/*
 * FindBugs - Find bugs in Java programs
 * Copyright (C) 2003-2008, University of Maryland
 * 
 * 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
 */

package edu.umd.cs.findbugs.plan;

import edu.umd.cs.findbugs.graph.AbstractEdge;

/**
 * Edge in a ConstraintGraph.
 * Edges flow from earlier detectors to later detectors.
 *
 * @see ConstraintGraph
 * @see DetectorNode
 * @see ExecutionPlan
 * @author David Hovemeyer
 */
public class ConstraintEdge
	extends AbstractEdge<ConstraintEdge, DetectorNode>
{
	private DetectorOrderingConstraint constraint;
	
	/**
	 * Constructor.
	 *
	 * @param source the source vertex (earlier Detector)
	 * @param target the target vertex (later Detector)
	 */
	public ConstraintEdge(DetectorNode source, DetectorNode target) {
		super(source, target);
	}

	/**
	 * Set the DetectorOrderingConstraint that created this edge.
	 * 
	 * @param constraint the DetectorOrderingConstraint that created this edge
	 */
	public void setConstraint(DetectorOrderingConstraint constraint) {
		this.constraint = constraint;
	}
	
	/**
	 * Determine whether or not this ConstraintEdge resulted from
	 * an ordering constraint having a single detector as its source
	 * (ealier detector).  Such constraints automatically enable
	 * the source (earlier) detector if the target (later)
	 * detector is enabled.
	 * 
	 * @return true if this edge has a single detector as its source (earlier detector)
	 */
	public boolean isSingleSource() {
		return constraint.isSingleSource();
	}
}

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