org.apache.commons.collections.map

## Class HashedMap

- java.lang.Object
- - java.util.AbstractMap
  - - org.apache.commons.collections.map.AbstractHashedMap
    - - org.apache.commons.collections.map.HashedMap

- All Implemented Interfaces:
    Serializable, Cloneable, Map, IterableMap

      public class HashedMap
      extends AbstractHashedMap
      implements Serializable, Cloneable

  A `Map` implementation that is a general purpose alternative to `HashMap`.

  This implementation improves on the JDK1.4 HashMap by adding the `MapIterator` functionality and many methods for subclassing.

  Note that HashedMap is not synchronized and is not thread-safe. If you wish to use this map from multiple threads concurrently, you must use appropriate synchronization. The simplest approach is to wrap this map using `Collections.synchronizedMap(Map)`. This class may throw exceptions when accessed by concurrent threads without synchronization.

  Since:
    Commons Collections 3.0
  Version:
    $Revision: 646777 $ $Date: 2008-04-10 14:33:15 +0200 (Thu, 10 Apr 2008) $
  Author:
    Stephen Colebourne
  See Also:
    Serialized Form

- - ### Nested Class Summary

    - ### Nested classes/interfaces inherited from class org.apache.commons.collections.map.AbstractHashedMap

      `AbstractHashedMap.EntrySet, AbstractHashedMap.EntrySetIterator, AbstractHashedMap.HashEntry, AbstractHashedMap.HashIterator, AbstractHashedMap.HashMapIterator, AbstractHashedMap.KeySet, AbstractHashedMap.KeySetIterator, AbstractHashedMap.Values, AbstractHashedMap.ValuesIterator`

    - ### Nested classes/interfaces inherited from class java.util.AbstractMap

      `AbstractMap.SimpleEntry, AbstractMap.SimpleImmutableEntry`

    - ### Nested classes/interfaces inherited from interface java.util.Map

      `Map.Entry`

  - ### Field Summary

    - ### Fields inherited from class org.apache.commons.collections.map.AbstractHashedMap

      `data, DEFAULT_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_THRESHOLD, entrySet, GETKEY_INVALID, GETVALUE_INVALID, keySet, loadFactor, MAXIMUM_CAPACITY, modCount, NO_NEXT_ENTRY, NO_PREVIOUS_ENTRY, NULL, REMOVE_INVALID, SETVALUE_INVALID, size, threshold, values`

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `HashedMap()` Constructs a new empty map with default size and load factor.
    `HashedMap(int initialCapacity)` Constructs a new, empty map with the specified initial capacity.
    `HashedMap(int initialCapacity, float loadFactor)` Constructs a new, empty map with the specified initial capacity and load factor.
    `HashedMap(Map map)` Constructor copying elements from another map.

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `Object` | `clone()` Clones the map without cloning the keys or values.

    - ### Methods inherited from class org.apache.commons.collections.map.AbstractHashedMap

      `addEntry, addMapping, calculateNewCapacity, calculateThreshold, checkCapacity, clear, containsKey, containsValue, convertKey, createEntry, createEntrySetIterator, createKeySetIterator, createValuesIterator, destroyEntry, doReadObject, doWriteObject, ensureCapacity, entryHashCode, entryKey, entryNext, entrySet, entryValue, equals, get, getEntry, hash, hashCode, hashIndex, init, isEmpty, isEqualKey, isEqualValue, keySet, mapIterator, put, putAll, remove, removeEntry, removeMapping, reuseEntry, size, toString, updateEntry, values`

    - ### Methods inherited from class java.lang.Object

      `finalize, getClass, notify, notifyAll, wait, wait, wait`

- - ### Constructor Detail

    - #### HashedMap

          public HashedMap()

      Constructs a new empty map with default size and load factor.

    - #### HashedMap

          public HashedMap(int initialCapacity)

      Constructs a new, empty map with the specified initial capacity.
      Parameters:
        `initialCapacity` - the initial capacity
      Throws:
        `IllegalArgumentException` - if the initial capacity is less than one

    - #### HashedMap

          public HashedMap(int initialCapacity,
                   float loadFactor)

      Constructs a new, empty map with the specified initial capacity and load factor.
      Parameters:
        `initialCapacity` - the initial capacity
        `loadFactor` - the load factor
      Throws:
        `IllegalArgumentException` - if the initial capacity is less than one
        `IllegalArgumentException` - if the load factor is less than zero

    - #### HashedMap

          public HashedMap(Map map)

      Constructor copying elements from another map.
      Parameters:
        `map` - the map to copy
      Throws:
        `NullPointerException` - if the map is null

  - ### Method Detail

    - #### clone

          public Object clone()

      Clones the map without cloning the keys or values.
      Overrides:
        `clone` in class `AbstractHashedMap`
      Returns:
        a shallow clone

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