org.hsqldb.jdbc
Class jdbcClob
- Clob
public final class jdbcClob
extends java.lang.Object
implements Clob
The mapping in the Java
TM programming
language for the SQL CLOB type.
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.
<!-- start Release-specific documentation -->
HSQLDB-Specific Information:
Including 1.8.x, the HSQLDB driver does not implement Clob using an SQL
locator(CLOB). That is, an HSQLDB Clob object does not contain a logical
pointer to SQL CLOB data; rather it directly contains an immutable
representation of the data (a String object). As a result, an HSQLDB
Clob object itself is valid beyond the duration of the transaction in which
is was created, although it does not necessarily represent a corresponding
value on the database.
Currently, the interface methods for updating a CLOB value are
unsupported. However, the truncate method is supported for local use.
<!-- end release-specific documentation -->
jdbcClob(String data) - Constructs a new jdbcClob object wrapping the given character
sequence.
|
java.io.InputStream | getAsciiStream() - Retrieves the
CLOB value designated by this
Clob object as an ascii stream.
|
java.io.Reader | getCharacterStream() - Retrieves the
CLOB value designated by this
Clob object as a java.io.Reader object
(or as a stream of characters).
|
String | getSubString(long pos, int length) - Retrieves a copy of the specified substring in the
CLOB
value designated by this Clob object.
|
long | length() - Retrieves the number of characters in the
CLOB value
designated by this Clob object.
|
long | position(Clob searchstr, long start) - Retrieves the character position at which the specified
Clob object searchstr appears in this
Clob object.
|
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.
|
java.io.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 .
|
java.io.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 .
|
int | setString(long pos, String str) - Writes the given Java
String to the CLOB
value that this Clob object designates at the position
pos .
|
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.
|
void | truncate(long len) - Truncates the
CLOB value that this Clob
designates to have a length of len
characters.
|
jdbcClob
public jdbcClob(String data)
throws SQLException
Constructs a new jdbcClob object wrapping the given character
sequence.
This constructor is used internally to retrieve result set values as
Clob objects, yet it must be public to allow access from other packages.
As such (in the interest of efficiency) this object maintains a reference
to the given String object rather than making a copy and so it is
gently suggested (in the interest of effective memory management) that
extenal clients using this constructor either take pause to consider
the implications or at least take care to provide a String object whose
internal character buffer is not much larger than required to represent
the value.
data
- the character sequence representing the Clob value
getAsciiStream
public java.io.InputStream getAsciiStream()
throws SQLException
Retrieves the CLOB
value designated by this
Clob
object as an ascii stream.
- a
java.io.InputStream
object containing the
CLOB
data
getCharacterStream
public java.io.Reader getCharacterStream()
throws SQLException
Retrieves the CLOB
value designated by this
Clob
object as a java.io.Reader
object
(or as a stream of characters).
- a
java.io.Reader
object containing the
CLOB
data
getSubString
public String getSubString(long pos,
int length)
throws SQLException
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.
<!-- start release-specific documentation -->
HSQLDB-Specific Information:
The official specification above is ambiguous in that it does not
precisely indicate the policy to be observed when
pos > this.length() - length. One policy would be to retrieve the
characters from pos to this.length(). Another would be to throw
an exception. HSQLDB observes the later policy.
<!-- end release-specific documentation -->
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
- a
String
that is the specified substring in
the CLOB
value designated by this
Clob
object
length
public long length()
throws SQLException
Retrieves the number of characters in the CLOB
value
designated by this Clob
object.
- length of the
CLOB
in characters
position
public long position(Clob searchstr,
long start)
throws SQLException
Retrieves the character position at which the specified
Clob
object searchstr
appears in this
Clob
object. The search begins at position
start
.
searchstr
- the Clob
object for which to searchstart
- the position at which to begin searching; the first
position is 1
- the position at which the
Clob
object appears
or -1 if it is not present; the first position is 1
position
public long position(String searchstr,
long start)
throws SQLException
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
.
searchstr
- the substring for which to searchstart
- the position at which to begin searching; the
first position is 1
- the position at which the substring appears or -1 if it is not
present; the first position is 1
setAsciiStream
public java.io.OutputStream setAsciiStream(long pos)
throws SQLException
Retrieves a stream to be used to write Ascii characters to the
CLOB
value that this
Clob
object represents,
starting at position
pos
.
<!-- start release-specific documentation -->
HSQLDB-Specific Information:
HSLQDB 1.7.2 does not support this feature.
Calling this method always throws an
SQLException
.
<!-- end release-specific documentation -->
pos
- the position at which to start writing to this
CLOB
object
- the stream to which ASCII encoded characters can be written
setCharacterStream
public java.io.Writer setCharacterStream(long pos)
throws SQLException
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
.
<!-- start release-specific documentation -->
HSQLDB-Specific Information:
HSLQDB 1.7.2 does not support this feature.
Calling this method always throws an
SQLException
.
<!-- end release-specific documentation -->
pos
- the position at which to start writing to the
CLOB
value
- a stream to which Unicode encoded characters can be written
setString
public int setString(long pos,
String str)
throws SQLException
Writes the given Java
String
to the
CLOB
value that this
Clob
object designates at the position
pos
.
<!-- start release-specific documentation -->
HSQLDB-Specific Information:
HSLQDB 1.7.2 does not support this feature.
Calling this method always throws an
SQLException
.
<!-- end release-specific documentation -->
pos
- the position at which to start writing to the
CLOB
value that this Clob
object
representsstr
- the string to be written to the CLOB
value that this Clob
designates
- the number of characters written
setString
public int setString(long pos,
String str,
int offset,
int len)
throws SQLException
Writes
len
characters of
str
, starting
at character
offset
, to the
CLOB
value
that this
Clob
represents.
<!-- start release-specific documentation -->
HSQLDB-Specific Information:
HSLQDB 1.7.2 does not support this feature.
Calling this method always throws an
SQLException
.
<!-- end release-specific documentation -->
pos
- the position at which to start writing to this
CLOB
objectstr
- the string to be written to the CLOB
value that this Clob
object representsoffset
- the offset into str
to start reading
the characters to be writtenlen
- the number of characters to be written
- the number of characters written
truncate
public void truncate(long len)
throws SQLException
Truncates the
CLOB
value that this
Clob
designates to have a length of
len
characters.
<!-- start release-specific documentation -->
HSQLDB-Specific Information:
This operation affects only the client-side value; it has no effect upon
the value as it is stored in the database.
<!-- end release-specific documentation -->
len
- the length, in bytes, to which the CLOB
value
should be truncated
Copyright B) 2001 - 2005 HSQL Development Group. All Rights Reserved.