javax.enterprise.util.AnnotationLiteral Maven / Gradle / Ivy

package javax.enterprise.util;

import java.io.Serializable;
import java.lang.annotation.Annotation;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.Arrays;

/**
 * Created by sven on 02.05.15.
 */
public abstract class AnnotationLiteral implements Annotation, Serializable {

  private static final long serialVersionUID = 1L;

  private transient Class annotationType;
  private transient Method[] members;
  private transient Integer cachedHashCode;

  protected AnnotationLiteral() {
    if (getMembers().length == 0) {
      this.cachedHashCode = 0;
    } else {
      this.cachedHashCode = null;
    }
  }

  private static Class getAnnotationLiteralSubclass(Class clazz) {
    Class superclass = clazz.getSuperclass();
    if (superclass.equals(AnnotationLiteral.class)) {
      return clazz;
    } else if (superclass.equals(Object.class)) {
      return null;
    } else {
      return (getAnnotationLiteralSubclass(superclass));
    }
  }

  @SuppressWarnings("unchecked")
  private static  Class getTypeParameter(Class annotationLiteralSuperclass) {
    Type type = annotationLiteralSuperclass.getGenericSuperclass();
    if (type instanceof ParameterizedType) {
      ParameterizedType parameterizedType = (ParameterizedType) type;
      if (parameterizedType.getActualTypeArguments().length == 1) {
        return (Class) parameterizedType.getActualTypeArguments()[0];
      }
    }
    return null;
  }

  private static Object getMemberValue(Method member, Annotation instance) {
    Object value = invoke(member, instance);
    if (value == null) {
      throw new IllegalArgumentException("Annotation member value " + instance.getClass().getName() + "."
          + member.getName() + " must not be null");
    }
    return value;
  }

  private static Object invoke(Method method, Object instance) {
    try {
      if (!method.isAccessible())
        method.setAccessible(true);
      return method.invoke(instance);
    } catch (IllegalArgumentException e) {
      throw new RuntimeException("Error checking value of member method " + method.getName() + " on "
          + method.getDeclaringClass(), e);
    } catch (IllegalAccessException e) {
      throw new RuntimeException("Error checking value of member method " + method.getName() + " on "
          + method.getDeclaringClass(), e);
    } catch (InvocationTargetException e) {
      throw new RuntimeException("Error checking value of member method " + method.getName() + " on "
          + method.getDeclaringClass(), e);
    }
  }

  private Method[] getMembers() {
    if (members == null) {
      members = annotationType().getDeclaredMethods();
      if (members.length > 0 && !annotationType().isAssignableFrom(this.getClass())) {
        throw new RuntimeException(getClass() + " does not implement the annotation type with members "
            + annotationType().getName());
      }
    }
    return members;
  }

  public Class annotationType() {
    if (annotationType == null) {
      Class annotationLiteralSubclass = getAnnotationLiteralSubclass(this.getClass());
      if (annotationLiteralSubclass == null) {
        throw new RuntimeException(getClass() + " is not a subclass of AnnotationLiteral");
      }
      annotationType = getTypeParameter(annotationLiteralSubclass);
      if (annotationType == null) {
        throw new RuntimeException(getClass() + " does not specify the type parameter T of AnnotationLiteral");
      }
    }
    return annotationType;
  }

  private void appendInBraces(StringBuilder buf, String s) {
    buf.append('{').append(s.substring(1, s.length() - 1)).append('}');
  }

  @Override
  public int hashCode() {
    if (cachedHashCode != null) {
      return cachedHashCode;
    } else {
      int hashCode = 0;
      for (Method member : getMembers()) {
        int memberNameHashCode = 127 * member.getName().hashCode();
        Object value = getMemberValue(member, this);
        int memberValueHashCode;
        if (value instanceof boolean[]) {
          memberValueHashCode = Arrays.hashCode((boolean[]) value);
        } else if (value instanceof short[]) {
          memberValueHashCode = Arrays.hashCode((short[]) value);
        } else if (value instanceof int[]) {
          memberValueHashCode = Arrays.hashCode((int[]) value);
        } else if (value instanceof long[]) {
          memberValueHashCode = Arrays.hashCode((long[]) value);
        } else if (value instanceof float[]) {
          memberValueHashCode = Arrays.hashCode((float[]) value);
        } else if (value instanceof double[]) {
          memberValueHashCode = Arrays.hashCode((double[]) value);
        } else if (value instanceof byte[]) {
          memberValueHashCode = Arrays.hashCode((byte[]) value);
        } else if (value instanceof char[]) {
          memberValueHashCode = Arrays.hashCode((char[]) value);
        } else if (value instanceof Object[]) {
          memberValueHashCode = Arrays.hashCode((Object[]) value);
        } else {
          memberValueHashCode = value.hashCode();
        }
        hashCode += memberNameHashCode ^ memberValueHashCode;
      }
      return hashCode;
    }
  }

  @Override
  public boolean equals(Object other) {
    if (other == this) {
      return true;
    }
    if (other == null) {
      return false;
    }
    if (other instanceof Annotation) {
      Annotation that = (Annotation) other;
      if (this.annotationType().equals(that.annotationType())) {
        for (Method member : getMembers()) {
          Object thisValue = getMemberValue(member, this);
          Object thatValue = getMemberValue(member, that);
          if (thisValue instanceof byte[] && thatValue instanceof byte[]) {
            if (!Arrays.equals((byte[]) thisValue, (byte[]) thatValue))
              return false;
          } else if (thisValue instanceof short[] && thatValue instanceof short[]) {
            if (!Arrays.equals((short[]) thisValue, (short[]) thatValue))
              return false;
          } else if (thisValue instanceof int[] && thatValue instanceof int[]) {
            if (!Arrays.equals((int[]) thisValue, (int[]) thatValue))
              return false;
          } else if (thisValue instanceof long[] && thatValue instanceof long[]) {
            if (!Arrays.equals((long[]) thisValue, (long[]) thatValue))
              return false;
          } else if (thisValue instanceof float[] && thatValue instanceof float[]) {
            if (!Arrays.equals((float[]) thisValue, (float[]) thatValue))
              return false;
          } else if (thisValue instanceof double[] && thatValue instanceof double[]) {
            if (!Arrays.equals((double[]) thisValue, (double[]) thatValue))
              return false;
          } else if (thisValue instanceof char[] && thatValue instanceof char[]) {
            if (!Arrays.equals((char[]) thisValue, (char[]) thatValue))
              return false;
          } else if (thisValue instanceof boolean[] && thatValue instanceof boolean[]) {
            if (!Arrays.equals((boolean[]) thisValue, (boolean[]) thatValue))
              return false;
          } else if (thisValue instanceof Object[] && thatValue instanceof Object[]) {
            if (!Arrays.equals((Object[]) thisValue, (Object[]) thatValue))
              return false;
          } else {
            if (!thisValue.equals(thatValue))
              return false;
          }
        }
        return true;
      }
    }
    return false;
  }

  @Override
  public String toString() {
    StringBuilder string = new StringBuilder();
    string.append('@').append(annotationType().getName()).append('(');
    for (int i = 0; i < getMembers().length; i++) {
      string.append(getMembers()[i].getName()).append('=');
      Object value = getMemberValue(getMembers()[i], this);
      if (value instanceof boolean[]) {
        appendInBraces(string, Arrays.toString((boolean[]) value));
      } else if (value instanceof byte[]) {
        appendInBraces(string, Arrays.toString((byte[]) value));
      } else if (value instanceof short[]) {
        appendInBraces(string, Arrays.toString((short[]) value));
      } else if (value instanceof int[]) {
        appendInBraces(string, Arrays.toString((int[]) value));
      } else if (value instanceof long[]) {
        appendInBraces(string, Arrays.toString((long[]) value));
      } else if (value instanceof float[]) {
        appendInBraces(string, Arrays.toString((float[]) value));
      } else if (value instanceof double[]) {
        appendInBraces(string, Arrays.toString((double[]) value));
      } else if (value instanceof char[]) {
        appendInBraces(string, Arrays.toString((char[]) value));
      } else if (value instanceof String[]) {
        String[] strings = (String[]) value;
        String[] quoted = new String[strings.length];
        for (int j = 0; j < strings.length; j++) {
          quoted[j] = "\"" + strings[j] + "\"";
        }
        appendInBraces(string, Arrays.toString(quoted));
      } else if (value instanceof Class[]) {
        Class[] classes = (Class[]) value;
        String[] names = new String[classes.length];
        for (int j = 0; j < classes.length; j++) {
          names[j] = classes[j].getName() + ".class";
        }
        appendInBraces(string, Arrays.toString(names));
      } else if (value instanceof Object[]) {
        appendInBraces(string, Arrays.toString((Object[]) value));
      } else if (value instanceof String) {
        string.append('"').append(value).append('"');
      } else if (value instanceof Class) {
        string.append(((Class) value).getName()).append(".class");
      } else {
        string.append(value);
      }
      if (i < getMembers().length - 1) {
        string.append(", ");
      }
    }
    return string.append(')').toString();
  }

}