SymbolTable (Apache Tomcat 7.0.109 API Documentation)

java.lang.Object
- org.apache.jasper.xmlparser.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:
- 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.
Author:

Andy Clark

Nested Class Summary

Nested Classes
Modifier and Type Class and Description

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

Nested Classes
Modifier and Type	Class and Description
`protected static class`	`SymbolTable.Entry` This class is a symbol table entry.

Field Summary

Fields
Modifier and Type Field and Description

protected SymbolTable.Entry[] fBuckets
Buckets.

protected int fTableSize

protected static int TABLE_SIZE
Default table size.

Fields
Modifier and Type	Field and Description
`protected SymbolTable.Entry[]`	`fBuckets` Buckets.
`protected int`	`fTableSize`
`protected static int`	`TABLE_SIZE` Default table size.

Constructor Summary

Constructors
Constructor and Description
`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

Methods
Modifier and Type	Method and Description
`String`	`addSymbol(char[] buffer, int offset, int length)` Adds the specified symbol to the symbol table and returns a reference to the unique symbol.
`String`	`addSymbol(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(String symbol)` Returns true if the symbol table already contains the specified symbol.
`int`	`hash(char[] buffer, int offset, int length)` Returns a hashcode value for the specified symbol information.
`int`	`hash(String symbol)` Returns a hashcode value for the specified symbol.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - TABLE_SIZE
```
protected static final int TABLE_SIZE
```
    Default table size.
    
    See Also:
    Constant Field Values
  - fBuckets
```
protected SymbolTable.Entry[] fBuckets
```
    Buckets.
  - fTableSize
```
protected int fTableSize
```
- 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.
  - 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.
  - 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.

Class SymbolTable

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

TABLE_SIZE

fBuckets

fTableSize

Constructor Detail

SymbolTable

SymbolTable

Method Detail

addSymbol

addSymbol

hash

hash

containsSymbol

containsSymbol