Package com.singularsys.jep.misc.overloadedfunctions

Class OverloadedBinaryFunction

java.lang.Object

com.singularsys.jep.functions.PostfixMathCommand

com.singularsys.jep.functions.BinaryFunction

com.singularsys.jep.misc.overloadedfunctions.OverloadedBinaryFunction

All Implemented Interfaces:

JepComponent, PostfixMathCommandI, Serializable

public class OverloadedBinaryFunction
extends BinaryFunction
implements JepComponent

Allows function to be overloaded with two candidate functions and a predicate that tests the values of the arguments to see which function should be applied. For example if we have a custom value type

        class MyVal {
                double val;

                public MyVal(double val) {
                        super();
                        this.val = val;
                }

                MyVal add(MyVal arg) {
                        return new MyVal(val+arg.val);
                }
        }
 

The addition operator could be overload with a custom function that uses the MyVal.add(MyVal) method.

        var fun1 = new OverloadedBinaryFunction(
                BinaryFunction.instanceOf(MyVal.class, (x,y) -> x.add(y) ),
                new Add(),
                (l,r) -> l instanceof MyVal && r instanceof MyVal );
        jep.getOperatorTable().getAdd().setPFMC(fun1);
        jep.reinitializeComponents();
 

In the constructor for the OverloadedFunction the first argument is our new function created by using a lambda expression and the static method BinaryFunction#instanceOf(Class,BiFunctionWithException). The second argument is the regular multiplication function and the third argument is the predicate that returns true when the values of the lhs and rhs arguments are strings.

Since:

Jep 4.1

See Also:

• Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class com.singularsys.jep.functions.BinaryFunction

BinaryFunction.BiFunctionWithException<T>

Field Summary

Fields inherited from class com.singularsys.jep.functions.PostfixMathCommand

curNumberOfParameters, description, name, NaN, numberOfParameters

Constructor Summary

Constructors

Constructor	Description
OverloadedBinaryFunction(PostfixMathCommandI function1, PostfixMathCommandI function2, BiPredicate<Object,Object> argTest)	Constructor.

Method Summary

Modifier and Type	Method	Description
Object	eval(Object l, Object r)	Evaluate the function
String	getDescription()	Return a description of the function from the properties file.
Object	getFunction1()
PostfixMathCommandI	getFunction2()
JepComponent	getLightWeightInstance()	Gets a light-weight instance suitable for using in multiple threads.
BiPredicate<Object,Object>	getPredicate()
void	init(Jep jep)	Initialize the component.

Methods inherited from class com.singularsys.jep.functions.BinaryFunction

instanceOf, instanceOf, instanceOf, instanceOf, run

Methods inherited from class com.singularsys.jep.functions.PostfixMathCommand

asArray, asBool, asDouble, asInt, asLong, asStrictInt, asString, asType, checkNumberOfParameters, getDescription, getDescriptionWithType, getName, getNumberOfParameters, setCurNumberOfParameters, setDescription, setName, toString, toString

Methods inherited from class java.lang.Object

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

Constructor Details

OverloadedBinaryFunction

public OverloadedBinaryFunction(PostfixMathCommandI function1,
 PostfixMathCommandI function2,
 BiPredicate<Object,Object> argTest)

Constructor. Each function can be a BinaryFunction or a NaryBinaryFunction or any other PostfixMathCommandI that uses the PostfixMathCommandI.run(Stack) method.

Parameters:

function1 - the first function

function2 - the second function

argTest - a predicate that tests the arguments

Method Details

eval

public Object eval(Object l,
 Object r)
            throws EvaluationException

Description copied from class: BinaryFunction

Evaluate the function

Specified by:

eval in class BinaryFunction

Parameters:

l - lhs argument

r - rhs argument

Returns:

the results

Throws:

EvaluationException - if the function cannot be evaluated.

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

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:

either a new instance, null or 'this'.

getFunction1

public Object getFunction1()

getFunction2

public PostfixMathCommandI getFunction2()

getPredicate

public BiPredicate<Object,Object> getPredicate()

getDescription

public String getDescription()

Description copied from class: PostfixMathCommand

Return a description of the function from the properties file. The property name is the class name followed by ".description". The property is found using the JepMessages class, which can be configured to add additional properties files. If PostfixMathCommand.setDescription(String) has been called, return the description set by that method instead.

Specified by:

getDescription in interface PostfixMathCommandI

Overrides:

getDescription in class PostfixMathCommand

Returns:

the description of the function