org.apache.xerces.util
Class SoftReferenceSymbolTable

java.lang.Object
  org.apache.xerces.util.SymbolTable
      org.apache.xerces.util.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

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

java.lang.String	addSymbol(char[] buffer, int offset, int length) Adds the specified symbol to the symbol table and returns a reference to the unique symbol.
java.lang.String	addSymbol(java.lang.String symbol) Adds the specified symbol to the symbol table and returns a reference to the unique symbol.
boolean	containsSymbol(char[] buffer, int offset, int length) Returns true if the symbol table already contains the specified symbol.
boolean	containsSymbol(java.lang.String symbol) Returns true if the symbol table already contains the specified symbol.

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

hash, hash

Methods inherited from class java.lang.Object

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

Constructor Detail

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.

Throws:

java.lang.IllegalArgumentException - if the initial capacity is less than zero, or if the load factor is nonpositive.

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.

Throws:

java.lang.IllegalArgumentException - if the initial capacity is less than zero.

SoftReferenceSymbolTable

public SoftReferenceSymbolTable()

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

Method Detail

addSymbol

public java.lang.String addSymbol(java.lang.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 class SymbolTable

Parameters:

symbol - The new symbol.

addSymbol

public java.lang.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 class 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(java.lang.String symbol)

Returns true if the symbol table already contains the specified symbol.

Overrides:

containsSymbol in class 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 class 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.