Esercizio 1

Si modifichi il codice dato, per creare un sistema client-server, in cui client e server comunicano attraverso socket.

public class OperationRequest {
	int CCnumber;
	int amount;
	String request;

	OperationRequest(int cc, int val, String what){
		CCnumber=cc;
		amount=val;
		request=what;
	}
	
	public int getCCnumber() {
		return CCnumber;
	}

	public int getAmount() {
		return amount;
	}

	public String getRequest() {
		return request;
	}
}

import java.util.Random;

public class Client {
	Bank myBank;
	int myAccountNum;

	Client(int accNum, Bank b){
		myBank = b;
		myAccountNum=accNum;
	}

	public static void main(String[] args) {
		Client c=new Client(1, new Bank());
		c.exec();
	}

	public void exec() {
		Result r;
		String opReq=null;
		int howMuch=0;
		int times=new Random().nextInt(10);

		for(int i=0; i<times; i++) {
			howMuch=new Random().nextInt(1000);
			if(new Random().nextBoolean()) {
				r=myBank.executeOperation(new OperationRequest(1, howMuch, "Deposit"));
			} else {
				r=myBank.executeOperation(new OperationRequest(1, howMuch, "Withdraw"));
			}
			System.out.println(r);
		}
		r=myBank.executeOperation(new OperationRequest(1,2,"Double"));
		System.out.println(r);
	}
}

public class Bank {
	int ccAmounts[]={0,0,0};

	public Result executeOperation(OperationRequest op) {
		int ccNum=op.getCCnumber();
		String opType=op.getRequest();

		if(ccNum<0 || ccNum>2) {
			return new Result(-1, 0, opType, false);
		}

		if(opType.equals("Deposit")) {
			ccAmounts[ccNum]+=op.getAmount();
			return new Result(ccNum, ccAmounts[ccNum], opType, true);
		} else if (opType.equals("Withdraw")) {
			if(op.getAmount()>ccAmounts[ccNum]) {
				return new Result(ccNum, 0, opType, false);
			} else {
				ccAmounts[ccNum]-=op.getAmount();
				return new Result(ccNum, ccAmounts[ccNum],opType,true);
			}
		} else { 
			return new Result(ccNum, 0, "unknown", false);
		}
	}
}

public class Result {
	int CCnumber;
	int amount;
	String opType;
	boolean successful;

	Result(int cc, int val, String ot, boolean ok){
		CCnumber=cc;
		amount=val;
		opType=ot;
		successful=ok;
	}

	public int getCCnumber() { return CCnumber; }

	public int getAmount() { return amount; }

	public boolean isSuccessful() { return successful; }

	public String getType() { return opType; }

	public String toString() {
		return "op. "+opType+" on CC num. "+ CCnumber+
			(successful?" OK":" KO")+" resulting amount="+amount;
	}
}

Testo multiclient

Soluzione

Soluzione proxy