org.basex.data

Class MemData

java.lang.Object

org.basex.data.Data

org.basex.data.MemData

public final class MemData
extends Data

This class stores and organizes the database table and the index structures for textual content in a compressed memory structure. The table mapping is documented in Data.

Author:

BaseX Team 2005-12, BSD License, Christian Gruen

Field Summary

Fields inherited from class org.basex.data.Data

atnindex, ATTR, atvindex, COMM, DOC, ELEM, ftxindex, meta, nspaces, paths, PI, pins, resources, tagindex, TEXT, txtindex

Constructor Summary

Constructors

Constructor and Description
MemData(Data data) Light-weight constructor, adopting data structures from the specified database.
MemData(Names tag, Names att, PathSummary ps, Namespaces ns, Prop pr) Constructor.
MemData(Prop pr) Constructor, creating a new, empty database.

Method Summary

Methods

Modifier and Type	Method and Description
void	close() Closes the database.
void	closeIndex(IndexToken.IndexType type) Closes the specified index.
protected void	delete(int pre, boolean text) Deletes the specified text entry.
void	finishUpdate() Finishes an update operation: removes the update file and the exclusive lock.
protected long	index(int pre, int id, byte[] txt, int kind) Indexes a text and returns the reference.
protected void	indexDelete(int pre, int size) Delete a node and its descendants from the corresponding indexes.
void	setIndex(IndexToken.IndexType type, Index index) Assigns the specified index.
boolean	startUpdate() Starts an update operation: writes a file to disk to indicate that an update is going on, and exclusively locks the table.
byte[]	text(int pre, boolean text) Returns a text (text, comment, pi) or attribute value.
double	textDbl(int pre, boolean text) Returns a text (text, comment, pi) or attribute value as double value.
long	textItr(int pre, boolean text) Returns a text (text, comment, pi) or attribute value as integer value.
int	textLen(int pre, boolean text) Returns the byte length of a text (text, comment, pi).
void	updateText(int pre, byte[] val, int kind) Updates the specified text or attribute value.

Methods inherited from class org.basex.data.Data

atom, attr, attSize, attValue, count, delete, doc, elem, id, info, inMemory, insert, insert, insertAttr, isEmpty, iter, kind, name, name, ns, nsFlag, nsFlag, parent, pre, pre, replace, single, size, size, text, toString, update, update, uri

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

MemData

public MemData(Names tag,
       Names att,
       PathSummary ps,
       Namespaces ns,
       Prop pr)

Constructor.

Parameters:

tag - tag index

att - attribute name index

ps - path summary

ns - namespaces

pr - database properties

MemData

public MemData(Data data)

Light-weight constructor, adopting data structures from the specified database.

Parameters:

data - data reference

MemData

public MemData(Prop pr)

Constructor, creating a new, empty database.

Parameters:

pr - property reference

Method Detail

close

public void close()

Description copied from class: Data

Closes the database.

Specified by:

close in class Data

closeIndex

public void closeIndex(IndexToken.IndexType type)

Description copied from class: Data

Closes the specified index.

Specified by:

closeIndex in class Data

Parameters:

type - index to be closed

setIndex

public void setIndex(IndexToken.IndexType type,
            Index index)

Description copied from class: Data

Assigns the specified index.

Specified by:

setIndex in class Data

Parameters:

type - index to be opened

index - index instance

startUpdate

public boolean startUpdate()

Description copied from class: Data

Starts an update operation: writes a file to disk to indicate that an update is going on, and exclusively locks the table.

Specified by:

startUpdate in class Data

Returns:

success flag

finishUpdate

public void finishUpdate()

Description copied from class: Data

Finishes an update operation: removes the update file and the exclusive lock.

Specified by:

finishUpdate in class Data

text

public byte[] text(int pre,
          boolean text)

Description copied from class: Data

Returns a text (text, comment, pi) or attribute value.

Specified by:

text in class Data

Parameters:

pre - pre value

text - text/attribute flag

Returns:

atomized value

textItr

public long textItr(int pre,
           boolean text)

Description copied from class: Data

Returns a text (text, comment, pi) or attribute value as integer value.

Specified by:

textItr in class Data

Parameters:

pre - pre value

text - text/attribute flag

Returns:

numeric value

textDbl

public double textDbl(int pre,
             boolean text)

Description copied from class: Data

Returns a text (text, comment, pi) or attribute value as double value.

Specified by:

textDbl in class Data

Parameters:

pre - pre value

text - text/attribute flag

Returns:

numeric value

textLen

public int textLen(int pre,
          boolean text)

Description copied from class: Data

Returns the byte length of a text (text, comment, pi).

Specified by:

textLen in class Data

Parameters:

pre - pre value

text - text/attribute flag

Returns:

length

delete

protected void delete(int pre,
          boolean text)

Description copied from class: Data

Deletes the specified text entry.

Specified by:

delete in class Data

Parameters:

pre - pre value

text - text (text, comment or pi) or attribute flag

updateText

public void updateText(int pre,
              byte[] val,
              int kind)

Description copied from class: Data

Updates the specified text or attribute value.

Specified by:

updateText in class Data

Parameters:

pre - pre value

val - content

kind - node kind

index

protected long index(int pre,
         int id,
         byte[] txt,
         int kind)

Description copied from class: Data

Indexes a text and returns the reference.

Specified by:

index in class Data

Parameters:

pre - pre value

id - id value

txt - text to be indexed

kind - node kind

Returns:

reference

indexDelete

protected void indexDelete(int pre,
               int size)

Description copied from class: Data

Delete a node and its descendants from the corresponding indexes.

Specified by:

indexDelete in class Data

Parameters:

pre - pre value of the node to delete

size - number of descendants