banker.java

Banker s Algorithm Implement by Java

/*
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 * and open the template in the editor.
 */

package Bankers;

import java.util.Scanner;
/**
 *
 * @author RUMI
 */
public class Banker {

    public int Process, Resource;
    String [] name = {"A", "B", "C", "D", "E", "F", "G", "H", "I", "J"};
    int[] Avaiable=new int[10];
    int[][] Allocation=new int[10][10];
    int[][] Maximum=new int [10][10];
    int[][] Need=new int[10][10];
    int[] Work=new int [10];
    int[][] Tallocation=new int[10][10];
    int[][] Tneed=new int[10][10];
    int[] Tavaiable=new int[10];

    int[] Answer=new int[10];
    int[] Request=new int[10];
    
    boolean[] Finish=new boolean[10];

    int init ()
    {
        for (int i=0;i<6;i++)
        {
            Avaiable[i]=0;
            Work[i]=0;
            Answer[i]=0;
            Request[i]=0;

            for (int j=0;j<6;j++)
            {
                Maximum[i][j]=Allocation[i][j]=Need[i][j]=0;
            }
        }
        return 0;
    }

    boolean safe_sequence()
    {
        int i,j,k,get=0;

        for(i=0;i<Resource;i++)
        {
        	Work[i]=Avaiable[i];
        }

        for(i=0;i<Process;i++)
        {
        	Finish[i]=false;
        }

        boolean flag;

        for(i=0;i<Process;i++)
        {
        	for(j=0;j<Process;j++)
        	{
        		if(Finish[j]==false)
            	{
                	flag=true;
                    for(k=0;k<Resource;k++)
                    {
                        if(Need[j][k]>Work[k])
                        {
                            flag=false;
                            break;
                        }
                    }

                    if(flag==true)
                    {
                        Answer[get]=j;
                        get++;

                    	for(k=0;k<Resource;k++)
                    	{
                        	Work[k]=Work[k]+Allocation[j][k];
                        }

                    	Finish[j]=true;
                        //break;
                    }
                }
            }
        }

        boolean tag=true;

        for(i=0;i<Process;i++)
        {
            if(Finish[i]==false)
            {
                tag=false;
                break;
            }
        }

        if(tag==false)
        {
            System.out.printf("\n\n----NO SAFE SEQUENCE----\n\n");
    		return false;
        }
        else
        {
            //int temp;
            System.out.printf("\n\n----THERE IS A SAFE SEQUENCE----\n");
            System.out.printf("      ");
            for(i=0;i<Process;i++)
            {
                //System.out.printf("<P%ld>", Answer[i]);
                //temp = Answer [i]-1;
                System.out.printf("<P"+Answer[i]+">");
            }
            System.out.printf("\n");

            return true;
        }
    }

    void input()
    {
            Scanner sc = new Scanner(System.in);
            int i;
            int j;

            System.out.printf("\nBANKER'S ALGORITHM\n");
            System.out.printf("==================\n");

            System.out.printf("\nHow many Process: ");

            Process = sc.nextInt();
            System.out.printf("\nHow many Resource: ");

            Resource = sc.nextInt();
            System.out.printf("\n\nAvaiable Resources:");
            System.out.printf("\n===================\n");
            for (i = 0; i < Resource; i++) {
                System.out.printf("Resource "+name[i]+": ");
                Avaiable[i]= sc.nextInt();
                Tavaiable[i] = Avaiable[i];
            }
            System.out.printf("\n\nAllocate Resource for Processes :");
            System.out.printf("\n================================");
            for (i = 0; i < Process; i++) {
                System.out.printf("\nProcess P"+i+" --- \n");
                for (j = 0; j < Resource; j++) {
                    System.out.printf("Allocation "+name[j]+": ");
                    Allocation[i][j]= sc.nextInt();
                    Tallocation[i][j] = Allocation[i][j];
                }
            }
            System.out.printf("\n\nMaximum Resource Allocation :");
            System.out.printf("\n============================");
            for (i = 0; i < Process; i++) {
                System.out.printf("\nProcess P"+i+" --- \n");
                for (j = 0; j < Resource; j++) {
                    System.out.printf("Maximum "+name[j]+" : ");
                    Maximum[i][j] = sc.nextInt();
                }
            }
            for (i = 0; i < Process; i++) {
                for (j = 0; j < Resource; j++) {
                    Tneed[i][j] = Need[i][j] = Maximum[i][j] - Allocation[i][j];
                }
            }

            System.out.printf("\n\nNeed :");
            System.out.printf("\n======");
            System.out.printf("\n               ");

            for(int k=0;k<Resource;k++){
                System.out.printf(name[k]+" ");
            }
            for(i=0;i<Process;i++){
                System.out.printf("\nProcess P"+i+" --- ");
                for (j = 0; j < Resource; j++) {
                    System.out.print(Need[i][j]+" ");
                }
            }
    }


   public void request()
   {
        int i,j,k;
        Scanner sc1 = new Scanner(System.in);
        String ch = "";
        int reqProcess =0;
        boolean req;

        while(true)
        {
            init();
            input();
            req = safe_sequence();

            while(true)
            {
                System.out.printf("Any other request? [y/n] : ");
                
                ch =  sc1.next();
                
                req=true;

                if(ch.equals("y"))
                {
                    System.out.printf("Request for Process : ");
                        
                        reqProcess = sc1.nextInt();
                    
                    System.out.printf("Enter Resource Request for P"+reqProcess+": \n");

                    for(i=0;i<Resource;i++)
                    {
                        System.out.printf("Resource "+name[i]+": ");
                        Request[i]= sc1.nextInt();
                    }

                    for(i=0;i<Resource;i++)
                    {
    					if(Need[reqProcess][i]<Request[i])
        				{
            				req=false;
                			break;
                    	}
                    }

                    for(i=0;i<Resource;i++)
                    {
    					if(Avaiable[i]<Request[i])
        				{
            				req=false;
                			break;
                    	}
                    }

                    if(req==true)
                    {
                    	for(i=0;i<Resource;i++)
                    	{
                        	Avaiable[i]=Avaiable[i]-Request[i];
                            Allocation[reqProcess][i]=Allocation[reqProcess][i]+Request[i];
                            Need[reqProcess][i]=Need[reqProcess][i]-Request[i];
                        }

                        if(safe_sequence()==false)
                        {
                        	System.out.printf("----REQUEST REJECTED----\n");
                        	for(i=0;i<Process;i++)
                        	{
                        		for(j=0;j<Resource;j++)
                        		{
                        			Avaiable[i]=Tavaiable[i];
                        			Allocation[reqProcess][i]=Tallocation[reqProcess][i];
                        			Need[reqProcess][i]=Tneed[reqProcess][i];
                        		}
    						}
    					}
    					else
    					{
    						for(i=0;i<Process;i++)
    						{
    							for(j=0;j<Resource;j++)
    							{
    								Tavaiable[i]=Avaiable[i];
    								Tallocation[reqProcess][i]=Allocation[reqProcess][i];
    								Tneed[reqProcess][i]=Need[reqProcess][i];
    							}
    						}
    					}
    				}
    				else
    				{
    					System.out.printf("----REQUEST REJECTED----\n");
    				}
                }
                else
                {
                	break;
                }
            }
        }
   }
    //    return 0;
    
    public static void main(String[] args) {
        Banker bnk = new Banker();
        bnk.request();
    }
}