# Package org.apache.commons.collections4.collection

This package contains implementations of the `Collection` interface.

See: Description

- Interface Summary
  Interface | Description
  --- | ---
  CompositeCollection.CollectionMutator<E> | Pluggable strategy to handle changes to the composite.

- Class Summary
  Class | Description
  --- | ---
  AbstractCollectionDecorator<E> | Decorates another `Collection` to provide additional behaviour.
  CompositeCollection<E> | Decorates a collection of other collections to provide a single unified view.
  IndexedCollection<K,C> | An IndexedCollection is a Map-like view onto a Collection.
  PredicatedCollection<E> | Decorates another `Collection` to validate that additions match a specified predicate.
  PredicatedCollection.Builder<E> | Builder for creating predicated collections.
  SynchronizedCollection<E> | Decorates another `Collection` to synchronize its behaviour for a multi-threaded environment.
  TransformedCollection<E> | Decorates another `Collection` to transform objects that are added.
  UnmodifiableBoundedCollection<E> | `UnmodifiableBoundedCollection` decorates another `BoundedCollection` to ensure it can't be altered.
  UnmodifiableCollection<E> | Decorates another `Collection` to ensure it can't be altered.

## Package org.apache.commons.collections4.collection Description

This package contains implementations of the `Collection` interface.

The following implementations are provided in the package:

- CompositeCollection - a collection that combines multiple collections into one

The following decorators are provided in the package:

- Synchronized - synchronizes method access for multi-threaded environments
- Unmodifiable - ensures the collection cannot be altered
- Predicated - ensures that only elements that are valid according to a predicate can be added
- Transformed - transforms elements as they are added
- Indexed - provides a map-like view onto another collection

Copyright © 2001–2019 The Apache Software Foundation. All rights reserved.