How can modify this program to implement two of the shortest- path algorithms: Dijkstra's and Bellman-Ford

Graph.java

import java.util.ArrayList;

import java.util.Comparator;

import java.util.HashMap;

import java.util.LinkedList;

import java.util.List;

import java.util.Map;

import java.util.PriorityQueue;

import java.util.Scanner;

import java.io.*;

public class Graph

{

private static final double INF = Double.MAX_VALUE;

private ArrayList table = new ArrayList();

int numV = 0;

private Map vertexMap = new HashMap();

public Graph()

{

table = new ArrayList();

numV = 0;

vertexMap = new HashMap();

}

public void addEdge(String srcName, String destName, double cost)

{

Vertex v = getVertex(srcName);

Vertex w = getVertex(destName);

v.adj.add(new Edge(w, cost));

}

public void addUndirectedEdge(String srcName, String destName, double cost)

{

Vertex v = getVertex(srcName);

Vertex w = getVertex(destName);

v.adj.add(new Edge(w, cost));

w.adj.add(new Edge(v, cost));

}

private Vertex getVertex(String name)

{

Vertex v;

Integer i = vertexMap.get(name);

if (i == null) { // first time we've seen this vertex name

v = new Vertex(name);

table.add(v);

vertexMap.put(name, numV);

numV++;

}

else

v = table.get(i);

return v;

}

public void printGraph()

{

for(Vertex v : table) {

System.out.print(v.name + ":");

for(Edge e : v.adj) {

System.out.print(" " + e.dest.name + "(" + e.cost + ")");

}

System.out.println();

}

}

public void dijkstra(String sourceName)

{

}

public void bellmanFord(String sourceName)

{

}

public double getDist(String vname)

{

return 0.0;

}

public ArrayList getPath(String vname)

{

return new ArrayList();

}

public void readGraph(String fname)

//

// read in a graph, where file fname has following format:

//

// first line: single integer n = number of edges

// each of next n lines: two Strings v1 v2 and double c indicating

// an edge from v1 to v2 with cost c

//

{

Scanner fin = null;

try {

fin = new Scanner(new FileInputStream(fname));

} catch (IOException e) {

System.out.println(e);

System.exit(-1);

}

int nedges = fin.nextInt();

for(int i=1; i<=nedges; i++) {

String v1 = fin.next();

String v2 = fin.next();;

double cost = fin.nextDouble();

addEdge(v1, v2, cost);

}

}

public static void main(String [] args)

//

// example driver program

//

{

Graph g = new Graph();

g.readGraph("bfexample.graph");

g.printGraph();

g.bellmanFord("v0");

ArrayList path = g.getPath("v3");

System.out.print("Path to v3:");

for(Vertex v : path) {

System.out.print(" " + v.name);

}

System.out.println(" Dist to v3: " + g.getDist("v3"));

}

}

Vertex.java

import java.util.*;

class Vertex

{

public String name;

public List adj;

public Vertex(String n)

{

name = n;

adj = new LinkedList();

}

}

Edge.java

public class Edge

{

public Vertex dest;

public double cost;

public Edge(Vertex w, double c)

{

dest = w;

cost = c;

}

}

a sample input file example.graph:

12 v0 v1 4 v0 v3 0 v0 v5 3 v0 v2 0 v2 v1 1 v3 v5 5 v4 v2 -3 v4 v3 -1 v5 v1 -1 v5 v3 -2 v5 v4 -3 v1 v3 1