Known Indirect Subclasses |
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.
Public Method Summary
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 | |
abstract long | |
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 | |
abstract int | |
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 theCLOB
data
Throws
SQLException | if there is an error accessing the
CLOB value |
---|---|
SQLFeatureNotSupportedException | if the JDBC driver does not support this method |
See Also
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 theCLOB
data
Throws
SQLException | if there is an error accessing the
CLOB value |
---|---|
SQLFeatureNotSupportedException | if the JDBC driver does not support this method |
See Also
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 partialClob
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 theCLOB
value designated by thisClob
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 |
See Also
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 |