Package org.geotools.util
Class DerivedSet<B,E>
Object
AbstractCollection<E>
AbstractSet<E>
DerivedSet<B,E>
- Type Parameters:
B
- The type of elements in the backing set.E
- The type of elements in this set.
- All Implemented Interfaces:
Serializable
,Iterable<E>
,Collection<E>
,Set<E>
,CheckedCollection<E>
public abstract class DerivedSet<B,E>
extends AbstractSet<E>
implements CheckedCollection<E>, Serializable
A set whose values are derived from an other set. The values are derived only when requested, which make it possible
to backup potentially large sets. Implementations need only to overrides
baseToDerived(B)
and
derivedToBase(E)
methods. This set do not supports null
value, since null
is used when no
mapping from base to this
exists. This class is serializable if the underlying
base set is serializable too.
This class is not thread-safe. Synchronizations (if wanted) are user's reponsability.
- Since:
- 2.0
- Author:
- Martin Desruisseaux (IRD)
- See Also:
-
Field Summary
Fields -
Constructor Summary
ConstructorsConstructorDescriptionDerivedSet
(Set<B> base, Class<E> derivedType) Creates a new derived set from the specified base set. -
Method Summary
Modifier and TypeMethodDescriptionboolean
Ensures that this set contains the specified element.protected abstract E
baseToDerived
(B element) Transforms a value in the base set to a value in this set.boolean
Returnstrue
if this set contains the specified element.protected abstract B
derivedToBase
(E element) Transforms a value in this set to a value in the base set.Returns the derived element type.boolean
isEmpty()
Returnstrue
if this set contains no elements.iterator()
Returns an iterator over the elements contained in this set.boolean
Removes a single instance of the specified element from this set.int
size()
Returns the number of elements in this set.Methods inherited from class AbstractSet
equals, hashCode, removeAll
Methods inherited from class AbstractCollection
addAll, clear, containsAll, retainAll, toArray, toArray, toString
Methods inherited from interface Collection
parallelStream, removeIf, stream, toArray
Methods inherited from interface Set
addAll, clear, containsAll, retainAll, spliterator, toArray, toArray
-
Field Details
-
base
The base set whose values are derived from.- See Also:
-
-
Constructor Details
-
DerivedSet
Creates a new derived set from the specified base set.- Parameters:
base
- The base set.derivedType
- The type of elements in this derived set.- Since:
- 2.5
-
-
Method Details
-
getElementType
Returns the derived element type.- Specified by:
getElementType
in interfaceCheckedCollection<B>
- Returns:
- The element type.
- Since:
- 2.5
-
baseToDerived
Transforms a value in the base set to a value in this set. If there is no mapping in the derived set for the specified element, then this method returnsnull
.- Parameters:
element
- A value in the base set.- Returns:
- The value that this view should contains instead of
element
, ornull
.
-
derivedToBase
Transforms a value in this set to a value in the base set.- Parameters:
element
- A value in this set.- Returns:
- The value stored in the base set.
-
iterator
Returns an iterator over the elements contained in this set. The iterator will invokesbaseToDerived(B)
for each element. -
size
public int size()Returns the number of elements in this set. The default implementation counts the number of elements returned by theiterator
.- Specified by:
size
in interfaceCollection<B>
- Specified by:
size
in interfaceSet<B>
- Specified by:
size
in classAbstractCollection<E>
- Returns:
- the number of elements in this set.
-
isEmpty
public boolean isEmpty()Returnstrue
if this set contains no elements.- Specified by:
isEmpty
in interfaceCollection<B>
- Specified by:
isEmpty
in interfaceSet<B>
- Overrides:
isEmpty
in classAbstractCollection<E>
- Returns:
true
if this set contains no elements.
-
contains
Returnstrue
if this set contains the specified element. The default implementation invokesbase.contains(derivedToBase(element))
.- Specified by:
contains
in interfaceCollection<B>
- Specified by:
contains
in interfaceSet<B>
- Overrides:
contains
in classAbstractCollection<E>
- Parameters:
element
- object to be checked for containment in this set.- Returns:
true
if this set contains the specified element.
-
add
Ensures that this set contains the specified element. The default implementation invokesbase.add(derivedToBase(element))
.- Specified by:
add
in interfaceCollection<B>
- Specified by:
add
in interfaceSet<B>
- Overrides:
add
in classAbstractCollection<E>
- Parameters:
element
- element whose presence in this set is to be ensured.- Returns:
true
if the set changed as a result of the call.- Throws:
UnsupportedOperationException
- if the base set doesn't supports theadd
operation.
-
remove
Removes a single instance of the specified element from this set. The default implementation invokesbase.remove(derivedToBase(element))
.- Specified by:
remove
in interfaceCollection<B>
- Specified by:
remove
in interfaceSet<B>
- Overrides:
remove
in classAbstractCollection<E>
- Parameters:
element
- element to be removed from this set, if present.- Returns:
true
if the set contained the specified element.- Throws:
UnsupportedOperationException
- if the base set doesn't supports theremove
operation.
-