AnnotationValuesTestCase.java

package org.springframework.roo.classpath.details.annotations.populator;

import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertNotNull;
import static org.junit.Assert.assertTrue;

import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;

import org.apache.commons.lang3.Validate;
import org.junit.Test;

/**
 * Convenience superclass for unit-testing subclasses of
 * {@link AbstractAnnotationValues}
 * 
 * @author Andrew Swan
 * @since 1.2.0
 * @param <A> the annotation type
 * @param <V> the annotation values class
 */
public abstract class AnnotationValuesTestCase<A, V extends AbstractAnnotationValues> {

  /**
   * Subclasses must return the class of annotation whose value class is being
   * tested
   * 
   * @return a non-<code>null</code> annotation type
   */
  protected abstract Class<A> getAnnotationClass();

  /**
   * Subclasses must return the values class being tested
   * 
   * @return a non-<code>null</code> class
   */
  protected abstract Class<V> getValuesClass();

  @Test
  public void testAllAnnotationAttributesHaveAValueField() {
    final Class<A> annotationClass = getAnnotationClass();
    assertTrue("Invalid annotation class " + annotationClass, annotationClass.isAnnotation());
    for (final Method method : annotationClass.getDeclaredMethods()) {
      // Look for a field of this name in the values class or any
      // superclass
      final Field valueField = findField(getValuesClass(), method.getName());
      assertNotNull("No value field found for annotation attribute " + method, valueField);
      final int fieldModifiers = valueField.getModifiers();
      assertFalse("Value field " + valueField + " is final", Modifier.isFinal(fieldModifiers));
      assertNotNull("Value field " + valueField + " is not auto-populated",
          valueField.getAnnotation(AutoPopulate.class));
    }
  }

  private Field findField(final Class<?> clazz, final String name) {
    Validate.notNull(clazz, "Class must not be null");
    Validate.notNull(name, "Either name or type of the field must be specified");
    Class<?> searchType = clazz;
    while (!Object.class.equals(searchType) && searchType != null) {
      final Field[] fields = searchType.getDeclaredFields();
      for (final Field field : fields) {
        if (name.equals(field.getName())) {
          return field;
        }
      }
      searchType = searchType.getSuperclass();
    }
    return null;
  }
}