Class HashedMap

  • All Implemented Interfaces:
    java.io.Serializable, java.lang.Cloneable, java.util.Map, IterableMap

    public class HashedMap
    extends AbstractHashedMap
    implements java.io.Serializable, java.lang.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) $
    See Also:
    Serialized Form
    • Field Detail

      • serialVersionUID

        private static final long serialVersionUID
        Serialisation version
        See Also:
        Constant Field Values
    • 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:
        java.lang.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:
        java.lang.IllegalArgumentException - if the initial capacity is less than one
        java.lang.IllegalArgumentException - if the load factor is less than zero
      • HashedMap

        public HashedMap​(java.util.Map map)
        Constructor copying elements from another map.
        Parameters:
        map - the map to copy
        Throws:
        java.lang.NullPointerException - if the map is null
    • Method Detail

      • clone

        public java.lang.Object clone()
        Clones the map without cloning the keys or values.
        Overrides:
        clone in class AbstractHashedMap
        Returns:
        a shallow clone
      • writeObject

        private void writeObject​(java.io.ObjectOutputStream out)
                          throws java.io.IOException
        Write the map out using a custom routine.
        Throws:
        java.io.IOException
      • readObject

        private void readObject​(java.io.ObjectInputStream in)
                         throws java.io.IOException,
                                java.lang.ClassNotFoundException
        Read the map in using a custom routine.
        Throws:
        java.io.IOException
        java.lang.ClassNotFoundException