uk.co.strangeskies.collection

Class SetTransformationView<F,T>

java.lang.Object

java.util.AbstractCollection<E>

java.util.AbstractSet<T>

uk.co.strangeskies.collection.SetTransformationView<F,T>

Type Parameters:

T - The type of the elements of this list.

F - The type of the elements of the backing list.

All Implemented Interfaces:

java.lang.Iterable<T>, java.util.Collection<T>, java.util.Set<T>

public class SetTransformationView<F,T>
extends java.util.AbstractSet<T>

A view of a set which will be automatically updated along with the original, but who's elements will be a transformation of the original associated elements by way of the function passed to the constructor. The implementation employs lazy evaluation, so try to use get() as little as possible by reusing the result.

Unlike the Stream.map(Function) function, which can provide similar functionality in certain circumstances, this class provides a view which is reusable and backed by the original collection, such that it will reflect changes.

If the constructor is supplied with an InvertibleFunction, it will be possible to add elements to this collection.

Constructor Summary

Constructors

Constructor and Description
SetTransformationView(java.util.Collection<F> backingCollection, java.util.function.Function<? super F,? extends T> function)
SetTransformationView(java.util.Collection<F> backingCollection, InvertibleFunction<F,T> function)

Method Summary

Modifier and Type	Method and Description
boolean	add(T e)
java.util.Collection<F>	getBackingCollection()
InvertibleFunction<F,T>	getFunction()
protected java.util.Collection<F>	getModifiablebackingCollection()
java.util.Iterator<T>	iterator()
int	size()

Methods inherited from class java.util.AbstractSet

equals, hashCode, removeAll

Methods inherited from class java.util.AbstractCollection

addAll, clear, contains, containsAll, isEmpty, remove, retainAll, toArray, toArray, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Set

addAll, clear, contains, containsAll, isEmpty, remove, retainAll, spliterator, toArray, toArray

Methods inherited from interface java.util.Collection

parallelStream, removeIf, stream

Methods inherited from interface java.lang.Iterable

forEach

Constructor Detail

SetTransformationView

public SetTransformationView(java.util.Collection<F> backingCollection,
                             java.util.function.Function<? super F,? extends T> function)

Parameters:

backingCollection - The backing collection this class presents a view over.

function - The function which transforms elements into the form in which they are represented in by this view.

SetTransformationView

public SetTransformationView(java.util.Collection<F> backingCollection,
                             InvertibleFunction<F,T> function)

Parameters:

backingCollection - The backing collection this class presents a view over.

function - The function which transforms elements into the form in which they are represented in by this view.

Method Detail

add

public boolean add(T e)

Specified by:

add in interface java.util.Collection<T>

Specified by:

add in interface java.util.Set<T>

Overrides:

add in class java.util.AbstractCollection<T>

getFunction

public final InvertibleFunction<F,T> getFunction()

Returns:

The function which transforms elements into the form in which they are represented in by this view.

getBackingCollection

public final java.util.Collection<F> getBackingCollection()

Returns:

The backing collection this class presents a view over.

getModifiablebackingCollection

protected final java.util.Collection<F> getModifiablebackingCollection()

size

public final int size()

Specified by:

size in interface java.util.Collection<T>

Specified by:

size in interface java.util.Set<T>

Specified by:

size in class java.util.AbstractCollection<T>

iterator

public java.util.Iterator<T> iterator()

Specified by:

iterator in interface java.lang.Iterable<T>

Specified by:

iterator in interface java.util.Collection<T>

Specified by:

iterator in interface java.util.Set<T>

Specified by:

iterator in class java.util.AbstractCollection<T>