/*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You 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 org.apache.commons.functor.core.algorithm;
  
  import static org.junit.Assert.assertEquals;
  
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.List;
  
  import org.apache.commons.functor.BaseFunctorTest;
  import org.apache.commons.functor.BinaryFunction;
  import org.apache.commons.functor.generator.loop.IteratorToGeneratorAdapter;
  import org.junit.Test;
  
  /**
   * Tests {@link FoldRight} algorithm.
   */
  public class TestFoldRight extends BaseFunctorTest {
  
      @Override
      protected Object makeFunctor() throws Exception {
          return new FoldRight<Object>(new StringConcatenator());
      }
      
      @Test
      public void testFoldRight() {
          FoldRight<Object> foldRight = new FoldRight<Object>(new BinaryFunction<Object, Object, Object>() {
              public Object evaluate(Object left, Object right) {
                  StringBuilder buf = left instanceof StringBuilder ? (StringBuilder) left : new StringBuilder().append(left);
                  return buf.append(right);
              }
          });
          assertEquals("0123456789", foldRight.evaluate(IteratorToGeneratorAdapter.adapt(list.iterator())).toString());
          assertEquals("0123456789x", foldRight.evaluate(IteratorToGeneratorAdapter.adapt(list.iterator()), "x").toString());
          assertEquals("x", foldRight.evaluate(IteratorToGeneratorAdapter.adapt(new ArrayList<Object>().iterator()), "x").toString());
      }
  
      // Attributes
      // ------------------------------------------------------------------------
      private List<Object> list = Arrays.<Object>asList(0,1,2,3,4,5,6,7,8,9);
  
      // Classes
      // ------------------------------------------------------------------------
      
      static class StringConcatenator implements BinaryFunction<Object, Object, Object> {
  
          public Object evaluate(Object left, Object right) {
              StringBuilder buf = left instanceof StringBuilder ? (StringBuilder) left : new StringBuilder().append(left);
              return buf.append(right);
          }
          
          @Override
          public boolean equals(Object obj) {
              if(this == obj) {
                  return true;
              }
              return obj != null && obj instanceof StringConcatenator;
          }
          
          @Override
          public int hashCode() {
              return "StringConcatenator".hashCode();
          }
      }
      
  }