com.mockobjects.util
Class Null

java.lang.Object
  extended bycom.mockobjects.util.Null

public class Null
extends java.lang.Object

A class that represents the null value. The Null class is used when an Expectation is set to expect nothing.

Example usage:

 public class MockX {
    private Expectation... anExpectation = new Expectation...(...);

    public MockX() {
       anExpectation.setExpectNothing();
    }

    public void setAnExpectation(Object value) {
       anExpectation.setExpected(value);
    }

    public void setActual(Object value) {
       anExpectation.setActual(value);
    }
 }
 
The act of calling Expectation.setExpectNothing() tells the expectation that it should expect no values to change. Since all Null objects are equal to themselves, most expectations set their expected value to an instance of Null, and at the same time, set their actual value to another instance of Null. This way, when verify() checks expectations, they will compare two Null objects together, which is guaranteed to succeed.

Version:
$Id: Null.java,v 1.3 2002/03/28 18:16:54 custommonkey Exp $
Author:
Francois Beausoleil (fbos@users.sourceforge.net)

Field Summary
static java.lang.String DEFAULT_DESCRIPTION
          The default description for all Null objects.
static Null NULL
          A default Null object.
 
Constructor Summary
Null()
          Instantiates a new Null object with the default description.
Null(java.lang.String description)
          Instantiates a new Null object and sets it's description.
 
Method Summary
 boolean equals(java.lang.Object other)
          Determines equality between two objects.
 int hashCode()
          Returns this Null object's hashCode.
 java.lang.String toString()
          Returns a string representation of this Null object.
 
Methods inherited from class java.lang.Object
getClass, notify, notifyAll, wait, wait, wait
 

Field Detail

DEFAULT_DESCRIPTION

public static final java.lang.String DEFAULT_DESCRIPTION
The default description for all Null objects. This String is equal to "Null".

See Also:
Constant Field Values

NULL

public static final Null NULL
A default Null object. Instead of always instantiating new Null objects, consider using a reference to this object instead. This way, the virtual machine will not be taking the time required to instantiate an object everytime it is required.

Constructor Detail

Null

public Null()
Instantiates a new Null object with the default description.

See Also:
DEFAULT_DESCRIPTION

Null

public Null(java.lang.String description)
Instantiates a new Null object and sets it's description.

Parameters:
description -
Method Detail

equals

public boolean equals(java.lang.Object other)
Determines equality between two objects. Null objects are only equal to another instance of themselves.

Parameters:
other -

hashCode

public int hashCode()
Returns this Null object's hashCode. All Null return the same hashCode value.


toString

public java.lang.String toString()
Returns a string representation of this Null object. This merely returns the string passed to the constructor initially.



Copyright © 2002 Mock Objects. All Rights Reserved.