/*?==========================================
?*?JGraphT?:?a?free?Java?graph-theory?library
?*?==========================================
?*
?*?Project?Info:??http://jgrapht.sourceforge.net/
?*?Project?Creator:??Barak?Naveh?（http://sourceforge.net/users/barak_naveh）
?*
?*?（C）?Copyright?2003-2008?by?Barak?Naveh?and?Contributors.
?*
?*?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.
?*/
/*?------------------
?*?DirectedGraph.java
?*?------------------
?*?（C）?Copyright?2003-2008?by?Barak?Naveh?and?Contributors.
?*
?*?Original?Author:??Barak?Naveh
?*?Contributor（s）:???Christian?Hammer
?*
?*?$Id$
?*
?*?Changes
?*?-------
?*?24-Jul-2003?:?Initial?revision?（BN）;
?*?11-Mar-2004?:?Made?generic?（CH）;
?*?07-May-2006?:?Changed?from?List?to?Set?（JVS）;
?*
?*/
package?org.jgrapht;

import?java.util.*;


/**
?*?A?graph?whose?all?edges?are?directed.?This?is?the?root?interface?of?all
?*?directed?graphs.
?*
?*?
See?
?*?http://mathworld.wolfram.com/DirectedGraph.html?for?more?on?directed
?*?graphs.

?*
?*?@author?Barak?Naveh
?*?@since?Jul?14?2003
?*/
public?interface?DirectedGraph
????extends?Graph
{
????//~?Methods?----------------------------------------------------------------

????/**
?????*?Returns?the?“in?degree“?of?the?specified?vertex.?An?in?degree?of?a?vertex
?????*?in?a?directed?graph?is?the?number?of?inward?directed?edges?from?that
?????*?vertex.?See?
?????*?http://mathworld.wolfram.com/Indegree.html.
?????*
?????*?@param?vertex?vertex?whose?degree?is?to?be?calculated.
?????*
?????*?@return?the?degree?of?the?specified?vertex.
?????*/
????public?int?inDegreeOf（V?vertex）;

????/**
?????*?Returns?a?set?of?all?edges?incoming?into?the?specified?vertex.
?????*
?????*?@param?vertex?the?vertex?for?which?the?list?of?incoming?edges?to?be
?????*?returned.
?????*
?????*?@return?a?set?of?all?edges?incoming?into?the?specified?vertex.
?????*/
????public?Set?incomingEdgesOf（V?vertex）;

????/**
?????*?Returns?the?“out?degree“?of?the?specified?vertex.?An?out?degree?of?a
?????*?vertex?in?a?directed?graph?is?the?number?of?outward?directed?edges?from
?????*?that?vertex.?See?
?????*?http://mathworld