net.sf.jga.fn.property
Class GetField<T,R>

java.lang.Object
  net.sf.jga.fn.UnaryFunctor<T,R>
      net.sf.jga.fn.property.GetField<T,R>

All Implemented Interfaces:

java.io.Serializable, Visitable

public class GetField<T,R>
extends UnaryFunctor<T,R>

Unary Functor that returns the value of the named field for the argument. The field name and type are set at construction.

Copyright © 2002 David A. Hall

Author:

David A. Hall

See Also:

Serialized Form

Nested Class Summary

static interface

GetField.Visitor Interface for classes that may interpret a GetField function.

Constructor Summary

GetField(java.lang.Class<T> argclass, java.lang.reflect.Field field)
Builds a GetField for the given field

GetField(java.lang.Class<T> argclass, java.lang.String fieldName)
Builds a GetField for the given field, using the given class to find the desired field.

Method Summary

void	accept(Visitor v) Calls the Visitor's visit(GetField) field, if it implements the nested Visitor interface.
R	fn(T arg) Returns the value of the designated field of the argument
java.lang.String	getFieldName() Returns the name of the field that this functor retrieves.
java.lang.Class<R>	getFieldType() Returns the type of field that this functor retrieves.
java.lang.String	toString()

Methods inherited from class net.sf.jga.fn.UnaryFunctor

bind, compose, compose, generate

Methods inherited from class java.lang.Object

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

Constructor Detail

GetField

public GetField(java.lang.Class<T> argclass,
                java.lang.reflect.Field field)

Builds a GetField for the given field

Throws:

java.lang.IllegalArgumentException - if the field is null, or is not a field of the given class

GetField

public GetField(java.lang.Class<T> argclass,
                java.lang.String fieldName)

Builds a GetField for the given field, using the given class to find the desired field.

Throws:

java.lang.IllegalArgumentException - if the field name is null or empty,

Method Detail

getFieldName

public java.lang.String getFieldName()

Returns the name of the field that this functor retrieves.

getFieldType

public java.lang.Class<R> getFieldType()

Returns the type of field that this functor retrieves.

fn

public R fn(T arg)

Returns the value of the designated field of the argument

Specified by:

fn in class UnaryFunctor<T,R>

Returns:

the value of the designated field of the argument

Throws:

EvaluationException - if the argument does not have the designated public field, or if it is not of the correct type.

accept

public void accept(Visitor v)

Calls the Visitor's visit(GetField) field, if it implements the nested Visitor interface.

Specified by:

accept in interface Visitable

Overrides:

accept in class UnaryFunctor<T,R>

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object