Package org.apache.directory.api.util

Class SequencedHashMap

    • Constructor Detail

      • SequencedHashMap

        public SequencedHashMap()
        Construct a new sequenced hash map with default initial size and load factor.

      • SequencedHashMap

        public SequencedHashMap​(int initialSize)
        Construct a new sequenced hash map with the specified initial size and default load factor.
        Parameters:
        initialSize - the initial size for the hash table
        See Also:
        HashMap(int)

      • SequencedHashMap

        public SequencedHashMap​(int initialSize,
                        float loadFactor)
        Construct a new sequenced hash map with the specified initial size and load factor.
        Parameters:
        initialSize - the initial size for the hash table
        loadFactor - the load factor for the hash table.
        See Also:
        HashMap(int,float)

      • SequencedHashMap

        public SequencedHashMap​(Map m)
        Construct a new sequenced hash map and add all the elements in the specified map. The order in which the mappings in the specified map are added is defined by putAll(Map).
        Parameters:
        m - The original map

    • Method Detail

      • getFirst

        public Map.Entry getFirst()
        Return the entry for the "oldest" mapping. That is, return the Map.Entry for the key-value pair that was first put into the map when compared to all the other pairings in the map. This behavior is equivalent to using entrySet().iterator().next(), but this method provides an optimized implementation.
        Returns:
        The first entry in the sequence, or null if the map is empty.

      • getFirstKey

        public Object getFirstKey()
        Return the key for the "oldest" mapping. That is, return the key for the mapping that was first put into the map when compared to all the other objects in the map. This behavior is equivalent to using getFirst().getKey(), but this method provides a slightly optimized implementation.
        Returns:
        The first key in the sequence, or null if the map is empty.

      • getFirstValue

        public Object getFirstValue()
        Return the value for the "oldest" mapping. That is, return the value for the mapping that was first put into the map when compared to all the other objects in the map. This behavior is equivalent to using getFirst().getValue(), but this method provides a slightly optimized implementation.
        Returns:
        The first value in the sequence, or null if the map is empty.

      • getLast

        public Map.Entry getLast()
        Return the entry for the "newest" mapping. That is, return the Map.Entry for the key-value pair that was first put into the map when compared to all the other pairings in the map. The behavior is equivalent to: 
         Object obj = null;
 Iterator iter = entrySet().iterator();
 while ( iter.hasNext() )
 {
     obj = iter.next();
 }
 return ( Map.Entry ) obj;
        However, the implementation of this method ensures an O(1) lookup of the last key rather than O(n).
        Returns:
        The last entry in the sequence, or null if the map is empty.

      • getLastKey

        public Object getLastKey()
        Return the key for the "newest" mapping. That is, return the key for the mapping that was last put into the map when compared to all the other objects in the map. This behavior is equivalent to using getLast().getKey(), but this method provides a slightly optimized implementation.
        Returns:
        The last key in the sequence, or null if the map is empty.

      • getLastValue

        public Object getLastValue()
        Return the value for the "newest" mapping. That is, return the value for the mapping that was last put into the map when compared to all the other objects in the map. This behavior is equivalent to using getLast().getValue(), but this method provides a slightly optimized implementation.
        Returns:
        The last value in the sequence, or null if the map is empty.

      • putAll

        public void putAll​(Map t)
        Adds all the mappings in the specified map to this map, replacing any mappings that already exist (as per Map.putAll(Map)). The order in which the entries are added is determined by the iterator returned from Map.entrySet() for the specified map.
        Specified by:
        putAll in interface Map
        Parameters:
        t - the mappings that should be added to this map.
        Throws:
        NullPointerException - if t is null

      • toString

        public String toString()
        Provides a string representation of the entries within the map. The format of the returned string may change with different releases, so this method is suitable for debugging purposes only. If a specific format is required, use entrySet().iterator() and iterate over the entries in the map formatting them as appropriate.
        Overrides:
        toString in class Object

      • clone

        public Object clone()
             throws CloneNotSupportedException
        Creates a shallow copy of this object, preserving the internal structure by copying only references. The keys and values themselves are not clone()'d. The cloned object maintains the same sequence.
        Returns:
        A clone of this instance.
        Throws:
        CloneNotSupportedException - if clone is not supported by a subclass.

      • get

        public Object get​(int index)
        Gets the key at the specified index.
        Parameters:
        index - the index to retrieve
        Returns:
        the key at the specified index, or null
        Throws:
        ArrayIndexOutOfBoundsException - if the index is < 0 or > the size of the map.

      • getValue

        public Object getValue​(int index)
        Gets the value at the specified index.
        Parameters:
        index - the index to retrieve
        Returns:
        the value at the specified index, or null
        Throws:
        ArrayIndexOutOfBoundsException - if the index is < 0 or > the size of the map.

      • indexOf

        public int indexOf​(Object key)
        Gets the index of the specified key.
        Parameters:
        key - the key to find the index of
        Returns:
        the index, or -1 if not found

      • iterator

        public Iterator iterator()
        Gets an iterator over the keys.
        Returns:
        an iterator over the keys

      • lastIndexOf

        public int lastIndexOf​(Object key)
        Gets the last index of the specified key.
        Parameters:
        key - the key to find the index of
        Returns:
        the index, or -1 if not found

      • sequence

        public List sequence()
        Returns a List view of the keys rather than a set view. The returned list is unmodifiable. This is required because changes to the values of the list (using ListIterator.set(Object)) will effectively remove the value from the list and reinsert that value at the end of the list, which is an unexpected side effect of changing the value of a list. This occurs because changing the key, changes when the mapping is added to the map and thus where it appears in the list.

        An alternative to this method is to use keySet()

        Returns:
        The ordered list of keys.
        See Also:
        keySet()

      • remove

        public Object remove​(int index)
        Removes the element at the specified index.
        Parameters:
        index - The index of the object to remove.
        Returns:
        The previous value corresponding the key, or null if none existed.
        Throws:
        ArrayIndexOutOfBoundsException - if the index is < 0 or > the size of the map.