Package org.linkki.util

Class LazyInitializingMap<K,​V>

  • Type Parameters:
    K - the type of key stored in this map
    V - the type of values stored in this map
    public class LazyInitializingMap<K,​V>
extends Object
    Key-value store that initializes its values lazily. Values will be initialized using the initializer function the map is created with.

    • Constructor Detail

      • LazyInitializingMap

        public LazyInitializingMap​(Function<K,​V> initializer)
        Parameters:
        initializer - the initializer function for lazily creating values. This function throws a NullPointerException when given null. Returns non- null values otherwise.

    • Method Detail

      • get

        public V get​(K key)
        Returns the value the given key maps to. Creates a new value if none is present using this map's initializer. Never returns null.

        Use as replacement for the usual "get or initialize and get" code: 

         if (!contains(key)) {
     initValue(key);
 }
 return get(key);
        Throws:
        NullPointerException - if either the key is null, or if the initializer function violates its contract and returns null.

      • getIfPresent

        @CheckForNull
public V getIfPresent​(K key)
        Returns the value the given key maps to. Returns null if the key does not map to a value.

      • clear

        public void clear()
        Clears this map.

      • remove

        @CheckForNull
public V remove​(K key)
        Removes the key from the map. Returns the removed value or null if the key does not map to a value.
        See Also:
        Map.remove(Object)