Class FixedSizeMap<K,V>
- java.lang.Object
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- org.apache.commons.collections4.map.AbstractIterableMap<K,V>
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- org.apache.commons.collections4.map.AbstractMapDecorator<K,V>
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- org.apache.commons.collections4.map.FixedSizeMap<K,V>
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- All Implemented Interfaces:
java.io.Serializable
,java.util.Map<K,V>
,BoundedMap<K,V>
,Get<K,V>
,IterableGet<K,V>
,IterableMap<K,V>
,Put<K,V>
public class FixedSizeMap<K,V> extends AbstractMapDecorator<K,V> implements BoundedMap<K,V>, java.io.Serializable
Decorates anotherMap
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
- Version:
- $Id: FixedSizeMap.java 1686855 2015-06-22 13:00:27Z tn $
- See Also:
- Serialized Form
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Constructor Summary
Constructors Modifier Constructor Description protected
FixedSizeMap(java.util.Map<K,V> map)
Constructor that wraps (not copies).
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description void
clear()
java.util.Set<java.util.Map.Entry<K,V>>
entrySet()
static <K,V>
FixedSizeMap<K,V>fixedSizeMap(java.util.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.java.util.Set<K>
keySet()
int
maxSize()
Gets the maximum size of the map (the bound).V
put(K key, V value)
Note that the return type is Object, rather than V as in the Map interface.void
putAll(java.util.Map<? extends K,? extends V> mapToCopy)
V
remove(java.lang.Object key)
java.util.Collection<V>
values()
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Methods inherited from class org.apache.commons.collections4.map.AbstractMapDecorator
containsKey, containsValue, decorated, equals, get, hashCode, isEmpty, size, toString
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Methods inherited from class org.apache.commons.collections4.map.AbstractIterableMap
mapIterator
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Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
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Methods inherited from interface org.apache.commons.collections4.Get
containsKey, containsValue, get, isEmpty, size
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Methods inherited from interface org.apache.commons.collections4.IterableGet
mapIterator
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Method Detail
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fixedSizeMap
public static <K,V> FixedSizeMap<K,V> fixedSizeMap(java.util.Map<K,V> map)
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:
java.lang.NullPointerException
- if map is null- Since:
- 4.0
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put
public V put(K key, V value)
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.
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clear
public void clear()
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remove
public V remove(java.lang.Object key)
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keySet
public java.util.Set<K> keySet()
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values
public java.util.Collection<V> values()
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isFull
public boolean 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
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maxSize
public int 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
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