oracle.jbo.server.java.util
Class ArraySet

java.lang.Object
oracle.jbo.server.java.util.AbstractCollection
oracle.jbo.server.java.util.AbstractSet
oracle.jbo.server.java.util.ArraySet

All Implemented Interfaces:

java.lang.Cloneable, Collection, java.io.Serializable, Set

public class ArraySet

extends AbstractSet

implements Set, java.lang.Cloneable, java.io.Serializable

This class implements the Set interface, backed by an ArrayList. It is designed to offer good performance for very small Sets, especially those that are frequently created and destroyed. The performance will be extremely bad for large Sets: ArraySet provides linear time performance for the basic operations (add, remove and contains). This Set permit all elements, including null.

Note that this implementation is not synchronized. If multiple threads access an ArraySet concurrently, and at least one of the threads modifies the ArraySet, it must be synchronized externally. This is typically accomplished by synchronizing on some object that naturally encapsulates the ArraySet. If no such object exists, the ArraySet should be "wrapped" using the Collections.synchronizedSet method. This is best done at creation time, to prevent accidental unsynchronized access to the ArraySet:

        Set s = Collections.synchronizedSet(new ArraySet(...));
 

The Iterators returned by ArraySet's iterator method are fail-fast: if the HashSet is modified at any time after the Iterator is created, in any way except through the Iterator's own remove method, the Iterator will throw a ConcurrentModificationException. Thus, in the face of concurrent modification, the Iterator fails quickly and cleanly, rather than risking arbitrary, non-deterministic behavior at an undetermined time in the future.

Since:

JDK1.2

See Also:

Collection, Set, HashSet, Collections.SynchronizedSet, ArrayList, Serialized Form

Constructor Summary

ArraySet()
Constructs a new, empty ArraySet; the backing ArrayList has default initial capacity and capacity increment.

ArraySet(Collection c)
Constructs a new ArraySet containing the elements in the specified Collection.

ArraySet(int initialCapacity)
Constructs a new, empty ArraySet; the backing ArrayList has the specified initial capacity and default capacity increment.

Method Summary

boolean	add(java.lang.Object o) Adds the specified element to this Set if it is not already present.
void	clear() Removes all of the elements from this Set.
java.lang.Object	clone() Returns a shallow copy of this ArraySet.
boolean	contains(java.lang.Object o) Returns true if this ArraySet contains the specified element.
boolean	isEmpty() Returns true if this ArraySet contains no elements.
Iterator	iterator() Returns an Iterator over the elements in this ArraySet.
boolean	remove(java.lang.Object o) Removes the given element from this Set if it is present.
int	size() Returns the number of elements in this ArraySet (its cardinality).

Methods inherited from class oracle.jbo.server.java.util.AbstractSet

equals, hashCode

Methods inherited from class oracle.jbo.server.java.util.AbstractCollection

addAll, containsAll, removeAll, retainAll, toArray, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface oracle.jbo.server.java.util.Set

addAll, containsAll, equals, hashCode, removeAll, retainAll, toArray

Constructor Detail

ArraySet

public ArraySet()

Constructs a new, empty ArraySet; the backing ArrayList has default initial capacity and capacity increment.

Since:

JDK1.2

ArraySet

public ArraySet(Collection c)

Constructs a new ArraySet containing the elements in the specified Collection. The backing ArrayList has default initial capacity and capacity increment.

Throws:

java.lang.NullPointerException - the specified collection is null.

Since:

JDK1.2

ArraySet

public ArraySet(int initialCapacity)

Constructs a new, empty ArraySet; the backing ArrayList has the specified initial capacity and default capacity increment.

Parameters:

initialCapacity - the initial capacity of the ArrayList.

Since:

JDK1.2

Method Detail

iterator

public Iterator iterator()

Returns an Iterator over the elements in this ArraySet. The elements are returned in the order they were added.

Specified by:

iterator in interface Set

Specified by:

iterator in class AbstractCollection

Since:

JDK1.2

size

public int size()

Returns the number of elements in this ArraySet (its cardinality).

Specified by:

size in interface Set

Specified by:

size in class AbstractCollection

Since:

JDK1.2

isEmpty

public boolean isEmpty()

Returns true if this ArraySet contains no elements.

Specified by:

isEmpty in interface Set

Overrides:

isEmpty in class AbstractCollection

Since:

JDK1.2

contains

public boolean contains(java.lang.Object o)

Returns true if this ArraySet contains the specified element.

Specified by:

contains in interface Set

Overrides:

contains in class AbstractCollection

Since:

JDK1.2

add

public boolean add(java.lang.Object o)

Adds the specified element to this Set if it is not already present.

Specified by:

add in interface Set

Overrides:

add in class AbstractCollection

Parameters:

o - element to be added to this Set.

Returns:

true if the Set did not already contain the specified element.

Since:

JDK1.2

remove

public boolean remove(java.lang.Object o)

Removes the given element from this Set if it is present.

Specified by:

remove in interface Set

Overrides:

remove in class AbstractCollection

Parameters:

o - object to be removed from this Set, if present.

Returns:

true if the Set contained the specified element.

Since:

JDK1.2

clear

public void clear()

Removes all of the elements from this Set.

Specified by:

clear in interface Set

Overrides:

clear in class AbstractCollection

Since:

JDK1.2

clone

public java.lang.Object clone()

Returns a shallow copy of this ArraySet. (The elements themselves are not cloned.)

Since:

JDK1.2