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java.lang.Object org.hsqldb.jdbc.jdbcClob
The mapping in the JavaTM 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.
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.
Constructor Summary | |
jdbcClob(java.lang.String data)
Constructs a new jdbcClob object wrapping the given character sequence. |
Method Summary | |
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). |
java.lang.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(java.sql.Clob searchstr,
long start)
Retrieves the character position at which the specified Clob object searchstr appears in this
Clob object. |
long |
position(java.lang.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,
java.lang.String str)
Writes the given Java String to the CLOB
value that this Clob object designates at the position
pos . |
int |
setString(long pos,
java.lang.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. |
Methods inherited from class java.lang.Object |
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
public jdbcClob(java.lang.String data) throws java.sql.SQLException
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
java.sql.SQLException
- if the argument is nullMethod Detail |
public long length() throws java.sql.SQLException
CLOB
value
designated by this Clob
object.
length
in interface java.sql.Clob
CLOB
in characters
java.sql.SQLException
- if there is an error accessing the
length of the CLOB
valuepublic java.lang.String getSubString(long pos, int length) throws java.sql.SQLException
CLOB
value designated by this Clob
object. The substring begins
at position pos
and has up to length
consecutive characters.
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.
getSubString
in interface java.sql.Clob
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
String
that is the specified substring in
the CLOB
value designated by this
Clob
object
java.sql.SQLException
- if there is an error accessing the
CLOB
valuepublic java.io.Reader getCharacterStream() throws java.sql.SQLException
CLOB
value designated by this
Clob
object as a java.io.Reader
object
(or as a stream of characters).
getCharacterStream
in interface java.sql.Clob
java.io.Reader
object containing the
CLOB
data
java.sql.SQLException
- if there is an error accessing the
CLOB
valuesetCharacterStream(long)
public java.io.InputStream getAsciiStream() throws java.sql.SQLException
CLOB
value designated by this
Clob
object as an ascii stream.
getAsciiStream
in interface java.sql.Clob
java.io.InputStream
object containing the
CLOB
data
java.sql.SQLException
- if there is an error accessing the
CLOB
valuesetAsciiStream(long)
public long position(java.lang.String searchstr, long start) throws java.sql.SQLException
searchstr
appears in the SQL CLOB
value
represented by this Clob
object. The search
begins at position start
.
position
in interface java.sql.Clob
searchstr
- the substring for which to searchstart
- the position at which to begin searching; the
first position is 1
java.sql.SQLException
- if there is an error accessing the
CLOB
valuepublic long position(java.sql.Clob searchstr, long start) throws java.sql.SQLException
Clob
object searchstr
appears in this
Clob
object. The search begins at position
start
.
position
in interface java.sql.Clob
searchstr
- the Clob
object for which to searchstart
- the position at which to begin searching; the first
position is 1
Clob
object appears
or -1 if it is not present; the first position is 1
java.sql.SQLException
- if there is an error accessing the
CLOB
valuepublic int setString(long pos, java.lang.String str) throws java.sql.SQLException
String
to the CLOB
value that this Clob
object designates at the position
pos
.
HSLQDB 1.7.2 does not support this feature.
Calling this method always throws an SQLException
.
setString
in interface java.sql.Clob
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
java.sql.SQLException
- if there is an error accessing the
CLOB
valuepublic int setString(long pos, java.lang.String str, int offset, int len) throws java.sql.SQLException
len
characters of str
, starting
at character offset
, to the CLOB
value
that this Clob
represents.
HSLQDB 1.7.2 does not support this feature.
Calling this method always throws an SQLException
.
setString
in interface java.sql.Clob
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
java.sql.SQLException
- if there is an error accessing the
CLOB
valuepublic java.io.OutputStream setAsciiStream(long pos) throws java.sql.SQLException
CLOB
value that this Clob
object represents,
starting at position pos
.
HSLQDB 1.7.2 does not support this feature.
Calling this method always throws an SQLException
.
setAsciiStream
in interface java.sql.Clob
pos
- the position at which to start writing to this
CLOB
object
java.sql.SQLException
- if there is an error accessing the
CLOB
valuegetAsciiStream()
public java.io.Writer setCharacterStream(long pos) throws java.sql.SQLException
CLOB
value that this Clob
object
represents, at position pos
.
HSLQDB 1.7.2 does not support this feature.
Calling this method always throws an SQLException
.
setCharacterStream
in interface java.sql.Clob
pos
- the position at which to start writing to the
CLOB
value
java.sql.SQLException
- if there is an error accessing the
CLOB
valuegetCharacterStream()
public void truncate(long len) throws java.sql.SQLException
CLOB
value that this Clob
designates to have a length of len
characters.
This operation affects only the client-side value; it has no effect upon the value as it is stored in the database.
truncate
in interface java.sql.Clob
len
- the length, in bytes, to which the CLOB
value
should be truncated
java.sql.SQLException
- if there is an error accessing the
CLOB
value
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