org.jaxen.util
Class IdentityHashMap

java.lang.Object
  extended byjava.util.AbstractMap
      extended byorg.jaxen.util.IdentityHashMap
All Implemented Interfaces:
java.lang.Cloneable, java.util.Map, java.io.Serializable

public class IdentityHashMap
extends java.util.AbstractMap
implements java.util.Map, java.lang.Cloneable, java.io.Serializable

See Also:
Serialized Form

Nested Class Summary
private static class IdentityHashMap.EmptyHashIterator
           
private static class IdentityHashMap.Entry
          IdentityHashMap collision list entry.
private  class IdentityHashMap.HashIterator
           
 
Nested classes inherited from class java.util.AbstractMap
 
Field Summary
private  int count
          The total number of mappings in the hash table.
private static IdentityHashMap.EmptyHashIterator emptyHashIterator
           
private static int ENTRIES
           
private  java.util.Set entrySet
           
private static int KEYS
           
private  java.util.Set keySet
           
private  float loadFactor
          The load factor for the hashtable.
private  int modCount
          The number of times this HashMap has been structurally modified Structural modifications are those that change the number of mappings in the HashMap or otherwise modify its internal structure (e.g., rehash).
private static long serialVersionUID
           
private  IdentityHashMap.Entry[] table
          The hash table data.
private  int threshold
          The table is rehashed when its size exceeds this threshold.
private  java.util.Collection values
           
private static int VALUES
           
 
Constructor Summary
IdentityHashMap()
          Constructs a new, empty map with a default capacity and load factor, which is 0.75.
IdentityHashMap(int initialCapacity)
          Constructs a new, empty map with the specified initial capacity and default load factor, which is 0.75.
IdentityHashMap(int initialCapacity, float loadFactor)
          Constructs a new, empty map with the specified initial capacity and the specified load factor.
IdentityHashMap(java.util.Map t)
          Constructs a new map with the same mappings as the given map.
 
Method Summary
(package private)  int capacity()
           
 void clear()
          Removes all mappings from this map.
 java.lang.Object clone()
          Returns a shallow copy of this IdentityHashMap instance: the keys and values themselves are not cloned.
 boolean containsKey(java.lang.Object key)
          Returns true if this map contains a mapping for the specified key.
 boolean containsValue(java.lang.Object value)
          Returns true if this map maps one or more keys to the specified value.
 java.util.Set entrySet()
          Returns a collection view of the mappings contained in this map.
 java.lang.Object get(java.lang.Object key)
          Returns the value to which this map maps the specified key.
private  java.util.Iterator getHashIterator(int type)
           
 boolean isEmpty()
          Returns true if this map contains no key-value mappings.
 java.util.Set keySet()
          Returns a set view of the keys contained in this map.
(package private)  float loadFactor()
           
 java.lang.Object put(java.lang.Object key, java.lang.Object value)
          Associates the specified value with the specified key in this map.
 void putAll(java.util.Map t)
          Copies all of the mappings from the specified map to this one.
private  void readObject(java.io.ObjectInputStream s)
          Reconstitute the IdentityHashMap instance from a stream (i.e., deserialize it).
private  void rehash()
          Rehashes the contents of this map into a new IdentityHashMap instance with a larger capacity.
 java.lang.Object remove(java.lang.Object key)
          Removes the mapping for this key from this map if present.
 int size()
          Returns the number of key-value mappings in this map.
 java.util.Collection values()
          Returns a collection view of the values contained in this map.
private  void writeObject(java.io.ObjectOutputStream s)
          Save the state of the IdentityHashMap instance to a stream (i.e., serialize it).
 
Methods inherited from class java.util.AbstractMap
equals, hashCode, toString
 
Methods inherited from class java.lang.Object
finalize, getClass, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface java.util.Map
equals, hashCode
 

Field Detail

table

private transient IdentityHashMap.Entry[] table
The hash table data.


count

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


threshold

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


loadFactor

private float loadFactor
The load factor for the hashtable.


modCount

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


keySet

private transient java.util.Set keySet

entrySet

private transient java.util.Set entrySet

values

private transient java.util.Collection values

KEYS

private static final int KEYS
See Also:
Constant Field Values

VALUES

private static final int VALUES
See Also:
Constant Field Values

ENTRIES

private static final int ENTRIES
See Also:
Constant Field Values

emptyHashIterator

private static IdentityHashMap.EmptyHashIterator emptyHashIterator

serialVersionUID

private static final long serialVersionUID
See Also:
Constant Field Values
Constructor Detail

IdentityHashMap

public IdentityHashMap(int initialCapacity,
                       float loadFactor)
Constructs a new, empty map with the specified initial capacity and the specified load factor.

Parameters:
initialCapacity - the initial capacity of the HashMap.
loadFactor - the load factor of the HashMap
Throws:
java.lang.IllegalArgumentException - if the initial capacity is less than zero, or if the load factor is nonpositive.

IdentityHashMap

public IdentityHashMap(int initialCapacity)
Constructs a new, empty map with the specified initial capacity and default load factor, which is 0.75.

Parameters:
initialCapacity - the initial capacity of the HashMap.
Throws:
java.lang.IllegalArgumentException - if the initial capacity is less than zero.

IdentityHashMap

public IdentityHashMap()
Constructs a new, empty map with a default capacity and load factor, which is 0.75.


IdentityHashMap

public IdentityHashMap(java.util.Map t)
Constructs a new map with the same mappings as the given map. The map is created with a capacity of twice the number of mappings in the given map or 11 (whichever is greater), and a default load factor, which is 0.75.

Parameters:
t - the map whose mappings are to be placed in this map.
Method Detail

size

public int size()
Returns the number of key-value mappings in this map.

Specified by:
size in interface java.util.Map
Returns:
the number of key-value mappings in this map.

isEmpty

public boolean isEmpty()
Returns true if this map contains no key-value mappings.

Specified by:
isEmpty in interface java.util.Map
Returns:
true if this map contains no key-value mappings.

containsValue

public boolean containsValue(java.lang.Object value)
Returns true if this map maps one or more keys to the specified value.

Specified by:
containsValue in interface java.util.Map
Parameters:
value - value whose presence in this map is to be tested.
Returns:
true if this map maps one or more keys to the specified value.

containsKey

public boolean containsKey(java.lang.Object key)
Returns true if this map contains a mapping for the specified key.

Specified by:
containsKey in interface java.util.Map
Parameters:
key - key whose presence in this Map is to be tested.
Returns:
true if this map contains a mapping for the specified key.

get

public java.lang.Object get(java.lang.Object key)
Returns the value to which this map maps the specified key. Returns null if the map contains no mapping for this key. A return value of null does not necessarily indicate that the map contains no mapping for the key; it's also possible that the map explicitly maps the key to null. The containsKey operation may be used to distinguish these two cases.

Specified by:
get in interface java.util.Map
Parameters:
key - key whose associated value is to be returned.
Returns:
the value to which this map maps the specified key.

rehash

private void rehash()
Rehashes the contents of this map into a new IdentityHashMap instance with a larger capacity. This method is called automatically when the number of keys in this map exceeds its capacity and load factor.


put

public java.lang.Object put(java.lang.Object key,
                            java.lang.Object value)
Associates the specified value with the specified key in this map. If the map previously contained a mapping for this key, the old value is replaced.

Specified by:
put in interface java.util.Map
Parameters:
key - key with which the specified value is to be associated.
value - value to be associated with the specified key.
Returns:
previous value associated with specified key, or null if there was no mapping for key. A null return can also indicate that the IdentityHashMap previously associated null with the specified key.

remove

public java.lang.Object remove(java.lang.Object key)
Removes the mapping for this key from this map if present.

Specified by:
remove in interface java.util.Map
Parameters:
key - key whose mapping is to be removed from the map.
Returns:
previous value associated with specified key, or null if there was no mapping for key. A null return can also indicate that the map previously associated null with the specified key.

putAll

public void putAll(java.util.Map t)
Copies all of the mappings from the specified map to this one. These mappings replace any mappings that this map had for any of the keys currently in the specified Map.

Specified by:
putAll in interface java.util.Map
Parameters:
t - Mappings to be stored in this map.

clear

public void clear()
Removes all mappings from this map.

Specified by:
clear in interface java.util.Map

clone

public java.lang.Object clone()
Returns a shallow copy of this IdentityHashMap instance: the keys and values themselves are not cloned.

Returns:
a shallow copy of this map.

keySet

public java.util.Set keySet()
Returns a set view of the keys contained in this map. The set is backed by the map, so changes to the map are reflected in the set, and vice-versa. The set supports element removal, which removes the corresponding mapping from this map, via the Iterator.remove, Set.remove, removeAll, retainAll, and clear operations. It does not support the add or addAll operations.

Specified by:
keySet in interface java.util.Map
Returns:
a set view of the keys contained in this map.

values

public java.util.Collection values()
Returns a collection view of the values contained in this map. The collection is backed by the map, so changes to the map are reflected in the collection, and vice-versa. The collection supports element removal, which removes the corresponding mapping from this map, via the Iterator.remove, Collection.remove, removeAll, retainAll, and clear operations. It does not support the add or addAll operations.

Specified by:
values in interface java.util.Map
Returns:
a collection view of the values contained in this map.

entrySet

public java.util.Set entrySet()
Returns a collection view of the mappings contained in this map. Each element in the returned collection is a Map.Entry. The collection is backed by the map, so changes to the map are reflected in the collection, and vice-versa. The collection supports element removal, which removes the corresponding mapping from the map, via the Iterator.remove, Collection.remove, removeAll, retainAll, and clear operations. It does not support the add or addAll operations.

Specified by:
entrySet in interface java.util.Map
Returns:
a collection view of the mappings contained in this map.
See Also:
IdentityHashMap.Entry

getHashIterator

private java.util.Iterator getHashIterator(int type)

writeObject

private void writeObject(java.io.ObjectOutputStream s)
                  throws java.io.IOException
Save the state of the IdentityHashMap instance to a stream (i.e., serialize it).

Throws:
java.io.IOException

readObject

private void readObject(java.io.ObjectInputStream s)
                 throws java.io.IOException,
                        java.lang.ClassNotFoundException
Reconstitute the IdentityHashMap instance from a stream (i.e., deserialize it).

Throws:
java.io.IOException
java.lang.ClassNotFoundException

capacity

int capacity()

loadFactor

float loadFactor()