Java TypeVariable.getBounds方法代碼示例

import java.lang.reflect.TypeVariable; //導入方法依賴的package包/類
private static void checkOneParameterType(ParameterizedType toCheck, Class<?> rawType,
    Class<?>... bounds) {
  System.out.println(((Class<?>) toCheck.getRawType()).getName()
      .equals(rawType.getName()));
  Type[] parameters = toCheck.getActualTypeArguments();
  System.out.println(parameters.length);
  TypeVariable<?> parameter = (TypeVariable<?>) parameters[0];
  System.out.println(parameter.getName());
  Type[] actualBounds = parameter.getBounds();
  for (int i = 0; i < bounds.length; i++) {
    System.out.println(((Class<?>) actualBounds[i]).getName().equals(bounds[i].getName()));
  }
}
 

import java.lang.reflect.TypeVariable; //導入方法依賴的package包/類
@SuppressWarnings("unchecked")
public <T> T deserialze(DefaultJSONParser parser, Type type, Object fieldName) {
    if (type instanceof GenericArrayType) {
        Type componentType = ((GenericArrayType) type).getGenericComponentType();
        if (componentType instanceof TypeVariable) {
            TypeVariable<?> componentVar = (TypeVariable<?>) componentType;
            componentType = componentVar.getBounds()[0];
        }

        List<Object> list = new ArrayList<Object>();
        parser.parseArray(componentType, list);
        Class<?> componentClass;
        if (componentType instanceof Class) {
            componentClass = (Class<?>) componentType;
            Object[] array = (Object[]) Array.newInstance(componentClass, list.size());
            list.toArray(array);
            return (T) array;
        } else {
            return (T) list.toArray();
        }

    }
    
    if (type instanceof Class && type != Object.class && type != Serializable.class) {
        return (T) parser.parseObject(type);    
    }

    return (T) parser.parse(fieldName);
}
 

import java.lang.reflect.TypeVariable; //導入方法依賴的package包/類
public static void main(String[] args) throws NoSuchMethodException, SecurityException, NoSuchFieldException {
  for (TypeVariable<Class<Generic>> var : Generic.class.getTypeParameters()) {
    System.out.println(var.getName());
    Type bound = var.getBounds()[0];
    System.out.println(((Class<?>) bound).getName().equals(AA.class.getName()));
  }

  Field f = Generic.class.getField("f");
  ParameterizedType fieldType = (java.lang.reflect.ParameterizedType)f.getGenericType();
  checkOneParameterType(fieldType, Generic.class, AA.class);

  ParameterizedType methodReturnType =
      (ParameterizedType) Generic.class.getMethod("get").getGenericReturnType();
  checkOneParameterType(methodReturnType, Generic.class, AA.class);
}
 

import java.lang.reflect.TypeVariable; //導入方法依賴的package包/類
private static Class extractType(TypeVariable typeVariable) {
	java.lang.reflect.Type[] boundTypes = typeVariable.getBounds();
	if ( boundTypes == null || boundTypes.length != 1 ) {
		return null;
	}

	return (Class) boundTypes[0];
}
 

import java.lang.reflect.TypeVariable; //導入方法依賴的package包/類
VariableJavaType(final ImplementClass implementClass, final TypeVariable<?> typeVariable) {
	this.implementClass = implementClass;
	this.variableName = typeVariable.getName();
	this.bounds = typeVariable.getBounds();
	this.javaTypeBounds = new JavaType[this.bounds.length];
	this.general = getJavaType(0);
}
 

import java.lang.reflect.TypeVariable; //導入方法依賴的package包/類
@SuppressWarnings("unchecked")
public <T> T deserialze(DefaultJSONParser parser, Type type, Object fieldName) {
    if (type instanceof GenericArrayType) {
        Type componentType = ((GenericArrayType) type).getGenericComponentType();
        if (componentType instanceof TypeVariable) {
            TypeVariable<?> componentVar = (TypeVariable<?>) componentType;
            componentType = componentVar.getBounds()[0];
        }

        List<Object> list = new ArrayList<Object>();
        parser.parseArray(componentType, list);
        Class<?> componentClass;
        if (componentType instanceof Class) {
            componentClass = (Class<?>) componentType;
            if (componentClass == boolean.class) {
                return (T) TypeUtils.cast(list, boolean[].class, parser.getConfig());
            } else if (componentClass == short.class) {
                return (T) TypeUtils.cast(list, short[].class, parser.getConfig());
            } else if (componentClass == int.class) {
                return (T) TypeUtils.cast(list, int[].class, parser.getConfig());
            } else if (componentClass == long.class) {
                return (T) TypeUtils.cast(list, long[].class, parser.getConfig());
            } else if (componentClass == float.class) {
                return (T) TypeUtils.cast(list, float[].class, parser.getConfig());
            } else if (componentClass == double.class) {
                return (T) TypeUtils.cast(list, double[].class, parser.getConfig());
            }

            Object[] array = (Object[]) Array.newInstance(componentClass, list.size());
            list.toArray(array);
            return (T) array;
        } else {
            return (T) list.toArray();
        }

    }

    return (T) parser.parse(fieldName);
}
 

import java.lang.reflect.TypeVariable; //導入方法依賴的package包/類
@SuppressWarnings({"unchecked", "rawtypes"})
public <T> T deserialize(Object object, Type type) {

    JSONArray jsonArray;
    if (object instanceof JSONArray) {
        jsonArray = (JSONArray) object;
    } else {
        jsonArray = new JSONArray(object);
    }

    Class componentClass = null;
    Type componentType = null;
    if (type instanceof GenericArrayType) {
        componentType = ((GenericArrayType) type).getGenericComponentType();
        if (componentType instanceof TypeVariable) {
            TypeVariable<?> componentVar = (TypeVariable<?>) componentType;
            componentType = componentVar.getBounds()[0];
        }
        if (componentType instanceof Class<?>) {
            componentClass = (Class<?>) componentType;
        }
    } else {
        Class clazz = (Class) type;
        componentType = componentClass = clazz.getComponentType();
    }

    int size = jsonArray.size();
    Object array = Array.newInstance(componentClass, size);

    for (int i = 0; i < size; i++) {
        Object value = jsonArray.get(i);

        Deserializer deserializer = JSONParser.getDeserializer(componentClass);
        Array.set(array, i, deserializer.deserialize(value, componentType));
    }

    return (T) array;
}
 

import java.lang.reflect.TypeVariable; //導入方法依賴的package包/類
/**
 * Resolves {@code var} using the encapsulated type mapping. If it maps to yet another
 * non-reified type or has bounds, {@code forDependants} is used to do further resolution, which
 * doesn't try to resolve any type variable on generic declarations that are already being
 * resolved.
 *
 * <p>Should only be called and overridden by {@link #resolve(TypeVariable)}.
 */
Type resolveInternal(TypeVariable<?> var, TypeTable forDependants) {
  Type type = map.get(new TypeVariableKey(var));
  if (type == null) {
    Type[] bounds = var.getBounds();
    if (bounds.length == 0) {
      return var;
    }
    Type[] resolvedBounds = new TypeResolver(forDependants).resolveTypes(bounds);
    /*
     * We'd like to simply create our own TypeVariable with the newly resolved bounds. There's
     * just one problem: Starting with JDK 7u51, the JDK TypeVariable's equals() method doesn't
     * recognize instances of our TypeVariable implementation. This is a problem because users
     * compare TypeVariables from the JDK against TypeVariables returned by TypeResolver. To
     * work with all JDK versions, TypeResolver must return the appropriate TypeVariable
     * implementation in each of the three possible cases:
     *
     * 1. Prior to JDK 7u51, the JDK TypeVariable implementation interoperates with ours.
     * Therefore, we can always create our own TypeVariable.
     *
     * 2. Starting with JDK 7u51, the JDK TypeVariable implementations does not interoperate
     * with ours. Therefore, we have to be careful about whether we create our own TypeVariable:
     *
     * 2a. If the resolved types are identical to the original types, then we can return the
     * original, identical JDK TypeVariable. By doing so, we sidestep the problem entirely.
     *
     * 2b. If the resolved types are different from the original types, things are trickier. The
     * only way to get a TypeVariable instance for the resolved types is to create our own. The
     * created TypeVariable will not interoperate with any JDK TypeVariable. But this is OK: We
     * don't _want_ our new TypeVariable to be equal to the JDK TypeVariable because it has
     * _different bounds_ than the JDK TypeVariable. And it wouldn't make sense for our new
     * TypeVariable to be equal to any _other_ JDK TypeVariable, either, because any other JDK
     * TypeVariable must have a different declaration or name. The only TypeVariable that our
     * new TypeVariable _will_ be equal to is an equivalent TypeVariable that was also created
     * by us. And that equality is guaranteed to hold because it doesn't involve the JDK
     * TypeVariable implementation at all.
     */
    if (Types.NativeTypeVariableEquals.NATIVE_TYPE_VARIABLE_ONLY
        && Arrays.equals(bounds, resolvedBounds)) {
      return var;
    }
    return Types.newArtificialTypeVariable(
        var.getGenericDeclaration(), var.getName(), resolvedBounds);
  }
  // in case the type is yet another type variable.
  return new TypeResolver(forDependants).resolveType(type);
}
 

import java.lang.reflect.TypeVariable; //導入方法依賴的package包/類
private static ReifiedType getReifiedType(Type targetType, Collection<Type> variableTypes) {
	if (targetType instanceof Class) {
		if (Object.class.equals(targetType)) {
			return OBJECT;
		}
		return new GenericsReifiedType((Class<?>) targetType);
	}
	if (targetType instanceof ParameterizedType) {
		Type ata = ((ParameterizedType) targetType).getActualTypeArguments()[0];
		return getReifiedType(ata, variableTypes);
	}
	if (targetType instanceof WildcardType) {
		WildcardType wt = (WildcardType) targetType;
		Type[] lowerBounds = wt.getLowerBounds();
		if (ObjectUtils.isEmpty(lowerBounds)) {
			// there's always an upper bound (Object)
			Type upperBound = wt.getUpperBounds()[0];
			return getReifiedType(upperBound, variableTypes);
		}

		return getReifiedType(lowerBounds[0], variableTypes);
	}

	if (targetType instanceof TypeVariable) {
		TypeVariable<?> typeVariable = (TypeVariable<?>) targetType;
		if (variableTypes.contains(targetType)) {
			//Looped around on itself via a recursive Generics definition
			return OBJECT;
		}
		variableTypes.add(targetType);
		Type[] bounds = typeVariable.getBounds();
		
		return getReifiedType(bounds[0], variableTypes);
	}

	if (targetType instanceof GenericArrayType) {
		return getReifiedType(((GenericArrayType) targetType).getGenericComponentType(), variableTypes);
	}

	throw new IllegalArgumentException("Unknown type " + targetType.getClass());
}