Class IdentityHashMap

src/main/java/freemarker/ext/util/IdentityHashMap.java:72–947

A variant of java.util.HashMap that uses System#identityHashCode(Object) for hashing, and reference comparison instead of Object#equals(Object). Note that this applies only to keys, and not to values, i.e. #containsValue(Object) still uses {@link Object#equals(Object)

 * @author  Attila Szegedi
 */
public class IdentityHashMap
    extends AbstractMap
    implements Map, Cloneable, java.io.Serializable
{

    public static final long serialVersionUID = 362498820763181265L;
    /**
     * The hash table data.
     */
    private transient Entry table[];

    /**
     * The total number of mappings in the hash table.
     */
    private transient int count;

    /**
     * The table is rehashed when its size exceeds this threshold.  (The
     * value of this field is (int)(capacity * loadFactor).)
     *
     * @serial
     */
    private int threshold;

    /**
     * The load factor for the hashtable.
     *
     * @serial
     */
    private float loadFactor;

    /**
     * The number of times this IdentityHashMap has been structurally modified
     * Structural modifications are those that change the number of mappings in
     * the IdentityHashMap or otherwise modify its internal structure (e.g.,
     * rehash).  This field is used to make iterators on Collection-views of
     * the IdentityHashMap fail-fast.  (See ConcurrentModificationException).
     */
    private transient int modCount = 0;

    /**
     * Constructs a new, empty map with the specified initial
     * capacity and the specified load factor.
     *
     * @param      initialCapacity   the initial capacity of the IdentityHashMap.
     * @param      loadFactor        the load factor of the IdentityHashMap
     * @throws     IllegalArgumentException  if the initial capacity is less
     *               than zero, or if the load factor is nonpositive.
     */
    public IdentityHashMap(int initialCapacity, float loadFactor)
    {
        if (initialCapacity < 0)
            throw new IllegalArgumentException(
                "Illegal Initial Capacity: " + initialCapacity);
        if (loadFactor <= 0 || Float.isNaN(loadFactor))
            throw new IllegalArgumentException(
                "Illegal Load factor: " + loadFactor);
        if (initialCapacity == 0)