接收CycleDetected Exception

Question

我正在编写一个模仿Java命令行编译器的Java程序。它需要读入一个文本文件，并将其转换为有向图。然后，用户应该输入他们希望重新编译的类，并且它应该显示要重新编译类的顺序。

说有一个包含以下内容的文本文件

ClassA ClassC ClassE
ClassB ClassD ClassG
ClassE ClassB ClassF ClassH
ClassI ClassC

然后用户决定要重新编译ClassA。重新编译类的顺序如下：

ClassA ClassE ClassH ClassF ClassB ClassG ClassD ClassC

但是每当我尝试进行拓扑排序时，我都会得到一个循环异常（这是一个异常，只要检测到循环就会抛出）。当我尝试使用可以工作的类时，我只能在输出文本字段中输入我输入的类。我该怎么做才能解决这个问题？

定向图类

import java.io.*;
import java.util.*;


public class directedGraph2<T>
{
private ArrayList<LinkedList> vertices;
private Map<T, Integer>data;
private LinkedList<Integer> adjacencyList;
boolean[] found;
boolean[] completed;

public directedGraph2()
{
    vertices=new ArrayList<LinkedList>();
    data=new HashMap<T,Integer>();
}


public void addEdges(T from, T to)
{
    if(!data.containsKey(from))
    {
        data.put(from, data.size());

        int index=(int)data.get(from);
        vertices.add(index, new LinkedList<Integer>());
    }
    if(!data.containsKey(to))
    {
        data.put(to, data.size());

        int index=(int)data.get(to);
        vertices.add(index, new LinkedList<Integer>());
    }
    int fromIndex=(int) data.get(from);
    int toIndex=(int) data.get(to);


    vertices.get(fromIndex).add(toIndex);
}

public void depthFirstSearch(int index) throws CycleException
{
    if(found[index])
    {
        throw new CycleException("No");
    }
    if(completed[index])
    {
        return;
    }
    found[index]=true;

    LinkedList<Integer> aList=(LinkedList<Integer>)vertices.get(index).clone();
    while(!aList.isEmpty())
    {
        int nextIndex=aList.pop();
        depthFirstSearch(nextIndex);
    }
    completed[index]=true;
    adjacencyList.push(index);

}

public String topSort(T indexName) throws InvalidClassNameException, CycleException
{
    if(!data.containsKey(indexName))
    {
        throw new InvalidClassNameException("Nope sorry");
    }
    String topOrder="";
    int index=(int)data.get(indexName);
    found=new boolean[vertices.size()];
    completed=new boolean[vertices.size()];
    adjacencyList=new LinkedList<Integer>();
    depthFirstSearch(index);

    while(!adjacencyList.isEmpty())
    {
        int index2=adjacencyList.pop();
        topOrder+=indexToName(index2)+" ";
    }
    return topOrder;
}

public T indexToName(int index)
{
    for(Map.Entry<T, Integer>toConvert:data.entrySet())
    {
        if(toConvert.getValue().equals(index))
        {
            return toConvert.getKey();
        }
    }
    return null;
}




public void readFrom(String file) throws IOException, FileNotFoundException
{
     vertices=new ArrayList<LinkedList>();
     data=new HashMap<T,Integer>();


     FileReader myReader=null;
     BufferedReader myBufferedReader=null;

     try
     {
         myReader=new FileReader(file);
     }
     catch(FileNotFoundException f)
     {
         throw new FileNotFoundException("File couldn't be found");
     }

     try
     {
         myBufferedReader=new BufferedReader(myReader);
         String lineToRead;
         T[] tokens;
         T vertex;
         int index;
         while((lineToRead=myBufferedReader.readLine())!=null)
         {
             lineToRead=lineToRead.trim();
             if(!lineToRead.isEmpty())
             {
                 tokens=(T[]) lineToRead.split(" ");
                 vertex=tokens[0];

                 if(!data.containsKey(vertex))
                 {
                     data.put((T) vertex, data.size());
                     index=(int)data.get(vertex);
                     vertices.add(index, new LinkedList<Integer>());
                 }

                 if(tokens.length>1)
                 {
                     for(int i=0;i<tokens.length;i++)
                     {
                         addEdges(vertex,tokens[i]);
                     }
                 }
             }
         }
         myBufferedReader.close();
     }
     catch(IOException e)
     {
         throw new IOException("File can't open");
     }


}

GUI

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.io.*;
import java.util.*;

public class graphGUI扩展了JPanel    {

   directedGraph2 test=new directedGraph2();
   private JFrame frame;//The frame
   private JPanel panel;//The panel
   private JLabel inputFile;
   private JTextField input;
   private JButton buildGraph;
   private JLabel classToRecompile;
   private JTextField classInput;
   private JButton recompileClass;
   private JTextField output;












   //Builds the GUI
   public graphGUI()
   {
       frame=new JFrame("Graph GUI");
       panel=new JPanel();
       inputFile=new JLabel("Input file name");
       input=new JTextField("");
       buildGraph=new JButton("Build Directed Graph");
       classToRecompile=new JLabel("Class to recompile");
       classInput=new JTextField("");
       recompileClass=new JButton("Topological Order");
       output=new JTextField("");











           //Adding the parts together
       panel.setLayout(new GridLayout(3,3));
       panel.add(inputFile);
       panel.add(input);
       panel.add(buildGraph);
       panel.add(classToRecompile);
       panel.add(classInput);
       panel.add(recompileClass);
       panel.add(output);

       frame.add(panel);
       frame.pack();
       frame.setLocationRelativeTo(null);
       frame.setSize(600,300);
       frame.setBackground(Color.red);
       frame.setVisible(true);;








   buildGraph.addActionListener(new ActionListener()
   {

       public void actionPerformed(ActionEvent e)
       {


           String file=input.getText();
           try {
            test.readFrom(file);
            JOptionPane.showMessageDialog(null, "File successfully opened");

        } catch (IOException e1) {
            JOptionPane.showMessageDialog(null, "File failed to open");
        }

       } 
   });


   recompileClass.addActionListener(new ActionListener()
   {
       public void actionPerformed(ActionEvent e)
       {

           String recompileClass=classInput.getText();
           try
           {
               output.setText(test.topSort(recompileClass));
           }
           catch(CycleException c)
           {
               c.printStackTrace();
               JOptionPane.showMessageDialog(null, "Cycle detected");
           }


   };
   });
   }


   //Main method
   public static void main(String[] args)
   {
       graphGUI myGUI=new graphGUI();
   }
} 

循环异常类

public class CycleException extends RuntimeException
{
private String s;

public CycleException(String s)
{
    this.s=s;
}

public String getString()
{
    return s;
}
}

异常堆栈

CycleException
at directedGraph2.depthFirstSearch(directedGraph2.java:47)
at directedGraph2.depthFirstSearch(directedGraph2.java:59)
at directedGraph2.topSort(directedGraph2.java:77)
at graphGUI$2.actionPerformed(graphGUI.java:120)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$500(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)