Link-state routing algorithm simulation

课设要求实现使用dijkstra的路由算法。 

1. Dijkstra.java

package com.liu.hw3;import java.util.ArrayList;public class Dijkstra {int NumOfNodes;int routeTable[];int shortestPath[];int preTable[];public Dijkstra(int [][]matrix) {this.NumOfNodes = matrix.length;this.routeTable  = new int [matrix.length];this.shortestPath = new int[matrix.length];this.preTable = new int[matrix.length];}public int[] getshortestDistance(int [][] matrix, int src){//init int[] visited = new int[NumOfNodes];routeTable[src] = -2;shortestPath[src] = 0;visited[src] = 1;preTable[src] = -1;//if adjacent with src node, update pre table infofor(int i=0;i<NumOfNodes;i++){if(matrix[src][i] != 99999){preTable[i] = src;}}//for loop   循环的次数？？for(int count = 1;count <= NumOfNodes-1;count++){int k = -1;int dmin = Integer.MAX_VALUE;for(int i=0;i<NumOfNodes;i++){if(visited[i] ==0 && matrix[src][i]<dmin){dmin = matrix[src][i];k = i;}}shortestPath[k] = dmin;visited[k] = 1;//updatefor(int i=0;i<NumOfNodes;i++){if(visited[i] ==0 && matrix[src][k]+matrix[k][i]<matrix[src][i]){matrix[src][i] = matrix[src][k]+matrix[k][i];//update pre infopreTable[i] = k;}}}//System.out.println("print preTable:");//for(int i=0;i< NumOfNodes;i++){////System.out.println(preTable[i]+1);//}return shortestPath;}public int[] generateRoutingTable(int src){for(int i=0;i< NumOfNodes;i++){if(i == src){routeTable[src] = -1;//System.out.println("start node");}else if(preTable[i] == src){routeTable[i] = i;}else{int pointer = preTable[i];while(preTable[pointer]!=src){pointer = preTable[pointer];}routeTable[i] = pointer;//System.out.println("pre is "+ pointer);}}return routeTable;}public int[] getPreNodes(int src,int dest){//reverse sequenceArrayList<Integer> res = new ArrayList<Integer>();res.add((dest-1));int point = preTable[dest-1];while(point != (src-1)){res.add(point);point = preTable[point];}res.add((src-1));int size = res.size();int tmp[] = new int[size];int count = 1;//System.out.println("arrayList:");for(int item : res){tmp[size-count] = (item+1); // add one because of index start at 0//System.out.print(" "+item);count++;}//System.out.println("int tmp:");//for(int i=0;i<tmp.length;i++){//System.out.print(" "+tmp[i]);//}return tmp;}}

2. Menu.java

package com.liu.hw3;import java.io.IOException;import java.util.ArrayList;import java.util.Scanner;public class Menu {private Dijkstra dij ;private ReadTXT readTxt = new ReadTXT();int [][] path;int curnode;int numberOfNodes;public void display(){//use while loop to show infoScanner input = new Scanner(System.in);System.out.println("CS542 Link State Routing Simulator");while(true){System.out.println("(1) Create a Network Topology");System.out.println("(2) Build a Connection Table");System.out.println("(3) Shortest Path to Destination Router");System.out.println("(4) Modify a topology");System.out.println("(5) Exit");System.out.println("(6) display all routing table");System.out.println();System.out.print("Command:");String inputStr = input.next();if(inputStr.equals("1")){//System.out.println("press 1"); path = readTxt.readTxtFile("/Users/liuchang/Desktop/route5.txt");System.out.println("Review original topology matrix:");numberOfNodes = path.length;for (int i=0;i<path.length;i++){for(int j=0;j<path[0].length;j++){System.out.print(path[i][j]+"\t ");}System.out.println();}pause();}else if(inputStr.equals("2")){dij = new Dijkstra(path);System.out.println(" Select a source router:");int routeNum = input.nextInt();curnode = routeNum;// validation of route numberint[] shortestPath = dij.getshortestDistance(path, routeNum-1);int [] routingTalbe = dij.generateRoutingTable(routeNum-1);for(int i=0;i<routingTalbe.length;i++ ){if(routingTalbe[i] == -1){System.out.println((i+1)+"\t "+"-\t");}elseSystem.out.println((i+1)+"\t "+(routingTalbe[i]+1)+"\t");}pause();}else if(inputStr.equals("3")){System.out.println("Select the destination router:");int dest = input.nextInt();//System.out.println("The shortest path from router "+curnode+" to router "+dest+" is :");int[] preNodes = dij.getPreNodes(curnode, dest);for(int i=0;i<preNodes.length;i++){System.out.print(preNodes[i]+ " ");}System.out.println();int[] shortestPath = dij.getshortestDistance(path, (curnode-1));System.out.println("the shortest distance is :"+shortestPath[dest-1]);pause();}else if(inputStr.equals("4")){System.out.println("Select a router to be removed:");int route = input.nextInt();//copy to new arrayint [][] newpath = new int [numberOfNodes-1][numberOfNodes-1];numberOfNodes--;//left upfor(int i=0;i<(route-1);i++){for(int j=0;j<(route-1);j++){newpath[i][j] = path[i][j];}}//left down for(int i=(route-1);i<newpath.length;i++){for(int j=0;j<(route-1);j++){newpath[i][j] = path[i+1][j];}}//right upfor(int i=0;i<(route-1);i++){for(int j=(route-1);j<newpath.length;j++){newpath[i][j] = path[i][j+1];}}//right downfor(int i=(route-1);i<newpath.length;i++){for(int j=(route-1);j<newpath.length;j++){newpath[i][j] = path[i+1][j+1];}}path = newpath;System.out.println("updated new path:");for (int i=0;i<path.length;i++){for(int j=0;j<path[0].length;j++){System.out.print(path[i][j]+"\t ");}System.out.println();}pause();}else if(inputStr.equals("5")){System.out.println("Exit CS542 project. Good Bye!");break;}else if(inputStr.equals("6")){System.out.println("show all routing table:");System.out.println("number of nodes:"+numberOfNodes);int [][] allroutingtable = new int[numberOfNodes][numberOfNodes];dij = new Dijkstra(path);for(int j = 0;j<numberOfNodes;j++){dij.getshortestDistance(path, j);int [] routingTalbe = dij.generateRoutingTable(j);for(int i=0;i<routingTalbe.length;i++ ){allroutingtable[j][i] = routingTalbe[i];}}//display:System.out.print("\t");for(int i=0;i<numberOfNodes;i++)System.out.print((i+1)+"\t");System.out.println();for(int i=0;i<allroutingtable.length;i++){System.out.print((i+1)+":\t");for(int j=0;j< allroutingtable.length;j++){if(allroutingtable[i][j] == -1){System.out.print("-\t");}elseSystem.out.print((allroutingtable[i][j]+1)+"\t");}System.out.println();}pause();}else {System.out.println("wrong input try again");}}}public void pause(){System.out.println("press any botton");Scanner input = new Scanner(System.in);input.nextLine();}}

3. ReadTXT.java

package com.liu.hw3;import java.io.BufferedReader;import java.io.File;import java.io.FileInputStream;import java.io.InputStreamReader;import java.util.ArrayList;public class ReadTXT {public int  getNumOfNodes(String file_path){try {File file = new File(file_path);if (file.isFile() && file.exists()) {InputStreamReader reader = new InputStreamReader(new FileInputStream(file));BufferedReader bufferreader = new BufferedReader(reader);String line = bufferreader.readLine();String [] col = line.split(" ");return col.length;} elseSystem.out.println("Can't find the file!");    return -1;}catch(Exception e){System.out.println("Error");return -1;}}public int[][] readTxtFile(String file_path) {String line = null;int numberOfNodes = getNumOfNodes(file_path);int [][] pathMatrix = new int [numberOfNodes][numberOfNodes];try {File file = new File(file_path);if (file.isFile() && file.exists()) {InputStreamReader reader = new InputStreamReader(new FileInputStream(file));BufferedReader bufferreader = new BufferedReader(reader);int i=0;while ((line = bufferreader.readLine()) != null) {//System.out.println(line);//split for each rowString [] col = line.split(" ");for(int j=0;j<col.length;j++){if(!col[j].equals("-1")){pathMatrix[i][j] = Integer.parseInt(col[j]);}else{pathMatrix[i][j] = 99999;//max}}i++;}reader.close();return pathMatrix;} elseSystem.out.println("Can't find the file!");} catch (Exception e) {System.out.println("Error");e.printStackTrace();}return null;}}

4. TestMenu.java

package com.liu.hw3;public class TestMenu {public static void main(String args[]){Menu menu = new Menu();menu.display();}}