Class IntHashtable

  • All Implemented Interfaces:
    java.lang.Cloneable

    public class IntHashtable
    extends java.lang.Object
    implements java.lang.Cloneable

    A hash map that uses primitive ints for the key rather than objects.

    Note that this class is for internal optimization purposes only, and may not be supported in future releases of Jakarta Commons Lang. Utilities of this sort may be included in future releases of Jakarta Commons Collections.

    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description
      (package private) static class  IntHashtable.Entry
      Innerclass that acts as a datastructure to create a new entry in the table.
      (package private) static class  IntHashtable.IntHashtableIterator  
    • Field Summary

      Fields 
      Modifier and Type Field Description
      private int count
      The total number of entries in the hash table.
      private float loadFactor
      The load factor for the hashtable.
      private IntHashtable.Entry[] table
      The hash table data.
      private int threshold
      The table is rehashed when its size exceeds this threshold.
    • Constructor Summary

      Constructors 
      Constructor Description
      IntHashtable()
      Constructs a new, empty hashtable with a default capacity and load factor, which is 20 and 0.75 respectively.
      IntHashtable​(int initialCapacity)
      Constructs a new, empty hashtable with the specified initial capacity and default load factor, which is 0.75.
      IntHashtable​(int initialCapacity, float loadFactor)
      Constructs a new, empty hashtable with the specified initial capacity and the specified load factor.
    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void clear()
      Clears this hashtable so that it contains no keys.
      java.lang.Object clone()  
      boolean contains​(int value)
      Tests if some key maps into the specified value in this hashtable.
      boolean containsKey​(int key)
      Tests if the specified int is a key in this hashtable.
      boolean containsValue​(int value)
      Returns true if this HashMap maps one or more keys to this value.
      int get​(int key)
      Returns the value to which the specified key is mapped in this map.
      java.util.Iterator<IntHashtable.Entry> getEntryIterator()  
      int[] getKeys()  
      int getOneKey()  
      boolean isEmpty()
      Tests if this hashtable maps no keys to values.
      int put​(int key, int value)
      Maps the specified key to the specified value in this hashtable.
      protected void rehash()
      Increases the capacity of and internally reorganizes this hashtable, in order to accommodate and access its entries more efficiently.
      int remove​(int key)
      Removes the key (and its corresponding value) from this hashtable.
      int size()
      Returns the number of keys in this hashtable.
      int[] toOrderedKeys()  
      • Methods inherited from class java.lang.Object

        equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
    • Field Detail

      • count

        private transient int count
        The total number of entries in the hash table.
      • threshold

        private int threshold
        The table is rehashed when its size exceeds this threshold. (The value of this field is (int)(capacity * loadFactor).)
      • loadFactor

        private float loadFactor
        The load factor for the hashtable.
    • Constructor Detail

      • IntHashtable

        public IntHashtable()

        Constructs a new, empty hashtable with a default capacity and load factor, which is 20 and 0.75 respectively.

      • IntHashtable

        public IntHashtable​(int initialCapacity)

        Constructs a new, empty hashtable with the specified initial capacity and default load factor, which is 0.75.

        Parameters:
        initialCapacity - the initial capacity of the hashtable.
        Throws:
        java.lang.IllegalArgumentException - if the initial capacity is less than zero.
      • IntHashtable

        public IntHashtable​(int initialCapacity,
                            float loadFactor)

        Constructs a new, empty hashtable with the specified initial capacity and the specified load factor.

        Parameters:
        initialCapacity - the initial capacity of the hashtable.
        loadFactor - the load factor of the hashtable.
        Throws:
        java.lang.IllegalArgumentException - if the initial capacity is less than zero, or if the load factor is nonpositive.
    • Method Detail

      • size

        public int size()

        Returns the number of keys in this hashtable.

        Returns:
        the number of keys in this hashtable.
      • isEmpty

        public boolean isEmpty()

        Tests if this hashtable maps no keys to values.

        Returns:
        true if this hashtable maps no keys to values; false otherwise.
      • contains

        public boolean contains​(int value)

        Tests if some key maps into the specified value in this hashtable. This operation is more expensive than the containsKey method.

        Note that this method is identical in functionality to containsValue, (which is part of the Map interface in the collections framework).

        Parameters:
        value - a value to search for.
        Returns:
        true if and only if some key maps to the value argument in this hashtable as determined by the equals method; false otherwise.
        Throws:
        java.lang.NullPointerException - if the value is null.
        See Also:
        containsKey(int), containsValue(int), Map
      • containsValue

        public boolean containsValue​(int value)

        Returns true if this HashMap maps one or more keys to this value.

        Note that this method is identical in functionality to contains (which predates the Map interface).

        Parameters:
        value - value whose presence in this HashMap is to be tested.
        Returns:
        boolean true if the value is contained
        Since:
        JDK1.2
        See Also:
        Map
      • containsKey

        public boolean containsKey​(int key)

        Tests if the specified int is a key in this hashtable.

        Parameters:
        key - possible key.
        Returns:
        true if and only if the specified int is a key in this hashtable, as determined by the equals method; false otherwise.
        See Also:
        contains(int)
      • get

        public int get​(int key)

        Returns the value to which the specified key is mapped in this map.

        Parameters:
        key - a key in the hashtable.
        Returns:
        the value to which the key is mapped in this hashtable; 0 if the key is not mapped to any value in this hashtable.
        See Also:
        put(int, int)
      • rehash

        protected void rehash()

        Increases the capacity of and internally reorganizes this hashtable, in order to accommodate and access its entries more efficiently.

        This method is called automatically when the number of keys in the hashtable exceeds this hashtable's capacity and load factor.

      • put

        public int put​(int key,
                       int value)

        Maps the specified key to the specified value in this hashtable. The key cannot be null.

        The value can be retrieved by calling the get method with a key that is equal to the original key.

        Parameters:
        key - the hashtable key.
        value - the value.
        Returns:
        the previous value of the specified key in this hashtable, or null if it did not have one.
        Throws:
        java.lang.NullPointerException - if the key is null.
        See Also:
        get(int)
      • remove

        public int remove​(int key)

        Removes the key (and its corresponding value) from this hashtable.

        This method does nothing if the key is not present in the hashtable.

        Parameters:
        key - the key that needs to be removed.
        Returns:
        the value to which the key had been mapped in this hashtable, or null if the key did not have a mapping.
      • clear

        public void clear()

        Clears this hashtable so that it contains no keys.

      • toOrderedKeys

        public int[] toOrderedKeys()
      • getKeys

        public int[] getKeys()
      • getOneKey

        public int getOneKey()
      • clone

        public java.lang.Object clone()
        Overrides:
        clone in class java.lang.Object