Package org.apache.commons.collections.map

Class AbstractHashedMap

  • All Implemented Interfaces:
    Map, IterableMap
    Direct Known Subclasses:
    AbstractLinkedMap, AbstractReferenceMap, CaseInsensitiveMap, HashedMap, IdentityMap
    @Deprecated(since="2021-04-30")
public class AbstractHashedMap
extends AbstractMap
implements IterableMap
    Deprecated.
    Commons Collections 3 is in maintenance mode. Commons Collections 4 should be used instead.
    An abstract implementation of a hash-based map which provides numerous points for subclasses to override.

    This class implements all the features necessary for a subclass hash-based map. Key-value entries are stored in instances of the HashEntry class, which can be overridden and replaced. The iterators can similarly be replaced, without the need to replace the KeySet, EntrySet and Values view classes.

    Overridable methods are provided to change the default hashing behaviour, and to change how entries are added to and removed from the map. Hopefully, all you need for unusual subclasses is here.

    NOTE: From Commons Collections 3.1 this class extends AbstractMap. This is to provide backwards compatibility for ReferenceMap between v3.0 and v3.1. This extends clause will be removed in v4.0.

    Since:
    Commons Collections 3.0

    • Method Detail

      • get

        public Object get​(Object key)
        Deprecated.
        Gets the value mapped to the key specified.
        Specified by:
        get in interface Map
        Overrides:
        get in class AbstractMap
        Parameters:
        key - the key
        Returns:
        the mapped value, null if no match

      • size

        public int size()
        Deprecated.
        Gets the size of the map.
        Specified by:
        size in interface Map
        Overrides:
        size in class AbstractMap
        Returns:
        the size

      • isEmpty

        public boolean isEmpty()
        Deprecated.
        Checks whether the map is currently empty.
        Specified by:
        isEmpty in interface Map
        Overrides:
        isEmpty in class AbstractMap
        Returns:
        true if the map is currently size zero

      • containsKey

        public boolean containsKey​(Object key)
        Deprecated.
        Checks whether the map contains the specified key.
        Specified by:
        containsKey in interface Map
        Overrides:
        containsKey in class AbstractMap
        Parameters:
        key - the key to search for
        Returns:
        true if the map contains the key

      • containsValue

        public boolean containsValue​(Object value)
        Deprecated.
        Checks whether the map contains the specified value.
        Specified by:
        containsValue in interface Map
        Overrides:
        containsValue in class AbstractMap
        Parameters:
        value - the value to search for
        Returns:
        true if the map contains the value

      • put

        public Object put​(Object key,
                  Object value)
        Deprecated.
        Puts a key-value mapping into this map.
        Specified by:
        put in interface Map
        Overrides:
        put in class AbstractMap
        Parameters:
        key - the key to add
        value - the value to add
        Returns:
        the value previously mapped to this key, null if none

      • putAll

        public void putAll​(Map map)
        Deprecated.
        Puts all the values from the specified map into this map.

        This implementation iterates around the specified map and uses put(Object, Object).

        Specified by:
        putAll in interface Map
        Overrides:
        putAll in class AbstractMap
        Parameters:
        map - the map to add
        Throws:
        NullPointerException - if the map is null

      • remove

        public Object remove​(Object key)
        Deprecated.
        Removes the specified mapping from this map.
        Specified by:
        remove in interface Map
        Overrides:
        remove in class AbstractMap
        Parameters:
        key - the mapping to remove
        Returns:
        the value mapped to the removed key, null if key not in map

      • clear

        public void clear()
        Deprecated.
        Clears the map, resetting the size to zero and nullifying references to avoid garbage collection issues.
        Specified by:
        clear in interface Map
        Overrides:
        clear in class AbstractMap

      • mapIterator

        public MapIterator mapIterator()
        Deprecated.
        Gets an iterator over the map. Changes made to the iterator affect this map.

        A MapIterator returns the keys in the map. It also provides convenient methods to get the key and value, and set the value. It avoids the need to create an entrySet/keySet/values object. It also avoids creating the Map.Entry object.

        Specified by:
        mapIterator in interface IterableMap
        Returns:
        the map iterator

      • entrySet

        public Set entrySet()
        Deprecated.
        Gets the entrySet view of the map. Changes made to the view affect this map. To simply iterate through the entries, use mapIterator().
        Specified by:
        entrySet in interface Map
        Specified by:
        entrySet in class AbstractMap
        Returns:
        the entrySet view

      • keySet

        public Set keySet()
        Deprecated.
        Gets the keySet view of the map. Changes made to the view affect this map. To simply iterate through the keys, use mapIterator().
        Specified by:
        keySet in interface Map
        Overrides:
        keySet in class AbstractMap
        Returns:
        the keySet view

      • values

        public Collection values()
        Deprecated.
        Gets the values view of the map. Changes made to the view affect this map. To simply iterate through the values, use mapIterator().
        Specified by:
        values in interface Map
        Overrides:
        values in class AbstractMap
        Returns:
        the values view

      • equals

        public boolean equals​(Object obj)
        Deprecated.
        Compares this map with another.
        Specified by:
        equals in interface Map
        Overrides:
        equals in class AbstractMap
        Parameters:
        obj - the object to compare to
        Returns:
        true if equal

      • hashCode

        public int hashCode()
        Deprecated.
        Gets the standard Map hashCode.
        Specified by:
        hashCode in interface Map
        Overrides:
        hashCode in class AbstractMap
        Returns:
        the hash code defined in the Map interface

      • toString

        public String toString()
        Deprecated.
        Gets the map as a String.
        Overrides:
        toString in class AbstractMap
        Returns:
        a string version of the map