Package org.apache.commons.collections.bidimap

Class TreeBidiMap

  • All Implemented Interfaces:
    java.util.Map, BidiMap, IterableMap, OrderedBidiMap, OrderedMap
    public class TreeBidiMap
extends java.lang.Object
implements OrderedBidiMap
    Red-Black tree-based implementation of BidiMap where all objects added implement the Comparable interface.

    This class guarantees that the map will be in both ascending key order and ascending value order, sorted according to the natural order for the key's and value's classes.

    This Map is intended for applications that need to be able to look up a key-value pairing by either key or value, and need to do so with equal efficiency.

    While that goal could be accomplished by taking a pair of TreeMaps and redirecting requests to the appropriate TreeMap (e.g., containsKey would be directed to the TreeMap that maps values to keys, containsValue would be directed to the TreeMap that maps keys to values), there are problems with that implementation. If the data contained in the TreeMaps is large, the cost of redundant storage becomes significant. The DualTreeBidiMap and DualHashBidiMap implementations use this approach.

    This solution keeps minimizes the data storage by holding data only once. The red-black algorithm is based on java util TreeMap, but has been modified to simultaneously map a tree node by key and by value. This doubles the cost of put operations (but so does using two TreeMaps), and nearly doubles the cost of remove operations (there is a savings in that the lookup of the node to be removed only has to be performed once). And since only one node contains the key and value, storage is significantly less than that required by two TreeMaps.

    The Map.Entry instances returned by the appropriate methods will not allow setValue() and will throw an UnsupportedOperationException on attempts to call that method.

    Since:
    Commons Collections 3.0 (previously DoubleOrderedMap v2.0)
    Version:
    $Revision: 1713173 $ $Date: 2015-11-07 21:31:09 +0100 (Sat, 07 Nov 2015) $

    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description
      (package private) static class  TreeBidiMap.EntryView
      A view of this map.
      (package private) static class  TreeBidiMap.Inverse
      A node used to store the data.
      (package private) static class  TreeBidiMap.Node
      A node used to store the data.
      (package private) static class  TreeBidiMap.View
      A view of this map.
      (package private) static class  TreeBidiMap.ViewIterator
      An iterator over the map.
      (package private) static class  TreeBidiMap.ViewMapIterator
      An iterator over the map.

      • Nested classes/interfaces inherited from interface java.util.Map

        java.util.Map.Entry<K extends java.lang.Object,​V extends java.lang.Object>

    • Constructor Summary

      Constructors 
      Constructor Description
      TreeBidiMap()
      Constructs a new empty TreeBidiMap.
      TreeBidiMap​(java.util.Map map)
      Constructs a new TreeBidiMap by copying an existing Map.

    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      private static void checkKey​(java.lang.Object key)
      check a key for validity (non-null and implements Comparable)
      private static void checkKeyAndValue​(java.lang.Object key, java.lang.Object value)
      check a key and a value for validity (non-null and implements Comparable)
      private static void checkNonNullComparable​(java.lang.Object o, int index)
      check if an object is fit to be proper input ...
      private static void checkValue​(java.lang.Object value)
      check a value for validity (non-null and implements Comparable)
      void clear()
      Removes all mappings from this map.
      private static int compare​(java.lang.Comparable o1, java.lang.Comparable o2)
      Compare two objects
      boolean containsKey​(java.lang.Object key)
      Checks whether this map contains the a mapping for the specified key.
      boolean containsValue​(java.lang.Object value)
      Checks whether this map contains the a mapping for the specified value.
      private static void copyColor​(TreeBidiMap.Node from, TreeBidiMap.Node to, int index)
      copy the color from one node to another, dealing with the fact that one or both nodes may, in fact, be null
      private boolean doEquals​(java.lang.Object obj, int type)
      Compares for equals as per the API.
      private java.lang.Object doGet​(java.lang.Comparable obj, int index)
      Common get logic, used to get by key or get by value
      private int doHashCode​(int type)
      Gets the hash code value for this map as per the API.
      private java.lang.Object doPut​(java.lang.Comparable key, java.lang.Comparable value, int index)
      Common put logic, differing only in the return value.
      private void doRedBlackDelete​(TreeBidiMap.Node deletedNode)
      complicated red-black delete stuff.
      private void doRedBlackDeleteFixup​(TreeBidiMap.Node replacementNode, int index)
      complicated red-black delete stuff.
      private void doRedBlackInsert​(TreeBidiMap.Node insertedNode, int index)
      complicated red-black insert stuff.
      private java.lang.Object doRemove​(java.lang.Comparable o, int index)
      Remove by object (remove by key or remove by value)
      private java.lang.String doToString​(int type)
      Gets the string form of this map as per AbstractMap.
      java.util.Set entrySet()
      Returns a set view of the entries contained in this map in key order.
      boolean equals​(java.lang.Object obj)
      Compares for equals as per the API.
      java.lang.Object firstKey()
      Gets the first (lowest) key currently in this map.
      java.lang.Object get​(java.lang.Object key)
      Gets the value to which this map maps the specified key.
      private static TreeBidiMap.Node getGrandParent​(TreeBidiMap.Node node, int index)
      get a node's grandparent.
      java.lang.Object getKey​(java.lang.Object value)
      Returns the key to which this map maps the specified value.
      private static TreeBidiMap.Node getLeftChild​(TreeBidiMap.Node node, int index)
      get a node's left child.
      private static TreeBidiMap.Node getParent​(TreeBidiMap.Node node, int index)
      get a node's parent.
      private static TreeBidiMap.Node getRightChild​(TreeBidiMap.Node node, int index)
      get a node's right child.
      private static TreeBidiMap.Node greatestNode​(TreeBidiMap.Node node, int index)
      Find the greatest node from a given node.
      private void grow()
      bump up the size and note that the map has changed
      int hashCode()
      Gets the hash code value for this map as per the API.
      private void insertValue​(TreeBidiMap.Node newNode)
      insert a node by its value
      BidiMap inverseBidiMap()
      Gets the inverse map for comparison.
      OrderedBidiMap inverseOrderedBidiMap()
      Gets the inverse map for comparison.
      private static boolean isBlack​(TreeBidiMap.Node node, int index)
      is the specified black red? if the node does not exist, sure, it's black, thank you
      boolean isEmpty()
      Checks whether the map is empty or not.
      private static boolean isLeftChild​(TreeBidiMap.Node node, int index)
      is this node its parent's left child? mind you, the node, or its parent, may not exist.
      private static boolean isRed​(TreeBidiMap.Node node, int index)
      is the specified node red? if the node does not exist, no, it's black, thank you
      private static boolean isRightChild​(TreeBidiMap.Node node, int index)
      is this node its parent's right child? mind you, the node, or its parent, may not exist.
      java.util.Set keySet()
      Returns a set view of the keys contained in this map in key order.
      java.lang.Object lastKey()
      Gets the last (highest) key currently in this map.
      private static TreeBidiMap.Node leastNode​(TreeBidiMap.Node node, int index)
      Find the least node from a given node.
      private TreeBidiMap.Node lookup​(java.lang.Comparable data, int index)
      do the actual lookup of a piece of data
      private static void makeBlack​(TreeBidiMap.Node node, int index)
      force a node (if it exists) black
      private static void makeRed​(TreeBidiMap.Node node, int index)
      force a node (if it exists) red
      MapIterator mapIterator()
      Gets an iterator over the map entries.
      private void modify()
      increment the modification count -- used to check for concurrent modification of the map through the map and through an Iterator from one of its Set or Collection views
      private TreeBidiMap.Node nextGreater​(TreeBidiMap.Node node, int index)
      get the next larger node from the specified node
      java.lang.Object nextKey​(java.lang.Object key)
      Gets the next key after the one specified.
      private TreeBidiMap.Node nextSmaller​(TreeBidiMap.Node node, int index)
      get the next larger node from the specified node
      private static int oppositeIndex​(int index)
      Get the opposite index of the specified index
      OrderedMapIterator orderedMapIterator()
      Gets an ordered iterator over the map entries.
      java.lang.Object previousKey​(java.lang.Object key)
      Gets the previous key before the one specified.
      java.lang.Object put​(java.lang.Object key, java.lang.Object value)
      Puts the key-value pair into the map, replacing any previous pair.
      void putAll​(java.util.Map map)
      Puts all the mappings from the specified map into this map.
      java.lang.Object remove​(java.lang.Object key)
      Removes the mapping for this key from this map if present.
      java.lang.Object removeValue​(java.lang.Object value)
      Removes the mapping for this value from this map if present.
      private void rotateLeft​(TreeBidiMap.Node node, int index)
      do a rotate left.
      private void rotateRight​(TreeBidiMap.Node node, int index)
      do a rotate right.
      private void shrink()
      decrement the size and note that the map has changed
      int size()
      Returns the number of key-value mappings in this map.
      private void swapPosition​(TreeBidiMap.Node x, TreeBidiMap.Node y, int index)
      swap two nodes (except for their content), taking care of special cases where one is the other's parent ...
      java.lang.String toString()
      Returns a string version of this Map in standard format.
      java.util.Collection values()
      Returns a set view of the values contained in this map in key order.

      • Methods inherited from class java.lang.Object

        clone, finalize, getClass, notify, notifyAll, wait, wait, wait

      • Methods inherited from interface java.util.Map

        compute, computeIfAbsent, computeIfPresent, forEach, getOrDefault, merge, putIfAbsent, remove, replace, replace, replaceAll

    • Constructor Detail

      • TreeBidiMap

        public TreeBidiMap()
        Constructs a new empty TreeBidiMap.

      • TreeBidiMap

        public TreeBidiMap​(java.util.Map map)
        Constructs a new TreeBidiMap by copying an existing Map.
        Parameters:
        map - the map to copy
        Throws:
        java.lang.ClassCastException - if the keys/values in the map are not Comparable or are not mutually comparable
        java.lang.NullPointerException - if any key or value in the map is null

    • Method Detail

      • size

        public int size()
        Returns the number of key-value mappings in this map.
        Specified by:
        size in interface java.util.Map
        Returns:
        the number of key-value mappings in this map

      • isEmpty

        public boolean isEmpty()
        Checks whether the map is empty or not.
        Specified by:
        isEmpty in interface java.util.Map
        Returns:
        true if the map is empty

      • containsKey

        public boolean containsKey​(java.lang.Object key)
        Checks whether this map contains the a mapping for the specified key.

        The key must implement Comparable.

        Specified by:
        containsKey in interface java.util.Map
        Parameters:
        key - key whose presence in this map is to be tested
        Returns:
        true if this map contains a mapping for the specified key
        Throws:
        java.lang.ClassCastException - if the key is of an inappropriate type
        java.lang.NullPointerException - if the key is null

      • containsValue

        public boolean containsValue​(java.lang.Object value)
        Checks whether this map contains the a mapping for the specified value.

        The value must implement Comparable.

        Specified by:
        containsValue in interface java.util.Map
        Parameters:
        value - value whose presence in this map is to be tested
        Returns:
        true if this map contains a mapping for the specified value
        Throws:
        java.lang.ClassCastException - if the value is of an inappropriate type
        java.lang.NullPointerException - if the value is null

      • get

        public java.lang.Object get​(java.lang.Object key)
        Gets the value to which this map maps the specified key. Returns null if the map contains no mapping for this key.

        The key must implement Comparable.

        Specified by:
        get in interface java.util.Map
        Parameters:
        key - key whose associated value is to be returned
        Returns:
        the value to which this map maps the specified key, or null if the map contains no mapping for this key
        Throws:
        java.lang.ClassCastException - if the key is of an inappropriate type
        java.lang.NullPointerException - if the key is null

      • put

        public java.lang.Object put​(java.lang.Object key,
                            java.lang.Object value)
        Puts the key-value pair into the map, replacing any previous pair.

        When adding a key-value pair, the value may already exist in the map against a different key. That mapping is removed, to ensure that the value only occurs once in the inverse map. 

          BidiMap map1 = new TreeBidiMap();
  map.put("A","B");  // contains A mapped to B, as per Map
  map.put("A","C");  // contains A mapped to C, as per Map
 
  BidiMap map2 = new TreeBidiMap();
  map.put("A","B");  // contains A mapped to B, as per Map
  map.put("C","B");  // contains C mapped to B, key A is removed

        Both key and value must implement Comparable.

        Specified by:
        put in interface BidiMap
        Specified by:
        put in interface java.util.Map
        Parameters:
        key - key with which the specified value is to be associated
        value - value to be associated with the specified key
        Returns:
        the previous value for the key
        Throws:
        java.lang.ClassCastException - if the key is of an inappropriate type
        java.lang.NullPointerException - if the key is null

      • putAll

        public void putAll​(java.util.Map map)
        Puts all the mappings from the specified map into this map.

        All keys and values must implement Comparable.

        Specified by:
        putAll in interface java.util.Map
        Parameters:
        map - the map to copy from

      • remove

        public java.lang.Object remove​(java.lang.Object key)
        Removes the mapping for this key from this map if present.

        The key must implement Comparable.

        Specified by:
        remove in interface java.util.Map
        Parameters:
        key - key whose mapping is to be removed from the map.
        Returns:
        previous value associated with specified key, or null if there was no mapping for key.
        Throws:
        java.lang.ClassCastException - if the key is of an inappropriate type
        java.lang.NullPointerException - if the key is null

      • clear

        public void clear()
        Removes all mappings from this map.
        Specified by:
        clear in interface java.util.Map

      • getKey

        public java.lang.Object getKey​(java.lang.Object value)
        Returns the key to which this map maps the specified value. Returns null if the map contains no mapping for this value.

        The value must implement Comparable.

        Specified by:
        getKey in interface BidiMap
        Parameters:
        value - value whose associated key is to be returned.
        Returns:
        the key to which this map maps the specified value, or null if the map contains no mapping for this value.
        Throws:
        java.lang.ClassCastException - if the value is of an inappropriate type
        java.lang.NullPointerException - if the value is null

      • removeValue

        public java.lang.Object removeValue​(java.lang.Object value)
        Removes the mapping for this value from this map if present.

        The value must implement Comparable.

        Specified by:
        removeValue in interface BidiMap
        Parameters:
        value - value whose mapping is to be removed from the map
        Returns:
        previous key associated with specified value, or null if there was no mapping for value.
        Throws:
        java.lang.ClassCastException - if the value is of an inappropriate type
        java.lang.NullPointerException - if the value is null

      • firstKey

        public java.lang.Object firstKey()
        Gets the first (lowest) key currently in this map.
        Specified by:
        firstKey in interface OrderedMap
        Returns:
        the first (lowest) key currently in this sorted map
        Throws:
        java.util.NoSuchElementException - if this map is empty

      • lastKey

        public java.lang.Object lastKey()
        Gets the last (highest) key currently in this map.
        Specified by:
        lastKey in interface OrderedMap
        Returns:
        the last (highest) key currently in this sorted map
        Throws:
        java.util.NoSuchElementException - if this map is empty

      • nextKey

        public java.lang.Object nextKey​(java.lang.Object key)
        Gets the next key after the one specified.

        The key must implement Comparable.

        Specified by:
        nextKey in interface OrderedMap
        Parameters:
        key - the key to search for next from
        Returns:
        the next key, null if no match or at end

      • previousKey

        public java.lang.Object previousKey​(java.lang.Object key)
        Gets the previous key before the one specified.

        The key must implement Comparable.

        Specified by:
        previousKey in interface OrderedMap
        Parameters:
        key - the key to search for previous from
        Returns:
        the previous key, null if no match or at start

      • keySet

        public java.util.Set keySet()
        Returns a set view of the keys contained in this map in key order.

        The set is backed by the map, so changes to the map are reflected in the set, and vice-versa. If the map is modified while an iteration over the set is in progress, the results of the iteration are undefined.

        The set supports element removal, which removes the corresponding mapping from the map. It does not support the add or addAll operations.

        Specified by:
        keySet in interface java.util.Map
        Returns:
        a set view of the keys contained in this map.

      • values

        public java.util.Collection values()
        Returns a set view of the values contained in this map in key order. The returned object can be cast to a Set.

        The set is backed by the map, so changes to the map are reflected in the set, and vice-versa. If the map is modified while an iteration over the set is in progress, the results of the iteration are undefined.

        The set supports element removal, which removes the corresponding mapping from the map. It does not support the add or addAll operations.

        Specified by:
        values in interface java.util.Map
        Returns:
        a set view of the values contained in this map.

      • entrySet

        public java.util.Set entrySet()
        Returns a set view of the entries contained in this map in key order. For simple iteration through the map, the MapIterator is quicker.

        The set is backed by the map, so changes to the map are reflected in the set, and vice-versa. If the map is modified while an iteration over the set is in progress, the results of the iteration are undefined.

        The set supports element removal, which removes the corresponding mapping from the map. It does not support the add or addAll operations. The returned MapEntry objects do not support setValue.

        Specified by:
        entrySet in interface java.util.Map
        Returns:
        a set view of the values contained in this map.

      • mapIterator

        public MapIterator mapIterator()
        Gets an iterator over the map entries.

        For this map, this iterator is the fastest way to iterate over the entries.

        Specified by:
        mapIterator in interface BidiMap
        Specified by:
        mapIterator in interface IterableMap
        Returns:
        an iterator

      • orderedMapIterator

        public OrderedMapIterator orderedMapIterator()
        Gets an ordered iterator over the map entries.

        This iterator allows both forward and reverse iteration over the entries.

        Specified by:
        orderedMapIterator in interface OrderedMap
        Returns:
        an iterator

      • equals

        public boolean equals​(java.lang.Object obj)
        Compares for equals as per the API.
        Specified by:
        equals in interface java.util.Map
        Overrides:
        equals in class java.lang.Object
        Parameters:
        obj - the object to compare to
        Returns:
        true if equal

      • hashCode

        public int hashCode()
        Gets the hash code value for this map as per the API.
        Specified by:
        hashCode in interface java.util.Map
        Overrides:
        hashCode in class java.lang.Object
        Returns:
        the hash code value for this map

      • toString

        public java.lang.String toString()
        Returns a string version of this Map in standard format.
        Overrides:
        toString in class java.lang.Object
        Returns:
        a standard format string version of the map

      • doGet

        private java.lang.Object doGet​(java.lang.Comparable obj,
                               int index)
        Common get logic, used to get by key or get by value
        Parameters:
        obj - the key or value that we're looking for
        index - the KEY or VALUE int
        Returns:
        the key (if the value was mapped) or the value (if the key was mapped); null if we couldn't find the specified object

      • doPut

        private java.lang.Object doPut​(java.lang.Comparable key,
                               java.lang.Comparable value,
                               int index)
        Common put logic, differing only in the return value.
        Parameters:
        key - the key, always the main map key
        value - the value, always the main map value
        index - the KEY or VALUE int, for the return value only
        Returns:
        the previously mapped value

      • doRemove

        private java.lang.Object doRemove​(java.lang.Comparable o,
                                  int index)
        Remove by object (remove by key or remove by value)
        Parameters:
        o - the key, or value, that we're looking for
        index - the KEY or VALUE int
        Returns:
        the key, if remove by value, or the value, if remove by key. null if the specified key or value could not be found

      • lookup

        private TreeBidiMap.Node lookup​(java.lang.Comparable data,
                                int index)
        do the actual lookup of a piece of data
        Parameters:
        data - the key or value to be looked up
        index - the KEY or VALUE int
        Returns:
        the desired Node, or null if there is no mapping of the specified data

      • nextGreater

        private TreeBidiMap.Node nextGreater​(TreeBidiMap.Node node,
                                     int index)
        get the next larger node from the specified node
        Parameters:
        node - the node to be searched from
        index - the KEY or VALUE int
        Returns:
        the specified node

      • nextSmaller

        private TreeBidiMap.Node nextSmaller​(TreeBidiMap.Node node,
                                     int index)
        get the next larger node from the specified node
        Parameters:
        node - the node to be searched from
        index - the KEY or VALUE int
        Returns:
        the specified node

      • oppositeIndex

        private static int oppositeIndex​(int index)
        Get the opposite index of the specified index
        Parameters:
        index - the KEY or VALUE int
        Returns:
        VALUE (if KEY was specified), else KEY

      • compare

        private static int compare​(java.lang.Comparable o1,
                           java.lang.Comparable o2)
        Compare two objects
        Parameters:
        o1 - the first object
        o2 - the second object
        Returns:
        negative value if o1 < o2; 0 if o1 == o2; positive value if o1 > o2

      • leastNode

        private static TreeBidiMap.Node leastNode​(TreeBidiMap.Node node,
                                          int index)
        Find the least node from a given node.
        Parameters:
        node - the node from which we will start searching
        index - the KEY or VALUE int
        Returns:
        the smallest node, from the specified node, in the specified mapping

      • greatestNode

        private static TreeBidiMap.Node greatestNode​(TreeBidiMap.Node node,
                                             int index)
        Find the greatest node from a given node.
        Parameters:
        node - the node from which we will start searching
        index - the KEY or VALUE int
        Returns:
        the greatest node, from the specified node

      • copyColor

        private static void copyColor​(TreeBidiMap.Node from,
                              TreeBidiMap.Node to,
                              int index)
        copy the color from one node to another, dealing with the fact that one or both nodes may, in fact, be null
        Parameters:
        from - the node whose color we're copying; may be null
        to - the node whose color we're changing; may be null
        index - the KEY or VALUE int

      • isRed

        private static boolean isRed​(TreeBidiMap.Node node,
                             int index)
        is the specified node red? if the node does not exist, no, it's black, thank you
        Parameters:
        node - the node (may be null) in question
        index - the KEY or VALUE int

      • isBlack

        private static boolean isBlack​(TreeBidiMap.Node node,
                               int index)
        is the specified black red? if the node does not exist, sure, it's black, thank you
        Parameters:
        node - the node (may be null) in question
        index - the KEY or VALUE int

      • makeRed

        private static void makeRed​(TreeBidiMap.Node node,
                            int index)
        force a node (if it exists) red
        Parameters:
        node - the node (may be null) in question
        index - the KEY or VALUE int

      • makeBlack

        private static void makeBlack​(TreeBidiMap.Node node,
                              int index)
        force a node (if it exists) black
        Parameters:
        node - the node (may be null) in question
        index - the KEY or VALUE int

      • getGrandParent

        private static TreeBidiMap.Node getGrandParent​(TreeBidiMap.Node node,
                                               int index)
        get a node's grandparent. mind you, the node, its parent, or its grandparent may not exist. no problem
        Parameters:
        node - the node (may be null) in question
        index - the KEY or VALUE int

      • getParent

        private static TreeBidiMap.Node getParent​(TreeBidiMap.Node node,
                                          int index)
        get a node's parent. mind you, the node, or its parent, may not exist. no problem
        Parameters:
        node - the node (may be null) in question
        index - the KEY or VALUE int

      • getRightChild

        private static TreeBidiMap.Node getRightChild​(TreeBidiMap.Node node,
                                              int index)
        get a node's right child. mind you, the node may not exist. no problem
        Parameters:
        node - the node (may be null) in question
        index - the KEY or VALUE int

      • getLeftChild

        private static TreeBidiMap.Node getLeftChild​(TreeBidiMap.Node node,
                                             int index)
        get a node's left child. mind you, the node may not exist. no problem
        Parameters:
        node - the node (may be null) in question
        index - the KEY or VALUE int

      • isLeftChild

        private static boolean isLeftChild​(TreeBidiMap.Node node,
                                   int index)
        is this node its parent's left child? mind you, the node, or its parent, may not exist. no problem. if the node doesn't exist ... it's its non-existent parent's left child. If the node does exist but has no parent ... no, we're not the non-existent parent's left child. Otherwise (both the specified node AND its parent exist), check.
        Parameters:
        node - the node (may be null) in question
        index - the KEY or VALUE int

      • isRightChild

        private static boolean isRightChild​(TreeBidiMap.Node node,
                                    int index)
        is this node its parent's right child? mind you, the node, or its parent, may not exist. no problem. if the node doesn't exist ... it's its non-existent parent's right child. If the node does exist but has no parent ... no, we're not the non-existent parent's right child. Otherwise (both the specified node AND its parent exist), check.
        Parameters:
        node - the node (may be null) in question
        index - the KEY or VALUE int

      • rotateLeft

        private void rotateLeft​(TreeBidiMap.Node node,
                        int index)
        do a rotate left. standard fare in the world of balanced trees
        Parameters:
        node - the node to be rotated
        index - the KEY or VALUE int

      • rotateRight

        private void rotateRight​(TreeBidiMap.Node node,
                         int index)
        do a rotate right. standard fare in the world of balanced trees
        Parameters:
        node - the node to be rotated
        index - the KEY or VALUE int

      • doRedBlackInsert

        private void doRedBlackInsert​(TreeBidiMap.Node insertedNode,
                              int index)
        complicated red-black insert stuff. Based on Sun's TreeMap implementation, though it's barely recognizable any more
        Parameters:
        insertedNode - the node to be inserted
        index - the KEY or VALUE int

      • doRedBlackDelete

        private void doRedBlackDelete​(TreeBidiMap.Node deletedNode)
        complicated red-black delete stuff. Based on Sun's TreeMap implementation, though it's barely recognizable any more
        Parameters:
        deletedNode - the node to be deleted

      • doRedBlackDeleteFixup

        private void doRedBlackDeleteFixup​(TreeBidiMap.Node replacementNode,
                                   int index)
        complicated red-black delete stuff. Based on Sun's TreeMap implementation, though it's barely recognizable any more. This rebalances the tree (somewhat, as red-black trees are not perfectly balanced -- perfect balancing takes longer)
        Parameters:
        replacementNode - the node being replaced
        index - the KEY or VALUE int

      • swapPosition

        private void swapPosition​(TreeBidiMap.Node x,
                          TreeBidiMap.Node y,
                          int index)
        swap two nodes (except for their content), taking care of special cases where one is the other's parent ... hey, it happens.
        Parameters:
        x - one node
        y - another node
        index - the KEY or VALUE int

      • checkNonNullComparable

        private static void checkNonNullComparable​(java.lang.Object o,
                                           int index)
        check if an object is fit to be proper input ... has to be Comparable and non-null
        Parameters:
        o - the object being checked
        index - the KEY or VALUE int (used to put the right word in the exception message)
        Throws:
        java.lang.NullPointerException - if o is null
        java.lang.ClassCastException - if o is not Comparable

      • checkKey

        private static void checkKey​(java.lang.Object key)
        check a key for validity (non-null and implements Comparable)
        Parameters:
        key - the key to be checked
        Throws:
        java.lang.NullPointerException - if key is null
        java.lang.ClassCastException - if key is not Comparable

      • checkValue

        private static void checkValue​(java.lang.Object value)
        check a value for validity (non-null and implements Comparable)
        Parameters:
        value - the value to be checked
        Throws:
        java.lang.NullPointerException - if value is null
        java.lang.ClassCastException - if value is not Comparable

      • checkKeyAndValue

        private static void checkKeyAndValue​(java.lang.Object key,
                                     java.lang.Object value)
        check a key and a value for validity (non-null and implements Comparable)
        Parameters:
        key - the key to be checked
        value - the value to be checked
        Throws:
        java.lang.NullPointerException - if key or value is null
        java.lang.ClassCastException - if key or value is not Comparable

      • modify

        private void modify()
        increment the modification count -- used to check for concurrent modification of the map through the map and through an Iterator from one of its Set or Collection views

      • grow

        private void grow()
        bump up the size and note that the map has changed

      • shrink

        private void shrink()
        decrement the size and note that the map has changed

      • insertValue

        private void insertValue​(TreeBidiMap.Node newNode)
                  throws java.lang.IllegalArgumentException
        insert a node by its value
        Parameters:
        newNode - the node to be inserted
        Throws:
        java.lang.IllegalArgumentException - if the node already exists in the value mapping

      • doEquals

        private boolean doEquals​(java.lang.Object obj,
                         int type)
        Compares for equals as per the API.
        Parameters:
        obj - the object to compare to
        type - the KEY or VALUE int
        Returns:
        true if equal

      • doHashCode

        private int doHashCode​(int type)
        Gets the hash code value for this map as per the API.
        Parameters:
        type - the KEY or VALUE int
        Returns:
        the hash code value for this map

      • doToString

        private java.lang.String doToString​(int type)
        Gets the string form of this map as per AbstractMap.
        Parameters:
        type - the KEY or VALUE int
        Returns:
        the string form of this map