import java.util.ArrayList;

public class TransferManager {
	private ArrayList<Transfer> openTransfers;
	private int issuedTransfers;
	private int performedTransfers;
	
	public TransferManager() {
		openTransfers = new ArrayList<Transfer>();
		issuedTransfers = 0;
		performedTransfers = 0;
	}
	
	public void issueTransfer(Account from, Account to, int amount) {
		openTransfers.add(new Transfer(from, to, amount));
		issuedTransfers++;
	}
	
	public void performTransfers() {
		for(Transfer transaction : openTransfers) {
			transaction.performTransfer();
			performedTransfers++;
		}		
		openTransfers.clear();
	}
	
	@Override
	public String toString() {
		return "TransferManager (openTransfers: " + openTransfers.size() + "; issuedTransfers: " + issuedTransfers + "; performedTransfers: " + performedTransfers + ")";
	}
	
	private static class Transfer {
		private Account from, to;
		private int amount;
		
		public Transfer(Account from, Account to, int amount) {
			this.from = from;
			this.to = to;
			this.amount = amount;
		}
		
		public void performTransfer() {
			from.transfer(-amount);
			to.transfer(amount);
		}
	}
}