public decimal GetAccountBalance(string account)
{
using (CAP_EventSourcingEntities entities = new CAP_EventSourcingEntities())
{
DateTime dateOfBusiness = AccountUtility.GetDateOfBusiness(entities);
DateTime snapshotDate = dateOfBusiness - TimeSpan.FromDays(2.0);
return AccountUtility.GetAccountBalance(account, snapshotDate, dateOfBusiness, entities);
}
}
public decimal GetAccountBalance(string account)
{
using (CAP_EventSourcingEntities entities = new CAP_EventSourcingEntities())
{
DateTime dateOfBusiness = AccountUtility.GetDateOfBusiness(entities);
DateTime snapshotDate = dateOfBusiness - TimeSpan.FromDays(2.0);
return(AccountUtility.GetAccountBalance(account, snapshotDate, dateOfBusiness, entities));
}
}
private static AccountBalance GetSnapshot(string account, DateTime snapshotDate, CAP_EventSourcingEntities entities)
{
IQueryable<AccountBalance> snapshots =
from b in entities.AccountBalances
where
b.Account == account &&
b.DateOfBusiness == snapshotDate
select b;
AccountBalance snapshot = snapshots.FirstOrDefault();
if (snapshot == null)
throw new ApplicationException("No such account.");
return snapshot;
}
// TODO 3c: Query is more complex.
public static decimal GetAccountBalance(string account, DateTime snapshotDate, DateTime closingDate, CAP_EventSourcingEntities entities)
{
AccountBalance snapshot = GetSnapshot(account, snapshotDate, entities);
IQueryable<decimal?> transfersFrom =
from t in entities.Transfers
where
t.From == account &&
t.DateOfBusiness > snapshotDate &&
t.DateOfBusiness <= closingDate
select (decimal?)t.Amount;
IQueryable<decimal?> transfersTo =
from t in entities.Transfers
where
t.To == account &&
t.DateOfBusiness > snapshotDate &&
t.DateOfBusiness <= closingDate
select (decimal?)t.Amount;
return snapshot.Balance - (transfersFrom.Sum() ?? 0.0m) + (transfersTo.Sum() ?? 0.0m);
}
// TODO 3d: Command is just an insert.
public void Transfer(string fromAccount, string toAccount, decimal amount)
{
using (CAP_EventSourcingEntities entities = new CAP_EventSourcingEntities())
{
DateTime dateOfBusiness = AccountUtility.GetDateOfBusiness(entities);
DateTime snapshotDate = dateOfBusiness - TimeSpan.FromDays(2.0);
decimal accountBalance = AccountUtility.GetAccountBalance(fromAccount, snapshotDate, dateOfBusiness, entities);
if (accountBalance < amount)
throw new ApplicationException("Insufficient funds");
entities.AddToTransfers(new Transfer()
{
From = fromAccount,
To = toAccount,
Amount = amount,
DateOfBusiness = dateOfBusiness
});
entities.SaveChanges();
}
}
// TODO 3d: Command is just an insert.
public void Transfer(string fromAccount, string toAccount, decimal amount)
{
using (CAP_EventSourcingEntities entities = new CAP_EventSourcingEntities())
{
DateTime dateOfBusiness = AccountUtility.GetDateOfBusiness(entities);
DateTime snapshotDate = dateOfBusiness - TimeSpan.FromDays(2.0);
decimal accountBalance = AccountUtility.GetAccountBalance(fromAccount, snapshotDate, dateOfBusiness, entities);
if (accountBalance < amount)
{
throw new ApplicationException("Insufficient funds");
}
entities.AddToTransfers(new Transfer()
{
From = fromAccount,
To = toAccount,
Amount = amount,
DateOfBusiness = dateOfBusiness
});
entities.SaveChanges();
}
}
public static DateTime GetDateOfBusiness(CAP_EventSourcingEntities entities)
{
return entities.Current.Single().DateOfBusiness;
}
private static AccountBalance GetSnapshot(string account, DateTime snapshotDate, CAP_EventSourcingEntities entities)
{
IQueryable <AccountBalance> snapshots =
from b in entities.AccountBalances
where
b.Account == account &&
b.DateOfBusiness == snapshotDate
select b;
AccountBalance snapshot = snapshots.FirstOrDefault();
if (snapshot == null)
{
throw new ApplicationException("No such account.");
}
return(snapshot);
}
// TODO 3c: Query is more complex.
public static decimal GetAccountBalance(string account, DateTime snapshotDate, DateTime closingDate, CAP_EventSourcingEntities entities)
{
AccountBalance snapshot = GetSnapshot(account, snapshotDate, entities);
IQueryable <decimal?> transfersFrom =
from t in entities.Transfers
where
t.From == account &&
t.DateOfBusiness > snapshotDate &&
t.DateOfBusiness <= closingDate
select(decimal?) t.Amount;
IQueryable <decimal?> transfersTo =
from t in entities.Transfers
where
t.To == account &&
t.DateOfBusiness > snapshotDate &&
t.DateOfBusiness <= closingDate
select(decimal?) t.Amount;
return(snapshot.Balance - (transfersFrom.Sum() ?? 0.0m) + (transfersTo.Sum() ?? 0.0m));
}
public static DateTime GetDateOfBusiness(CAP_EventSourcingEntities entities)
{
return(entities.Current.Single().DateOfBusiness);
}
