org.apache.commons.collections.map

Class FixedSizeMap

java.lang.Object

org.apache.commons.collections.map.AbstractMapDecorator

org.apache.commons.collections.map.FixedSizeMap

All Implemented Interfaces:

java.io.Serializable, java.util.Map, BoundedMap

public class FixedSizeMap
extends AbstractMapDecorator
implements java.util.Map, BoundedMap, java.io.Serializable

Decorates another 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:

Commons Collections 3.0

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface java.util.Map

java.util.Map.Entry<K,V>

Method Summary

Modifier and Type	Method and Description
void	clear()
static java.util.Map	decorate(java.util.Map map) Factory method to create a fixed size map.
java.util.Set	entrySet()
boolean	isFull() Returns true if this map is full and no new elements can be added.
java.util.Set	keySet()
int	maxSize() Gets the maximum size of the map (the bound).
java.lang.Object	put(java.lang.Object key, java.lang.Object value)
void	putAll(java.util.Map mapToCopy)
java.lang.Object	remove(java.lang.Object key)
java.util.Collection	values()

Methods inherited from class org.apache.commons.collections.map.AbstractMapDecorator

containsKey, containsValue, equals, get, hashCode, isEmpty, size, toString

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

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

Method Detail

decorate

public static java.util.Map decorate(java.util.Map map)

Factory method to create a fixed size map.

Parameters:

map - the map to decorate, must not be null

Throws:

java.lang.IllegalArgumentException - if map is null

put

public java.lang.Object put(java.lang.Object key,
                            java.lang.Object value)

Specified by:

put in interface java.util.Map

Overrides:

put in class AbstractMapDecorator

putAll

public void putAll(java.util.Map mapToCopy)

Specified by:

putAll in interface java.util.Map

Overrides:

putAll in class AbstractMapDecorator

clear

public void clear()

Specified by:

clear in interface java.util.Map

Overrides:

clear in class AbstractMapDecorator

remove

public java.lang.Object remove(java.lang.Object key)

Specified by:

remove in interface java.util.Map

Overrides:

remove in class AbstractMapDecorator

entrySet

public java.util.Set entrySet()

Specified by:

entrySet in interface java.util.Map

Overrides:

entrySet in class AbstractMapDecorator

keySet

public java.util.Set keySet()

Specified by:

keySet in interface java.util.Map

Overrides:

keySet in class AbstractMapDecorator

values

public java.util.Collection values()

Specified by:

values in interface java.util.Map

Overrides:

values in class AbstractMapDecorator

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 interface BoundedMap

Returns:

true if the map is full

maxSize

public int maxSize()

Description copied from interface: BoundedMap

Gets the maximum size of the map (the bound).

Specified by:

maxSize in interface BoundedMap

Returns:

the maximum number of elements the map can hold