org.apache.commons.collections4.map

Class PredicatedMap<K,V>

java.lang.Object

org.apache.commons.collections4.map.AbstractIterableMap<K,V>

org.apache.commons.collections4.map.AbstractMapDecorator<K,V>

org.apache.commons.collections4.map.PredicatedMap<K,V>

Type Parameters:

K - the type of the keys in this map

V - the type of the values in this map

All Implemented Interfaces:

java.io.Serializable, java.util.Map<K,V>, Get<K,V>, IterableGet<K,V>, IterableMap<K,V>, Put<K,V>

Direct Known Subclasses:

PredicatedSortedMap

public class PredicatedMap<K,V>
extends AbstractMapDecorator<K,V>
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:

3.0

See Also:

Serialized Form

Nested Class Summary

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

java.util.Map.Entry<K,V>

Method Summary

Modifier and Type	Method and Description
java.util.Set<java.util.Map.Entry<K,V>>	entrySet()
static <K,V> PredicatedMap<K,V>	predicatedMap(java.util.Map<K,V> map, Predicate<? super K> keyPredicate, Predicate<? super V> valuePredicate) Factory method to create a predicated (validating) map.
V	put(K key, V value) Note that the return type is Object, rather than V as in the Map interface.
void	putAll(java.util.Map<? extends K,? extends V> mapToCopy)

Methods inherited from class org.apache.commons.collections4.map.AbstractMapDecorator

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

Methods inherited from class org.apache.commons.collections4.map.AbstractIterableMap

mapIterator

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Map

compute, computeIfAbsent, computeIfPresent, forEach, getOrDefault, merge, putIfAbsent, remove, replace, replace, replaceAll

Method Detail

predicatedMap

public static <K,V> PredicatedMap<K,V> predicatedMap(java.util.Map<K,V> map,
                                                     Predicate<? super K> keyPredicate,
                                                     Predicate<? super V> valuePredicate)

Factory method to create a predicated (validating) map.

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

Type Parameters:

K - the key type

V - the value type

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

Returns:

a new predicated map

Throws:

java.lang.NullPointerException - if the map is null

Since:

4.0

put

public V put(K key,
             V value)

Description copied from interface: Put

Note that the return type is Object, rather than V as in the Map interface. See the class Javadoc for further info.

Specified by:

put in interface java.util.Map<K,V>

Specified by:

put in interface Put<K,V>

Overrides:

put in class AbstractMapDecorator<K,V>

Parameters:

key - key with which the specified value is to be associated

value - value to be associated with the specified key

Returns:

the previous value associated with key, or null if there was no mapping for key. (A null return can also indicate that the map previously associated null with key, if the implementation supports null values.)

See Also:

Map.put(Object, Object)

putAll

public void putAll(java.util.Map<? extends K,? extends V> mapToCopy)

Specified by:

putAll in interface java.util.Map<K,V>

Specified by:

putAll in interface Put<K,V>

Overrides:

putAll in class AbstractMapDecorator<K,V>

Parameters:

mapToCopy - mappings to be stored in this map

See Also:

Map.putAll(Map)

entrySet

public java.util.Set<java.util.Map.Entry<K,V>> entrySet()

Specified by:

entrySet in interface java.util.Map<K,V>

Specified by:

entrySet in interface Get<K,V>

Overrides:

entrySet in class AbstractMapDecorator<K,V>

Returns:

a set view of the mappings contained in this map

See Also:

Map.entrySet()