org.apache.jasper.xmlparser
Class SymbolTable
java.lang.Object
org.apache.jasper.xmlparser.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:
-
A new string object does not need to be created in order to
retrieve a unique reference. Symbols can be added by using
a series of characters in a character array.
-
Users of the symbol table can provide their own symbol hashing
implementation. For example, a simple string hashing algorithm
may fail to produce a balanced set of hashcodes for symbols
that are mostly unique. Strings with similar leading
characters are especially prone to this poor hashing behavior.
$Id: SymbolTable.java 466606 2006-10-21 23:07:12Z markt $
SymbolTable() - Constructs a symbol table with a default number of buckets.
|
SymbolTable(int tableSize) - Constructs a symbol table with a specified number of buckets.
|
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.
|
TABLE_SIZE
protected static final int TABLE_SIZE
Default table size.
fTableSize
protected int fTableSize
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.
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.
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.
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.
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.
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.
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.
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 ?? 2000-2004 Apache Software Foundation. All Rights Reserved.