Package org.codehaus.groovy.runtime
Class NullObject
java.lang.Object
groovy.lang.GroovyObjectSupport
org.codehaus.groovy.runtime.NullObject
- All Implemented Interfaces:
GroovyObject
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Method Summary
Modifier and TypeMethodDescriptionbooleanA null object coerces to false.Type conversion method for null.clone()Since this is implemented as a singleton, avoid the use of the clone method.booleannull is only equal to null.static NullObjectReturns the NullObject reference.getProperty(String name) Tries to get a property on null, which fails except for "class" and "metaClass".inthashCode()invokeMethod(String name, Object arguments) Tries to invoke a method on null, which fails.booleanTests for equal references.iterator()iterator() method to be able to iterate on null.Fallback fornull+null.Allows to add a String to null.voidsetProperty(String name, Object value) Tries to set a property on null, which fails.toString()<T> TDeprecated.Methods inherited from class groovy.lang.GroovyObjectSupport
getMetaClass, setMetaClass
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Method Details
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getNullObject
Returns the NullObject reference.- Returns:
- the null object
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clone
Since this is implemented as a singleton, avoid the use of the clone method.- Overrides:
clonein classObject- Returns:
- never
- Throws:
NullPointerException
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equals
null is only equal to null. -
hashCode
public int hashCode()- Overrides:
hashCodein classObject- Returns:
- never
- Throws:
NullPointerException
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toString
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getProperty
Tries to get a property on null, which fails except for "class" and "metaClass".- Parameters:
name- the name of the property of interest- Returns:
- never
- Throws:
NullPointerException
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setProperty
Tries to set a property on null, which fails.- Parameters:
name- the name of the property of interestvalue- the new value for the property- Throws:
NullPointerException
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invokeMethod
Tries to invoke a method on null, which fails.- Parameters:
name- the name of the method to callarguments- the arguments to use for the method call- Returns:
- never
- Throws:
NullPointerException
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asBoolean
public boolean asBoolean()A null object coerces to false.- Returns:
- false
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asType
Type conversion method for null.- Returns:
- null
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is
Tests for equal references.- Returns:
- true if object is null
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iterator
iterator() method to be able to iterate on null. Note: this part is from Invoker- Returns:
- an empty iterator
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plus
Fallback fornull+null. Theplus(java.lang.String)variant catches the case of adding a non-null String to null.- Returns:
- never
- Throws:
NullPointerException
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plus
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.- Returns:
- the concatenated string
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with
Deprecated.Allows the closure to be called for NullObject.- Parameters:
closure- the closure to call on the object- Returns:
- result of calling the closure
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