File	Doc	Category	Size	Date	Package
TopLinkIdentityHashSet.java	API Doc	Glassfish v2 API	16059	Tue May 22 16:54:34 BST 2007	oracle.toplink.essentials.internal.helper

TopLinkIdentityHashSet

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

Fields Summary
static final long	serialVersionUID
static final int	DEFAULT_INITIAL_CAPACITY
static final int	MAXIMUM_CAPACITY
static final float	DEFAULT_LOAD_FACTOR
protected transient Entry[]	entries
protected transient int	count
protected int	threshold
protected float	loadFactor

Constructors Summary
public TopLinkIdentityHashSet(int initialCapacity, float loadFactor) Constructs a new TopLinkIdentityHashSet with the given initial capacity and the given loadFactor. param initialCapacity the initial capacity of the TopLinkIdentityHashSet. param loadFactor the loadFactor of the TopLinkIdentityHashSet. throws IllegalArgumentException if the initial capacity is less than zero, or if the loadFactor is nonpositive. if (initialCapacity < 0) { throw new IllegalArgumentException("Illegal initialCapacity: " + initialCapacity); } if (initialCapacity > MAXIMUM_CAPACITY) { initialCapacity = MAXIMUM_CAPACITY; } if ((loadFactor <= 0) || Float.isNaN(loadFactor)) { throw new IllegalArgumentException("Illegal loadFactor: " + loadFactor); } // Find a power of 2 >= initialCapacity int capacity = 1; while (capacity < initialCapacity) { capacity <<= 1; } this.loadFactor = loadFactor; threshold = (int)(capacity * loadFactor); entries = new Entry[capacity];
public TopLinkIdentityHashSet(int initialCapacity) Constructs a new TopLinkIdentityHashSet with the given initial capacity and a default loadFactor of 0.75. param initialCapacity the initial capacity of the TopLinkIdentityHashSet. throws IllegalArgumentException if the initial capacity is less than zero. this(initialCapacity, DEFAULT_LOAD_FACTOR);
public TopLinkIdentityHashSet() Constructs a new TopLinkIdentityHashSet with a default initial capacity of 32 and a loadfactor of 0.75. loadFactor = DEFAULT_LOAD_FACTOR; threshold = (int)(DEFAULT_INITIAL_CAPACITY * DEFAULT_LOAD_FACTOR); entries = new Entry[DEFAULT_INITIAL_CAPACITY];
public TopLinkIdentityHashSet(Collection c) Constructs a new TopLinkIdentityHashSet with the same contents as the given Collection. The new TopLinkIdentityHashSet is created with an initial capacity sufficient to hold the elements of the given Collection. param c the Collection whose contents are to be placed in the new TopLinkIdentityHashSet. this(Math.max((int)(c.size() / DEFAULT_LOAD_FACTOR) + 1, DEFAULT_INITIAL_CAPACITY), DEFAULT_LOAD_FACTOR); addAll(c);

Methods Summary
public boolean	add(java.lang.Object obj) Adds the given object to this TopLinkIdentityHashSet. param obj object to add. return true if this TopLinkIdentityHashSet did not already contain obj. throws NullPointerException if obj is null. if (obj == null) { throw new NullPointerException(); } // Makes sure the object is not already in the TopLinkIdentityHashSet. Entry[] copyOfEntries = entries; int hash = System.identityHashCode(obj); int index = (hash & 0x7FFFFFFF) % copyOfEntries.length; for (Entry e = copyOfEntries[index]; e != null; e = e.next) { if ((e.hash == hash) && (obj == e.value)) { return false; } } if (count >= threshold) { // Rehash the table if the threshold is exceeded rehash(); copyOfEntries = entries; index = (hash & 0x7FFFFFFF) % copyOfEntries.length; } // Creates the new entry. Entry e = new Entry(hash, obj, copyOfEntries[index]); copyOfEntries[index] = e; count++; return true;
public void	clear() Removes all of the objects from this TopLinkIdentityHashSet. if (count > 0) { Entry[] copyOfEntries = entries; for (int i = copyOfEntries.length; --i >= 0;) { copyOfEntries[i] = null; } count = 0; }
public java.lang.Object	clone() Returns a shallow copy of this TopLinkIdentityHashSet (the elements are not cloned). return a shallow copy of this TopLinkIdentityHashSet. try { Entry[] copyOfEntries = entries; TopLinkIdentityHashSet clone = (TopLinkIdentityHashSet)super.clone(); clone.entries = new Entry[copyOfEntries.length]; for (int i = copyOfEntries.length; i-- > 0;) { clone.entries[i] = (copyOfEntries[i] != null) ? (Entry)copyOfEntries[i].clone() : null; } return clone; } catch (CloneNotSupportedException e) { // this shouldn't happen, since we are Cloneable throw new InternalError(); }
public boolean	contains(java.lang.Object obj) Returns true if this TopLinkIdentityHashSet contains the given object. param obj the object to find. return true if this TopLinkIdentityHashSet contains obj by reference. if (obj == null) { return false; } Entry[] copyOfEntries = entries; int hash = System.identityHashCode(obj); int index = (hash & 0x7FFFFFFF) % copyOfEntries.length; for (Entry e = copyOfEntries[index]; e != null; e = e.next) { if ((e.hash == hash) && (obj == e.value)) { return true; } } return false;
public boolean	isEmpty() return true if this TopLinkIdentityHashSet is empty. return (count == 0);
public java.util.Iterator	iterator() Get an iterator for this TopLinkIdentityHashSet return new TopLinkIdentityHashSetIterator();
private void	readObject(java.io.ObjectInputStream s) Deserialize the TopLinkIdentityHashSet from a stream. // Read in the threshold, loadfactor (and any hidden 'magic' stuff). s.defaultReadObject(); // Read in number of buckets and allocate the bucket array; int numBuckets = s.readInt(); entries = new Entry[numBuckets]; // Read in size (count) int size = s.readInt(); // Read the objects and add to the TopLinkIdentityHashSet for (int i = 0; i < size; i++) { add(s.readObject()); }
private void	rehash() INTERNAL: Re-builds the internal array of Entry's with a larger capacity. This method is called automatically when the number of objects in this TopLinkIdentityHashSet exceeds its current threshold. int oldCapacity = entries.length; Entry[] oldEntries = entries; int newCapacity = (oldCapacity * 2) + 1; Entry[] newEntries = new Entry[newCapacity]; threshold = (int)(newCapacity * loadFactor); entries = newEntries; for (int i = oldCapacity; i-- > 0;) { for (Entry old = oldEntries[i]; old != null;) { Entry e = old; old = old.next; int index = (e.hash & 0x7FFFFFFF) % newCapacity; e.next = newEntries[index]; newEntries[index] = e; } }
public boolean	remove(java.lang.Object obj) Removes the given object from this TopLinkIdentityHashSet, if present. param obj the object to be removed from this TopLinkIdentityHashSet. return true if this TopLinkIdentityHashSet contained obj. if (obj == null) { return false; } Entry[] copyOfEntries = entries; int hash = System.identityHashCode(obj); int index = (hash & 0x7FFFFFFF) % copyOfEntries.length; for (Entry e = copyOfEntries[index], prev = null; e != null; prev = e, e = e.next) { if ((e.hash == hash) && (obj == e.value)) { if (prev != null) { prev.next = e.next; } else { copyOfEntries[index] = e.next; } count--; return true; } } return false;
public boolean	removeAll(java.util.Collection c) This implementation throws an UnsupportedOperationException because removeAll does not work correctly with reference equality testing. throw new UnsupportedOperationException("TopLinkIdentityHashSet removeAll");
public boolean	retainAll(java.util.Collection c) This implementation throws an UnsupportedOperationException. The Javadocs for {@link AbstractCollection} indicates that retainAll is an optional method. throw new UnsupportedOperationException("TopLinkIdentityHashSet retainAll");
public int	size() return the size of this TopLinkIdentityHashSet. return count;
private void	writeObject(java.io.ObjectOutputStream s) Serialize the state of this TopLinkIdentityHashSet to a stream. serialData The capacity of the TopLinkIdentityHashSet (the length of the bucket array) is emitted (int), followed by the size of the TopLinkIdentityHashSet, followed by the contents (in no particular order). // Write out the threshold, loadfactor (and any hidden 'magic' stuff). s.defaultWriteObject(); // Write out number of buckets s.writeInt(entries.length); // Write out count s.writeInt(count); // Write out contents for (Iterator i = iterator(); i.hasNext();) { s.writeObject(i.next()); }