org.apache.commons.collections.map
Class PredicatedMap

java.lang.Object
  extended by org.apache.commons.collections.map.AbstractMapDecorator
      extended by 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: 348007 $ $Date: 2005-11-21 22:52:57 +0000 (Mon, 21 Nov 2005) $
Author:
Stephen Colebourne, Paul Jack
See Also:
Serialized Form

Nested Class Summary
 
Nested classes/interfaces inherited from interface java.util.Map
Map.Entry<K,V>
 
Field Summary
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
protected PredicatedMap(Map map, Predicate keyPredicate, Predicate valuePredicate)
          Constructor that wraps (not copies).
 
Method Summary
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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