Package 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 2005-21, BSD License, Christian Gruen

Field Summary

Fields inherited from class org.basex.data.Data

ATTR, attrIndex, attrNames, closed, COMM, dbid, DOC, ELEM, elemNames, ftIndex, idmap, meta, nspaces, paths, PI, resources, table, TEXT, textIndex, tokenIndex, updateDists

Constructor Summary

Constructors

Constructor	Description
MemData(MainOptions opts)	Constructor for creating a new, empty database.
MemData(PathIndex paths, Namespaces nspaces, MainOptions opts)	Constructor.

Method Summary

Modifier and Type	Method	Description
void	createIndex(IndexType type, Command cmd)	Drops the specified index.
protected void	delete(int pre, boolean text)	Deletes the specified text entry.
void	dropIndex(IndexType type)	Drops the specified index.
void	finishUpdate(MainOptions opts)	Finishes an update operation: removes the update file and the exclusive lock.
void	flush(boolean all)	Flushes updated data.
boolean	inMemory()	Indicates if this data instance is in main memory or on disk.
void	startUpdate(MainOptions opts)	Starts an update operation: writes a file to disk to indicate that an update is going on, and exclusively locks the table file.
byte[]	text(int pre, boolean text)	Returns a text (text, comment, pi, document) or attribute value.
double	textDbl(int pre, boolean text)	Returns a text (text, comment, pi, document) or attribute value as double value.
long	textItr(int pre, boolean text)	Returns a text (text, comment, pi, document) or attribute value as integer value.
int	textLen(int pre, boolean text)	Returns the byte length of a (possibly compressed) text (text, comment, pi, document).
protected long	textRef(byte[] value, boolean text)	Generates a reference for a text (text, comment, pi, pi, document) or attribute value.
protected void	updateText(int pre, byte[] value, int kind)	Updates the specified text or attribute value.
TokenSet	values(boolean text)	Returns the string values of the database.

Methods inherited from class org.basex.data.Data

atom, attr, attSize, attValue, close, closed, costs, defaultNs, delete, dist, dist, doc, elem, id, id, index, indexAdd, indexDelete, info, insert, insert, insertAttr, iter, kind, name, nameId, namespaces, nsFlag, nsFlag, parent, pre, qname, replace, size, size, text, textRef, textRef, toString, update, update, uriId

Methods inherited from class java.lang.Object

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

Constructor Details

MemData

public MemData(PathIndex paths,
 Namespaces nspaces,
 MainOptions opts)

Constructor.

Parameters:

paths - path index

nspaces - namespaces

opts - database options

MemData

public MemData(MainOptions opts)

Constructor for creating a new, empty database.

Parameters:

opts - database options

Method Details

createIndex

public void createIndex(IndexType type,
 Command cmd)
                 throws IOException

Description copied from class: Data

Drops the specified index.

Specified by:

createIndex in class Data

Parameters:

type - index to be dropped

cmd - calling command

Throws:

IOException - I/O exception

dropIndex

public void dropIndex(IndexType type)
               throws BaseXException

Description copied from class: Data

Drops the specified index.

Specified by:

dropIndex in class Data

Parameters:

type - index to be dropped

Throws:

BaseXException - database exception

startUpdate

public void startUpdate(MainOptions opts)

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 file.

Specified by:

startUpdate in class Data

Parameters:

opts - main options

finishUpdate

public void finishUpdate(MainOptions opts)

Description copied from class: Data

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

Specified by:

finishUpdate in class Data

Parameters:

opts - main options

flush

public void flush(boolean all)

Description copied from class: Data

Flushes updated data.

Specified by:

flush in class Data

Parameters:

all - flush all data

text

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

Description copied from class: Data

Returns a text (text, comment, pi, document) 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, document) or attribute value as integer value. Long.MIN_VALUE is returned if the input is no valid integer.

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, document) or attribute value as double value. Double.NaN is returned if the input is no valid double.

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 (possibly compressed) text (text, comment, pi, document).

Specified by:

textLen in class Data

Parameters:

pre - pre value

text - text/attribute flag

Returns:

length

inMemory

public boolean inMemory()

Description copied from class: Data

Indicates if this data instance is in main memory or on disk.

Specified by:

inMemory in class Data

Returns:

result of check

values

public TokenSet values(boolean text)

Returns the string values of the database.

Parameters:

text - text/attribute flag

Returns:

set

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

protected void updateText(int pre,
 byte[] value,
 int kind)

Description copied from class: Data

Updates the specified text or attribute value.

Specified by:

updateText in class Data

Parameters:

pre - pre value

value - content

kind - node kind

textRef

protected long textRef(byte[] value,
 boolean text)

Description copied from class: Data

Generates a reference for a text (text, comment, pi, pi, document) or attribute value.

Specified by:

textRef in class Data

Parameters:

value - text to be indexed

text - text/attribute flag

Returns:

reference