How to use

ReflectionUtils

in

rocks.inspectit.server.diagnosis.engine.util

T annotation = findAnnotation(interfaze, annotationClass);
if (null != annotation) {
  return annotation;
return findAnnotation(superClazz, annotationClass);

  @Test(expectedExceptions = { RuntimeException.class })
  public void noDefaultConstructor() {
    ReflectionUtils.tryInstantiate(NoDefaultConstructorClass.class);
  }
}

/**
 * Extracts the {@link SessionVariableInjection}s from the given class by processing the
 * {@link SessionVariable} annotations.
 *
 * @param clazz
 *            The class to be analyzed.
 * @return List of SessionVariableInjections
 * @throws RuleDefinitionException
 *             If {@link SessionVariableInjection} annotations are invalid.
 */
public static List<SessionVariableInjection> describeSessionParameterInjections(Class<?> clazz) throws RuleDefinitionException {
  return ReflectionUtils.visitFieldsAnnotatedWith(SessionVariable.class, clazz, new Visitor<SessionVariable, Field, SessionVariableInjection>() {
    @Override
    public SessionVariableInjection visit(SessionVariable annotation, Field field) {
      return new SessionVariableInjection(annotation.name(), annotation.optional(), field);
    }
  });
}

Rule annotation = ReflectionUtils.findAnnotation(clazz, Rule.class);
if (annotation == null) {
  throw new RuleDefinitionException(clazz.getName() + " must be annotated with @Rule annotation.");
if (!ReflectionUtils.hasNoArgsConstructor(clazz)) {
  throw new RuleDefinitionException(clazz.getName() + " must define an empty default constructor.");

  /**
   * Extracts the {@link ConditionMethod}s from the given class by processing the
   * {@link Condition} annotation.
   *
   * @param clazz
   *            The class to be analyzed.
   * @return List of ConditionMethods
   * @throws RuleDefinitionException
   *             If {@link ConditionMethod} annotations are invalid.
   */
  public static List<ConditionMethod> describeConditionMethods(Class<?> clazz) throws RuleDefinitionException {
    List<ConditionMethod> conditions = ReflectionUtils.visitMethodsAnnotatedWith(Condition.class, clazz, new Visitor<Condition, Method, ConditionMethod>() {
      @Override
      public ConditionMethod visit(Condition annotation, Method method) throws RuleDefinitionException {
        return new ConditionMethod(annotation.name(), annotation.hint(), method);
      }
    });
    return conditions;
  }
}

@Test
public void noDefaultConstructor() {
  boolean constructor = ReflectionUtils.hasNoArgsConstructor(NoDefaultConstructorClass.class);
  assertThat(constructor, is(false));
}

/**
 * Invokes the given method on the passed target.
 *
 * @param method
 *            Method to invoke per reflection.
 * @param target
 *            Object on which to invoke the method.
 * @return The result object.
 * @throws InvocationTargetException
 *             If invocation target is invalid.
 * @throws IllegalArgumentException
 *             If arguments are invalid.
 * @throws IllegalAccessException
 *             If method cannot be accessed.
 */
public static Object invokeMethod(Method method, Object target) throws IllegalAccessException, IllegalArgumentException, InvocationTargetException {
  return invokeMethod(method, target, new Object[0]);
}

/**
 * Extracts the {@link Action} from the given class by processing the {@link Action} annotation.
 *
 * @param clazz
 *            The class to be analyzed.
 * @return List of ActionMethod
 * @throws RuleDefinitionException
 *             If {@link Action} annotation is invalid.
 */
public static ActionMethod describeActionMethod(Class<?> clazz) throws RuleDefinitionException {
  List<ActionMethod> actionMethods = ReflectionUtils.visitMethodsAnnotatedWith(Action.class, clazz, new Visitor<Action, Method, ActionMethod>() {
    @Override
    public ActionMethod visit(Action annotation, Method method) throws RuleDefinitionException {
      return new ActionMethod(method, annotation.resultTag(), annotation.resultQuantity());
    }
  });
  if ((null == actionMethods) || (actionMethods.size() != 1)) {
    throw new RuleDefinitionException("A rule must define exactly one method annotated with @Action. Otherwise the rule could never be exectued.");
  } else {
    return actionMethods.get(0);
  }
}

  @Test
  public void privateConstructor() {
    boolean constructor = ReflectionUtils.hasNoArgsConstructor(PrivateConstructorClass.class);
    assertThat(constructor, is(false));
  }
}

/**
 * Executes the action. Throws: RuleExecutionException in case of any error
 *
 * @param context
 *            The current executing {@link ExecutionContext}
 * @return A collection of {@link Tags}s
 * @throws RuleExecutionException
 *             If rule execution fails with an exception.
 * @see ExecutionContext
 * @see Tag
 */
public Collection<Tag> execute(ExecutionContext context) throws RuleExecutionException {
  try {
    Object result = ReflectionUtils.invokeMethod(getMethod(), context.getInstance());
    return transform(result, context);
  } catch (Exception e) {
    throw new RuleExecutionException("Failed to invoke action method (" + getMethod().getName() + ")", context, e);
  }
}

@Test(expectedExceptions = { NullPointerException.class })
public void visitorReturnsNull() throws RuleDefinitionException {
  ReflectionUtils.visitFieldsAnnotatedWith(TagValue.class, TestClass.class, new Visitor<TagValue, Field, String>() {
    @Override
    public String visit(TagValue annotation, Field field) {
      return field.getName().endsWith("2") ? null : "ok";
    }
  });
}

@Test(expectedExceptions = { NullPointerException.class })
public void visitorReturnsNull() throws RuleDefinitionException {
  ReflectionUtils.visitMethodsAnnotatedWith(Action.class, TestClass.class, new Visitor<Action, Method, String>() {
    @Override
    public String visit(Action annotation, Method method) {
      return method.getName().endsWith("C") ? null : "ok";
    }
  });
}

  @Test
  public void unavailableAnnotation() {
    Rule ruleAnnotation = ReflectionUtils.findAnnotation(NoDefaultConstructorClass.class, Rule.class);
    assertThat(ruleAnnotation, equalTo(null));
  }
}

@Test
public void validClass() {
  TestClass instance = ReflectionUtils.tryInstantiate(TestClass.class);
  assertThat(instance.par1, is(1));
}

@Test
public void defaultConstructor() {
  boolean constructor = ReflectionUtils.hasNoArgsConstructor(TestClass.class);
  assertThat(constructor, is(true));
}

/**
 * Executes this {@link ConditionMethod}. If the #method does not succeed a
 * {@link ConditionFailure} is returned. Otherwise null is returned.
 *
 * @param context
 *            The current executing {@link ExecutionContext}
 * @return A {@link ConditionFailure} if condition fails, null otherwise
 * @throws RuleExecutionException
 *             If execution of the condition method fails with an exception.
 * @see ExecutionContext
 * @see ConditionFailure
 */
public ConditionFailure execute(ExecutionContext context) throws RuleExecutionException {
  try {
    boolean valid = (boolean) ReflectionUtils.invokeMethod(getMethod(), context.getInstance());
    if (!valid) {
      // Store information about the failed condition for later usage
      return new ConditionFailure(getName(), getHint());
    }
    return null;
  } catch (Exception e) {
    throw new RuleExecutionException("Invocation of condition method failed.", context, e);
  }
}

/**
 * Extracts the {@link TagInjection}s from the given class by processing the
 * {@link TagInjection} annotations.
 *
 * @param clazz
 *            The class to be analyzed.
 * @return List of TagInjection
 * @throws RuleDefinitionException
 *             If {@link TagInjection} annotations are invalid. Contract is that a class must
 *             defined at least one field annotated with {@link TagValue}. Otherwise the rule
 *             could never fire, because no input could be determined.
 */
public static List<TagInjection> describeTagInjection(Class<?> clazz) throws RuleDefinitionException {
  List<TagInjection> tagInjections = ReflectionUtils.visitFieldsAnnotatedWith(TagValue.class, clazz, new Visitor<TagValue, Field, TagInjection>() {
    @Override
    public TagInjection visit(TagValue annotation, Field field) {
      return new TagInjection(annotation.type(), field, annotation.injectionStrategy());
    }
  });
  if (CollectionUtils.isEmpty(tagInjections)) {
    throw new RuleDefinitionException(clazz.getName() + " must annotate at least one field with @Value. Otherwise the " + "rule will never fire and is useless.");
  } else {
    return tagInjections;
  }
}

  @Test(expectedExceptions = { RuleDefinitionException.class })
  public void explicitVisitorException() throws RuleDefinitionException {
    ReflectionUtils.visitMethodsAnnotatedWith(Action.class, TestClass.class, new Visitor<Action, Method, String>() {
      @Override
      public String visit(Action annotation, Method method) throws RuleDefinitionException {
        if (method.getName().endsWith("C")) {
          throw new RuleDefinitionException("test exception");
        } else {
          return "ok";
        }
      }
    });
  }
}

@Test
public void availableAnnotationThroughSuperclass() {
  Rule ruleAnnotation = ReflectionUtils.findAnnotation(TestClass2.class, Rule.class);
  assertThat(ruleAnnotation, not(equalTo(null)));
}

@Override
public Session<I, R> makeObject() throws Exception {
  return new Session<>(ruleDefinitions, configuration.getResultCollector(), ReflectionUtils.tryInstantiate(configuration.getStorageClass()));
}