org.apache.xerces.util

Class SoftReferenceSymbolTable


public class SoftReferenceSymbolTable
extends SymbolTable

This symbol table uses SoftReferences to its String entries, which means that table entries that have no references to them can be garbage collected when memory is needed. Thus, in documents with very very large numbers of unique strings, using this SymbolTable will prevent an out of memory error from occuring.
Version:
$Id: SoftReferenceSymbolTable.java 496158 2007-01-14 21:27:15Z mrglavas $
Author:
Peter McCracken, IBM
See Also:
SymbolTable

Nested Class Summary

protected static class
SoftReferenceSymbolTable.SREntry
This class is a symbol table entry.
protected static class
SoftReferenceSymbolTable.SREntryData

Nested classes/interfaces inherited from class org.apache.xerces.util.SymbolTable

SymbolTable.Entry

Field Summary

protected SoftReferenceSymbolTable.SREntry[]
fBuckets

Fields inherited from class org.apache.xerces.util.SymbolTable

TABLE_SIZE, fBuckets, fCount, fLoadFactor, fTableSize, fThreshold

Constructor Summary

SoftReferenceSymbolTable()
Constructs a new, empty SymbolTable with a default initial capacity (101) and load factor, which is 0.75.
SoftReferenceSymbolTable(int initialCapacity)
Constructs a new, empty SymbolTable with the specified initial capacity and default load factor, which is 0.75.
SoftReferenceSymbolTable(int initialCapacity, float loadFactor)
Constructs a new, empty SymbolTable with the specified initial capacity and the specified load factor.

Method Summary

String
addSymbol(String symbol)
Adds the specified symbol to the symbol table and returns a reference to the unique symbol.
String
addSymbol(char[] buffer, int offset, int length)
Adds the specified symbol to the symbol table and returns a reference to the unique symbol.
boolean
containsSymbol(String symbol)
Returns true if the symbol table already contains the specified symbol.
boolean
containsSymbol(char[] buffer, int offset, int length)
Returns true if the symbol table already contains the specified symbol.
protected void
rehash()
Increases the capacity of and internally reorganizes this SymbolTable, in order to accommodate and access its entries more efficiently.

Methods inherited from class org.apache.xerces.util.SymbolTable

addSymbol, addSymbol, containsSymbol, containsSymbol, hash, hash, rehash

Field Details

fBuckets

protected SoftReferenceSymbolTable.SREntry[] fBuckets

Constructor Details

SoftReferenceSymbolTable

public SoftReferenceSymbolTable()
Constructs a new, empty SymbolTable with a default initial capacity (101) and load factor, which is 0.75.

SoftReferenceSymbolTable

public SoftReferenceSymbolTable(int initialCapacity)
Constructs a new, empty SymbolTable with the specified initial capacity and default load factor, which is 0.75.
Parameters:
initialCapacity - the initial capacity of the hashtable.

SoftReferenceSymbolTable

public SoftReferenceSymbolTable(int initialCapacity,
                                float loadFactor)
Constructs a new, empty SymbolTable with the specified initial capacity and the specified load factor.
Parameters:
initialCapacity - the initial capacity of the SymbolTable.
loadFactor - the load factor of the SymbolTable.

Method Details

addSymbol

public String addSymbol(String symbol)
Adds the specified symbol to the symbol table and returns a reference to the unique symbol. If the symbol already exists, the previous symbol reference is returned instead, in order guarantee that symbol references remain unique.
Overrides:
addSymbol in interface SymbolTable
Parameters:
symbol - The new symbol.

addSymbol

public String addSymbol(char[] buffer,
                        int offset,
                        int length)
Adds the specified symbol to the symbol table and returns a reference to the unique symbol. If the symbol already exists, the previous symbol reference is returned instead, in order guarantee that symbol references remain unique.
Overrides:
addSymbol in interface SymbolTable
Parameters:
buffer - The buffer containing the new symbol.
offset - The offset into the buffer of the new symbol.
length - The length of the new symbol in the buffer.

containsSymbol

public boolean containsSymbol(String symbol)
Returns true if the symbol table already contains the specified symbol.
Overrides:
containsSymbol in interface SymbolTable
Parameters:
symbol - The symbol to look for.

containsSymbol

public boolean containsSymbol(char[] buffer,
                              int offset,
                              int length)
Returns true if the symbol table already contains the specified symbol.
Overrides:
containsSymbol in interface SymbolTable
Parameters:
buffer - The buffer containing the symbol to look for.
offset - The offset into the buffer.
length - The length of the symbol in the buffer.

rehash

protected void rehash()
Increases the capacity of and internally reorganizes this SymbolTable, in order to accommodate and access its entries more efficiently. This method is called automatically when the number of keys in the SymbolTable exceeds this hashtable's capacity and load factor.
Overrides:
rehash in interface SymbolTable

Copyright © 1999-2007 The Apache Software Foundation. All Rights Reserved.