public class NullObject
extends GroovyObjectSupport

Method Detail

public boolean asBoolean()

A null object always coerces to false.

Returns:

false

public Object asType(Class c)

Type conversion method for null.

Parameters:

c - - the class to convert to

Returns:

always null

@Override public Object clone()

Since this is implemented as a singleton, we should avoid the use of the clone method

@Override public boolean equals(Object to)

null is only equal to null

Parameters:

to - - the reference object with which to compare

Returns:

- true if this object is the same as the to argument

public static NullObject getNullObject()

get the NullObject reference

Returns:

the null object

@Override public Object getProperty(String property)

Tries to get a property on null, which will always fail

Parameters:

property - - the property to get

Returns:

a NPE

@Override public int hashCode()

@Override public Object invokeMethod(String name, Object args)

Tries to invoke a method on null, which will always fail

Parameters:

name - the name of the method to invoke

args - - arguments to the method

Returns:

a NPE

public boolean is(Object other)

The method "is" is used to test for equal references. This method will return true only if the given parameter is null

Parameters:

other - - the object to test

Returns:

true if other is null

public Iterator iterator()

iterator() method to be able to iterate on null. Note: this part is from Invoker

Returns:

an iterator for an empty list

public Object plus(String s)

Allows to add a String to null. The result is concatenated String of the result of calling toString() on this object and the String in the parameter.

Parameters:

s - - the String to concatenate

Returns:

the concatenated string

public Object plus(Object o)

Fallback for null+null. The result is always a NPE. The plus(String) version will catch the case of adding a non null String to null.

Parameters:

o - - the Object

Returns:

nothing

@Override public void setProperty(String property, Object newValue)

Tries to set a property on null, which will always fail

Parameters:

property - - the proprty to set

newValue - - the new value of the property

@Override public String toString()

<T> public T with(Closure<T> closure)

Allows the closure to be called for NullObject

Parameters:

closure - the closure to call on the object

Returns:

result of calling the closure