Package com.singularsys.jep.standard

Class StandardEvaluator

java.lang.Object

com.singularsys.jep.standard.StandardEvaluator

All Implemented Interfaces:

Evaluator, JepComponent, ParserVisitor, Serializable

public final class StandardEvaluator
extends Object
implements Evaluator, ParserVisitor

The older standard evaluator. Since Jep 3.3 the default Evaluator is FastEvaluator which can be up to six times faster.

This evaluator uses the PostfixMathCommandI.run(Stack) method to evaluate functions and operators, the FastEvaluator uses more efficient methods like BinaryFunction.eval(Object, Object).

See Also:

• Serialized Form

Constructor Summary

Constructors

Constructor	Description
StandardEvaluator()

Method Summary

Modifier and Type	Method	Description
Object	eval(Node node)	Evaluates a sub expression.
Object	evaluate(Node node)	Main entry point, evaluates a node and returns and object with the value of the node.
JepComponent	getLightWeightInstance()	Gets a light-weight instance suitable for using in multiple threads.
void	init(Jep jep)	Initialize the component.
boolean	isTrapInfinity()
boolean	isTrapNaN()
boolean	isTrapNullValues()	Whether null values for variables are trapped.
void	setTrapInfinity(boolean trapInfinity)
void	setTrapNaN(boolean trapNaN)
void	setTrapNullValues(boolean trapNullValues)	Sets whether null values for variables are trapped.
Object	visit(ASTConstant node, Object data)
Object	visit(ASTFunNode node, Object data)
Object	visit(ASTOpNode node, Object data)
Object	visit(ASTVarNode node, Object data)
Object	visitConstant(Node node)
Object	visitVar(Node node)

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.singularsys.jep.Evaluator

eval

Constructor Details

StandardEvaluator

public StandardEvaluator()

Method Details

init

public void init(Jep jep)

Description copied from interface: JepComponent

Initialize the component. This method is called whenever a component is added to Jep. Hence, it allows components to keep track of the other components they may rely on.

Specified by:

init in interface JepComponent

Parameters:

jep - the current Jep instance

eval

public Object eval(Node node)
            throws EvaluationException

Description copied from interface: Evaluator

Evaluates a sub expression. This method can be called by PostfixMathCommands which implement CallbackEvaluationI

Specified by:

eval in interface Evaluator

Parameters:

node - node to evaluate

Returns:

The value after evaluating the sub expression.

Throws:

EvaluationException - if errors occur during evaluation;

evaluate

public Object evaluate(Node node)
                throws EvaluationException

Description copied from interface: Evaluator

Main entry point, evaluates a node and returns and object with the value of the node.

Specified by:

evaluate in interface Evaluator

Parameters:

node - node to evaluate

Returns:

value after evaluation

Throws:

EvaluationException - if errors occur during evaluation;

visit

public Object visit(ASTConstant node,
 Object data)
             throws EvaluationException

Specified by:

visit in interface ParserVisitor

Throws:

EvaluationException

visitConstant

public Object visitConstant(Node node)
                     throws EvaluationException

Throws:

EvaluationException

visit

public Object visit(ASTFunNode node,
 Object data)
             throws EvaluationException

Specified by:

visit in interface ParserVisitor

Throws:

EvaluationException

visit

public Object visit(ASTVarNode node,
 Object data)
             throws EvaluationException

Specified by:

visit in interface ParserVisitor

Throws:

EvaluationException

visitVar

public Object visitVar(Node node)
                throws EvaluationException

Throws:

EvaluationException

visit

public Object visit(ASTOpNode node,
 Object data)
             throws EvaluationException

Specified by:

visit in interface ParserVisitor

Throws:

EvaluationException

isTrapNullValues

public boolean isTrapNullValues()

Whether null values for variables are trapped.

Returns:

the status if the trap null values flag.

setTrapNullValues

public void setTrapNullValues(boolean trapNullValues)

Sets whether null values for variables are trapped. If set (the default) then an EvaluationException is thrown for null values of variables. If not set then null values are passed to PostfixMathCommands who will need to test for null values.

Parameters:

trapNullValues -

isTrapNaN

public boolean isTrapNaN()

setTrapNaN

public void setTrapNaN(boolean trapNaN)

isTrapInfinity

public boolean isTrapInfinity()

setTrapInfinity

public void setTrapInfinity(boolean trapInfinity)

getLightWeightInstance

public JepComponent getLightWeightInstance()

Description copied from interface: JepComponent

Gets a light-weight instance suitable for using in multiple threads.

Specified by:

getLightWeightInstance in interface JepComponent

Returns:

a new StandardEvaluator