content: /*
   * Copyright 2005 JBoss Inc
   *
   * 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 lambdasinaction.dsl;
  
  import lambdasinaction.dsl.model.Order;
  import lambdasinaction.dsl.model.Tax;
  
  import java.util.function.Function;
  
  public class TaxCalculator {
  
      public static double calculate( Order order, boolean useRegional, boolean useGeneral, boolean useSurcharge ) {
          double value = order.getValue();
          if (useRegional) value = Tax.regional(value);
          if (useGeneral) value = Tax.general(value);
          if (useSurcharge) value = Tax.surcharge(value);
          return value;
      }
  
      private boolean useRegional;
      private boolean useGeneral;
      private boolean useSurcharge;
  
      public TaxCalculator withTaxRegional() {
          useRegional = true;
          return this;
      }
  
      public TaxCalculator withTaxGeneral() {
          useGeneral= true;
          return this;
      }
  
      public TaxCalculator withTaxSurcharge() {
          useSurcharge = true;
          return this;
      }
  
      public double calculate(Order order) {
          return calculate( order, useRegional, useGeneral, useSurcharge );
      }
  
      public Function<Double, Double> taxFuncion = Function.identity();
  
      public TaxCalculator with(Function<Double, Double> f) {
          taxFuncion.andThen( f );
          return this;
      }
  
      public double calculateF(Order order) {
          return taxFuncion.apply( order.getValue() );
      }
  
      public static void main(String[] args) {
          Order order = new Order();
  
          double value = TaxCalculator.calculate( order, true, false, true );
  
          value = new TaxCalculator().withTaxRegional()
                                     .withTaxSurcharge()
                                     .calculate( order );
  
          value = new TaxCalculator().with(Tax::regional)
                                     .with(Tax::surcharge)
                                     .calculate( order );
      }
  }
  