de.rwth.domains.templates
Class IdentityFunction

java.lang.Object
  |
  +--de.rwth.domains.templates.IdentityFunction

All Implemented Interfaces:

Function

public class IdentityFunction

extends java.lang.Object

implements Function

Implements functions which always return their argument.

Version:

$Id: IdentityFunction.java,v 1.2 2002/09/17 06:53:53 mohnen Exp $

Author:

Markus Mohnen

Inner classes inherited from class de.rwth.domains.Function

Function.Tools

Field Summary

protected Set

set The domain and range of the function.

Constructor Summary

IdentityFunction(Set set)
Creates a new IdentityFunction instance.

Method Summary

java.lang.Object	apply(java.lang.Object x) Returns the argument if it is an element of the domain.
Set	getDomain() Returns the domain of this function.
Set	getRange() Returns the range (co-domain) of this function.
java.lang.String	toString() Returns "id".

Methods inherited from class java.lang.Object

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

Field Detail

set

protected Set set

The domain and range of the function.

Constructor Detail

IdentityFunction

public IdentityFunction(Set set)

Creates a new IdentityFunction instance.

Parameters:

set - a Set value

Method Detail

getDomain

public Set getDomain()

Description copied from interface: Function

Returns the domain of this function.

Specified by:

getDomain in interface Function

Following copied from interface: de.rwth.domains.Function

Returns:

a value of type Set

getRange

public Set getRange()

Description copied from interface: Function

Returns the range (co-domain) of this function.

Specified by:

getRange in interface Function

Following copied from interface: de.rwth.domains.Function

Returns:

a value of type Set

apply

public java.lang.Object apply(java.lang.Object x)
                       throws FunctionException

Returns the argument if it is an element of the domain.

Specified by:

apply in interface Function

Parameters:

x - an Object value

Returns:

an Object value

Throws:

FunctionException - if the argument is not an element of the domain.

toString

public java.lang.String toString()

Returns "id".

Overrides:

toString in class java.lang.Object

Returns:

a String value