content: /*
   * 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.beam.sdk.values;
  
  import static org.apache.beam.sdk.values.TypeDescriptors.integers;
  import static org.apache.beam.sdk.values.TypeDescriptors.iterables;
  import static org.apache.beam.sdk.values.TypeDescriptors.kvs;
  import static org.apache.beam.sdk.values.TypeDescriptors.lists;
  import static org.apache.beam.sdk.values.TypeDescriptors.sets;
  import static org.apache.beam.sdk.values.TypeDescriptors.strings;
  import static org.hamcrest.MatcherAssert.assertThat;
  import static org.junit.Assert.assertEquals;
  import static org.junit.Assert.assertNotEquals;
  import static org.junit.Assert.assertNotNull;
  
  import java.util.List;
  import java.util.Set;
  import org.hamcrest.CoreMatchers;
  import org.junit.Test;
  import org.junit.runner.RunWith;
  import org.junit.runners.JUnit4;
  
  /** Tests for {@link TypeDescriptors}. */
  @RunWith(JUnit4.class)
  public class TypeDescriptorsTest {
    @Test
    public void testTypeDescriptorsIterables() throws Exception {
      TypeDescriptor<Iterable<String>> descriptor = iterables(strings());
      assertEquals(descriptor, new TypeDescriptor<Iterable<String>>() {});
    }
  
    @Test
    public void testTypeDescriptorsSets() throws Exception {
      TypeDescriptor<Set<String>> descriptor = sets(strings());
      assertEquals(descriptor, new TypeDescriptor<Set<String>>() {});
    }
  
    @Test
    public void testTypeDescriptorsKV() throws Exception {
      TypeDescriptor<KV<String, Integer>> descriptor = kvs(strings(), integers());
      assertEquals(descriptor, new TypeDescriptor<KV<String, Integer>>() {});
    }
  
    @Test
    @SuppressWarnings("JUnitIncompatibleType")
    public void testTypeDescriptorsLists() throws Exception {
      TypeDescriptor<List<String>> descriptor = lists(strings());
      assertEquals(descriptor, new TypeDescriptor<List<String>>() {});
      assertNotEquals(descriptor, new TypeDescriptor<List<Boolean>>() {});
    }
  
    @Test
    public void testTypeDescriptorsListsOfLists() throws Exception {
      TypeDescriptor<List<List<String>>> descriptor = lists(lists(strings()));
      assertEquals(descriptor, new TypeDescriptor<List<List<String>>>() {});
      assertNotEquals(descriptor, new TypeDescriptor<List<String>>() {});
      assertNotEquals(descriptor, new TypeDescriptor<List<Boolean>>() {});
    }
  
    private interface Generic<FooT, BarT> {}
  
    private static <ActualFooT> Generic<ActualFooT, String> typeErasedGeneric() {
      return new Generic<ActualFooT, String>() {};
    }
  
    private static <ActualFooT, ActualBarT> TypeDescriptor<ActualFooT> extractFooT(
        Generic<ActualFooT, ActualBarT> instance) {
      return TypeDescriptors.extractFromTypeParameters(
          instance,
          Generic.class,
          new TypeDescriptors.TypeVariableExtractor<
              Generic<ActualFooT, ActualBarT>, ActualFooT>() {});
    }
  
    private static <ActualFooT, ActualBarT> TypeDescriptor<ActualBarT> extractBarT(
        Generic<ActualFooT, ActualBarT> instance) {
      return TypeDescriptors.extractFromTypeParameters(
          instance,
          Generic.class,
          new TypeDescriptors.TypeVariableExtractor<
              Generic<ActualFooT, ActualBarT>, ActualBarT>() {});
    }
  
    private static <ActualFooT, ActualBarT> TypeDescriptor<KV<ActualFooT, ActualBarT>> extractKV(
        Generic<ActualFooT, ActualBarT> instance) {
      return TypeDescriptors.extractFromTypeParameters(
          instance,
          Generic.class,
          new TypeDescriptors.TypeVariableExtractor<
              Generic<ActualFooT, ActualBarT>, KV<ActualFooT, ActualBarT>>() {});
    }
  
    @Test
    public void testTypeDescriptorsTypeParameterOf() throws Exception {
      assertEquals(strings(), extractFooT(new Generic<String, Integer>() {}));
      assertEquals(integers(), extractBarT(new Generic<String, Integer>() {}));
      assertEquals(kvs(strings(), integers()), extractKV(new Generic<String, Integer>() {}));
    }
  
    @Test
    public void testTypeDescriptorsTypeParameterOfErased() throws Exception {
      Generic<Integer, String> instance = TypeDescriptorsTest.typeErasedGeneric();
  
      TypeDescriptor<Integer> fooT = extractFooT(instance);
      assertNotNull(fooT);
      // Using toString() assertions because verifying the contents of a Type is very cumbersome,
      // and the expected types can not be easily constructed directly.
      assertEquals("ActualFooT", fooT.toString());
  
      assertEquals(strings(), extractBarT(instance));
  
      TypeDescriptor<KV<Integer, String>> kvT = extractKV(instance);
      assertNotNull(kvT);
      assertThat(kvT.toString(), CoreMatchers.containsString("KV<ActualFooT, java.lang.String>"));
    }
  }
  