Groovy 2.2.1

org.codehaus.groovy.runtime
[Java] Class NullObject

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

public class NullObject
extends GroovyObjectSupport

Method Summary
boolean asBoolean()

A null object always coerces to false.

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.

Object plus(Object o)

Fallback for null+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, equals, toString, hashCode, getClass, notify, notifyAll
 

Method Detail

asBoolean

public boolean asBoolean()
A null object always coerces to false.
Returns:
false


asType

public Object asType(Class c)
Type conversion method for null.
Parameters:
c - - the class to convert to
Returns:
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
Parameters:
to - - the reference object with which to compare
Returns:
- true if this object is the same as the to argument


getNullObject

public static NullObject getNullObject()
get the NullObject reference
Returns:
the null object


getProperty

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


hashCode

public int hashCode()


invokeMethod

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


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
Parameters:
other - - the object to test
Returns:
true if other is null


iterator

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


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.
Parameters:
s - - the String to concatenate
Returns:
the concatenated string


plus

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


setProperty

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


toString

public String toString()


 

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