it.unimi.dsi.fastutil.objects
Class Reference2ReferenceFunctions.EmptyFunction<K,V>

java.lang.Object
  extended by it.unimi.dsi.fastutil.objects.AbstractReference2ReferenceFunction<K,V>
      extended by it.unimi.dsi.fastutil.objects.Reference2ReferenceFunctions.EmptyFunction<K,V>
All Implemented Interfaces:
Function<K,V>, Reference2ReferenceFunction<K,V>, java.io.Serializable, java.lang.Cloneable
Direct Known Subclasses:
Reference2ReferenceMaps.EmptyMap
Enclosing class:
Reference2ReferenceFunctions

public static class Reference2ReferenceFunctions.EmptyFunction<K,V>
extends AbstractReference2ReferenceFunction<K,V>
implements java.io.Serializable, java.lang.Cloneable

An immutable class representing an empty type-specific function.

This class may be useful to implement your own in case you subclass a type-specific function.

See Also:
Serialized Form

Method Summary
 void clear()
          Removes all associations from this function (optional operation).
 java.lang.Object clone()
           
 boolean containsKey(java.lang.Object k)
          Returns true if this function contains a mapping for the specified key.
 V defaultReturnValue()
          Gets the default return value.
 void defaultReturnValue(V defRetValue)
          Sets the default return value.
 V get(java.lang.Object k)
          Returns the value associated by this function to the specified key.
 int size()
          Returns the intended number of keys in this function, or -1 if no such number exists.
 
Methods inherited from class it.unimi.dsi.fastutil.objects.AbstractReference2ReferenceFunction
put, remove
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Method Detail

get

public V get(java.lang.Object k)
Description copied from interface: Function
Returns the value associated by this function to the specified key.

Specified by:
get in interface Function<K,V>
Parameters:
k - the key.
Returns:
the corresponding value, or null if no value was present for the given key.
See Also:
Map.get(Object)

containsKey

public boolean containsKey(java.lang.Object k)
Description copied from interface: Function
Returns true if this function contains a mapping for the specified key.

Note that for some kind of functions (e.g., hashes) this method will always return true.

Specified by:
containsKey in interface Function<K,V>
Parameters:
k - the key.
Returns:
true if this function associates a value to key.
See Also:
Map.containsKey(Object)

defaultReturnValue

public V defaultReturnValue()
Description copied from interface: Reference2ReferenceFunction
Gets the default return value.

Specified by:
defaultReturnValue in interface Reference2ReferenceFunction<K,V>
Overrides:
defaultReturnValue in class AbstractReference2ReferenceFunction<K,V>
Returns:
the current default return value.

defaultReturnValue

public void defaultReturnValue(V defRetValue)
Description copied from interface: Reference2ReferenceFunction
Sets the default return value. This value must be returned by type-specific versions of get(), put() and remove() to denote that the map does not contain the specified key. It must be 0/false/null by default.

Specified by:
defaultReturnValue in interface Reference2ReferenceFunction<K,V>
Overrides:
defaultReturnValue in class AbstractReference2ReferenceFunction<K,V>
Parameters:
defRetValue - the new default return value.
See Also:
Reference2ReferenceFunction.defaultReturnValue()

size

public int size()
Description copied from interface: Function
Returns the intended number of keys in this function, or -1 if no such number exists.

Most function implementations will have some knowledge of the intended number of keys in their domain. In some cases, however, this might not be possible.

Specified by:
size in interface Function<K,V>
Returns:
the intended number of keys in this function, or -1 if that number is not available.

clear

public void clear()
Description copied from interface: Function
Removes all associations from this function (optional operation).

Specified by:
clear in interface Function<K,V>
Overrides:
clear in class AbstractReference2ReferenceFunction<K,V>
See Also:
Map.clear()

clone

public java.lang.Object clone()
Overrides:
clone in class java.lang.Object