org.apache.jasper.xmlparser

Class SymbolTable


public class SymbolTable
extends java.lang.Object

This class is a symbol table implementation that guarantees that strings used as identifiers are unique references. Multiple calls to addSymbol will always return the same string reference.

The symbol table performs the same task as String.intern() with the following differences:

Version:
$Id: SymbolTable.java 306179 2005-07-27 15:12:04Z yoavs $
Author:
Andy Clark

Nested Class Summary

protected static class
SymbolTable.Entry
This class is a symbol table entry.

Field Summary

protected static int
TABLE_SIZE
Default table size.
protected SymbolTable.Entry[]
fBuckets
Buckets.
protected int
fTableSize

Constructor Summary

SymbolTable()
Constructs a symbol table with a default number of buckets.
SymbolTable(int tableSize)
Constructs a symbol table with a specified number of buckets.

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.
int
hash(String symbol)
Returns a hashcode value for the specified symbol.
int
hash(char[] buffer, int offset, int length)
Returns a hashcode value for the specified symbol information.

Field Details

TABLE_SIZE

protected static final int TABLE_SIZE
Default table size.
Field Value:
101

fBuckets

protected SymbolTable.Entry[] fBuckets
Buckets.

fTableSize

protected int fTableSize

Constructor Details

SymbolTable

public SymbolTable()
Constructs a symbol table with a default number of buckets.

SymbolTable

public SymbolTable(int tableSize)
Constructs a symbol table with a specified number of buckets.

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.
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.
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.
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.
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.

hash

public int hash(String symbol)
Returns a hashcode value for the specified symbol. The value returned by this method must be identical to the value returned by the hash(char[],int,int) method when called with the character array that comprises the symbol string.
Parameters:
symbol - The symbol to hash.

hash

public int hash(char[] buffer,
                int offset,
                int length)
Returns a hashcode value for the specified symbol information. The value returned by this method must be identical to the value returned by the hash(String) method when called with the string object created from the symbol information.
Parameters:
buffer - The character buffer containing the symbol.
offset - The offset into the character buffer of the start of the symbol.
length - The length of the symbol.

Copyright B) 2000-2004 Apache Software Foundation. All Rights Reserved.