BiParamAVLIterator.java

/*
Copyright 2008-2010 Gephi
Authors : Mathieu Bastian <mathieu.bastian@gephi.org>
Website : http://www.gephi.org

This file is part of Gephi.

DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.

Copyright 2011 Gephi Consortium. All rights reserved.

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"License"). You may not use this file except in compliance with the
License. You can obtain a copy of the License at
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or /cddl-1.0.txt and /gpl-3.0.txt. See the License for the
specific language governing permissions and limitations under the
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*/
package org.gephi.utils.collection.avl;

import java.util.Iterator;

/**
 * Identical at <code>ParamAVLIterator</code>, but with two trees. When the first is fully browsed, 
 * the iterator moves to the second tree items. Used for <b>IN</b> and <b>OUT</b> edges tree.
 * <p>
 * Support <code>null</code> values for trees.
 *
 * @author Mathieu Bastian
 * @param <Item> The type of Object in the tree
 */
public class BiParamAVLIterator<Item> implements Iterator<Item> {

    private ParamAVLTree tree2;
    private ParamAVLTree currentTree;
    private ParamAVLNode<Item> next;
    private Item current;

    public BiParamAVLIterator(ParamAVLTree tree1, ParamAVLTree tree2) {
        if (tree1 == null) {
            this.currentTree = tree2;
        } else {
            this.currentTree = tree1;
            this.tree2 = tree2;
        }
        if (currentTree != null) {
            next = currentTree.root;
        }
        goToDownLeft();
    }

    private void goToDownLeft() {
        if (next != null) {
            while (next.left != null) {
                next = next.left;
            }
        }
    }

    public boolean hasNext() {
        if (next == null) {
            if (tree2 != null && currentTree != tree2) {
                currentTree = tree2;
                next = currentTree.root;
                if (next == null) {
                    return false;
                }
                goToDownLeft();
            } else {
                return false;
            }
        }

        current = this.next.item;

        if (next.right == null) {
            while ((next.parent != null) && (next == next.parent.right)) {
                this.next = this.next.parent;
            }

            this.next = this.next.parent;
        } else {
            this.next = this.next.right;

            while (this.next.left != null) {
                this.next = this.next.left;
            }
        }

        return true;
    }

    public Item next() {
        return current;
    }

    public void remove() {
        currentTree.remove(current);   //TODO Optimize, remove in O(1) instead of O(ln(n))
    }
}