Package org.apache.commons.collections4.map

Class MultiValueMap<K,V>

java.lang.Object
org.apache.commons.collections4.map.AbstractIterableMap<K,V>
org.apache.commons.collections4.map.AbstractMapDecorator<K,Object>
org.apache.commons.collections4.map.MultiValueMap<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,Object>, Get<K,Object>, IterableGet<K,Object>, IterableMap<K,Object>, MultiMap<K,V>, Put<K,Object>
@Deprecated public class MultiValueMap<K,V> extends AbstractMapDecorator<K,Object> implements MultiMap<K,V>, Serializable
Deprecated.
since 4.1, use MultiValuedMap instead
A MultiValueMap decorates another map, allowing it to have more than one value for a key.

A MultiMap is a Map with slightly different semantics. Putting a value into the map will add the value to a Collection at that key. Getting a value will return a Collection, holding all the values put to that key.

This implementation is a decorator, allowing any Map implementation to be used as the base.

In addition, this implementation allows the type of collection used for the values to be controlled. By default, an ArrayList is used, however a Class to instantiate may be specified, or a factory that returns a Collection instance.

Note that MultiValueMap is not synchronized and is not thread-safe. If you wish to use this map from multiple threads concurrently, you must use appropriate synchronization. This class may throw exceptions when accessed by concurrent threads without synchronization.

Since:
3.2
See Also:

  • Constructor Details

    • MultiValueMap

      public MultiValueMap()
      Deprecated.
      Creates a MultiValueMap based on a HashMap and storing the multiple values in an ArrayList.

    • MultiValueMap

      protected MultiValueMap(Map<K,? super C> map, Factory<C> collectionFactory)
      Deprecated.
      Creates a MultiValueMap which decorates the given map and creates the value collections using the supplied collectionFactory.
      Type Parameters:
      C - the collection class type
      Parameters:
      map - the map to decorate
      collectionFactory - the collection factory which must return a Collection instance

  • Method Details

    • multiValueMap

      public static <K, V, C extends Collection<V>> MultiValueMap<K,V> multiValueMap(Map<K,? super C> map, Class<C> collectionClass)
      Deprecated.
      Creates a map which decorates the given map and maps keys to collections of type collectionClass.
      Type Parameters:
      K - the key type
      V - the value type
      C - the collection class type
      Parameters:
      map - the map to wrap
      collectionClass - the type of the collection class
      Returns:
      a new multi-value map
      Since:
      4.0

    • multiValueMap

      public static <K, V, C extends Collection<V>> MultiValueMap<K,V> multiValueMap(Map<K,? super C> map, Factory<C> collectionFactory)
      Deprecated.
      Creates a map which decorates the given map and creates the value collections using the supplied collectionFactory.
      Type Parameters:
      K - the key type
      V - the value type
      C - the collection class type
      Parameters:
      map - the map to decorate
      collectionFactory - the collection factory (must return a Collection object).
      Returns:
      a new multi-value map
      Since:
      4.0

    • multiValueMap

      public static <K, V> MultiValueMap<K,V> multiValueMap(Map<K,? super Collection<V>> map)
      Deprecated.
      Creates a map which wraps the given map and maps keys to ArrayLists.
      Type Parameters:
      K - the key type
      V - the value type
      Parameters:
      map - the map to wrap
      Returns:
      a new multi-value map
      Since:
      4.0

    • clear

      public void clear()
      Deprecated.
      Clear the map.
      Specified by:
      clear in interface Map<K,V>
      Specified by:
      clear in interface Put<K,V>
      Overrides:
      clear in class AbstractMapDecorator<K,Object>
      See Also:

    • containsValue

      public boolean containsValue(Object value)
      Deprecated.
      Checks whether the map contains the value specified.

      This checks all collections against all keys for the value, and thus could be slow.

      Specified by:
      containsValue in interface Get<K,V>
      Specified by:
      containsValue in interface Map<K,V>
      Specified by:
      containsValue in interface MultiMap<K,V>
      Overrides:
      containsValue in class AbstractMapDecorator<K,Object>
      Parameters:
      value - the value to search for
      Returns:
      true if the map contains the value
      See Also:

    • containsValue

      public boolean containsValue(Object key, Object value)
      Deprecated.
      Checks whether the collection at the specified key contains the value.
      Parameters:
      key - the key to search for
      value - the value to search for
      Returns:
      true if the map contains the value

    • createCollection

      protected Collection<V> createCollection(int size)
      Deprecated.
      Creates a new instance of the map value Collection container using the factory.

      This method can be overridden to perform your own processing instead of using the factory.

      Parameters:
      size - the collection size that is about to be added
      Returns:
      the new collection

    • entrySet

      public Set<Map.Entry<K,Object>> entrySet()
      Deprecated.

      NOTE: the returned Entry objects will contain as value a Collection of all values that are mapped to the given key. To get a "flattened" version of all mappings contained in this map, use iterator().

      Specified by:
      entrySet in interface Get<K,V>
      Specified by:
      entrySet in interface Map<K,V>
      Overrides:
      entrySet in class AbstractMapDecorator<K,Object>
      Returns:
      a set view of the mappings contained in this map
      See Also:

    • getCollection

      public Collection<V> getCollection(Object key)
      Deprecated.
      Gets the collection mapped to the specified key. This method is a convenience method to typecast the result of get(key).
      Parameters:
      key - the key to retrieve
      Returns:
      the collection mapped to the key, null if no mapping

    • iterator

      public Iterator<Map.Entry<K,V>> iterator()
      Deprecated.
      Gets an iterator for all mappings stored in this MultiValueMap.

      The iterator will return multiple Entry objects with the same key if there are multiple values mapped to this key.

      NOTE: calling Map.Entry.setValue(Object) on any of the returned elements will result in a UnsupportedOperationException.

      Returns:
      the iterator of all mappings in this map
      Since:
      4.0

    • iterator

      public Iterator<V> iterator(Object key)
      Deprecated.
      Gets an iterator for the collection mapped to the specified key.
      Parameters:
      key - the key to get an iterator for
      Returns:
      the iterator of the collection at the key, empty iterator if key not in map

    • put

      public Object put(K key, Object value)
      Deprecated.
      Adds the value to the collection associated with the specified key.

      Unlike a normal Map the previous value is not replaced. Instead, the new value is added to the collection stored against the key.

      Specified by:
      put in interface Map<K,V>
      Specified by:
      put in interface MultiMap<K,V>
      Specified by:
      put in interface Put<K,V>
      Overrides:
      put in class AbstractMapDecorator<K,Object>
      Parameters:
      key - the key to store against
      value - the value to add to the collection at the key
      Returns:
      the value added if the map changed and null if the map did not change
      See Also:

    • putAll

      public boolean putAll(K key, Collection<V> values)
      Deprecated.
      Adds a collection of values to the collection associated with the specified key.
      Parameters:
      key - the key to store against
      values - the values to add to the collection at the key, null ignored
      Returns:
      true if this map changed

    • putAll

      public void putAll(Map<? extends K,?> map)
      Deprecated.
      Override superclass to ensure that MultiMap instances are correctly handled.

      If you call this method with a normal map, each entry is added using put(Object,Object). If you call this method with a multi map, each entry is added using putAll(Object,Collection).

      Specified by:
      putAll in interface Map<K,V>
      Specified by:
      putAll in interface Put<K,V>
      Overrides:
      putAll in class AbstractMapDecorator<K,Object>
      Parameters:
      map - the map to copy (either a normal or multi map)
      See Also:

    • removeMapping

      public boolean removeMapping(Object key, Object value)
      Deprecated.
      Removes a specific value from map.

      The item is removed from the collection mapped to the specified key. Other values attached to that key are unaffected.

      If the last value for a key is removed, null will be returned from a subsequent get(key).

      Specified by:
      removeMapping in interface MultiMap<K,V>
      Parameters:
      key - the key to remove from
      value - the value to remove
      Returns:
      true if the mapping was removed, false otherwise

    • size

      public int size(Object key)
      Deprecated.
      Gets the size of the collection mapped to the specified key.
      Parameters:
      key - the key to get size for
      Returns:
      the size of the collection at the key, zero if key not in map

    • totalSize

      public int totalSize()
      Deprecated.
      Gets the total size of the map by counting all the values.
      Returns:
      the total size of the map counting all values

    • values

      public Collection<Object> values()
      Deprecated.
      Gets a collection containing all the values in the map.

      This returns a collection containing the combination of values from all keys.

      Specified by:
      values in interface Get<K,V>
      Specified by:
      values in interface Map<K,V>
      Specified by:
      values in interface MultiMap<K,V>
      Overrides:
      values in class AbstractMapDecorator<K,Object>
      Returns:
      a collection view of the values contained in this map
      See Also: