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anwiba commons lang project

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/*
 * #%L
 * anwiba commons core
 * %%
 * Copyright (C) 2007 - 2016 Andreas Bartels
 * %%
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation, either version 2.1 of the
 * License, or (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Lesser Public License for more details.
 * 
 * You should have received a copy of the GNU General Lesser Public
 * License along with this program.  If not, see
 * .
 * #L%
 */
package net.anwiba.commons.lang.tree.walker;

import net.anwiba.commons.lang.tree.IItem;
import net.anwiba.commons.lang.tree.ITreeItem;
import net.anwiba.commons.lang.tree.iterator.SortedItemIterator;

import java.util.Iterator;

public class TreeWalker implements ITreeWalker {

  private final ITreeItem first;
  private final ITreeItem root;

  public TreeWalker(final ITreeItem first, final ITreeItem root) {
    this.first = first;
    this.root = root;
  }

  @Override
  public void walk(final IItemVisitor handler) {
    final ITreeItem item = this.root;
    walkTo(handler, item);
  }

  private void walkTo(final IItemVisitor handler, final ITreeItem item) {
    handler.arrive(item);
    if (item.getLeft() != null) {
      walkTo(handler, item.getLeft());
    }
    if (item.getRight() != null) {
      walkTo(handler, item.getRight());
    }
    handler.leave(item);
  }

  @Override
  public Iterator> iterator() {
    return new SortedItemIterator<>(this.first);
  }
}