Package org.apache.commons.collections.map

Class 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

    • 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