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

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

public class Expression
extends Object

Field Summary

ExpressionNode	enode The top of the parse tree.
Vector	symbolQueue The symbol queue created for operator-precedence parsing.
Stack	symbolStack The operator, expression node stack created for operator-precedence parsing.

Constructor Summary

Expression()

Expression(String expr)

Method Summary

boolean	appendSymbol(Symbol sym) Append a symbol to the end of an expression.
boolean	eval(HashSet value) Evaluate the expression.
String	getErrMsg() Return a string indicates where the parsing error occurs.
static Symbol	nextSymbol(StreamTokenizer st) Fetch the next symbol from the input expression string.
static Symbol	toSymbol(String s) Convert a string to a symbol.

Methods inherited from class java.lang.Object

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

Field Detail

enode

public ExpressionNode enode

The top of the parse tree.

symbolQueue

public Vector symbolQueue

The symbol queue created for operator-precedence parsing.

symbolStack

public Stack symbolStack

The operator, expression node stack created for operator-precedence parsing.

Constructor Detail

Expression

public Expression()

Expression

public Expression(String expr)
           throws ExpressionException

Throws:

ExpressionException

Method Detail

appendSymbol

public boolean appendSymbol(Symbol sym)
                     throws ExpressionException

Append a symbol to the end of an expression.

Returns:

true if the whole expression is reduced into a single expression node or if the expression is empty.

Throws:

ExpressionException

eval

public boolean eval(HashSet value)

Evaluate the expression.

toSymbol

public static Symbol toSymbol(String s)

Convert a string to a symbol.

nextSymbol

public static Symbol nextSymbol(StreamTokenizer st)
                         throws IOException,
                                ExpressionException

Fetch the next symbol from the input expression string.

Throws:

IOException

ExpressionException

getErrMsg

public String getErrMsg()

Return a string indicates where the parsing error occurs.