grareader.java

Java实现的常用数据结构算法

package graph;
import java.awt.*;
import java.io.*;
import java.net.*;
import java.awt.event.*;
public class GraReader{
	public  Graph graph;
	public int count=0;
	public int num;
	public GraReader(int no){
		num=no;
	}
	public  Graph getGraph(String name)throws IOException{
		InputStream is=(new File(name+".obj")).toURL().openStream();
		return getGraph(is);
	}
	public Graph getGraph(InputStream is)throws IOException{
    graph=new Graph(num);
	StreamTokenizer st = new StreamTokenizer(
      new BufferedReader(new InputStreamReader(is, "UTF-8")));
      st.eolIsSignificant(true);
      st.commentChar('#');
    scan:
	while (true) {
	    switch (st.nextToken()) {
	      default:
		break scan;
	      case StreamTokenizer.TT_EOL:
		break;
	      case StreamTokenizer.TT_WORD:
	    if("size".equals(st.sval)){
	    	if(st.nextToken() == StreamTokenizer.TT_NUMBER){
	    		graph=new Graph((int)st.nval);
	    	}
	    }else if ("v".equals(st.sval)) {
		    double x = 0, y = 0;
		    if (st.nextToken() == StreamTokenizer.TT_NUMBER) {
			x = st.nval;
			if (st.nextToken() == StreamTokenizer.TT_NUMBER) {
			    y = st.nval;
			}
		    }
		    
		    addVert((int) x, (int) y);
		    while (st.ttype != StreamTokenizer.TT_EOL &&
			    st.ttype != StreamTokenizer.TT_EOF)
			st.nextToken();
		} else if ("l".equals(st.sval)) {
		    int start = 0;
		    int prev = 0;
		    int n = 0;
		    while (true)
			if (st.nextToken() == StreamTokenizer.TT_NUMBER) {
			    n = (int) st.nval;
			    if (prev >= 0)
				addLine(prev , n );
			    if (start < 0)
				start = n;
			    prev = n;
			} else if (st.ttype == '/')
			    st.nextToken();
			else
			    break;
		    if (start >= 0)
			addLine(start, prev);
		    if (st.ttype != StreamTokenizer.TT_EOL)
			break scan;
		} else {
		    while (st.nextToken() != StreamTokenizer.TT_EOL
			    && st.ttype != StreamTokenizer.TT_EOF);
		}
	    }
	}
	is.close();
	  return graph;  
	}
	public void addVert(int x,int y){
		if(count>graph.labels.length-1)
		return;
		Point v=new Point(x,y);
		graph.setLabel(count,v);
		 count++;		
	}
	public void addLine(int i,int j){
		graph.addEdge(i,j);		
	}
}
/*class Test{
	public static void main(String args[]){
		Graph grap=null;
		try{
			GraReader g=new GraReader();
			grap=g.getGraph("graph");
		}catch(IOException e){
			e.printStackTrace();
		}
		for(int i=0;i<6;i++){
			Point p=(Point)grap.labels[i];
			System.out.println("Vertex:<"+p.x+","+p.y+">");
		}
		
		
	}
}*/