eworks.RQL.engine
Class SymbolTable

java.lang.Object
  java.util.Dictionary
      java.util.Hashtable
          eworks.RQL.engine.SymbolTable

All Implemented Interfaces:

Cloneable, Map, Serializable

public class SymbolTable

extends Hashtable

A symbol table that is used by RqlEngine class for storing the values of variables.

Version:

1.00 (2003-11-03)

Author:

Fabian Wleklinski (fabian@wleklinski.de)

See Also:

RqlEngine, Serialized Form

Constructor Summary

SymbolTable()
Creates a new and empty symbol table using the default capacity.

SymbolTable(int initialCapacity)
Creates a new and empty symbol table with the given intial capacity.

Method Summary

void	bind(Variable variable, LiteralValue value) Binds the variable variable to the value value.
LiteralValue	get(String name) Returns the value of the variable specified by name.
Tuple	getTuple() Returns all bound variables and their values as tuple, using an instance of Tuple.

Methods inherited from class java.util.Hashtable

clear, clone, contains, containsKey, containsValue, elements, entrySet, equals, get, hashCode, isEmpty, keys, keySet, put, putAll, rehash, remove, size, toString, values

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

SymbolTable

public SymbolTable()

Creates a new and empty symbol table using the default capacity.

SymbolTable

public SymbolTable(int initialCapacity)

Creates a new and empty symbol table with the given intial capacity.

Parameters:

initialCapacity - The symbol table's initial capicity

Method Detail

get

public LiteralValue get(String name)
                 throws VariableNotBoundException

Returns the value of the variable specified by name.

Parameters:

name - The variable's name

Returns:

The variable's value

Throws:

VariableNotBoundException - Thrown if there is no bound variable named name

getTuple

public Tuple getTuple()

Returns all bound variables and their values as tuple, using an instance of Tuple.

Returns:

A tuple built by all contained variables and their values.

bind

public void bind(Variable variable,
                 LiteralValue value)
          throws VariableAlreadyBoundException

Binds the variable variable to the value value.

Parameters:

variable - The variable to be bound.

value - The value to be bound.

Throws:

VariableAlreadyBoundException - is thrown if the variable variable is already bound.