/*
 *    GeoTools - The Open Source Java GIS Toolkit
 *    http://geotools.org
 *    
 *    (C) 2001-2006  Vivid Solutions
 *    (C) 2001-2008, Open Source Geospatial Foundation (OSGeo)
 *    
 *    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;
 *    version 2.1 of the License.
 *
 *    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.
 */
package org.geotools.geometry.iso.topograph2D;

import org.geotools.geometry.iso.util.Assert;

/**
 * A GraphComponent is the parent class for the objects' that form a graph. Each
 * GraphComponent can carry a Label.
 *
 *
 *
 * @source $URL$
 */
abstract public class GraphComponent {

	protected Label label;

	/**
	 * isInResult indicates if this component has already been included in the
	 * result
	 */
	private boolean isInResult = false;

	private boolean isCovered = false;

	private boolean isCoveredSet = false;

	private boolean isVisited = false;

	public GraphComponent() {
	}

	public GraphComponent(Label label) {
		this.label = label;
	}

	public Label getLabel() {
		return label;
	}

	public void setLabel(Label label) {
		this.label = label;
	}

	public void setInResult(boolean isInResult) {
		this.isInResult = isInResult;
	}

	public boolean isInResult() {
		return isInResult;
	}

	public void setCovered(boolean isCovered) {
		this.isCovered = isCovered;
		this.isCoveredSet = true;
	}

	public boolean isCovered() {
		return isCovered;
	}

	public boolean isCoveredSet() {
		return isCoveredSet;
	}

	public boolean isVisited() {
		return isVisited;
	}

	public void setVisited(boolean isVisited) {
		this.isVisited = isVisited;
	}

	/**
	 * @return a coordinate in this component (or null, if there are none)
	 */
	abstract public Coordinate getCoordinate();

	/**
	 * compute the contribution to an IM for this component
	 */
	abstract protected void computeIM(IntersectionMatrix im);

	/**
	 * An isolated component is one that does not intersect or touch any other
	 * component. This is the case if the label has valid locations for only a
	 * single Geometry.
	 * 
	 * @return true if this component is isolated
	 */
	abstract public boolean isIsolated();

	/**
	 * Update the IM with the contribution for this component. A component only
	 * contributes if it has a labelling for both parent geometries
	 */
	public void updateIM(IntersectionMatrix im) {
		Assert.isTrue(label.getGeometryCount() >= 2, "found partial label");
		computeIM(im);
	}

}