freemarker.ext.util
Class IdentityHashMap
AbstractMap
freemarker.ext.util.IdentityHashMap
- Cloneable, Map, java.io.Serializable
public class IdentityHashMap
extends AbstractMap
implements Map, Cloneable, java.io.Serializable
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
Object.equals(Object)
.
IdentityHashMap() - Constructs a new, empty map with a default capacity and load
factor, which is 0.75.
|
IdentityHashMap(Map t) - Constructs a new map with the same mappings as the given map.
|
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.
|
void | clear() - Removes all mappings from this map.
|
Object | clone() - Returns a shallow copy of this IdentityHashMap instance: the keys and
values themselves are not cloned.
|
boolean | containsKey(Object key) - Returns true if this map contains a mapping for the specified
key.
|
boolean | containsValue(Object value) - Returns true if this map maps one or more keys to the
specified value.
|
Set | entrySet() - Returns a collection view of the mappings contained in this map.
|
Object | get(Object key) - Returns the value to which this map maps the specified key.
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boolean | isEmpty() - Returns true if this map contains no key-value mappings.
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Set | keySet() - Returns a set view of the keys contained in this map.
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Object | put(Object key, Object value) - Associates the specified value with the specified key in this map.
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void | putAll(Map t) - Copies all of the mappings from the specified map to this one.
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Object | remove(Object key) - Removes the mapping for this key from this map if present.
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int | size() - Returns the number of key-value mappings in this map.
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Collection | values() - Returns a collection view of the values contained in this map.
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serialVersionUID
public static final long serialVersionUID
IdentityHashMap
public IdentityHashMap()
Constructs a new, empty map with a default capacity and load
factor, which is 0.75.
IdentityHashMap
public IdentityHashMap(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.
t
- the map whose mappings are to be placed in this map.
IdentityHashMap
public IdentityHashMap(int initialCapacity)
Constructs a new, empty map with the specified initial capacity
and default load factor, which is 0.75.
initialCapacity
- the initial capacity of the IdentityHashMap.
IdentityHashMap
public IdentityHashMap(int initialCapacity,
float loadFactor)
Constructs a new, empty map with the specified initial
capacity and the specified load factor.
initialCapacity
- the initial capacity of the IdentityHashMap.loadFactor
- the load factor of the IdentityHashMap
clear
public void clear()
Removes all mappings from this map.
clone
public Object clone()
Returns a shallow copy of this IdentityHashMap instance: the keys and
values themselves are not cloned.
- a shallow copy of this map.
containsKey
public boolean containsKey(Object key)
Returns true if this map contains a mapping for the specified
key.
key
- key whose presence in this Map is to be tested.
- true if this map contains a mapping for the specified
key.
containsValue
public boolean containsValue(Object value)
Returns true if this map maps one or more keys to the
specified value.
value
- value whose presence in this map is to be tested.
- true if this map maps one or more keys to the
specified value.
entrySet
public 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.
- a collection view of the mappings contained in this map.
get
public Object get(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.
key
- key whose associated value is to be returned.
- the value to which this map maps the specified key.
isEmpty
public boolean isEmpty()
Returns true if this map contains no key-value mappings.
- true if this map contains no key-value mappings.
keySet
public 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.
- a set view of the keys contained in this map.
put
public Object put(Object key,
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.
key
- key with which the specified value is to be associated.value
- value to be associated with the specified key.
- 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.
putAll
public void putAll(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.
t
- Mappings to be stored in this map.
remove
public Object remove(Object key)
Removes the mapping for this key from this map if present.
key
- key whose mapping is to be removed from the map.
- 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.
size
public int size()
Returns the number of key-value mappings in this map.
- the number of key-value mappings in this map.
values
public 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.
- a collection view of the values contained in this map.