Class AbstractHashMap<K,V>

java.lang.Object
de.tomatengames.util.map.AbstractHashMap<K,V>
Type Parameters:
K - The key type.
V - The type of the values.
All Implemented Interfaces:
Iterable<AbstractEntry<K,V>>
public abstract class AbstractHashMap<K,V> extends Object implements Iterable<AbstractEntry<K,V>>
A HashMap-like data structure that maps K keys to object values. Equality of keys is checked by using the abstract keyEquals(key1, key2) method.

This map does not allow null values. This implementation does not allow concurrent modifications.

Since:
1.5

  • Constructor Details

    • AbstractHashMap

      public AbstractHashMap()
      Creates a new and empty AbstractHashMap.

    • AbstractHashMap

      public AbstractHashMap(AbstractHashMap<K,V> map)
      Creates a new AbstractHashMap that contains all the mappings of the specified map.
      Parameters:
      map - The mappings that should be cloned.

  • Method Details

    • size

      public long size()
      Returns the number of entries in this map.
      Returns:
      The number of entries.

    • isEmpty

      public boolean isEmpty()
      Returns if this map does not contain any entry.
      Returns:
      If this map has no entries.

    • put

      public V put(K key, V value)
      Associates the specified key with the specified value. If the key is already present in this map, the previous value is replaced.
      Parameters:
      key - The key of the new mapping.
      value - The value of the new mapping. Must not null.
      Returns:
      The value that was previously mapped to the key. If the key was not present in this map, null is returned.
      Throws:
      IllegalArgumentException - If the value is null.

    • putIfAbsent

      public V putIfAbsent(K key, V value)
      Associates the specified key with the specified value. If the key is already present in this map, nothing happens.
      Parameters:
      key - The key of the new mapping.
      value - The value of the new mapping. Must not null.
      Returns:
      The value that was previously mapped to the key. If null, the new value has been put into the map. Otherwise, the previous value is still present.
      Throws:
      IllegalArgumentException - If the value is null.

    • get

      public V get(K key)
      Returns the value that is mapped to the specified key.
      Parameters:
      key - The key whose value should be returned.
      Returns:
      The value that the specified key is mapped to. If this map does not contain the key, null is returned.

    • containsKey

      public boolean containsKey(K key)
      Returns if the specified key is present in this map. This method is semantically equivalent to 
      get(key) != null
      Parameters:
      key - The key that should be checked.
      Returns:
      If the specified key is present in this map.

    • remove

      public V remove(K key)
      Removes the entry with the specified key from this map. If the map does not contain the key, nothing happens.
      Parameters:
      key - The key of the entry that should be removed.
      Returns:
      The value of the entry that was removed. If no entry was removed, null is returned.

    • clear

      public void clear()
      Removes all entries from this map.

    • forEach

      public void forEach(Consumer<? super AbstractEntry<K,V>> action)
      Specified by:
      forEach in interface Iterable<K>

    • putAll

      public void putAll(AbstractHashMap<K,V> otherMap)
      Puts all mappings of the specified map into this map. Keys that are present in both maps are replaced in this map. If the specified map is null or this map, nothing happens.
      Parameters:
      otherMap - The map whose mappings should be put into this map. May be null.

    • equals

      public boolean equals(Object obj)
      Overrides:
      equals in class Object

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object

    • keyHash

      public abstract int keyHash(K key)
      Calculate the hash code of the specified key.
      Parameters:
      key - The key whose hash code should be calculated.
      Returns:
      The hash code.

    • keyEquals

      public abstract boolean keyEquals(K key1, K key2)
      Returns if the specified keys should be considered equal.
      Parameters:
      key1 - The first key.
      key2 - The second key.
      Returns:
      If both keys should be considered equal.

    • iterator

      public Iterator<AbstractEntry<K,V>> iterator()
      Specified by:
      iterator in interface Iterable<K>