/*

  * To change this template, choose Tools | Templates

  * and open the template in the editor.

  */

 package org.apidesign.apifest08.test;

 import java.math.BigDecimal;

 import java.util.Currency;

 import junit.framework.Assert;

 import org.apidesign.apifest08.currency.Convertor;

 import org.apidesign.apifest08.currency.DelegatingConvertor;

 import org.apidesign.apifest08.currency.MonetaryAmount;

 /**

  * A delegating convertor that checks preconditions and postconditions.

  * Useful for testing.

  * @author jdvorak

  */

 public class ContractImposingDelegatingConvertor extends DelegatingConvertor {

     public ContractImposingDelegatingConvertor( final Convertor underlyingConvertor ) {

         super( underlyingConvertor );

     }

     @Override

     public ConversionResult convert( final ConversionRequest req ) {

         Assert.assertNotNull( "The request", req );

         final ConversionResult result = super.convert( req );

         Assert.assertNotNull( "Result of the convert() call", result );

         final MonetaryAmount netAmount = result.getNetAmount();

         if ( netAmount != null ) {

             Assert.assertEquals( "Converted to a different currency than specified in the request", req.getTgtCurrency(), netAmount.getCurrency() );

         }

         return result;

     }

     /**

      * Do some tests on our own.

      * @return this

      */

     public Convertor test() {

         try {

             final Currency aCurrency = Currency.getInstance( "EUR" );

             new ConversionRequest( new MonetaryAmount( BigDecimal.ONE, aCurrency ), aCurrency );

             Assert.fail( "Should have thrown an IllegalArgumentException" );

         } catch ( final IllegalArgumentException e ) {

             Assert.assertEquals( "Cannot request conversion from EUR to EUR", e.getMessage() );

         }

         return this;

     }

 }