pos</code>. If the end of the <code>Clob</code> value is reached
 * while writing characters to the stream, then the length of the <code>Clob</code>
 * value will be increased to accommodate the extra characters.
 * <p>
 * <b>Note:</b> If the value specified for <code>pos</code>
 * is greater then the length+1 of the <code>CLOB</code> value then the
 * behavior is undefined. Some JDBC drivers may throw a
 * <code>SQLException</code> while other drivers may support this
 * operation.
 *
 * @param pos the position at which to start writing to this
 * <code>CLOB</code> object; The first position is 1
 * @return the stream to which ASCII encoded characters can be written
 * @exception SQLException if there is an error accessing the
 * <code>CLOB</code> value or if pos is less than 1
 * @exception SQLFeatureNotSupportedException if the JDBC driver does not support
 * this method
 * @see #getAsciiStream
 *
 * @since 1.4
 */
 java.io.OutputStream setAsciiStream(long pos) throws SQLException;

 /**
 * Retrieves a stream to be used to write a stream of Unicode characters
 * to the <code>CLOB</code> value that this <code>Clob</code> object
 * represents, at position <code>pos</code>. Characters written to the stream
 * will overwrite the existing characters
 * in the <code>Clob</code> object starting at the position
 * <code>pos</code>. If the end of the <code>Clob</code> value is reached
 * while writing characters to the stream, then the length of the <code>Clob</code>
 * value will be increased to accommodate the extra characters.
 * <p>
 * <b>Note:</b> If the value specified for <code>pos</code>
 * is greater then the length+1 of the <code>CLOB</code> value then the
 * behavior is undefined. Some JDBC drivers may throw a
 * <code>SQLException</code> while other drivers may support this
 * operation.
 *
 * @param pos the position at which to start writing to the
 * <code>CLOB</code> value; The first position is 1
 *
 * @return a stream to which Unicode encoded characters can be written
 * @exception SQLException if there is an error accessing the
 * <code>CLOB</code> value or if pos is less than 1
 * @exception SQLFeatureNotSupportedException if the JDBC driver does not support
 * this method
 * @see #getCharacterStream
 *
 * @since 1.4
 */
 java.io.Writer setCharacterStream(long pos) throws SQLException;

 /**
 * Truncates the <code>CLOB</code> value that this <code>Clob</code>
 * designates to have a length of <code>len</code>
 * characters.
 * <p>
 * <b>Note:</b> If the value specified for <code>pos</code>
 * is greater then the length+1 of the <code>CLOB</code> value then the
 * behavior is undefined. Some JDBC drivers may throw a
 * <code>SQLException</code> while other drivers may support this
 * operation.
 *
 * @param len the length, in characters, to which the <code>CLOB</code> value
 * should be truncated
 * @exception SQLException if there is an error accessing the
 * <code>CLOB</code> 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>Clob</code> object and releases the resources the resources
 * that it holds. The object is invalid once the <code>free</code> method
 * is called.
 * <p>
 * After <code>free</code> has been called, any attempt to invoke a
 * method other than <code>free</code> will result in a <code>SQLException</code>
 * being thrown. If <code>free</code> is called multiple times, the subsequent
 * calls to <code>free</code> are treated as a no-op.
 * <p>
 * @throws SQLException if an error occurs releasing
 * the Clob's resources
 *
 * @exception SQLFeatureNotSupportedException if the JDBC driver does not support
 * this method
 * @since 1.6
 */
 void free() throws SQLException;

 /**
 * Returns a <code>Reader</code> object that contains a partial <code>Clob</code> value, starting
 * with the character specified by pos, which is length characters in length.
 *
 * @param pos the offset to the first character of the partial value to
 * be retrieved. The first character in the Clob is at position 1.
 * @param length the length in characters of the partial value to be retrieved.
 * @return <code>Reader</code> through which the partial <code>Clob</code> value can be read.
 * @throws SQLException if pos is less than 1 or if pos is greater than the number of
 * characters in the <code>Clob</code> or if pos + length is greater than the number of
 * characters in the <code>Clob</code>
 *
 * @exception SQLFeatureNotSupportedException if the JDBC driver does not support
 * this method
 * @since 1.6
 */
 Reader getCharacterStream(long pos, long length) throws SQLException;

}