org.apache.jasper.xmlparser

Class SymbolTable

public class SymbolTable extends 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 467222 2006-10-24 03:17:11Z markt $

Author: Andy Clark

Nested Class Summary
protected static classSymbolTable.Entry
This class is a symbol table entry.
Field Summary
protected SymbolTable.Entry[]fBuckets
Buckets.
protected intfTableSize
protected static intTABLE_SIZE
Default table size.
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
StringaddSymbol(String symbol)
Adds the specified symbol to the symbol table and returns a reference to the unique symbol.
StringaddSymbol(char[] buffer, int offset, int length)
Adds the specified symbol to the symbol table and returns a reference to the unique symbol.
booleancontainsSymbol(String symbol)
Returns true if the symbol table already contains the specified symbol.
booleancontainsSymbol(char[] buffer, int offset, int length)
Returns true if the symbol table already contains the specified symbol.
inthash(String symbol)
Returns a hashcode value for the specified symbol.
inthash(char[] buffer, int offset, int length)
Returns a hashcode value for the specified symbol information.

Field Detail

fBuckets

protected SymbolTable.Entry[] fBuckets
Buckets.

fTableSize

protected int fTableSize

TABLE_SIZE

protected static final int TABLE_SIZE
Default table size.

Constructor Detail

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 Detail

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.

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