# Class UnmodifiableSet<E>

java.lang.Object
org.apache.commons.collections4.collection.AbstractCollectionDecorator<E>
org.apache.commons.collections4.set.AbstractSetDecorator<E>
org.apache.commons.collections4.set.AbstractSerializableSetDecorator<E>
org.apache.commons.collections4.set.UnmodifiableSet<E>

Type Parameters:
  `E` - the type of the elements in this set

All Implemented Interfaces:
  `Serializable`, `Iterable<E>`, `Collection<E>`, `Set<E>`, `Unmodifiable`

public final class UnmodifiableSet<E> extends AbstractSerializableSetDecorator<E> implements Unmodifiable
Decorates another `Set` to ensure it can't be altered.

This class is Serializable from Commons Collections 3.1.

Attempts to modify it will result in an UnsupportedOperationException.

Since:
  3.0
See Also:
  - Serialized Form

- ## Method Summary

  Modifier and Type
  Method
  Description
  `boolean`
  `add(E object)`
  `boolean`
  `addAll(Collection<? extends E> coll)`
  `void`
  `clear()`
  `Iterator<E>`
  `iterator()`
  `boolean`
  `remove(Object object)`
  `boolean`
  `removeAll(Collection<?> coll)`
  `boolean`
  `removeIf(Predicate<? super E> filter)`
  `boolean`
  `retainAll(Collection<?> coll)`
  `static <E> Set<E>`
  `unmodifiableSet(Set<? extends E> set)`
  Factory method to create an unmodifiable set.

  ### Methods inherited from class org.apache.commons.collections4.set.AbstractSetDecorator

  `decorated, equals, hashCode`

  ### Methods inherited from class org.apache.commons.collections4.collection.AbstractCollectionDecorator

  `contains, containsAll, isEmpty, setCollection, size, toArray, toArray, toString`

  ### Methods inherited from class java.lang.Object

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

  ### Methods inherited from interface java.util.Collection

  `parallelStream, stream`

  ### Methods inherited from interface java.lang.Iterable

  `forEach`

  ### Methods inherited from interface java.util.Set

  `contains, containsAll, isEmpty, size, spliterator, toArray, toArray`

- ## Method Details

  - ### unmodifiableSet

    public static <E> Set<E> unmodifiableSet(Set<? extends E> set)
    Factory method to create an unmodifiable set.
    Type Parameters:
      `E` - the element type
    Parameters:
      `set` - the set to decorate, must not be null
    Returns:
      a new unmodifiable set
    Throws:
      `NullPointerException` - if set is null
    Since:
      4.0

  - ### add

    public boolean add(E object)
    Specified by:
      `add` in interface `Collection<E>`
    Specified by:
      `add` in interface `Set<E>`
    Overrides:
      `add` in class `AbstractCollectionDecorator<E>`

  - ### addAll

    public boolean addAll(Collection<? extends E> coll)
    Specified by:
      `addAll` in interface `Collection<E>`
    Specified by:
      `addAll` in interface `Set<E>`
    Overrides:
      `addAll` in class `AbstractCollectionDecorator<E>`

  - ### clear

    public void clear()
    Specified by:
      `clear` in interface `Collection<E>`
    Specified by:
      `clear` in interface `Set<E>`
    Overrides:
      `clear` in class `AbstractCollectionDecorator<E>`

  - ### iterator

    public Iterator<E> iterator()
    Specified by:
      `iterator` in interface `Collection<E>`
    Specified by:
      `iterator` in interface `Iterable<E>`
    Specified by:
      `iterator` in interface `Set<E>`
    Overrides:
      `iterator` in class `AbstractCollectionDecorator<E>`

  - ### remove

    public boolean remove(Object object)
    Specified by:
      `remove` in interface `Collection<E>`
    Specified by:
      `remove` in interface `Set<E>`
    Overrides:
      `remove` in class `AbstractCollectionDecorator<E>`

  - ### removeAll

    public boolean removeAll(Collection<?> coll)
    Specified by:
      `removeAll` in interface `Collection<E>`
    Specified by:
      `removeAll` in interface `Set<E>`
    Overrides:
      `removeAll` in class `AbstractCollectionDecorator<E>`

  - ### removeIf

    public boolean removeIf(Predicate<? super E> filter)
    Specified by:
      `removeIf` in interface `Collection<E>`
    Overrides:
      `removeIf` in class `AbstractCollectionDecorator<E>`
    Since:
      4.4

  - ### retainAll

    public boolean retainAll(Collection<?> coll)
    Specified by:
      `retainAll` in interface `Collection<E>`
    Specified by:
      `retainAll` in interface `Set<E>`
    Overrides:
      `retainAll` in class `AbstractCollectionDecorator<E>`