Build 1.0_r1(from source)

java.util
Class AbstractCollection<E>

java.lang.Object
  extended by java.util.AbstractCollection<E>
All Implemented Interfaces:
Iterable<E>, Collection<E>
Direct Known Subclasses:
AbstractList, AbstractQueue, AbstractSet, ConcurrentHashMap.Values, TreeMap.SubMapValuesCollection

public abstract class AbstractCollection<E>
extends Object
implements Collection<E>

AbstractCollection is an abstract implementation of the Collection interface. This implementation does not support adding. A subclass must implement the abstract methods iterator() and size().

Since:
1.2

Constructor Summary
protected AbstractCollection()
          Constructs a new instance of this AbstractCollection.
 
Method Summary
 boolean add(E object)
          If the specified element is not contained within this collection, and addition of this element succeeds, then true will be returned.
 boolean addAll(Collection<? extends E> collection)
          Adds the objects in the specified Collection to this Collection.
 void clear()
          Removes all the elements in this collection.
 boolean contains(Object object)
          Searches this Collection for the specified object.
 boolean containsAll(Collection<?> collection)
          Searches this Collection for all objects in the specified Collection.
 boolean isEmpty()
          Returns true if the collection has no element, otherwise false.
abstract  Iterator<E> iterator()
          Returns an Iterator on the elements of this Collection.
 boolean remove(Object object)
          Removes the first occurrence of the specified object from this Collection.
 boolean removeAll(Collection<?> collection)
          Removes all occurrences in this Collection of each object in the specified Collection.
 boolean retainAll(Collection<?> collection)
          Removes all objects from this Collection that are not contained in the specified Collection.
abstract  int size()
          Returns the number of elements in this Collection.
 Object[] toArray()
          Returns a new array containing all elements contained in this Collection.
<T> T[]
toArray(T[] contents)
          Returns an array containing all elements contained in this Collection.
 String toString()
          Returns the string representation of this Collection.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface java.util.Collection
equals, hashCode
 

Constructor Detail

AbstractCollection

protected AbstractCollection()
Constructs a new instance of this AbstractCollection.

Method Detail

add

public boolean add(E object)
If the specified element is not contained within this collection, and addition of this element succeeds, then true will be returned. If the specified element is already contained within this collection, or duplication is not permitted, false will be returned. Different implementations may add specific limitations on this method to filter permitted elements. For example, in some implementation, null element may be denied, and NullPointerException will be thrown out. These limitations should be explicitly documented by specific collection implementation. Add operation is not supported in this implementation, and UnsupportedOperationException will always be thrown out.

Specified by:
add in interface Collection<E>
Parameters:
object - the element to be added.
Returns:
true if the collection is changed successfully after invoking this method. Otherwise, false.
Throws:
UnsupportedOperationException - if add operation is not supported by this class.
NullPointerException - if null is used to invoke this method, and null is not permitted by this collection.
ClassCastException - if the class type of the specified element is not compatible with the permitted class type.
IllegalArgumentException - if limitations of this collection prevent the specified element from being added

addAll

public boolean addAll(Collection<? extends E> collection)
Adds the objects in the specified Collection to this Collection.

Specified by:
addAll in interface Collection<E>
Parameters:
collection - the Collection of objects
Returns:
true if this Collection is modified, false otherwise
Throws:
UnsupportedOperationException - when adding to this Collection is not supported
NullPointerException - if null is used to invoke this method

clear

public void clear()
Removes all the elements in this collection. This collection will be cleared up after this operation. The operation iterates over the collection, removes every element using Iterator.remove method. UnsupportedOperationException will be thrown out if the iterator returned by this collection does not implement the remove method and the collection is not zero length.

Specified by:
clear in interface Collection<E>
Throws:
UnsupportedOperationException - if this operation is not implemented.
See Also:
Collection.isEmpty(), Collection.size()

contains

public boolean contains(Object object)
Searches this Collection for the specified object.

Specified by:
contains in interface Collection<E>
Parameters:
object - the object to search for
Returns:
true if object is an element of this Collection, false otherwise

containsAll

public boolean containsAll(Collection<?> collection)
Searches this Collection for all objects in the specified Collection.

Specified by:
containsAll in interface Collection<E>
Parameters:
collection - the Collection of objects
Returns:
true if all objects in the specified Collection are elements of this Collection, false otherwise
Throws:
NullPointerException - if null is used to invoke this method

isEmpty

public boolean isEmpty()
Returns true if the collection has no element, otherwise false.

Specified by:
isEmpty in interface Collection<E>
Returns:
true if the collection has no element.
See Also:
Collection.size()

iterator

public abstract Iterator<E> iterator()
Returns an Iterator on the elements of this Collection. A subclass must implement the abstract methods iterator() and size().

Specified by:
iterator in interface Iterable<E>
Specified by:
iterator in interface Collection<E>
Returns:
an Iterator on the elements of this Collection
See Also:
Iterator

remove

public boolean remove(Object object)
Removes the first occurrence of the specified object from this Collection. This operation traverses over the collection, looking for the specified object. Once the object is found, the object will be removed from the collection using the iterator's remove method. This collection will throw an UnsupportedOperationException if the iterator returned does not implement remove method, and the specified object is in this collection.

Specified by:
remove in interface Collection<E>
Parameters:
object - the object to remove
Returns:
true if this Collection is modified, false otherwise
Throws:
UnsupportedOperationException - when removing from this Collection is not supported

removeAll

public boolean removeAll(Collection<?> collection)
Removes all occurrences in this Collection of each object in the specified Collection. This operation traverses over the collection itself, to verify whether each element is contained in the specified collection. The object will be removed from the collection itself using the iterator's remove method if it is contained in the specified collection. This collection will throw an UnsupportedOperationException if the iterator returned does not implement remove method, and the element in the specified collection is contained in this collection.

Specified by:
removeAll in interface Collection<E>
Parameters:
collection - the Collection of objects to remove
Returns:
true if this Collection is modified, false otherwise
Throws:
UnsupportedOperationException - when removing from this Collection is not supported
NullPointerException - if null is used to invoke this method

retainAll

public boolean retainAll(Collection<?> collection)
Removes all objects from this Collection that are not contained in the specified Collection. This operation traverses over the collection itself, to verify whether any element is contained in the specified collection. The object will be removed from the collection itself using the iterator's remove method if it is not contained in the specified collection. This collection will throw an UnsupportedOperationException if the iterator returned does not implement remove method, and the collection itself does contain elements which do not exist in the specified collection.

Specified by:
retainAll in interface Collection<E>
Parameters:
collection - the Collection of objects to retain
Returns:
true if this Collection is modified, false otherwise
Throws:
UnsupportedOperationException - when removing from this Collection is not supported
NullPointerException - if null is used to invoke this method

size

public abstract int size()
Returns the number of elements in this Collection.

Specified by:
size in interface Collection<E>
Returns:
the number of elements in this Collection

toArray

public Object[] toArray()
Returns a new array containing all elements contained in this Collection. All the elements in the array will not be referenced by the collection. The elements in the returned array will be sorted to the same order as those returned by the iterator of this collection itself if the collection guarantees the order.

Specified by:
toArray in interface Collection<E>
Returns:
an array of the elements from this Collection

toArray

public <T> T[] toArray(T[] contents)
Returns an array containing all elements contained in this Collection. If the specified array is large enough to hold the elements, the specified array is used, otherwise an array of the same type is created. If the specified array is used and is larger than this Collection, the array element following the collection elements is set to null.

Specified by:
toArray in interface Collection<E>
Parameters:
contents - the array
Returns:
an array of the elements from this Collection
Throws:
ArrayStoreException - when the type of an element in this Collection cannot be stored in the type of the specified array
NullPointerException - if null is used to invoke this method

toString

public String toString()
Returns the string representation of this Collection. The presentation has a specific format. It is enclosed by square brackets ("[]"). Elements are separated by ', ' (comma and space).

Overrides:
toString in class Object
Returns:
the string representation of this Collection

Build 1.0_r1(from source)

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