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:
    Serializable, Map, BoundedMap

      public class FixedSizeMap
      extends AbstractMapDecorator
      implements Map, BoundedMap, 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
  Version:
    $Revision: 646777 $ $Date: 2008-04-10 14:33:15 +0200 (Thu, 10 Apr 2008) $
  Author:
    Stephen Colebourne, Paul Jack
  See Also:
    Serialized Form

- - ### Nested Class Summary

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

      `Map.Entry`

  - ### Field Summary

    - ### Fields inherited from class org.apache.commons.collections.map.AbstractMapDecorator

      `map`

  - ### Constructor Summary

    Constructors
    Modifier | Constructor and Description
    --- | ---
    `protected` | `FixedSizeMap(Map map)` Constructor that wraps (not copies).

  - ### Method Summary

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

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

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

    - ### Methods inherited from class java.lang.Object

      `clone, finalize, getClass, notify, notifyAll, wait, wait, wait`

    - ### Methods inherited from interface java.util.Map

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

- - ### Constructor Detail

    - #### FixedSizeMap

          protected FixedSizeMap(Map map)

      Constructor that wraps (not copies).
      Parameters:
        `map` - the map to decorate, must not be null
      Throws:
        `IllegalArgumentException` - if map is null

  - ### Method Detail

    - #### decorate

          public static Map decorate(Map map)

      Factory method to create a fixed size map.
      Parameters:
        `map` - the map to decorate, must not be null
      Throws:
        `IllegalArgumentException` - if map is null

    - #### put

          public Object put(Object key,
                   Object value)

      Specified by:
        `put` in interface `Map`
      Overrides:
        `put` in class `AbstractMapDecorator`

    - #### putAll

          public void putAll(Map mapToCopy)

      Specified by:
        `putAll` in interface `Map`
      Overrides:
        `putAll` in class `AbstractMapDecorator`

    - #### clear

          public void clear()

      Specified by:
        `clear` in interface `Map`
      Overrides:
        `clear` in class `AbstractMapDecorator`

    - #### remove

          public Object remove(Object key)

      Specified by:
        `remove` in interface `Map`
      Overrides:
        `remove` in class `AbstractMapDecorator`

    - #### entrySet

          public Set entrySet()

      Specified by:
        `entrySet` in interface `Map`
      Overrides:
        `entrySet` in class `AbstractMapDecorator`

    - #### keySet

          public Set keySet()

      Specified by:
        `keySet` in interface `Map`
      Overrides:
        `keySet` in class `AbstractMapDecorator`

    - #### values

          public Collection values()

      Specified by:
        `values` in interface `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

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