| /* |
| * Copyright 2017 The Mifos Initiative. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package io.mifos.individuallending.internal.service; |
| |
| import org.javamoney.calc.CalculationContext; |
| import org.javamoney.calc.common.Rate; |
| |
| import javax.annotation.Nonnegative; |
| import javax.annotation.Nonnull; |
| import javax.money.MonetaryAmount; |
| import javax.money.MonetaryOperator; |
| import java.math.BigDecimal; |
| import java.util.Objects; |
| |
| /** |
| * @author Myrle Krantz |
| */ |
| final class AnnuityPayment implements MonetaryOperator { |
| private Rate rate; |
| private int periods; |
| |
| /** |
| * Private constructor. |
| * |
| * @param rate the target rate, not null. |
| * @param periods the periods, >= 0. |
| */ |
| private AnnuityPayment(final @Nonnull Rate rate, final @Nonnegative int periods) |
| { |
| this.rate = Objects.requireNonNull(rate); |
| if (periods < 0) { |
| throw new IllegalArgumentException("Periods < 0"); |
| } |
| this.periods = periods; |
| } |
| |
| public static AnnuityPayment of(final @Nonnull Rate rate, final @Nonnegative int periods) |
| { |
| return new AnnuityPayment(rate, periods); |
| } |
| |
| static MonetaryAmount calculate( |
| final @Nonnull MonetaryAmount amount, |
| final @Nonnull Rate rate, |
| final @Nonnegative int periods) |
| { |
| Objects.requireNonNull(amount, "Amount required"); |
| Objects.requireNonNull(rate, "Rate required"); |
| // AP(m) = m*r / [ (1-((1 + r).pow(-n))) ] |
| |
| return amount.multiply(rate.get()).divide( |
| BigDecimal.ONE.subtract((BigDecimal.ONE.add(rate.get()) |
| .pow(-1 * periods, CalculationContext.mathContext())))); |
| } |
| |
| @Override |
| public MonetaryAmount apply(final @Nonnull MonetaryAmount amount) { |
| return calculate(amount, rate, periods); |
| } |
| |
| @Override |
| public String toString() { |
| return "AnnuityPayment{" + |
| "rate=" + rate + |
| ", periods=" + periods + |
| '}'; |
| } |
| } |