Package it.unimi.dsi.fastutil.objects

Class AbstractObject2ObjectMap<K,​V>

java.lang.Object
it.unimi.dsi.fastutil.objects.AbstractObject2ObjectFunction<K,​V>
it.unimi.dsi.fastutil.objects.AbstractObject2ObjectMap<K,​V>
All Implemented Interfaces:
Function<K,​V>, Object2ObjectFunction<K,​V>, Object2ObjectMap<K,​V>, java.io.Serializable, java.util.function.Function<K,​V>, java.util.Map<K,​V>
Direct Known Subclasses:
AbstractObject2ObjectSortedMap, Object2ObjectArrayMap, Object2ObjectOpenCustomHashMap, Object2ObjectOpenHashMap
public abstract class AbstractObject2ObjectMap<K,​V>
extends AbstractObject2ObjectFunction<K,​V>
implements Object2ObjectMap<K,​V>, java.io.Serializable
An abstract class providing basic methods for maps implementing a type-specific interface.

Optional operations just throw an UnsupportedOperationException. Generic versions of accessors delegate to the corresponding type-specific counterparts following the interface rules (they take care of returning null on a missing key).

As a further help, this class provides a BasicEntry inner class that implements a type-specific version of Map.Entry; it is particularly useful for those classes that do not implement their own entries (e.g., most immutable maps).

See Also:
Serialized Form

  • Method Details

    • containsKey

      public boolean containsKey​(java.lang.Object k)
      Returns true if this function contains a mapping for the specified key.
      Specified by:
      containsKey in interface Function<K,​V>
      Specified by:
      containsKey in interface java.util.Map<K,​V>
      Specified by:
      containsKey in interface Object2ObjectMap<K,​V>
      Parameters:
      k - the key.
      Returns:
      true if this function associates a value to key.
      See Also:
      Map.containsKey(Object)
      Implementation Specification:
      This implementation does a linear search over the entry set, finding an entry that has the key specified.

      If you override keySet(), you should probably override this method too to take advantage of the (presumably) faster key membership test your keySet() provides.

      If you override this method but not keySet(), then the returned key set will take advantage of this method.

    • containsValue

      public boolean containsValue​(java.lang.Object v)
      Specified by:
      containsValue in interface java.util.Map<K,​V>
      Implementation Specification:
      This implementation does a linear search over the entry set, finding an entry that has the value specified.

      If you override values(), you should probably override this method too to take advantage of the (presumably) faster value membership test your values() provides.

      If you override this method but not values(), then the returned values collection will take advantage of this method.

    • isEmpty

      public boolean isEmpty()
      Specified by:
      isEmpty in interface java.util.Map<K,​V>

    • keySet

      public ObjectSet<K> keySet()
      Returns a type-specific-set view of the keys of this map.

      The view is backed by the set returned by Map.entrySet(). Note that no attempt is made at caching the result of this method, as this would require adding some attributes that lightweight implementations would not need. Subclasses may easily override this policy by calling this method and caching the result, but implementors are encouraged to write more efficient ad-hoc implementations.

      Specified by:
      keySet in interface java.util.Map<K,​V>
      Specified by:
      keySet in interface Object2ObjectMap<K,​V>
      Returns:
      a set view of the keys of this map; it may be safely cast to a type-specific interface.
      See Also:
      Map.keySet()

    • values

      public ObjectCollection<V> values()
      Returns a type-specific-set view of the values of this map.

      The view is backed by the set returned by Map.entrySet(). Note that no attempt is made at caching the result of this method, as this would require adding some attributes that lightweight implementations would not need. Subclasses may easily override this policy by calling this method and caching the result, but implementors are encouraged to write more efficient ad-hoc implementations.

      Specified by:
      values in interface java.util.Map<K,​V>
      Specified by:
      values in interface Object2ObjectMap<K,​V>
      Returns:
      a set view of the values of this map; it may be safely cast to a type-specific interface.
      See Also:
      Map.values()

    • putAll

      public void putAll​(java.util.Map<? extends K,​? extends V> m)
      Specified by:
      putAll in interface java.util.Map<K,​V>

    • hashCode

      public int hashCode()
      Returns a hash code for this map. The hash code of a map is computed by summing the hash codes of its entries.
      Specified by:
      hashCode in interface java.util.Map<K,​V>
      Overrides:
      hashCode in class java.lang.Object
      Returns:
      a hash code for this map.

    • equals

      public boolean equals​(java.lang.Object o)
      Specified by:
      equals in interface java.util.Map<K,​V>
      Overrides:
      equals in class java.lang.Object

    • toString

      public java.lang.String toString()
      Overrides:
      toString in class java.lang.Object