AbstractCollectionDecorator (The Adobe AEM Quickstart and Web Application.)

java.lang.Object
- org.apache.commons.collections4.collection.AbstractCollectionDecorator<E>

Type Parameters:

E - the type of the elements in the collection

All Implemented Interfaces:

java.io.Serializable, java.lang.Iterable<E>, java.util.Collection<E>

Direct Known Subclasses:

AbstractBagDecorator, AbstractListDecorator, AbstractMultiSetDecorator, AbstractQueueDecorator, AbstractSetDecorator, IndexedCollection, PredicatedCollection, TransformedCollection, UnmodifiableBoundedCollection, UnmodifiableCollection
```
public abstract class AbstractCollectionDecorator<E>
extends java.lang.Object
implements java.util.Collection<E>, java.io.Serializable
```
Decorates another Collection to provide additional behaviour.
Each method call made on this Collection is forwarded to the decorated Collection. This class is used as a framework on which to build to extensions such as synchronized and unmodifiable behaviour. The main advantage of decoration is that one decorator can wrap any implementation of Collection, whereas sub-classing requires a new class to be written for each implementation.

This implementation does not perform any special processing with iterator(). Instead it simply returns the value from the wrapped collection. This may be undesirable, for example if you are trying to write an unmodifiable implementation it might provide a loophole.

This implementation does not forward the hashCode and equals methods through to the backing object, but relies on Object's implementation. This is necessary to preserve the symmetry of equals. Custom definitions of equality are usually based on an interface, such as Set or List, so that the implementation of equals can cast the object being tested for equality to the custom interface. AbstractCollectionDecorator does not implement such custom interfaces directly; they are implemented only in subclasses. Therefore, forwarding equals would break symmetry, as the forwarding object might consider itself equal to the object being tested, but the reverse could not be true. This behavior is consistent with the JDK's collection wrappers, such as Collections.unmodifiableCollection(Collection). Use an interface-specific subclass of AbstractCollectionDecorator, such as AbstractListDecorator, to preserve equality behavior, or override equals directly.

Since:

3.0

See Also:

Serialized Form

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`boolean`	`add(E object)`
`boolean`	`addAll(java.util.Collection<? extends E> coll)`
`void`	`clear()`
`boolean`	`contains(java.lang.Object object)`
`boolean`	`containsAll(java.util.Collection<?> coll)`
`boolean`	`isEmpty()`
`java.util.Iterator<E>`	`iterator()`
`boolean`	`remove(java.lang.Object object)`
`boolean`	`removeAll(java.util.Collection<?> coll)`
`boolean`	`removeIf(java.util.function.Predicate<? super E> filter)`
`boolean`	`retainAll(java.util.Collection<?> coll)`
`int`	`size()`
`java.lang.Object[]`	`toArray()`
`<T> T[]`	`toArray(T[] object)`
`java.lang.String`	`toString()`

Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Collection
equals, hashCode, parallelStream, spliterator, stream

Methods inherited from interface java.lang.Iterable
forEach

- Method Detail
  - add
```
public boolean add(E object)
```
    Specified by:
    
    add in interface java.util.Collection<E>
  - addAll
```
public boolean addAll(java.util.Collection<? extends E> coll)
```
    Specified by:
    
    addAll in interface java.util.Collection<E>
  - clear
```
public void clear()
```
    Specified by:
    
    clear in interface java.util.Collection<E>
  - contains
```
public boolean contains(java.lang.Object object)
```
    Specified by:
    
    contains in interface java.util.Collection<E>
  - isEmpty
```
public boolean isEmpty()
```
    Specified by:
    
    isEmpty in interface java.util.Collection<E>
  - iterator
```
public java.util.Iterator<E> iterator()
```
    Specified by:
    
    iterator in interface java.lang.Iterable<E>
    
    Specified by:
    
    iterator in interface java.util.Collection<E>
  - remove
```
public boolean remove(java.lang.Object object)
```
    Specified by:
    
    remove in interface java.util.Collection<E>
  - size
```
public int size()
```
    Specified by:
    
    size in interface java.util.Collection<E>
  - toArray
```
public java.lang.Object[] toArray()
```
    Specified by:
    
    toArray in interface java.util.Collection<E>
  - toArray
```
public <T> T[] toArray(T[] object)
```
    Specified by:
    
    toArray in interface java.util.Collection<E>
  - containsAll
```
public boolean containsAll(java.util.Collection<?> coll)
```
    Specified by:
    
    containsAll in interface java.util.Collection<E>
  - removeIf
```
public boolean removeIf(java.util.function.Predicate<? super E> filter)
```
    Specified by:
    
    removeIf in interface java.util.Collection<E>
    
    Since:
    
    4.4
  - removeAll
```
public boolean removeAll(java.util.Collection<?> coll)
```
    Specified by:
    
    removeAll in interface java.util.Collection<E>
  - retainAll
```
public boolean retainAll(java.util.Collection<?> coll)
```
    Specified by:
    
    retainAll in interface java.util.Collection<E>
  - toString
```
public java.lang.String toString()
```
    Overrides:
    
    toString in class java.lang.Object

Class AbstractCollectionDecorator<E>

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface java.util.Collection

Methods inherited from interface java.lang.Iterable

Method Detail

add

addAll

clear

contains

isEmpty

iterator

remove

size

toArray

toArray

containsAll

removeIf

removeAll

retainAll

toString