Clob - JRE Emulation | JRE Emulation
public interface

Clob

java.sql.Clob
Known Indirect Subclasses

Class Overview

The mapping in the JavaTM programming language for the SQL CLOB type. An SQL CLOB 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 Clob object using an SQL locator(CLOB), which means that a Clob object contains a logical pointer to the SQL CLOB data rather than the data itself. A Clob object is valid for the duration of the transaction in which it was created.

The Clob interface provides methods for getting the length of an SQL CLOB (Character Large Object) value, for materializing a CLOB value on the client, and for searching for a substring or CLOB object within a CLOB value. Methods in the interfaces ResultSet, CallableStatement, and PreparedStatement, such as getClob and setClob allow a programmer to access an SQL CLOB value. In addition, this interface has methods for updating a CLOB value.

All methods on the Clob interface must be fully implemented if the JDBC driver supports the data type.

Summary

Public Methods
abstract void free()
This method frees the Clob object and releases the resources the resources that it holds.
abstract InputStream getAsciiStream()
Retrieves the CLOB value designated by this Clob object as an ascii stream.
abstract Reader getCharacterStream()
Retrieves the CLOB value designated by this Clob object as a java.io.Reader object (or as a stream of characters).
abstract Reader getCharacterStream(long pos, long length)
Returns a Reader object that contains a partial Clob value, starting with the character specified by pos, which is length characters in length.
abstract String getSubString(long pos, int length)
Retrieves a copy of the specified substring in the CLOB value designated by this Clob object.
abstract long length()
Retrieves the number of characters in the CLOB value designated by this Clob object.
abstract long position(String searchstr, long start)
Retrieves the character position at which the specified substring searchstr appears in the SQL CLOB value represented by this Clob object.
abstract long position(Clob searchstr, long start)
Retrieves the character position at which the specified Clob object searchstr appears in this Clob object.
abstract OutputStream setAsciiStream(long pos)
Retrieves a stream to be used to write Ascii characters to the CLOB value that this Clob object represents, starting at position pos.
abstract Writer setCharacterStream(long pos)
Retrieves a stream to be used to write a stream of Unicode characters to the CLOB value that this Clob object represents, at position pos.
abstract int setString(long pos, String str, int offset, int len)
Writes len characters of str, starting at character offset, to the CLOB value that this Clob represents.
abstract int setString(long pos, String str)
Writes the given Java String to the CLOB value that this Clob object designates at the position pos.
abstract void truncate(long len)
Truncates the CLOB value that this Clob designates to have a length of len characters.

Public Methods

public abstract void free ()

This method frees the Clob object and releases the resources the resources that it holds. The object is invalid once the free method is called.

After free has been called, any attempt to invoke a method other than free will result in a SQLException being thrown. If free is called multiple times, the subsequent calls to free are treated as a no-op.

Throws
SQLException if an error occurs releasing the Clob's resources
SQLFeatureNotSupportedException if the JDBC driver does not support this method

public abstract InputStream getAsciiStream ()

Retrieves the CLOB value designated by this Clob object as an ascii stream.

Returns
  • a java.io.InputStream object containing the CLOB data
Throws
SQLException if there is an error accessing the CLOB value
SQLFeatureNotSupportedException if the JDBC driver does not support this method

public abstract Reader getCharacterStream ()

Retrieves the CLOB value designated by this Clob object as a java.io.Reader object (or as a stream of characters).

Returns
  • a java.io.Reader object containing the CLOB data
Throws
SQLException if there is an error accessing the CLOB value
SQLFeatureNotSupportedException if the JDBC driver does not support this method

public abstract Reader getCharacterStream (long pos, long length)

Returns a Reader object that contains a partial Clob value, starting with the character specified by pos, which is length characters in length.

Parameters
pos the offset to the first character of the partial value to be retrieved. The first character in the Clob is at position 1.
length the length in characters of the partial value to be retrieved.
Returns
  • Reader through which the partial Clob value can be read.
Throws
SQLException if pos is less than 1 or if pos is greater than the number of characters in the Clob or if pos + length is greater than the number of characters in the Clob
SQLFeatureNotSupportedException if the JDBC driver does not support this method

public abstract String getSubString (long pos, int length)

Retrieves a copy of the specified substring in the CLOB value designated by this Clob object. The substring begins at position pos and has up to length consecutive characters.

Parameters
pos the first character of the substring to be extracted. The first character is at position 1.
length the number of consecutive characters to be copied; the value for length must be 0 or greater
Returns
  • a String that is the specified substring in the CLOB value designated by this Clob object
Throws
SQLException if there is an error accessing the CLOB value; if pos is less than 1 or length is less than 0
SQLFeatureNotSupportedException if the JDBC driver does not support this method

public abstract long length ()

Retrieves the number of characters in the CLOB value designated by this Clob object.

Returns
  • length of the CLOB in characters
Throws
SQLException if there is an error accessing the length of the CLOB value
SQLFeatureNotSupportedException if the JDBC driver does not support this method

public abstract long position (String searchstr, long start)

Retrieves the character position at which the specified substring searchstr appears in the SQL CLOB value represented by this Clob object. The search begins at position start.

Parameters
searchstr the substring for which to search
start the position at which to begin searching; the first position is 1
Returns
  • the position at which the substring appears or -1 if it is not present; the first position is 1
Throws
SQLException if there is an error accessing the CLOB value or if pos is less than 1
SQLFeatureNotSupportedException if the JDBC driver does not support this method

public abstract long position (Clob searchstr, long start)

Retrieves the character position at which the specified Clob object searchstr appears in this Clob object. The search begins at position start.

Parameters
searchstr the Clob object for which to search
start the position at which to begin searching; the first position is 1
Returns
  • the position at which the Clob object appears or -1 if it is not present; the first position is 1
Throws
SQLException if there is an error accessing the CLOB value or if start is less than 1
SQLFeatureNotSupportedException if the JDBC driver does not support this method

public abstract OutputStream setAsciiStream (long pos)

Retrieves a stream to be used to write Ascii characters to the CLOB value that this Clob object represents, starting at position pos. Characters written to the stream will overwrite the existing characters in the Clob object starting at the position pos. If the end of the Clob value is reached while writing characters to the stream, then the length of the Clob value will be increased to accomodate the extra characters.

Note: If the value specified for pos is greater then the length+1 of the CLOB value then the behavior is undefined. Some JDBC drivers may throw a SQLException while other drivers may support this operation.

Parameters
pos the position at which to start writing to this CLOB object; The first position is 1
Returns
  • the stream to which ASCII encoded characters can be written
Throws
SQLException if there is an error accessing the CLOB value or if pos is less than 1
SQLFeatureNotSupportedException if the JDBC driver does not support this method
See Also

public abstract Writer setCharacterStream (long pos)

Retrieves a stream to be used to write a stream of Unicode characters to the CLOB value that this Clob object represents, at position pos. Characters written to the stream will overwrite the existing characters in the Clob object starting at the position pos. If the end of the Clob value is reached while writing characters to the stream, then the length of the Clob value will be increased to accomodate the extra characters.

Note: If the value specified for pos is greater then the length+1 of the CLOB value then the behavior is undefined. Some JDBC drivers may throw a SQLException while other drivers may support this operation.

Parameters
pos the position at which to start writing to the CLOB value; The first position is 1
Returns
  • a stream to which Unicode encoded characters can be written
Throws
SQLException if there is an error accessing the CLOB value or if pos is less than 1
SQLFeatureNotSupportedException if the JDBC driver does not support this method

public abstract int setString (long pos, String str, int offset, int len)

Writes len characters of str, starting at character offset, to the CLOB value that this Clob represents. The string will overwrite the existing characters in the Clob object starting at the position pos. If the end of the Clob value is reached while writing the given string, then the length of the Clob value will be increased to accomodate the extra characters.

Note: If the value specified for pos is greater then the length+1 of the CLOB value then the behavior is undefined. Some JDBC drivers may throw a SQLException while other drivers may support this operation.

Parameters
pos the position at which to start writing to this CLOB object; The first position is 1
str the string to be written to the CLOB value that this Clob object represents
offset the offset into str to start reading the characters to be written
len the number of characters to be written
Returns
  • the number of characters written
Throws
SQLException if there is an error accessing the CLOB value or if pos is less than 1
SQLFeatureNotSupportedException if the JDBC driver does not support this method

public abstract int setString (long pos, String str)

Writes the given Java String to the CLOB value that this Clob object designates at the position pos. The string will overwrite the existing characters in the Clob object starting at the position pos. If the end of the Clob value is reached while writing the given string, then the length of the Clob value will be increased to accomodate the extra characters.

Note: If the value specified for pos is greater then the length+1 of the CLOB value then the behavior is undefined. Some JDBC drivers may throw a SQLException while other drivers may support this operation.

Parameters
pos the position at which to start writing to the CLOB value that this Clob object represents; The first position is 1
str the string to be written to the CLOB value that this Clob designates
Returns
  • the number of characters written
Throws
SQLException if there is an error accessing the CLOB value or if pos is less than 1
SQLFeatureNotSupportedException if the JDBC driver does not support this method

public abstract void truncate (long len)

Truncates the CLOB value that this Clob designates to have a length of len characters.

Note: If the value specified for pos is greater then the length+1 of the CLOB value then the behavior is undefined. Some JDBC drivers may throw a SQLException while other drivers may support this operation.

Parameters
len the length, in characters, to which the CLOB value should be truncated
Throws
SQLException if there is an error accessing the CLOB value or if len is less than 0
SQLFeatureNotSupportedException if the JDBC driver does not support this method