info.aduna.gee.publication.servlets.car
Class ExpressionNode

java.lang.Object
  info.aduna.gee.publication.servlets.car.ExpressionNode

public class ExpressionNode
extends Object

A reduced expression node in an operator-precedence parsing tree.

Field Summary

protected ExpressionNode	_node1 Expression node 1 contained in the current expression node.
protected ExpressionNode	_node2 Expression node 2 contained in the current expression node.
protected String	_nval Constant contained in the current expression node.
protected int	_operator One of Symbol.TK_AND, Symbol.TK_OR, Symbol.TK_NOT.
int	etype Expression node type.

Constructor Summary

ExpressionNode()
Create a default empty expression node.

Method Summary

protected void	_pushExpression(ExpressionNode n) Pushes an expression node into the expression node.
protected void	_pushNumber(long nval) Pushes a const into the expression node.
protected void	_pushOperator(int operator) Pushes a function into the expression node.
boolean	eval(HashSet value) Evaluate the expression node.
void	push(Symbol sym) Pushes a symbol into the expression node.
String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

etype

public int etype

Expression node type.

_node1

protected ExpressionNode _node1

Expression node 1 contained in the current expression node. It is valid when the type of current expression node is one of the following: EXPNODE_NODE, EXPNODE_UNARYFUNC and EXPNODE_BINFUNC.

_node2

protected ExpressionNode _node2

Expression node 2 contained in the current expression node. It is valid when the type of current expression node is EXPNODE_BINFUNC.

_nval

protected String _nval

Constant contained in the current expression node. It is valid when the type of current expression node is EXPNODE_CONST.

_operator

protected int _operator

One of Symbol.TK_AND, Symbol.TK_OR, Symbol.TK_NOT.

Constructor Detail

ExpressionNode

public ExpressionNode()

Create a default empty expression node.

Method Detail

push

public void push(Symbol sym)
          throws ExpressionException

Pushes a symbol into the expression node. It will dispatch corresponding operation depending on the type of input symbol.

Throws:

ExpressionException

_pushExpression

protected void _pushExpression(ExpressionNode n)
                        throws ExpressionException

Pushes an expression node into the expression node.

Throws:

ExpressionException

_pushOperator

protected void _pushOperator(int operator)
                      throws ExpressionException

Pushes a function into the expression node.

Throws:

ExpressionException

_pushNumber

protected void _pushNumber(long nval)
                    throws ExpressionException

Pushes a const into the expression node.

Throws:

ExpressionException

eval

public boolean eval(HashSet value)
             throws ExpressionException

Evaluate the expression node.

Throws:

ExpressionException

toString

public String toString()

Overrides:

toString in class Object

Returns:

the string representation of the expression node.