com.vividsolutions.jts.index.strtree.AbstractNode Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of JTSplus Show documentation
JTS Topology Suite 1.14 with additional functions for GeoSpark
There is a newer version: 0.1.4

/*
 * The JTS Topology Suite is a collection of Java classes that
 * implement the fundamental operations required to validate a given
 * geo-spatial data set to a known topological specification.
 *
 * Copyright (C) 2001 Vivid Solutions
 *
 * This library 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 library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * For more information, contact:
 *
 *     Vivid Solutions
 *     Suite #1A
 *     2328 Government Street
 *     Victoria BC  V8T 5G5
 *     Canada
 *
 *     (250)385-6040
 *     www.vividsolutions.com
 */
package com.vividsolutions.jts.index.strtree;
import com.vividsolutions.jts.util.*;

import java.io.Serializable;
import java.util.*;

/**
 * A node of an {@link AbstractSTRtree}. A node is one of:
 * 
 * empty
 * 
an interior node containing child {@link AbstractNode}s
 * 
a leaf node containing data items ({@link ItemBoundable}s). 
 * 
 * A node stores the bounds of its children, and its level within the index tree.
 *
 * @version 1.7
 */
public abstract class AbstractNode implements Boundable, Serializable {
  /**
   * 
   */
  private static final long serialVersionUID = 6493722185909573708L;
  
  private ArrayList childBoundables = new ArrayList();
  private Object bounds = null;
  private int level;

  /**
   * Default constructor required for serialization.
   */
  public AbstractNode() {
  }

  /**
   * Constructs an AbstractNode at the given level in the tree
   * @param level 0 if this node is a leaf, 1 if a parent of a leaf, and so on; the
   * root node will have the highest level
   */
  public AbstractNode(int level) {
    this.level = level;
  }

  /**
   * Returns either child {@link AbstractNode}s, or if this is a leaf node, real data (wrapped
   * in {@link ItemBoundable}s).
   */
  public List getChildBoundables() {
    return childBoundables;
  }

  /**
   * Returns a representation of space that encloses this Boundable,
   * preferably not much bigger than this Boundable's boundary yet fast to
   * test for intersection with the bounds of other Boundables. The class of
   * object returned depends on the subclass of AbstractSTRtree.
   *
   * @return an Envelope (for STRtrees), an Interval (for SIRtrees), or other
   *         object (for other subclasses of AbstractSTRtree)
   * @see AbstractSTRtree.IntersectsOp
   */
  protected abstract Object computeBounds();

  /**
   * Gets the bounds of this node
   * 
   * @return the object representing bounds in this index
   */
  public Object getBounds() {
    if (bounds == null) {
      bounds = computeBounds();
    }
    return bounds;
  }

  /**
   * Returns 0 if this node is a leaf, 1 if a parent of a leaf, and so on; the
   * root node will have the highest level
   */
  public int getLevel() {
    return level;
  }

  /**
   * Gets the count of the {@link Boundable}s at this node.
   * 
   * @return the count of boundables at this node
   */
  public int size()
  {
    return childBoundables.size();
  }
  
  /**
   * Tests whether there are any {@link Boundable}s at this node.
   * 
   * @return true if there are boundables at this node
   */
  public boolean isEmpty()
  {
    return childBoundables.isEmpty();
  }
  
  /**
   * Adds either an AbstractNode, or if this is a leaf node, a data object
   * (wrapped in an ItemBoundable)
   */
  public void addChildBoundable(Boundable childBoundable) {
    Assert.isTrue(bounds == null);
    childBoundables.add(childBoundable);
  }
}