org.exist.dom
Class SymbolTable

java.lang.Object
  org.exist.dom.SymbolTable

public class SymbolTable

extends java.lang.Object

Maintains a global symbol table shared by a database instance. The symbol table maps namespace URIs and node names to unique, numeric ids. Internally, the db does not store node QNames in clear text. Instead, it uses the numeric ids maintained here. The global SymbolTable singleton can be retrieved from DBBroker.getSymbols(). It is saved into the database file "symbols.dbx".

Author:

wolf

Field Summary

protected boolean	changed set to true if the symbol table needs to be saved
protected Object2IntHashMap	defaultMappings Contains default prefix-to-namespace mappings.
protected java.io.File	file the underlying symbols.dbx file
protected short	max contains the next local name id to be used
protected QNamePool	namePool Temporary name pool to share QName instances during indexing.
protected Int2ObjectHashMap	names Maps int ids to local node names
protected Int2ObjectHashMap	namespaces Maps int ids to namespace URIs
protected Object2IntHashMap	nameSymbols Maps local node names to an integer id
protected short	nsMax contains the next namespace URI id to be used
protected Object2IntHashMap	nsSymbols Maps namespace URIs to an integer id

Constructor Summary

SymbolTable(java.io.File file)

Method Summary

java.lang.String[]	defaultPrefixList() Returns a list of default prefixes registered.
java.lang.String	getDefaultNamespace(java.lang.String prefix) Returns a namespace URI for the given prefix if there's a default mapping.
java.io.File	getFile()
java.lang.String	getName(short id) Returns the local name registered for the id or null if the name is not known.
java.lang.String	getNamespace(short id) Returns the namespace URI registered for the id or null if the namespace URI is not known.
short	getNSSymbol(java.lang.String ns) Returns a unique id for the specified namespace URI.
QName	getQName(short type, java.lang.String namespaceURI, java.lang.String localName, java.lang.String prefix) Retrieve a shared QName instance from the temporary pool.
short	getSymbol(org.w3c.dom.Attr attr) Return a unique id for the local node name of the specified attribute.
short	getSymbol(org.w3c.dom.Element element) Return a unique id for the local node name of the specified element.
short	getSymbol(java.lang.String name) Returns a unique id for the specified local name.
boolean	hasChanged() Returns true if the symbol table needs to be saved to persistent storage.
void	read(VariableByteInput istream) Read the symbol table.
void	write(VariableByteOutputStream ostream) Write the symbol table to persistent storage.

Methods inherited from class java.lang.Object

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

Field Detail

nameSymbols

protected Object2IntHashMap nameSymbols

Maps local node names to an integer id

names

protected Int2ObjectHashMap names

Maps int ids to local node names

nsSymbols

protected Object2IntHashMap nsSymbols

Maps namespace URIs to an integer id

namespaces

protected Int2ObjectHashMap namespaces

Maps int ids to namespace URIs

defaultMappings

protected Object2IntHashMap defaultMappings

Contains default prefix-to-namespace mappings. For convenience, eXist tracks the first prefix-to-namespace mapping it finds in a document. If an undefined prefix is found in a query, the query engine will first look up the prefix in this table before throwing an error.

namePool

protected QNamePool namePool

Temporary name pool to share QName instances during indexing.

max

protected short max

contains the next local name id to be used

nsMax

protected short nsMax

contains the next namespace URI id to be used

changed

protected boolean changed

set to true if the symbol table needs to be saved

file

protected java.io.File file

the underlying symbols.dbx file

Constructor Detail

SymbolTable

public SymbolTable(java.io.File file)

Method Detail

getQName

public QName getQName(short type,
                      java.lang.String namespaceURI,
                      java.lang.String localName,
                      java.lang.String prefix)

Retrieve a shared QName instance from the temporary pool.

Parameters:

namespaceURI -

localName -

prefix -

Returns:

getSymbol

public short getSymbol(org.w3c.dom.Element element)

Return a unique id for the local node name of the specified element.

Parameters:

element -

Returns:

getSymbol

public short getSymbol(org.w3c.dom.Attr attr)

Return a unique id for the local node name of the specified attribute.

Parameters:

attr -

Returns:

getSymbol

public short getSymbol(java.lang.String name)

Returns a unique id for the specified local name. If the name is the local name of an attribute, it should start with a '@' character.

Parameters:

name -

Returns:

getNSSymbol

public short getNSSymbol(java.lang.String ns)

Returns a unique id for the specified namespace URI.

Parameters:

ns -

Returns:

getNamespace

public java.lang.String getNamespace(short id)

Returns the namespace URI registered for the id or null if the namespace URI is not known. Returns the empty string if the namespace is empty.

Parameters:

id -

Returns:

hasChanged

public boolean hasChanged()

Returns true if the symbol table needs to be saved to persistent storage.

Returns:

getName

public java.lang.String getName(short id)

Returns the local name registered for the id or null if the name is not known.

Parameters:

id -

Returns:

getDefaultNamespace

public java.lang.String getDefaultNamespace(java.lang.String prefix)

Returns a namespace URI for the given prefix if there's a default mapping.

Parameters:

prefix -

Returns:

defaultPrefixList

public java.lang.String[] defaultPrefixList()

Returns a list of default prefixes registered.

Returns:

write

public void write(VariableByteOutputStream ostream)
           throws java.io.IOException

Write the symbol table to persistent storage.

Parameters:

ostream -

Throws:

java.io.IOException

read

public void read(VariableByteInput istream)
          throws java.io.IOException

Read the symbol table.

Parameters:

istream -

Throws:

java.io.IOException

getFile

public java.io.File getFile()