// SPDX-FileCopyrightText: 2020 Roberto Posenato <roberto.posenato@univr.it>
//
// SPDX-License-Identifier: LGPL-3.0-or-later
package it.univr.di.cstnu.graph;

import it.univr.di.labeledvalue.ALabel;
import it.univr.di.labeledvalue.Label;
import it.univr.di.labeledvalue.LabeledLowerCaseValue;

/**
 * Represents the behavior of a CSTNU edge.
 * A CSTNU edge can be (mutually exclusive):
 * <ol>
 *     <li>ordinary (one or more labeled values)</li>
 *     <li>lower-case (1 lower-case value) </li>
 *     <li>upper-case (1 upper-case value)</li>
 *     <li>wait (1 or more upper-case values)</li>
 *     <li>ordinary and wait</li>
 * </ol>
 * <br>
 * In order to promote greater efficiency, some methods return a view of the internal data structures
 * (they are all methods that return a set of {@code Entry}).
 * Such view could be dangerous because it could be modified directly (don't do that!)
 * Such methods must be used only to read-only scan the labeled values or labeled values' labels in an efficiente way.
 * Moreover, such views are not more valid if a value is added to or removed from the edge.
 *
 * @author posenato
 * @version $Rev$
 */
@SuppressWarnings("InterfaceWithOnlyOneDirectInheritor")
public interface CSTNUEdge extends BasicCSTNUEdge {

	/**
	 * Removes the lower-case value from the edge.
	 */
	void removeLowerCaseValue();

	/**
	 * @return the labeled lower-case value object characteristics of a contingent/guarded link. Use
	 * {@link it.univr.di.labeledvalue.LabeledLowerCaseValue#isEmpty()} to check if it contains or not a significant
	 * value.
	 */
	LabeledLowerCaseValue getLowerCaseValue();

	/**
	 * Set a lower-case constraint with delay i for the node n with label l.<br>
	 * If a lower-case label for node n is already present, it is overwritten.
	 *
	 * @param l        It cannot be null or empty.
	 * @param nodeName the node. It cannot be null.
	 * @param i        It cannot be null.
	 */
	void setLowerCaseValue(Label l, ALabel nodeName, int i);
}