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:

java.io.Serializable, java.util.Map

Direct Known Subclasses:

PredicatedSortedMap

public class PredicatedMap
extends AbstractMapDecorator
implements java.io.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 13:33:15 +0100 (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

java.util.Map.Entry

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(java.util.Map map, Predicate keyPredicate, Predicate valuePredicate) Constructor that wraps (not copies).

Method Summary

protected java.lang.Object	checkSetValue(java.lang.Object value) Override to validate an object set into the map via setValue.
static java.util.Map	decorate(java.util.Map map, Predicate keyPredicate, Predicate valuePredicate) Factory method to create a predicated (validating) map.
java.util.Set	entrySet()
protected boolean	isSetValueChecking() Override to only return true when there is a value transformer.
java.lang.Object	put(java.lang.Object key, java.lang.Object value)
void	putAll(java.util.Map mapToCopy)
protected void	validate(java.lang.Object key, java.lang.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(java.util.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:

java.lang.IllegalArgumentException - if the map is null

Method Detail

decorate

public static java.util.Map decorate(java.util.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:

java.lang.IllegalArgumentException - if the map is null

validate

protected void validate(java.lang.Object key,
                        java.lang.Object value)

Validates a key value pair.

Parameters:

key - the key to validate

value - the value to validate

Throws:

java.lang.IllegalArgumentException - if invalid

checkSetValue

protected java.lang.Object checkSetValue(java.lang.Object value)

Override to validate an object set into the map via setValue.

Parameters:

value - the value to validate

Throws:

java.lang.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 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

entrySet

public java.util.Set entrySet()

Specified by:

entrySet in interface java.util.Map

Overrides:

entrySet in class AbstractMapDecorator