add start of Adhikar example for processing loan transactions.

mifosng-provider/src/main/java/org/mifosng/platform/loan/domain/AdhikarLoanRepaymentScheduleTransactionProcessor.java

@@ -0,0 +1,143 @@
+package org.mifosng.platform.loan.domain;
+
+import java.util.List;
+
+import org.joda.time.LocalDate;
+import org.mifosng.platform.currency.domain.MonetaryCurrency;
+import org.mifosng.platform.currency.domain.Money;
+
+/**
+ * Adhikar style {@link LoanRepaymentScheduleTransactionProcessor}.
+ * 
+ * From https://mifosforge.jira.com/browse/MIFOS-5636:
+ * 
+ * Per RBI regulations, all interest must be paid (both current and overdue) before principal is paid.
+ * 
+ * For example on a loan with two installments due (one current and one overdue) of 220 each (200 principal + 20 interest):
+ * 
+ * Partial Payment of 40
+ * 20 Payment to interest on Installment #1 (200 principal remaining)
+ * 20 Payment to interest on Installment #2 (200 principal remaining)
+ */
+public class AdhikarLoanRepaymentScheduleTransactionProcessor extends AbstractLoanRepaymentScheduleTransactionProcessor {
+
+	/**
+	 * For creocore, early is defined as any date before the installment due
+	 * date
+	 */
+	@Override
+	protected boolean isTransactionInAdvanceOfInstallment(
+			final int currentInstallmentIndex,
+			final List<LoanRepaymentScheduleInstallment> installments,
+			final LocalDate transactionDate, final Money transactionAmount) {
+
+		LoanRepaymentScheduleInstallment currentInstallment = installments.get(currentInstallmentIndex);
+
+		return transactionDate.isBefore(currentInstallment.getDueDate());
+	}
+
+	/**
+	 * For early/'in advance' repayments, pays off principal component only.
+	 */
+	@Override
+	protected Money handleTransactionThatIsPaymentInAdvanceOfInstallment(
+			final LoanRepaymentScheduleInstallment currentInstallment,
+			final List<LoanRepaymentScheduleInstallment> installments,
+			final LoanTransaction loanTransaction,
+			final LocalDate transactionDate, final Money paymentInAdvance) {
+		
+		return handleTransactionThatIsOnTimePaymentOfInstallment(currentInstallment, loanTransaction, paymentInAdvance);
+	}
+
+	/**
+	 * For late repayments, pay off in the same way as on-time payments,
+	 * interest first then principal.
+	 */
+	@Override
+	protected Money handleTransactionThatIsALateRepaymentOfInstallment(
+			final LoanRepaymentScheduleInstallment currentInstallment,
+			final List<LoanRepaymentScheduleInstallment> installments,
+			final LoanTransaction loanTransaction,
+			final Money transactionAmountUnprocessed) {
+		
+		// pay of overdue and current interest due given transaction date
+		MonetaryCurrency currency = transactionAmountUnprocessed.getCurrency();
+		Money transactionAmountRemaining = transactionAmountUnprocessed;
+		
+		LoanRepaymentScheduleInstallment currentInstallmentBasedOnTransactionDate = nearestInstallment(loanTransaction.getTransactionDate(), installments);
+		
+		for (LoanRepaymentScheduleInstallment installment : installments) {
+			if (
+				installment.isInterestDue(currency) && 
+				(installment.isOverdueOn(loanTransaction.getTransactionDate()) || installment.getInstallmentNumber().equals(currentInstallmentBasedOnTransactionDate.getInstallmentNumber()))
+			   ) {	
+				Money interestPortion = installment.payInterestComponent(transactionAmountRemaining);
+				transactionAmountRemaining = transactionAmountRemaining.minus(interestPortion);
+				
+				Money principalPortion = Money.zero(currency);
+				Money interestWaivedPortion = Money.zero(currency);
+				loanTransaction.updateComponents(principalPortion, interestPortion, interestWaivedPortion);
+			}
+		}
+		
+		// With whatever is remaining, pay off principal components of installments
+		for (LoanRepaymentScheduleInstallment installment : installments) {
+			if (installment.isPrincipalNotCompleted(currency) && transactionAmountRemaining.isGreaterThanZero()) {
+				Money principalPortion = installment.payPrincipalComponent(transactionAmountRemaining);
+				transactionAmountRemaining = transactionAmountRemaining.minus(principalPortion);
+				
+				Money interestPortion = Money.zero(currency);
+				Money interestWaivedPortion = Money.zero(currency);
+				loanTransaction.updateComponents(principalPortion, interestPortion, interestWaivedPortion);
+			}
+		}
+
+		return transactionAmountRemaining;
+	}
+
+	private LoanRepaymentScheduleInstallment nearestInstallment(final LocalDate transactionDate, List<LoanRepaymentScheduleInstallment> installments) {
+		
+		LoanRepaymentScheduleInstallment nearest = installments.get(0);
+		
+		for (LoanRepaymentScheduleInstallment installment : installments) {
+			if (installment.getDueDate().isAfter(transactionDate) || installment.getDueDate().isEqual(transactionDate)) {
+				nearest = installment;
+				break;
+			}
+		}
+		return nearest;
+	}
+
+	/**
+	 * For normal on-time repayments, pays off interest first, then principal.
+	 */
+	@Override
+	protected Money handleTransactionThatIsOnTimePaymentOfInstallment(
+			final LoanRepaymentScheduleInstallment currentInstallment,
+			final LoanTransaction loanTransaction,
+			final Money transactionAmountUnprocessed) {
+
+		Money transactionAmountRemaining = transactionAmountUnprocessed;
+		
+		Money interestPortion = currentInstallment.payInterestComponent(transactionAmountRemaining);
+		transactionAmountRemaining = transactionAmountRemaining.minus(interestPortion);
+
+		Money principalPortion = currentInstallment
+				.payPrincipalComponent(transactionAmountRemaining);
+		transactionAmountRemaining = transactionAmountRemaining
+				.minus(principalPortion);
+
+		Money interestWaivedPortion = Money.zero(transactionAmountRemaining
+				.getCurrency());
+		loanTransaction.updateComponents(principalPortion, interestPortion,
+				interestWaivedPortion);
+
+		return transactionAmountRemaining;
+	}
+
+	@Override
+	protected void onLoanOverpayment(final LoanTransaction loanTransaction,
+			final Money loanOverPaymentAmount) {
+		// dont do anything for with loan over-payment
+	}
+}

mifosng-provider/src/main/java/org/mifosng/platform/loan/domain/LoanRepaymentScheduleInstallment.java

@@ -85,25 +85,29 @@ public class LoanRepaymentScheduleInstallment extends AbstractAuditableCustom<Ap
         return new LocalDate(this.dueDate);
     }
 
-	public Money getPrincipal(MonetaryCurrency currency) {
+	public Money getPrincipal(final MonetaryCurrency currency) {
 		return Money.of(currency, this.principal);
 	}
 	
-	public Money getPrincipalCompleted(MonetaryCurrency currency) {
+	public Money getPrincipalCompleted(final MonetaryCurrency currency) {
 		return Money.of(currency, this.principalCompleted);
 	}
 	
-	public Money getInterest(MonetaryCurrency currency) {
+	public Money getInterest(final MonetaryCurrency currency) {
 		return Money.of(currency, this.interest);
 	}
 	
-	public Money getInterestCompleted(MonetaryCurrency currency) {
+	public Money getInterestCompleted(final MonetaryCurrency currency) {
 		return Money.of(currency, this.interestCompleted);
 	}
 	
-	public Money getInterestWaived(MonetaryCurrency currency) {
+	public Money getInterestWaived(final MonetaryCurrency currency) {
 		return Money.of(currency, this.interestWaived);
 	}
+
+	public boolean isInterestDue(final MonetaryCurrency currency) {
+		return getInterest(currency).minus(getInterestCompleted(currency).plus(getInterestWaived(currency))).isGreaterThanZero();
+	}
 	
 	public Money getTotal(MonetaryCurrency currency) {
 		return getPrincipal(currency).plus(getInterest(currency));
@@ -204,4 +208,8 @@ public class LoanRepaymentScheduleInstallment extends AbstractAuditableCustom<Ap
 		
 		return waivedInterestPortionOfTransaction;
 	}
+
+	public boolean isOverdueOn(final LocalDate transactionDate) {
+		return this.getDueDate().isBefore(transactionDate);
+	}
 }