CopyOnWriteArraySetE

CopyOnWriteArraySet<E>

java.util.concurrent

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Java 5.0

serializable collection

This class is a threadsafe java.util.Set implementation based on the CopyOnWriteArrayList class. Because the data structure is array-based, the contains( ) method is O(n) ; this means that this class is suitable only for relatively small sets. Because the data structure uses copy-on-write , the class is best suited to cases where read operations and traversals greatly outnumber update operations. Iteration over the members of the set is efficient, and the Iterator returned by iterator( ) never throws ConcurrentModificationException . The remove( ) method of the iterator throws UnsupportedOperationException . See also CopyOnWriteArrayList .

Figure 16-79. java.util.concurrent.CopyOnWriteArraySet<E>

 public class  CopyOnWriteArraySet<E>  extends java.util.AbstractSet<E> implements Serializable {  // Public Constructors  public  CopyOnWriteArraySet  ( );        public  CopyOnWriteArraySet  (java.util.Collection<? extends E>  c  );  // Methods Implementing Set  public boolean  add  (E  o  );        public boolean  addAll  (java.util.Collection<? extends E>  c  );        public void  clear  ( );        public boolean  contains  (Object  o  );        public boolean  containsAll  (java.util.Collection<?>  c  );        public boolean  isEmpty  ( );  default:true  public java.util.Iterator<E>  iterator  ( );        public boolean  remove  (Object  o  );        public boolean  retainAll  (java.util.Collection<?>  c  );        public int  size  ( );        public Object[ ]  toArray  ( );        public <T> T[ ]  toArray  (T[ ]  a  );  // Public Methods Overriding AbstractSet  public boolean  removeAll  (java.util.Collection<?>  c  );   }