Package java.util

Class Dictionary<K,​V>

  • Direct Known Subclasses:
    Hashtable
    public abstract class Dictionary<K,​V>
extends Object
    Note: Do not use this class since it is obsolete. Please use the Map interface for new implementations.

    Dictionary is an abstract class which is the superclass of all classes that associate keys with values, such as Hashtable.

    Since:
    1.0
    See Also:
    Hashtable

    • Constructor Detail

      • Dictionary

        public Dictionary()
        Constructs a new instance of this class.

    • Method Detail

      • elements

        public abstract Enumeration<V> elements()
        Returns an enumeration on the elements of this dictionary.
        Returns:
        an enumeration of the values of this dictionary.
        See Also:
        keys(), size(), Enumeration

      • get

        public abstract V get​(Object key)
        Returns the value which is associated with key.
        Parameters:
        key - the key of the value returned.
        Returns:
        the value associated with key, or null if the specified key does not exist.
        See Also:
        put(K, V)

      • isEmpty

        public abstract boolean isEmpty()
        Returns true if this dictionary has no key/value pairs.
        Returns:
        true if this dictionary has no key/value pairs, false otherwise.
        See Also:
        size()

      • keys

        public abstract Enumeration<K> keys()
        Returns an enumeration on the keys of this dictionary.
        Returns:
        an enumeration of the keys of this dictionary.
        See Also:
        elements(), size(), Enumeration

      • put

        public abstract V put​(K key,
                      V value)
        Associate key with value in this dictionary. If key exists in the dictionary before this call, the old value in the dictionary is replaced by value.
        Parameters:
        key - the key to add.
        value - the value to add.
        Returns:
        the old value previously associated with key or null if key is new to the dictionary.
        See Also:
        elements(), get(java.lang.Object), keys()

      • remove

        public abstract V remove​(Object key)
        Removes the key/value pair with the specified key from this dictionary.
        Parameters:
        key - the key to remove.
        Returns:
        the associated value before the deletion or null if key was not known to this dictionary.
        See Also:
        get(java.lang.Object), put(K, V)

      • size

        public abstract int size()
        Returns the number of key/value pairs in this dictionary.
        Returns:
        the number of key/value pairs in this dictionary.
        See Also:
        elements(), keys()