com.vividsolutions.jts.geomgraph.index.SweepLineEvent Maven / Gradle / Ivy

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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.geomgraph.index;

/**
 * @version 1.7
 */
public class SweepLineEvent
  implements Comparable
{ 
  private static final int INSERT = 1;
  private static final int DELETE = 2;

  private Object label;    // used for red-blue intersection detection
  private double xValue;
  private int eventType;
  private SweepLineEvent insertEvent = null; // null if this is an INSERT event
  private int deleteEventIndex;
  private Object obj;

  /**
   * Creates an INSERT event.
   * 
   * @param label the edge set label for this object
   * @param x the event location
   * @param obj the object being inserted
   */
  public SweepLineEvent(Object label, double x, Object obj)
  {
    this.eventType = INSERT;
    this.label = label;
    xValue = x;
    this.obj = obj;
  }

  /**
   * Creates a DELETE event.
   * 
   * @param x the event location
   * @param insertEvent the corresponding INSERT event
   */
  public SweepLineEvent(double x, SweepLineEvent insertEvent)
  {
    eventType = DELETE;
    xValue = x;
    this.insertEvent = insertEvent;
  }

  public boolean isInsert() { return eventType == INSERT; }
  public boolean isDelete() { return eventType == DELETE; }
  public SweepLineEvent getInsertEvent() { return insertEvent; }
  public int getDeleteEventIndex() { return deleteEventIndex; }
  public void setDeleteEventIndex(int deleteEventIndex) { this.deleteEventIndex = deleteEventIndex; }

  public Object getObject() { return obj; }

  public boolean isSameLabel(SweepLineEvent ev)
  {
    // no label set indicates single group
    if (label == null) return false;
    return label == ev.label;
  }
  /**
   * Events are ordered first by their x-value, and then by their eventType.
   * Insert events are sorted before Delete events, so that
   * items whose Insert and Delete events occur at the same x-value will be
   * correctly handled.
   */
  public int compareTo(Object o) {
    SweepLineEvent pe = (SweepLineEvent) o;
    if (xValue < pe.xValue) return  -1;
    if (xValue > pe.xValue) return   1;
    if (eventType < pe.eventType) return  -1;
    if (eventType > pe.eventType) return   1;
    return 0;
  }


}