org.apache.cayenne.util
Class MemoryClob

java.lang.Object
  extended by org.apache.cayenne.util.MemoryClob
All Implemented Interfaces:
Clob

public class MemoryClob
extends Object
implements Clob

A Clob implementation that stores contents in memory.

This implementation is based on jdbcClob from HSQLDB (copyright HSQL Development Group).

Since:
1.2

Constructor Summary
MemoryClob(String data)
          Constructs a new jdbcClob object wrapping the given character sequence.
 
Method Summary
 void free()
           
 InputStream getAsciiStream()
          Retrieves the CLOB value designated by this Clob object as an ascii stream.
 Reader getCharacterStream()
          Retrieves the CLOB value designated by this Clob object as a java.io.Reader object (or as a stream of characters).
 Reader getCharacterStream(long pos, long length)
           
 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.
 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.
 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.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

MemoryClob

public MemoryClob(String data)
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.

Parameters:
data - the character sequence representing the Clob value
Throws:
SQLException - if the argument is null
Method Detail

length

public long length()
            throws SQLException
Retrieves the number of characters in the CLOB value designated by this Clob object.

Specified by:
length in interface Clob
Returns:
length of the CLOB in characters
Throws:
SQLException - if there is an error accessing the length of the CLOB value

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.

Specified by:
getSubString in interface Clob
Throws:
SQLException

getCharacterStream

public 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).

Specified by:
getCharacterStream in interface Clob
Returns:
a java.io.Reader object containing the CLOB data
Throws:
SQLException - if there is an error accessing the CLOB value

getAsciiStream

public InputStream getAsciiStream()
                           throws SQLException
Retrieves the CLOB value designated by this Clob object as an ascii stream.

Specified by:
getAsciiStream in interface Clob
Returns:
a java.io.InputStream object containing the CLOB data
Throws:
SQLException - if there is an error accessing the CLOB value

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.

Specified by:
position in interface Clob
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

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.

Specified by:
position in interface Clob
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

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. Calling this method always throws an SQLException.

Specified by:
setString in interface Clob
Throws:
SQLException

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. Calling this method always throws an SQLException.

Specified by:
setString in interface Clob
Throws:
SQLException

setAsciiStream

public 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.

Calling this method always throws an SQLException.

Specified by:
setAsciiStream in interface Clob
Throws:
SQLException

setCharacterStream

public 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.

Calling this method always throws an SQLException.

Specified by:
setCharacterStream in interface Clob
Throws:
SQLException

truncate

public void truncate(long len)
              throws SQLException
Truncates the CLOB value that this Clob designates to have a length of len characters.

Specified by:
truncate in interface Clob
Throws:
SQLException

free

public void free()
          throws SQLException
Specified by:
free in interface Clob
Throws:
SQLException
Since:
3.0

getCharacterStream

public Reader getCharacterStream(long pos,
                                 long length)
                          throws SQLException
Specified by:
getCharacterStream in interface Clob
Throws:
SQLException
Since:
3.0


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