Package org.kingdoms.utils.internal.enumeration

Class QuickEnumMap<K extends Enum<K>,V>

java.lang.Object
org.kingdoms.utils.internal.enumeration.QuickEnumMap<K,V>
All Implemented Interfaces:
Map<K,V>
public class QuickEnumMap<K extends Enum<K>,V> extends Object implements Map<K,V>
A specialized Map implementation for use with enum type keys. All of the keys in an enum map must come from a single enum type that is specified, explicitly or implicitly, when the map is created. Enum maps are represented internally as arrays. This representation is extremely compact and efficient.

Enum maps are maintained in the natural order of their keys (the order in which the enum constants are declared). This is reflected in the iterators returned by the collections views (keySet(), entrySet(), and values()).

Iterators are not allowed.

Null keys are not permitted. Attempts to insert a null key will throw NullPointerException. Attempts to test for the presence of a null key or to remove one will, however, function properly. Null values are permitted.

Like most collection implementations EnumMap is not synchronized. If multiple threads access an enum map concurrently, and at least one of the threads modifies the map, it should be synchronized externally. This is typically accomplished by synchronizing on some object that naturally encapsulates the enum map. If no such object exists, the map should be "wrapped" using the Collections.synchronizedMap(java.util.Map<K, V>) method. This is best done at creation time, to prevent accidental unsynchronized access: 

     Map<EnumKey, V> m
         = Collections.synchronizedMap(new EnumMap<EnumKey, V>(...));

Implementation note: All basic operations execute in constant time. They are likely (though not guaranteed) to be faster than their HashMap counterparts.

This class is a member of the Java Collections Framework.

See Also:

  • Constructor Details

    • QuickEnumMap

      public QuickEnumMap(K[] universe)
      Creates an empty enum map with the fixed table size.

  • Method Details

    • size

      public int size()
      Returns the number of key-value mappings in this map.
      Specified by:
      size in interface Map<K extends Enum<K>,V>
      Returns:
      the number of key-value mappings in this map

    • isEmpty

      public boolean isEmpty()
      Specified by:
      isEmpty in interface Map<K extends Enum<K>,V>

    • containsValue

      public boolean containsValue(Object value)
      Returns true if this map maps one or more keys to the specified value.
      Specified by:
      containsValue in interface Map<K extends Enum<K>,V>
      Parameters:
      value - the value whose presence in this map is to be tested
      Returns:
      true if this map maps one or more keys to this value

    • containsKey

      public boolean containsKey(Object key)
      Returns true if this map contains a mapping for the specified key.
      Specified by:
      containsKey in interface Map<K extends Enum<K>,V>
      Parameters:
      key - the key whose presence in this map is to be tested
      Returns:
      true if this map contains a mapping for the specified key

    • get

      public V get(Object key)
      Returns the value to which the specified key is mapped, or null if this map contains no mapping for the key.

      More formally, if this map contains a mapping from a key k to a value v such that (key == k), then this method returns v; otherwise it returns null. (There can be at most one such mapping.)

      A return value of null does not necessarily indicate that the map contains no mapping for the key; it's also possible that the map explicitly maps the key to null. The containsKey operation may be used to distinguish these two cases.

      Specified by:
      get in interface Map<K extends Enum<K>,V>

    • put

      public V put(K key, V value)
      Associates the specified value with the specified key in this map. If the map previously contained a mapping for this key, the old value is replaced.
      Specified by:
      put in interface Map<K extends Enum<K>,V>
      Parameters:
      key - the key with which the specified value is to be associated
      value - the value to be associated with the specified key
      Returns:
      the previous value associated with specified key, or null if there was no mapping for key. (A null return can also indicate that the map previously associated null with the specified key.)
      Throws:
      NullPointerException - if the specified key is null

    • remove

      public V remove(Object key)
      Removes the mapping for this key from this map if present.
      Specified by:
      remove in interface Map<K extends Enum<K>,V>
      Parameters:
      key - the key whose mapping is to be removed from the map
      Returns:
      the previous value associated with specified key, or null if there was no entry for key. (A null return can also indicate that the map previously associated null with the specified key.)

    • putAll

      public void putAll(Map<? extends K,? extends V> m)
      Copies all of the mappings from the specified map to this map. These mappings will replace any mappings that this map had for any of the keys currently in the specified map.
      Specified by:
      putAll in interface Map<K extends Enum<K>,V>
      Parameters:
      m - the mappings to be stored in this map
      Throws:
      NullPointerException - the specified map is null, or if one or more keys in the specified map are null

    • clear

      public void clear()
      Specified by:
      clear in interface Map<K extends Enum<K>,V>

    • keySet

      public @NonNull Set<K> keySet()
      Specified by:
      keySet in interface Map<K extends Enum<K>,V>

    • values

      public @NonNull Collection<V> values()
      Specified by:
      values in interface Map<K extends Enum<K>,V>

    • entrySet

      public @NonNull Set<Map.Entry<K,V>> entrySet()
      Specified by:
      entrySet in interface Map<K extends Enum<K>,V>

    • equals

      public boolean equals(Object o)
      Specified by:
      equals in interface Map<K extends Enum<K>,V>
      Overrides:
      equals in class Object

    • hashCode

      public int hashCode()
      Specified by:
      hashCode in interface Map<K extends Enum<K>,V>
      Overrides:
      hashCode in class Object