Class BinaryTreeNode<E>

java.lang.Object
inet.ipaddr.format.util.BinaryTreeNode<E>
Type Parameters:
E -
All Implemented Interfaces:
TreeOps<E>, Serializable, Cloneable, Iterable<E>
Direct Known Subclasses:
AddressTrie.TrieNode
public class BinaryTreeNode<E> extends Object implements TreeOps<E>
A binary tree node.

Some binary tree nodes are considered "added" and others are not. Those nodes created for key elements added to the tree are "added" nodes. Those that are not added are those nodes created to serve as junctions for the added nodes. Only added elements contribute to the size of a tree. When removing nodes, non-added nodes are removed automatically whenever they are no longer needed, which is when an added node has less than two added sub-nodes.

BinaryTreeNode objects have a read-only API, in the sense that they cannot be constructed directly. Instead they are created indirectly by tree operations or by cloning existing nodes.

The API does allow you to remove them from trees, or to clone them. They can also be used to traverse a tree.

Nodes have various properties: the key, parent node, lower sub-node, upper sub-node, "added" property, and size. The "added" property can change if the node changes status following tree operations. If removed from a tree the parent property can change, and the sub-nodes can change when sub-nodes are removed from the tree, or other nodes are inserted into the tree, changing sub-nodes. However, none of these can be explicitly changed directly, they can only be changed indirectly by tree operations. The key of a node never changes.

Author:
scfoley
See Also:

  • Nested Class Summary

    Nested Classes
    Modifier and Type
    Class
    Description
    static interface 
    BinaryTreeNode.CachingIterator<N extends BinaryTreeNode<E>, E, C>
     

  • Method Summary

    Modifier and Type
    Method
    Description
    Iterator<? extends BinaryTreeNode<E>>
    allNodeIterator(boolean forward)
    Iterates through all the nodes of the sub-tree with this node as the root, in forward or reverse tree order.
    void
    clear()
    Removes this node and all sub-nodes from the tree, after which isEmpty() will return true.
    BinaryTreeNode<E>
    clone()
    Clones the node.
    BinaryTreeNode<E>
    cloneTree()
    Clones the sub-tree starting with this node as root.
    Iterator<? extends BinaryTreeNode<E>>
    containedFirstAllNodeIterator(boolean forwardSubNodeOrder)
    Returns an iterator that does a post-order binary tree traversal.
    Iterator<? extends BinaryTreeNode<E>>
    containedFirstIterator(boolean forwardSubNodeOrder)
    Returns an iterator that does a post-order binary tree traversal of the added nodes.
    <C> BinaryTreeNode.CachingIterator<? extends BinaryTreeNode<E>, E, C>
    containingFirstAllNodeIterator(boolean forwardSubNodeOrder)
    Returns an iterator that does a pre-order binary tree traversal.
    Iterator<? extends BinaryTreeNode<E>>
    containingFirstIterator(boolean forwardSubNodeOrder)
    Returns an iterator that does a pre-order binary tree traversal of the added nodes.
    Iterator<E>
    descendingIterator()
    Returns an iterator that iterates through the elements of the subtrie with this node as the root.
    boolean
    equals(Object o)
    Returns whether the key values match those of the given node
    BinaryTreeNode<E>
    firstAddedNode()
    Returns the first (lowest valued) added node in the sub-tree originating from this node, or null if there are no added entries in this tree or sub-tree
    BinaryTreeNode<E>
    firstNode()
    Returns the first (lowest valued) node in the sub-tree originating from this node.
    E
    getKey()
    Gets the key used for placing the node in the tree.
    BinaryTreeNode<E>
    getLowerSubNode()
    Gets the direct child node whose key is smallest in value
    BinaryTreeNode<E>
    getParent()
    Gets the node from which this node is a direct child node, or null if this is the root.
    BinaryTreeNode<E>
    getUpperSubNode()
    Gets the direct child node whose key is largest in value
    int
    hashCode()
    The hash code is the hash code of the key value
    boolean
    isAdded()
    Some binary tree nodes are considered "added" and others are not.
    boolean
    isEmpty()
    Returns where there are not any elements in the sub-tree with this node as the root.
    boolean
    isLeaf()
    Returns whether this node is in the tree (is a node for which isAdded() is true) and additional there are other elements in the sub-tree with this node as the root.
    boolean
    isRoot()
    Returns whether this is the root of the backing tree.
    Iterator<E>
    iterator()
    Returns an iterator that iterates through the elements of the sub-tree with this node as the root.
    BinaryTreeNode<E>
    lastAddedNode()
    Returns the last (highest valued) added node in the sub-tree originating from this node, or null if there are no added entries in this tree or sub-tree
    BinaryTreeNode<E>
    lastNode()
    Returns the last (highest valued) node in the sub-tree originating from this node.
    BinaryTreeNode<E>
    nextAddedNode()
    Returns the next node in the tree that is an added node, following the tree order, or null if there is no such node.
    BinaryTreeNode<E>
    nextNode()
    Returns the node that follows this node following the tree order
    Iterator<? extends BinaryTreeNode<E>>
    nodeIterator(boolean forward)
    Iterates through the added nodes of the sub-tree with this node as the root, in forward or reverse tree order.
    int
    nodeSize()
    Returns the count of all nodes in the tree starting from this node and extending to all sub-nodes.
    BinaryTreeNode<E>
    previousAddedNode()
    Returns the previous node in the tree that is an added node, following the tree order in reverse, or null if there is no such node.
    BinaryTreeNode<E>
    previousNode()
    Returns the node that precedes this node following the tree order.
    void
    remove()
    Removes this node from the list of added nodes, and also removes from the tree if possible.
    void
    setAdded()
    Make this node an added node, which is equivalent to adding the corresponding address to the tree.
    int
    size()
    Returns the count of nodes added to the sub-tree starting from this node as root and moving downwards to sub-nodes.
    String
    toString()
    Returns a visual representation of this node including the key, with an open circle indicating this node is not an added node, a closed circle indicating this node is an added node.
    String
    toTreeString(boolean withNonAddedKeys, boolean withSizes)
    Returns a visual representation of the sub-tree with this node as root, with one node per line.
    boolean
    treeEquals(BinaryTreeNode<?> other)
    Returns whether the sub-tree represented by this node as the root node matches the given sub-tree
    int
    treeHashCode()
    The hash code is the sum of the hash codes of all the added elements in the sub-tree with this node as the root

    Methods inherited from class Object

    getClass, notify, notifyAll, wait, wait, wait

    Methods inherited from interface Iterable

    forEach

    Methods inherited from interface TreeOps

    allNodeSpliterator, descendingSpliterator, nodeSpliterator, spliterator

  • Method Details

    • getKey

      public E getKey()
      Gets the key used for placing the node in the tree.
      Returns:
      the key used for placing the node in the tree.

    • isRoot

      public boolean isRoot()
      Returns whether this is the root of the backing tree.
      Returns:

    • getParent

      public BinaryTreeNode<E> getParent()
      Gets the node from which this node is a direct child node, or null if this is the root.
      Returns:

    • getUpperSubNode

      public BinaryTreeNode<E> getUpperSubNode()
      Gets the direct child node whose key is largest in value
      Returns:

    • getLowerSubNode

      public BinaryTreeNode<E> getLowerSubNode()
      Gets the direct child node whose key is smallest in value
      Returns:

    • isAdded

      public boolean isAdded()
      Some binary tree nodes are considered "added" and others are not. Those nodes created for key elements added to the tree are "added" nodes. Those that are not added are those nodes created to serve as junctions for the added nodes. Only added elements contribute to the size of a tree. When removing nodes, non-added nodes are removed automatically whenever they are no longer needed, which is when an added node has less than two added sub-nodes.
      Returns:
      whether this node represents an element added to the tree

    • setAdded

      public void setAdded()
      Make this node an added node, which is equivalent to adding the corresponding address to the tree. If already added, this method has no effect.

      You cannot set an added node to non-added, for that you should remove the node from the tree by calling remove(). A non-added node will only remain in the tree if it needs to in the tree.

    • size

      public int size()
      Returns the count of nodes added to the sub-tree starting from this node as root and moving downwards to sub-nodes. This is a constant-time operation since the size is maintained in each node and adjusted with each add and remove operation in the sub-tree.
      Returns:

    • nodeSize

      public int nodeSize()
      Returns the count of all nodes in the tree starting from this node and extending to all sub-nodes. Unlike size(), this is not a constant-time operation and must visit all sub-nodes of this node.
      Returns:

    • remove

      public void remove()
      Removes this node from the list of added nodes, and also removes from the tree if possible. If it has two sub-nodes, it cannot be removed from the tree, in which case it is marked as not "added", nor is it counted in the tree size. Only added nodes can be removed from the tree. If this node is not added, this method does nothing.

    • clear

      public void clear()
      Removes this node and all sub-nodes from the tree, after which isEmpty() will return true.

    • isEmpty

      public boolean isEmpty()
      Returns where there are not any elements in the sub-tree with this node as the root.

    • isLeaf

      public boolean isLeaf()
      Returns whether this node is in the tree (is a node for which isAdded() is true) and additional there are other elements in the sub-tree with this node as the root.

    • firstNode

      public BinaryTreeNode<E> firstNode()
      Returns the first (lowest valued) node in the sub-tree originating from this node.
      Returns:

    • firstAddedNode

      public BinaryTreeNode<E> firstAddedNode()
      Returns the first (lowest valued) added node in the sub-tree originating from this node, or null if there are no added entries in this tree or sub-tree
      Returns:

    • lastNode

      public BinaryTreeNode<E> lastNode()
      Returns the last (highest valued) node in the sub-tree originating from this node.
      Returns:

    • lastAddedNode

      public BinaryTreeNode<E> lastAddedNode()
      Returns the last (highest valued) added node in the sub-tree originating from this node, or null if there are no added entries in this tree or sub-tree
      Returns:

    • nextNode

      public BinaryTreeNode<E> nextNode()
      Returns the node that follows this node following the tree order
      Returns:

    • previousNode

      public BinaryTreeNode<E> previousNode()
      Returns the node that precedes this node following the tree order.
      Returns:

    • nextAddedNode

      public BinaryTreeNode<E> nextAddedNode()
      Returns the next node in the tree that is an added node, following the tree order, or null if there is no such node.
      Returns:

    • previousAddedNode

      public BinaryTreeNode<E> previousAddedNode()
      Returns the previous node in the tree that is an added node, following the tree order in reverse, or null if there is no such node.
      Returns:

    • iterator

      public Iterator<E> iterator()
      Returns an iterator that iterates through the elements of the sub-tree with this node as the root. The iteration is in sorted element order.
      Specified by:
      iterator in interface Iterable<E>
      Specified by:
      iterator in interface TreeOps<E>
      Returns:

    • descendingIterator

      public Iterator<E> descendingIterator()
      Returns an iterator that iterates through the elements of the subtrie with this node as the root. The iteration is in reverse sorted element order.
      Specified by:
      descendingIterator in interface TreeOps<E>
      Returns:

    • nodeIterator

      public Iterator<? extends BinaryTreeNode<E>> nodeIterator(boolean forward)
      Iterates through the added nodes of the sub-tree with this node as the root, in forward or reverse tree order.
      Specified by:
      nodeIterator in interface TreeOps<E>
      Parameters:
      forward - if true, goes in ascending order, otherwise descending
      Returns:

    • allNodeIterator

      public Iterator<? extends BinaryTreeNode<E>> allNodeIterator(boolean forward)
      Iterates through all the nodes of the sub-tree with this node as the root, in forward or reverse tree order.
      Specified by:
      allNodeIterator in interface TreeOps<E>
      Parameters:
      forward - if true, goes in ascending order, otherwise descending
      Returns:

    • containingFirstIterator

      public Iterator<? extends BinaryTreeNode<E>> containingFirstIterator(boolean forwardSubNodeOrder)
      Description copied from interface: TreeOps
      Returns an iterator that does a pre-order binary tree traversal of the added nodes. All added nodes will be visited before their added sub-nodes. For an address trie this means added containing subnet blocks will be visited before their added contained addresses and subnet blocks.

      This iterator supports the Iterator.remove() operation.

      See the docs for TreeOps for more details on the ordering.

      Specified by:
      containingFirstIterator in interface TreeOps<E>
      Parameters:
      forwardSubNodeOrder - if true, a left sub-node will be visited before the right sub-node of the same parent node.
      Returns:

    • containingFirstAllNodeIterator

      public <C> BinaryTreeNode.CachingIterator<? extends BinaryTreeNode<E>, E, C> containingFirstAllNodeIterator(boolean forwardSubNodeOrder)
      Description copied from interface: TreeOps
      Returns an iterator that does a pre-order binary tree traversal. All nodes will be visited before their sub-nodes. For an address trie this means containing subnet blocks will be visited before their contained addresses and subnet blocks.

      This iterator supports the Iterator.remove() operation.

      Once a given node is visited, the iterator allows you to cache an object corresponding to the lower or upper sub-node that can be retrieved when you later visit that sub-node. That allows you to provide iteration context from a parent to its sub-nodes when iterating. The caching and retrieval is done in constant-time and linear space (proportional to tree size).

      Here is an example showing usage of the caching. Consider this recursive code doing a pre-order traversal: 

      IPv6AddressTrie ipv6Tree = ...;
visitRecursive(ipv6Tree.getRoot(), null);

static <E> void visitRecursive(BinaryTreeNode<E> node, String direction) {
        if(direction == null) {
                direction = "root";
        }
        System.out.println("visited " + direction + " " + node);
        BinaryTreeNode<E> sub = node.getLowerSubNode();
        if(sub != null) {
                visitRecursive(sub, direction + " left");
        }
        sub = node.getUpperSubNode();
        if(sub != null) {
                visitRecursive(sub, direction + " right");
        }
}
      The following iterative code provides the same functionality: 
      visitIterative(ipv6Tree.getRoot());

static <E> void visitIterative(BinaryTreeNode<E> node) {        
        CachingIterator<? extends BinaryTreeNode<E>, E, String>iterator = node.containingFirstAllNodeIterator(true);
        while(iterator.hasNext()) {
                BinaryTreeNode<E> next = iterator.next();
                String direction = iterator.getCached();
                if(direction == null) {
                        direction = "root";
                }
                System.out.println("visited " + direction + " " + next);
                iterator.cacheWithLowerSubNode(direction + " left");
                iterator.cacheWithUpperSubNode(direction + " right");
        }
}

      See TreeOps for more details on the ordering.

      Specified by:
      containingFirstAllNodeIterator in interface TreeOps<E>
      Parameters:
      forwardSubNodeOrder - if true, a left sub-node will be visited before the right sub-node of the same parent node.
      Returns:

    • containedFirstIterator

      public Iterator<? extends BinaryTreeNode<E>> containedFirstIterator(boolean forwardSubNodeOrder)
      Description copied from interface: TreeOps
      Returns an iterator that does a post-order binary tree traversal of the added nodes. All added sub-nodes will be visited before their parent nodes. For an address trie this means contained addresses and subnets will be visited before their containing subnet blocks.

      This iterator supports the Iterator.remove() operation.

      See TreeOps for more details on the ordering.

      Specified by:
      containedFirstIterator in interface TreeOps<E>
      Parameters:
      forwardSubNodeOrder - if true, a left sub-node will be visited before the right sub-node of the same parent node.
      Returns:

    • containedFirstAllNodeIterator

      public Iterator<? extends BinaryTreeNode<E>> containedFirstAllNodeIterator(boolean forwardSubNodeOrder)
      Description copied from interface: TreeOps
      Returns an iterator that does a post-order binary tree traversal. All sub-nodes will be visited before their parent nodes. For an address trie this means contained addresses and subnets will be visited before their containing subnet blocks.

      This iterator does not support the Iterator.remove() operation. If Iterator.remove() is called it will throw UnsupportedOperationException.

      See TreeOps for more details on the ordering.

      Specified by:
      containedFirstAllNodeIterator in interface TreeOps<E>
      Parameters:
      forwardSubNodeOrder - if true, a left sub-node will be visited before the right sub-node of the same parent node.
      Returns:

    • toTreeString

      public String toTreeString(boolean withNonAddedKeys, boolean withSizes)
      Returns a visual representation of the sub-tree with this node as root, with one node per line.
      Parameters:
      withNonAddedKeys - whether to show nodes that are not added nodes
      withSizes - whether to include the counts of added nodes in each sub-tree
      Returns:

    • toString

      public String toString()
      Returns a visual representation of this node including the key, with an open circle indicating this node is not an added node, a closed circle indicating this node is an added node.
      Overrides:
      toString in class Object

    • clone

      public BinaryTreeNode<E> clone()
      Clones the node. Keys remain the same, but the parent node and the lower and upper sub-nodes are all set to null.

    • cloneTree

      public BinaryTreeNode<E> cloneTree()
      Clones the sub-tree starting with this node as root. The nodes are cloned, but their keys and values are not cloned.

    • hashCode

      public int hashCode()
      The hash code is the hash code of the key value
      Overrides:
      hashCode in class Object

    • treeHashCode

      public int treeHashCode()
      The hash code is the sum of the hash codes of all the added elements in the sub-tree with this node as the root

    • equals

      public boolean equals(Object o)
      Returns whether the key values match those of the given node
      Overrides:
      equals in class Object

    • treeEquals

      public boolean treeEquals(BinaryTreeNode<?> other)
      Returns whether the sub-tree represented by this node as the root node matches the given sub-tree