package soot.toolkits.graph;

/*-
 * #%L
 * Soot - a J*va Optimization Framework
 * %%
 * Copyright (C) 1999 Patrice Pominville, Raja Vallee-Rai
 * %%
 * This program 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 program 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 General Lesser Public License for more details.
 * 
 * You should have received a copy of the GNU General Lesser Public
 * License along with this program.  If not, see
 * <http://www.gnu.org/licenses/lgpl-2.1.html>.
 * #L%
 */

import java.util.Iterator;
import java.util.List;

/**
 * Defines the notion of a directed graph.
 * 
 * @param <N>
 *          node type
 */
public interface DirectedGraph<N> extends Iterable<N> {
  /**
   * Returns a list of entry points for this graph.
   */
  public List<N> getHeads();

  /** Returns a list of exit points for this graph. */
  public List<N> getTails();

  /**
   * Returns a list of predecessors for the given node in the graph.
   */
  public List<N> getPredsOf(N s);

  /**
   * Returns a list of successors for the given node in the graph.
   */
  public List<N> getSuccsOf(N s);

  /**
   * Returns the node count for this graph.
   */
  public int size();

  /**
   * Returns an iterator for the nodes in this graph. No specific ordering of the nodes is guaranteed.
   */
  @Override
  public Iterator<N> iterator();
}
