BFSAlgorithm

//Main Class
package bfsalgorithm;

/**
 *
 * @author Shaon Bhatta Shuvo
 */
public class BFSAlgorithm {

    public static void main(String[] args) {
        BFS bfs = new BFS();
        
        Vertex A = new Vertex('A');
        Vertex B = new Vertex('B');
        Vertex C = new Vertex('C');
        Vertex D = new Vertex('D');
        Vertex E = new Vertex('E');
        
        A.addNeighbourVertex(B);
        A.addNeighbourVertex(D);
        D.addNeighbourVertex(E);
        B.addNeighbourVertex(C);
        
        bfs.BFS_Implementation(A);
    }
    
//Vertex Class
package bfsalgorithm;

import java.util.ArrayList;
import java.util.List;

public class Vertex {
    private char data;
    private boolean visited;
    private List<Vertex> neighbourList;
    
    public Vertex(char data){
        this.data =data;
        this.neighbourList = new ArrayList<>();
    }

    public char getData() {
        return data;
    }

    public void setData(char data) {
        this.data = data;
    }

    public boolean isVisited() {
        return visited;
    }

    public void setVisited(boolean visited) {
        this.visited = visited;
    }

    public List<Vertex> getNeighbourList() {
        return neighbourList;
    }

    public void setNeighbourList(List<Vertex> neighbourList) {
        this.neighbourList = neighbourList;
    }
    public void addNeighbourVertex(Vertex vertex){
        neighbourList.add(vertex);
    }
    
    @Override
    public String toString(){
        return " "+this.data;
    }  
}

//BFS implementation class

package bfsalgorithm;

import java.util.LinkedList;
import java.util.Queue;

public class BFS {
    public void BFS_Implementation(Vertex root){
        Queue<Vertex> queue = new LinkedList<>();
        root.setVisited(true);
        queue.add(root);
        while(!queue.isEmpty()){
            Vertex actualVertex = queue.remove();
            System.out.println(actualVertex+" ");
            for (Vertex v :  actualVertex.getNeighbourList()){
                if(!v.isVisited()){
                    v.setVisited(true);
                    queue.add(v);
                }
            }
            
        }
    
    }
}