Class FixedSizeMap<K,V>
- Type Parameters:
K
- the type of the keys in this mapV
- the type of the values in this map
- All Implemented Interfaces:
Serializable
,Map<K,
,V> BoundedMap<K,
,V> Get<K,
,V> IterableGet<K,
,V> IterableMap<K,
,V> Put<K,
V>
Map
to fix the size, preventing add/remove.
Any action that would change the size of the map is disallowed. The put method is allowed to change the value associated with an existing key however.
If trying to remove or clear the map, an UnsupportedOperationException is thrown. If trying to put a new mapping into the map, an IllegalArgumentException is thrown. This is because the put method can succeed if the mapping's key already exists in the map, so the put method is not always unsupported.
Note that FixedSizeMap is not synchronized and is not thread-safe.
If you wish to use this map from multiple threads concurrently, you must use
appropriate synchronization. The simplest approach is to wrap this map
using Collections.synchronizedMap(Map)
. This class may throw
exceptions when accessed by concurrent threads without synchronization.
This class is Serializable from Commons Collections 3.1.
- Since:
- 3.0
- See Also:
-
Nested Class Summary
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Constructor Summary
ModifierConstructorDescriptionprotected
FixedSizeMap
(Map<K, V> map) Constructor that wraps (not copies). -
Method Summary
Modifier and TypeMethodDescriptionvoid
clear()
entrySet()
static <K,
V> FixedSizeMap<K, V> fixedSizeMap
(Map<K, V> map) Factory method to create a fixed size map.boolean
isFull()
Returns true if this map is full and no new elements can be added.keySet()
int
maxSize()
Gets the maximum size of the map (the bound).Note that the return type is Object, rather than V as in the Map interface.void
values()
Methods inherited from class org.apache.commons.collections4.map.AbstractMapDecorator
containsKey, containsValue, decorated, equals, get, hashCode, isEmpty, size, toString
Methods inherited from class org.apache.commons.collections4.map.AbstractIterableMap
mapIterator
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
Methods inherited from interface org.apache.commons.collections4.Get
containsKey, containsValue, get, isEmpty, size
Methods inherited from interface org.apache.commons.collections4.IterableGet
mapIterator
Methods inherited from interface java.util.Map
compute, computeIfAbsent, computeIfPresent, containsKey, containsValue, equals, forEach, get, getOrDefault, hashCode, isEmpty, merge, putIfAbsent, remove, replace, replace, replaceAll, size
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Constructor Details
-
FixedSizeMap
Constructor that wraps (not copies).- Parameters:
map
- the map to decorate, must not be null- Throws:
NullPointerException
- if map is null
-
-
Method Details
-
fixedSizeMap
Factory method to create a fixed size map.- Type Parameters:
K
- the key typeV
- the value type- Parameters:
map
- the map to decorate, must not be null- Returns:
- a new fixed size map
- Throws:
NullPointerException
- if map is null- Since:
- 4.0
-
clear
-
entrySet
-
isFull
Description copied from interface:BoundedMap
Returns true if this map is full and no new elements can be added.- Specified by:
isFull
in interfaceBoundedMap<K,
V> - Returns:
true
if the map is full
-
keySet
-
maxSize
Description copied from interface:BoundedMap
Gets the maximum size of the map (the bound).- Specified by:
maxSize
in interfaceBoundedMap<K,
V> - Returns:
- the maximum number of elements the map can hold
-
put
Description copied from interface:Put
Note that the return type is Object, rather than V as in the Map interface. See the class Javadoc for further info.- Specified by:
put
in interfaceMap<K,
V> - Specified by:
put
in interfacePut<K,
V> - Overrides:
put
in classAbstractMapDecorator<K,
V> - Parameters:
key
- key with which the specified value is to be associatedvalue
- value to be associated with the specified key- Returns:
- the previous value associated with
key
, ornull
if there was no mapping forkey
. (Anull
return can also indicate that the map previously associatednull
withkey
, if the implementation supportsnull
values.) - See Also:
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putAll
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remove
- Specified by:
remove
in interfaceGet<K,
V> - Specified by:
remove
in interfaceMap<K,
V> - Overrides:
remove
in classAbstractMapDecorator<K,
V> - Parameters:
key
- key whose mapping is to be removed from the map- Returns:
- the previous value associated with
key
, ornull
if there was no mapping forkey
. - See Also:
-
values
-