org.apache.commons.collections.map

## Class PredicatedMap

- java.lang.Object
- - org.apache.commons.collections.map.AbstractMapDecorator
  - - org.apache.commons.collections.map.PredicatedMap

- All Implemented Interfaces:
    Serializable, Map
  Direct Known Subclasses:
    PredicatedSortedMap

      public class PredicatedMap
      extends AbstractMapDecorator
      implements Serializable

  Decorates another `Map` to validate that additions match a specified predicate.

  This map exists to provide validation for the decorated map. It is normally created to decorate an empty map. If an object cannot be added to the map, an IllegalArgumentException is thrown.

  One usage would be to ensure that no null keys are added to the map.

      Map map = PredicatedSet.decorate(new HashMap(), NotNullPredicate.INSTANCE, null);

  Note that PredicatedMap 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
    Modifier and Type | Field and Description
    --- | ---
    `protected Predicate` | `keyPredicate` The key predicate to use
    `protected Predicate` | `valuePredicate` The value predicate to use

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

      `map`

  - ### Constructor Summary

    Constructors
    Modifier | Constructor and Description
    --- | ---
    `protected` | `PredicatedMap(Map map, Predicate keyPredicate, Predicate valuePredicate)` Constructor that wraps (not copies).

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `protected Object` | `checkSetValue(Object value)` Override to validate an object set into the map via `setValue`.
    `static Map` | `decorate(Map map, Predicate keyPredicate, Predicate valuePredicate)` Factory method to create a predicated (validating) map.
    `Set` | `entrySet()`
    `protected boolean` | `isSetValueChecking()` Override to only return true when there is a value transformer.
    `Object` | `put(Object key, Object value)`
    `void` | `putAll(Map mapToCopy)`
    `protected void` | `validate(Object key, Object value)` Validates a key value pair.

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

      `clear, containsKey, containsValue, equals, get, getMap, hashCode, isEmpty, keySet, remove, size, toString, values`

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

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

- - ### Field Detail

    - #### keyPredicate

          protected final Predicate keyPredicate

      The key predicate to use

    - #### valuePredicate

          protected final Predicate valuePredicate

      The value predicate to use

  - ### Constructor Detail

    - #### PredicatedMap

          protected PredicatedMap(Map map,
                       Predicate keyPredicate,
                       Predicate valuePredicate)

      Constructor that wraps (not copies).
      Parameters:
        `map` - the map to decorate, must not be null
        `keyPredicate` - the predicate to validate the keys, null means no check
        `valuePredicate` - the predicate to validate to values, null means no check
      Throws:
        `IllegalArgumentException` - if the map is null

  - ### Method Detail

    - #### decorate

          public static Map decorate(Map map,
                     Predicate keyPredicate,
                     Predicate valuePredicate)

      Factory method to create a predicated (validating) map.

      If there are any elements already in the list being decorated, they are validated.

      Parameters:
        `map` - the map to decorate, must not be null
        `keyPredicate` - the predicate to validate the keys, null means no check
        `valuePredicate` - the predicate to validate to values, null means no check
      Throws:
        `IllegalArgumentException` - if the map is null

    - #### validate

          protected void validate(Object key,
                      Object value)

      Validates a key value pair.
      Parameters:
        `key` - the key to validate
        `value` - the value to validate
      Throws:
        `IllegalArgumentException` - if invalid

    - #### checkSetValue

          protected Object checkSetValue(Object value)

      Override to validate an object set into the map via `setValue`.
      Parameters:
        `value` - the value to validate
      Throws:
        `IllegalArgumentException` - if invalid
      Since:
        Commons Collections 3.1

    - #### isSetValueChecking

          protected boolean isSetValueChecking()

      Override to only return true when there is a value transformer.
      Returns:
        true if a value predicate is in use
      Since:
        Commons Collections 3.1

    - #### 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`

    - #### entrySet

          public Set entrySet()

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

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