com.prosyst.mbs.services.db
Interface DBNode

public interface DBNode

This is an object-oriented representation of a node in the DB.

Author:

Svetozar Dimov

Method Summary

void	delete() Deletes the current node
void	deleteAllBefore() Deletes all parent nodes.
DBNode	firstChild() Retrieves the first child node of the current one
java.lang.String	getName() Retrieves the name of the node
byte	getType() Retrieves the type of the node
java.lang.Object	getValue() Retrieves the value of the node
int	getValue(byte[] bytes, int offset, int length) Reads length bytes from the value, associated with the current node and writes them at off position in the byteArray.
void	getValue(com.prosyst.util.io.Externalizable e) Reads the value of the node into an Externalizable object.
boolean	isValid() Checks if the node is valid.
DBNode	next() Retrieves the next node in the tree at the same level as the current one.
DBNode	parent() Retrieves the parent node.

Method Detail

getName

java.lang.String getName()
                         throws java.io.IOException

Retrieves the name of the node

Returns:

the node name

Throws:

java.io.IOException

next

DBNode next()
            throws java.io.IOException

Retrieves the next node in the tree at the same level as the current one.

Returns:

the next node

Throws:

java.io.IOException

firstChild

DBNode firstChild()
                  throws java.io.IOException

Retrieves the first child node of the current one

Returns:

the first child node

Throws:

java.io.IOException

parent

DBNode parent()
              throws java.io.IOException

Retrieves the parent node.

Returns:

the parent node

Throws:

java.io.IOException

getValue

java.lang.Object getValue()
                          throws java.io.IOException

Retrieves the value of the node

Returns:

The object associated with the node or null if there is no such node, or the node's type DB.EMPTY.

Throws:

java.io.IOException - on I/O error

java.lang.IllegalArgumentException - if the node is of type DB.EXTERN

See Also:

DB.getValue(String[])

getValue

void getValue(com.prosyst.util.io.Externalizable e)
              throws java.io.IOException

Reads the value of the node into an Externalizable object.

Parameters:

e - an empty Externalizable instance, whose data will be filled in by the DB, if it has properly implemented its Externalizable.readObject(java.io.InputStream) method.

Throws:

java.io.IOException

java.lang.IllegalArgumentException - if the node is of type DB.EMPTY

See Also:

DB.getValue(String[], Externalizable)

getValue

int getValue(byte[] bytes,
             int offset,
             int length)
             throws java.io.IOException

Reads length bytes from the value, associated with the current node and writes them at off position in the byteArray.

Parameters:

bytes - where data is read to

offset - start position to write in byteArray

length - count of bytes to read

Returns:

number of bytes read, or -1 if the node's type is DB.EMPTY or there is no such node

Throws:

java.io.IOException - If an IO error occurs.

java.lang.IndexOutOfBoundsException - If length is not valid for the supplied byteArray and length

See Also:

DB.getValue(String[], byte[], int, int)

getType

byte getType()
             throws java.io.IOException

Retrieves the type of the node

Returns:

the node type

Throws:

java.io.IOException - on I/O error

See Also:

DB.getType(String[])

delete

void delete()
            throws java.io.IOException

Deletes the current node

Throws:

java.io.IOException - on I/O error

See Also:

DB.delete(String[])

deleteAllBefore

void deleteAllBefore()
                     throws java.io.IOException

Deletes all parent nodes.

Throws:

java.io.IOException - on I/O error

isValid

boolean isValid()
                throws java.io.IOException

Checks if the node is valid. A valid node is one,that belong to open Database, exists and is not marked for deletion.

Returns:

true if the node is valid

Throws:

java.io.IOException