File	Doc	Category	Size	Date	Package
HashSet.java	API Doc	Android 1.5 API	6996	Wed May 06 22:41:04 BST 2009	java.util

HashSet

• java.lang.Object
  • java.util.AbstractCollection
    • java.util.AbstractSet

Fields Summary
private static final long	serialVersionUID
transient HashMap	backingMap

Constructors Summary
public HashSet() Constructs a new empty instance of {@code HashSet}. since Android 1.0 this(new HashMap<E, HashSet<E>>());
public HashSet(int capacity) Constructs a new instance of {@code HashSet} with the specified capacity. param capacity the initial capacity of this {@code HashSet}. since Android 1.0 this(new HashMap<E, HashSet<E>>(capacity));
public HashSet(int capacity, float loadFactor) Constructs a new instance of {@code HashSet} with the specified capacity and load factor. param capacity the initial capacity. param loadFactor the initial load factor. since Android 1.0 this(new HashMap<E, HashSet<E>>(capacity, loadFactor));
public HashSet(Collection collection) Constructs a new instance of {@code HashSet} containing the unique elements in the specified collection. param collection the collection of elements to add. since Android 1.0 this(new HashMap<E, HashSet<E>>(collection.size() < 6 ? 11 : collection.size() * 2)); for (E e : collection) { add(e); }
HashSet(HashMap backingMap) this.backingMap = backingMap;

Methods Summary
public boolean	add(E object) Adds the specified object to this {@code HashSet} if not already present. param object the object to add. return {@code true} when this {@code HashSet} did not already contain the object, {@code false} otherwise since Android 1.0 return backingMap.put(object, this) == null;
public void	clear() Removes all elements from this {@code HashSet}, leaving it empty. see #isEmpty see #size since Android 1.0 backingMap.clear();
public java.lang.Object	clone() Returns a new {@code HashSet} with the same elements and size as this {@code HashSet}. return a shallow copy of this {@code HashSet}. see java.lang.Cloneable since Android 1.0 try { HashSet<E> clone = (HashSet<E>) super.clone(); clone.backingMap = (HashMap<E, HashSet<E>>) backingMap.clone(); return clone; } catch (CloneNotSupportedException e) { return null; }
public boolean	contains(java.lang.Object object) Searches this {@code HashSet} for the specified object. param object the object to search for. return {@code true} if {@code object} is an element of this {@code HashSet}, {@code false} otherwise. since Android 1.0 return backingMap.containsKey(object);
java.util.HashMap	createBackingMap(int capacity, float loadFactor) return new HashMap<E, HashSet<E>>(capacity, loadFactor);
public boolean	isEmpty() Returns true if this {@code HashSet} has no elements, false otherwise. return {@code true} if this {@code HashSet} has no elements, {@code false} otherwise. see #size since Android 1.0 return backingMap.isEmpty();
public java.util.Iterator	iterator() Returns an Iterator on the elements of this {@code HashSet}. return an Iterator on the elements of this {@code HashSet}. see Iterator since Android 1.0 return backingMap.keySet().iterator();
private void	readObject(java.io.ObjectInputStream stream) stream.defaultReadObject(); int length = stream.readInt(); float loadFactor = stream.readFloat(); backingMap = createBackingMap(length, loadFactor); int elementCount = stream.readInt(); for (int i = elementCount; --i >= 0;) { E key = (E)stream.readObject(); backingMap.put(key, this); }
public boolean	remove(java.lang.Object object) Removes the specified object from this {@code HashSet}. param object the object to remove. return {@code true} if the object was removed, {@code false} otherwise. since Android 1.0 return backingMap.remove(object) != null;
public int	size() Returns the number of elements in this {@code HashSet}. return the number of elements in this {@code HashSet}. since Android 1.0 return backingMap.size();
private void	writeObject(java.io.ObjectOutputStream stream) stream.defaultWriteObject(); stream.writeInt(backingMap.elementData.length); stream.writeFloat(backingMap.loadFactor); stream.writeInt(backingMap.elementCount); for (int i = backingMap.elementData.length; --i >= 0;) { HashMap.Entry<E, HashSet<E>> entry = backingMap.elementData[i]; while (entry != null) { stream.writeObject(entry.key); entry = entry.next; } }