NullObject (Groovy 1.7.0)

Overview

Package

Class

Deprecated

Index

Help

Groovy 1.7.0

FRAMES NO FRAMES

SUMMARY: NESTED | FIELD | CONSTR | METHOD

DETAIL: FIELD | CONSTR | METHOD

org.codehaus.groovy.runtime
Class NullObject

java.lang.Object
  groovy.lang.GroovyObjectSupport
      org.codehaus.groovy.runtime.NullObject

class NullObject
extends GroovyObjectSupport

Constructor Summary
`private NullObject()` private constructor

Method Summary
`Object`	`asType(Class c)` Type conversion method for null.
`Object`	`clone()` Since this is implemented as a singleton, we should avoid the use of the clone method
`boolean`	`equals(Object to)` null is only equal to null
`static NullObject`	`getNullObject()` get the NullObject reference
`Object`	`getProperty(String property)` Tries to get a property on null, which will always fail
`int`	`hashCode()`
`Object`	`invokeMethod(String name, Object args)` Tries to invoke a method on null, which will always fail
`boolean`	`is(Object other)` The method "is" is used to test for equal references.
`Iterator`	`iterator()` iterator() method to be able to iterate on null.
`Object`	`plus(String s)` Allows to add a String to null.
`void`	`setProperty(String property, Object newValue)` Tries to set a property on null, which will always fail
`String`	`toString()`

Methods inherited from class GroovyObjectSupport
getMetaClass, getProperty, invokeMethod, setMetaClass, setProperty

Methods inherited from class Object
wait, wait, wait, hashCode, getClass, equals, toString, notify, notifyAll

Constructor Detail

NullObject

private NullObject()

private constructor

Method Detail

asType

public Object asType(Class c)

Type conversion method for null.

param:: c - the class to convert to

return:: always null

clone

public Object clone()

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

equals

public boolean equals(Object to)

null is only equal to null

param:: to - the reference object with which to compare

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

getNullObject

public static NullObject getNullObject()

get the NullObject reference

return:: the null object

getProperty

public Object getProperty(String property)

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

param:: property - the property to get

return:: a NPE

hashCode

public int hashCode()

invokeMethod

public Object invokeMethod(String name, Object args)

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

param:: name the name of the method to invoke

param:: args - arguments to the method

return:: a NPE

is

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

param:: other - the object to test

return:: true if other is null

iterator

public Iterator iterator()

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

return:: an iterator for an empty list

plus

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.

param:: s - the String to concatenate

return:: the concatenated string

setProperty

public void setProperty(String property, Object newValue)

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

param:: property - the proprty to set

param:: newValue - the new value of the property

toString

public String toString()

org.codehaus.groovy.runtime Class NullObject