Module java.sql.rowset

Package javax.sql.rowset.serial

Class SerialClob

java.lang.Object

javax.sql.rowset.serial.SerialClob

All Implemented Interfaces:

Serializable, Cloneable, Clob

public class SerialClob
extends Object
implements Clob, Serializable, Cloneable

A serialized mapping in the Java programming language of an SQL CLOB value.

The SerialClob class provides a constructor for creating an instance from a Clob object. Note that the Clob object should have brought the SQL CLOB value's data over to the client before a SerialClob object is constructed from it. The data of an SQL CLOB value can be materialized on the client as a stream of Unicode characters.

SerialClob methods make it possible to get a substring from a SerialClob object or to locate the start of a pattern of characters.

Thread safety

A SerialClob is not safe for use by multiple concurrent threads. If a SerialClob is to be used by more than one thread then access to the SerialClob should be controlled by appropriate synchronization.

Since:

1.5

See Also:

• Serialized Form

Constructor Summary

Constructors

Constructor	Description
SerialClob(char[] ch)	Constructs a SerialClob object that is a serialized version of the given char array.
SerialClob(Clob clob)	Constructs a SerialClob object that is a serialized version of the given Clob object.

Method Summary

Modifier and Type	Method	Description
Object	clone()	Returns a clone of this SerialClob.
boolean	equals(Object obj)	Compares this SerialClob to the specified object.
void	free()	This method frees the SerialClob object and releases the resources that it holds.
InputStream	getAsciiStream()	Retrieves the CLOB value designated by this SerialClob object as an ascii stream.
Reader	getCharacterStream()	Returns this SerialClob object's data as a stream of Unicode characters.
Reader	getCharacterStream(long pos, long length)	Returns a Reader object that contains a partial SerialClob value, starting with the character specified by pos, which is length characters in length.
String	getSubString(long pos, int length)	Returns a copy of the substring contained in this SerialClob object, starting at the given position and continuing for the specified number or characters.
int	hashCode()	Returns a hash code for this SerialClob.
long	length()	Retrieves the number of characters in this SerialClob object's array of characters.
long	position(String searchStr, long start)	Returns the position in this SerialClob object where the given String object begins, starting the search at the specified position.
long	position(Clob searchStr, long start)	Returns the position in this SerialClob object where the given Clob signature begins, starting the search at the specified position.
OutputStream	setAsciiStream(long pos)	Retrieves a stream to be used to write Ascii characters to the CLOB value that this SerialClob 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 SerialClob object represents, at position pos.
int	setString(long pos, String str)	Writes the given Java String to the CLOB value that this SerialClob object represents, at the position pos.
int	setString(long pos, String str, int offset, int length)	Writes len characters of str, starting at character offset, to the CLOB value that this Clob represents.
void	truncate(long length)	Truncates the CLOB value that this SerialClob object represents so that it has a length of len characters.

Methods declared in class java.lang.Object

finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Constructor Details

SerialClob

public SerialClob(char[] ch)
           throws SerialException,
SQLException

Constructs a SerialClob object that is a serialized version of the given char array.

The new SerialClob object is initialized with the data from the char array, thus allowing disconnected RowSet objects to establish a serialized Clob object without touching the data source.

Parameters:

ch - the char array representing the Clob object to be serialized

Throws:

SerialException - if an error occurs during serialization

SQLException - if a SQL error occurs

SerialClob

public SerialClob(Clob clob)
           throws SerialException,
SQLException

Constructs a SerialClob object that is a serialized version of the given Clob object.

The new SerialClob object is initialized with the data from the Clob object; therefore, the Clob object should have previously brought the SQL CLOB value's data over to the client from the database. Otherwise, the new SerialClob object object will contain no data.

Note: The Clob object supplied to this constructor must return non-null for both the Clob.getCharacterStream() and Clob.getAsciiStream methods. This SerialClob constructor cannot serialize a Clob object in this instance and will throw an SQLException object.

Parameters:

clob - the Clob object from which this SerialClob object is to be constructed; cannot be null

Throws:

SerialException - if an error occurs during serialization

SQLException - if a SQL error occurs in capturing the CLOB; if the Clob object is a null; or if either of the Clob.getCharacterStream() and Clob.getAsciiStream() methods on the Clob returns a null

See Also:

• Clob

Method Details

length

public long length()
            throws SerialException

Retrieves the number of characters in this SerialClob object's array of characters.

Specified by:

length in interface Clob

Returns:

a long indicating the length in characters of this SerialClob object's array of character

Throws:

SerialException - if an error occurs; if free had previously been called on this object

getCharacterStream

public Reader getCharacterStream()
                          throws SerialException

Returns this SerialClob object's data as a stream of Unicode characters. Unlike the related method, getAsciiStream, a stream is produced regardless of whether the SerialClob object was created with a Clob object or a char array.

Specified by:

getCharacterStream in interface Clob

Returns:

a java.io.Reader object containing this SerialClob object's data

Throws:

SerialException - if an error occurs; if free had previously been called on this object

See Also:

• Clob.setCharacterStream(long)

getAsciiStream

public InputStream getAsciiStream()
                           throws SerialException,
SQLException

Retrieves the CLOB value designated by this SerialClob object as an ascii stream. This method forwards the getAsciiStream call to the underlying Clob object in the event that this SerialClob object is instantiated with a Clob object. If this SerialClob object is instantiated with a char array, a SerialException object is thrown.

Specified by:

getAsciiStream in interface Clob

Returns:

a java.io.InputStream object containing this SerialClob object's data

Throws:

SerialException - if this SerialClob object was not instantiated with a Clob object; if free had previously been called on this object

SQLException - if there is an error accessing the CLOB value represented by the Clob object that was used to create this SerialClob object

See Also:

• Clob.setAsciiStream(long)

getSubString

public String getSubString(long pos,
 int length)
                    throws SerialException

Returns a copy of the substring contained in this SerialClob object, starting at the given position and continuing for the specified number or characters.

Specified by:

getSubString in interface Clob

Parameters:

pos - the position of the first character in the substring to be copied; the first character of the SerialClob object is at position 1; must not be less than 1, and the sum of the starting position and the length of the substring must be less than the length of this SerialClob object

length - the number of characters in the substring to be returned; must not be greater than the length of this SerialClob object, and the sum of the starting position and the length of the substring must be less than the length of this SerialClob object

Returns:

a String object containing a substring of this SerialClob object beginning at the given position and containing the specified number of consecutive characters

Throws:

SerialException - if either of the arguments is out of bounds; if free had previously been called on this object

position

public long position(String searchStr,
 long start)
              throws SerialException,
SQLException

Returns the position in this SerialClob object where the given String object begins, starting the search at the specified position. This method returns -1 if the pattern is not found.

Specified by:

position in interface Clob

Parameters:

searchStr - the String object for which to search

start - the position in this SerialClob object at which to start the search; the first position is 1; must not be less than 1 nor greater than the length of this SerialClob object

Returns:

the position at which the given String object begins, starting the search at the specified position; -1 if the given String object is not found or the starting position is out of bounds; position numbering for the return value starts at 1

Throws:

SerialException - if the free method had been previously called on this object

SQLException - if there is an error accessing the Clob value from the database.

position

public long position(Clob searchStr,
 long start)
              throws SerialException,
SQLException

Returns the position in this SerialClob object where the given Clob signature begins, starting the search at the specified position. This method returns -1 if the pattern is not found.

Specified by:

position in interface Clob

Parameters:

searchStr - the Clob object for which to search

start - the position in this SerialClob object at which to begin the search; the first position is 1; must not be less than 1 nor greater than the length of this SerialClob object

Returns:

the position at which the given Clob object begins in this SerialClob object, at or after the specified starting position

Throws:

SerialException - if an error occurs locating the Clob signature; if the free method had been previously called on this object

SQLException - if there is an error accessing the Clob value from the database

setString

public int setString(long pos,
 String str)
              throws SerialException

Writes the given Java String to the CLOB value that this SerialClob object represents, at the position pos.

Specified by:

setString in interface Clob

Parameters:

pos - the position at which to start writing to the CLOB value that this SerialClob object represents; the first position is 1; must not be less than 1 nor greater than the length+1 of this SerialClob object

str - the string to be written to the CLOB value that this SerialClob object represents

Returns:

the number of characters written

Throws:

SerialException - if there is an error accessing the CLOB value; if an invalid position is set; if the free method had been previously called on this object

setString

public int setString(long pos,
 String str,
 int offset,
 int length)
              throws SerialException

Writes len characters of str, starting at character offset, to the CLOB value that this Clob represents.

Specified by:

setString in interface Clob

Parameters:

pos - the position at which to start writing to the CLOB value that this SerialClob object represents; the first position is 1; must not be less than 1 nor greater than the length+1 of this SerialClob object

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

length - the number of characters to be written

Returns:

the number of characters written

Throws:

SerialException - if there is an error accessing the CLOB value; if an invalid position is set; if an invalid offset value is set; or the combined values of the length and offset is greater than the length of str; if the free method had been previously called on this object

setAsciiStream

public OutputStream setAsciiStream(long pos)
                            throws SerialException,
SQLException

Retrieves a stream to be used to write Ascii characters to the CLOB value that this SerialClob object represents, starting at position pos. This method forwards the setAsciiStream() call to the underlying Clob object in the event that this SerialClob object is instantiated with a Clob object. If this SerialClob object is instantiated with a char array, a SerialException object is thrown.

Specified by:

setAsciiStream in interface Clob

Parameters:

pos - the position at which to start writing to the CLOB object

Returns:

the stream to which ASCII encoded characters can be written

Throws:

SerialException - if SerialClob is not instantiated with a Clob object; if the free method had been previously called on this object

SQLException - if there is an error accessing the CLOB value

See Also:

• getAsciiStream()

setCharacterStream

public Writer setCharacterStream(long pos)
                          throws SerialException,
SQLException

Retrieves a stream to be used to write a stream of Unicode characters to the CLOB value that this SerialClob object represents, at position pos. This method forwards the setCharacterStream() call to the underlying Clob object in the event that this SerialClob object is instantiated with a Clob object. If this SerialClob object is instantiated with a char array, a SerialException is thrown.

Specified by:

setCharacterStream in interface Clob

Parameters:

pos - the position at which to start writing to the CLOB value

Returns:

a stream to which Unicode encoded characters can be written

Throws:

SerialException - if the SerialClob is not instantiated with a Clob object; if the free method had been previously called on this object

SQLException - if there is an error accessing the CLOB value

See Also:

• getCharacterStream()

truncate

public void truncate(long length)
              throws SerialException

Truncates the CLOB value that this SerialClob object represents so that it has a length of len characters.

Truncating a SerialClob object to length 0 has the effect of clearing its contents.

Specified by:

truncate in interface Clob

Parameters:

length - the length, in bytes, to which the CLOB value should be truncated

Throws:

SerialException - if there is an error accessing the CLOB value; if the free method had been previously called on this object

getCharacterStream

public Reader getCharacterStream(long pos,
 long length)
                          throws SQLException

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

Specified by:

getCharacterStream in interface Clob

Parameters:

pos - the offset to the first character of the partial value to be retrieved. The first character in the SerialClob is at position 1.

length - the length in characters of the partial value to be retrieved.

Returns:

Reader through which the partial SerialClob value can be read.

Throws:

SQLException - if pos is less than 1 or if pos is greater than the number of characters in the SerialClob or if pos + length is greater than the number of characters in the SerialClob;

SerialException - if the free method had been previously called on this object

Since:

1.6

free

public void free()
          throws SQLException

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

If free is called multiple times, the subsequent calls to free are treated as a no-op.

Specified by:

free in interface Clob

Throws:

SQLException - if an error occurs releasing the Clob's resources

Since:

1.6

equals

public boolean equals(Object obj)

Compares this SerialClob to the specified object. The result is true if and only if the argument is not null and is a SerialClob object that represents the same sequence of characters as this object.

Overrides:

equals in class Object

Parameters:

obj - The object to compare this SerialClob against

Returns:

true if the given object represents a SerialClob equivalent to this SerialClob, false otherwise

See Also:

• Object.hashCode()
• HashMap

hashCode

public int hashCode()

Returns a hash code for this SerialClob.

Overrides:

hashCode in class Object

Returns:

a hash code value for this object.

See Also:

• Object.equals(java.lang.Object)
• System.identityHashCode(java.lang.Object)

clone

public Object clone()

Returns a clone of this SerialClob. The copy will contain a reference to a clone of the internal character array, not a reference to the original internal character array of this SerialClob object. The underlying Clob object will be set to null.

Overrides:

clone in class Object

Returns:

a clone of this SerialClob

See Also:

• Cloneable