core/src/test/java/org/jclouds/reflect/Reflection2Test.java

/*
 * 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.jclouds.reflect;

import static com.google.common.base.Functions.toStringFunction;
import static org.jclouds.reflect.Reflection2.constructors;
import static org.jclouds.reflect.Reflection2.method;
import static org.jclouds.reflect.Reflection2.methods;
import static org.jclouds.reflect.Reflection2.typeToken;
import static org.testng.Assert.assertEquals;

import java.util.HashSet;
import java.util.Set;
import java.util.SortedSet;

import org.testng.annotations.Test;

import com.google.common.base.Function;
import com.google.common.base.Predicates;
import com.google.common.collect.FluentIterable;
import com.google.common.collect.ImmutableSet;
import com.google.common.reflect.Invokable;
import com.google.common.reflect.Parameter;
import com.google.common.reflect.TypeToken;
import com.google.inject.TypeLiteral;

@Test
public class Reflection2Test {

   /**
    * useful when converting to and from type literals from other libraries such as guice and gson.
    */
   public void testTypeTokenForType() {
      TypeLiteral<Set<String>> guice = new TypeLiteral<Set<String>>() {
      };

      assertEquals(typeToken(guice.getType()), new TypeToken<Set<String>>() {
         private static final long serialVersionUID = 1L;
      });
   }

   public void testConstructors() {
      Set<String> ctorParams = FluentIterable.from(constructors(TypeToken.of(HashSet.class)))
            .transform(new Function<Invokable<?, ?>, Iterable<Parameter>>() {
               public Iterable<Parameter> apply(Invokable<?, ?> input) {
                  return input.getParameters();
               }
            }).transform(toStringFunction()).toSet();

      assertEquals(ctorParams, ImmutableSet.of("[]", "[java.util.Collection<? extends E> arg0]",
            "[int arg0, float arg1]", "[int arg0]", "[int arg0, float arg1, boolean arg2]"));
   }

   private abstract static class MyValue {
      abstract String foo();

      static MyValue create(String foo){
         return null;
      }
   }

   public void testConstructorsReturnsFactoryMethods() {
      Set<String> ctorParams = FluentIterable.from(constructors(TypeToken.of(MyValue.class)))
            .transform(new Function<Invokable<?, ?>, Iterable<Parameter>>() {
               public Iterable<Parameter> apply(Invokable<?, ?> input) {
                  return input.getParameters();
               }
            }).transform(toStringFunction()).toSet();

      assertEquals(ctorParams, ImmutableSet.of("[]", "[java.lang.String arg0]"));
   }

   public void testTypeTokenForClass() {
      assertEquals(typeToken(String.class), TypeToken.of(String.class));
   }

   public void testMethodFromJavaMethod() throws SecurityException, NoSuchMethodException {
      assertEquals(method(typeToken(String.class), String.class.getMethod("toString")), TypeToken.of(String.class)
            .method(String.class.getMethod("toString")).returning(String.class));
   }

   public void testMethodFromClassAndNoParams() {
      @SuppressWarnings("rawtypes")
      Invokable<Set, Object> methodInSuper = method(Set.class, "iterator");

      assertEquals(methodInSuper.getOwnerType(), typeToken(Set.class));
   }

   public void testMethodFromClassAndParams() {
      @SuppressWarnings("rawtypes")
      Invokable<Set, Object> methodInSuper = method(Set.class, "equals", Object.class);

      assertEquals(methodInSuper.getOwnerType(), typeToken(Set.class));
      assertEquals(methodInSuper.getParameters().get(0).getType().getRawType(), Object.class);
   }

   private static final ImmutableSet<String> SET_METHODS = ImmutableSet.of(
         // Java 6 and 7 methods
         "add",
         "addAll",
         "clear",
         "contains",
         "containsAll",
         "equals",
         "hashCode",
         "isEmpty",
         "iterator",
         "remove",
         "removeAll",
         "retainAll",
         "size",
         "toArray",
         // Java 8 methods
         "forEach",
         "parallelStream",
         "removeIf",
         "spliterator",
         "stream",
         // Java 9 methods
         "of");

   private static final ImmutableSet<String> SORTED_SET_METHODS = ImmutableSet.<String>builder()
         .addAll(SET_METHODS)
         .add("comparator")
         .add("first")
         .add("headSet")
         .add("last")
         .add("subSet")
         .add("tailSet")
         .build();

   public void testMethods() {
      Set<String> methodNames = FluentIterable.from(methods(Set.class)).transform(invokableToName)
            .transform(toStringFunction())
            .filter(Predicates.not(Predicates.<String>in(SET_METHODS)))
            .toSet();

      assertEquals(methodNames, ImmutableSet.<String>of());
   }

   public void testMethodsSubClass() {
      Set<String> methodNames = FluentIterable.from(methods(SortedSet.class)).transform(invokableToName)
            .transform(toStringFunction())
            .filter(Predicates.not(Predicates.<String>in(SORTED_SET_METHODS)))
            .toSet();

      assertEquals(methodNames, ImmutableSet.<String>of());
   }

   static final Function<Invokable<?, ?>, String> invokableToName = new Function<Invokable<?, ?>, String>() {
      public String apply(Invokable<?, ?> input) {
         return input.getName();
      }
   };
}