Package 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.AbstractInputCheckedMapDecorator<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:
Serializable, 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 AbstractInputCheckedMapDecorator<K,V> 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:
3.0
See Also:

  • Field Details

    • serialVersionUID

      private static final long serialVersionUID
      Serialization version
      See Also:

    • keyPredicate

      protected final Predicate<? super K> keyPredicate
      The key predicate to use

    • valuePredicate

      protected final Predicate<? super V> valuePredicate
      The value predicate to use

  • Constructor Details

    • PredicatedMap

      protected PredicatedMap(Map<K,V> map, Predicate<? super K> keyPredicate, Predicate<? super V> 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:
      NullPointerException - if the map is null

  • Method Details

    • predicatedMap

      public static <K, V> PredicatedMap<K,V> predicatedMap(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:
      NullPointerException - if the map is null
      Since:
      4.0

    • checkSetValue

      protected V checkSetValue(V value)
      Override to validate an object set into the map via setValue.
      Specified by:
      checkSetValue in class AbstractInputCheckedMapDecorator<K,V>
      Parameters:
      value - the value to validate
      Returns:
      the value itself
      Throws:
      IllegalArgumentException - if invalid
      Since:
      3.1

    • isSetValueChecking

      protected boolean isSetValueChecking()
      Override to only return true when there is a value transformer.
      Overrides:
      isSetValueChecking in class AbstractInputCheckedMapDecorator<K,V>
      Returns:
      true if a value predicate is in use
      Since:
      3.1

    • put

      public V put(K key, V value)
      Description copied from interface: Put
      Associates the specified value with the specified key in this map.

      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 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:

    • putAll

      public void putAll(Map<? extends K,? extends V> mapToCopy)
      Description copied from interface: Put
      Copies all of the mappings from the specified map to this map.
      Specified by:
      putAll in interface 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:

    • readObject

      private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException
      Deserializes the map in using a custom routine.
      Parameters:
      in - the input stream
      Throws:
      IOException - if an error occurs while reading from the stream
      ClassNotFoundException - if an object read from the stream cannot be loaded
      Since:
      3.1

    • validate

      protected void validate(K key, V value)
      Validates a key value pair.
      Parameters:
      key - the key to validate
      value - the value to validate
      Throws:
      IllegalArgumentException - if invalid

    • writeObject

      private void writeObject(ObjectOutputStream out) throws IOException
      Serializes this object to an ObjectOutputStream.
      Parameters:
      out - the target ObjectOutputStream.
      Throws:
      IOException - thrown when an I/O errors occur writing to the target stream.
      Since:
      3.1