/*
* 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.apache.flink.util;
import org.apache.flink.annotation.Internal;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.Arrays;
import java.util.Collections;
import java.util.Iterator;
@Internal
public final class ReflectionUtil {
public static <T> T newInstance(Class<T> clazz) {
try {
return clazz.newInstance();
} catch (Exception e) {
throw new RuntimeException(e);
}
}
@SuppressWarnings("unchecked")
public static <T> Class<T> getTemplateType(Class<?> clazz, int num) {
return (Class<T>) getSuperTemplateTypes(clazz)[num];
}
@SuppressWarnings("unchecked")
public static <T> Class<T> getTemplateType(Class<?> clazz, Class<?> classWithParameter, int num) {
return (Class<T>) getSuperTemplateTypes(clazz)[num];
}
public static <T> Class<T> getTemplateType1(Class<?> clazz) {
return getTemplateType(clazz, 0);
}
public static <T> Class<T> getTemplateType1(Type type) {
if (type instanceof ParameterizedType) {
return (Class<T>) getTemplateTypes((ParameterizedType) type)[0];
} else {
throw new IllegalArgumentException();
}
}
public static <T> Class<T> getTemplateType2(Class<?> clazz) {
return getTemplateType(clazz, 1);
}
public static <T> Class<T> getTemplateType3(Class<?> clazz) {
return getTemplateType(clazz, 2);
}
public static <T> Class<T> getTemplateType4(Class<?> clazz) {
return getTemplateType(clazz, 3);
}
public static <T> Class<T> getTemplateType5(Class<?> clazz) {
return getTemplateType(clazz, 4);
}
public static <T> Class<T> getTemplateType6(Class<?> clazz) {
return getTemplateType(clazz, 5);
}
public static <T> Class<T> getTemplateType7(Class<?> clazz) {
return getTemplateType(clazz, 6);
}
public static <T> Class<T> getTemplateType8(Class<?> clazz) {
return getTemplateType(clazz, 7);
}
public static Class<?>[] getSuperTemplateTypes(Class<?> clazz) {
Type type = clazz.getGenericSuperclass();
while (true) {
if (type instanceof ParameterizedType) {
return getTemplateTypes((ParameterizedType) type);
}
if (clazz.getGenericSuperclass() == null) {
throw new IllegalArgumentException();
}
type = clazz.getGenericSuperclass();
clazz = clazz.getSuperclass();
}
}
public static Class<?>[] getSuperTemplateTypes(Class<?> clazz, Class<?> searchedSuperClass) {
if (clazz == null || searchedSuperClass == null) {
throw new NullPointerException();
}
Class<?> superClass = null;
do {
superClass = clazz.getSuperclass();
if (superClass == searchedSuperClass) {
break;
}
}
while ((clazz = superClass) != null);
if (clazz == null) {
throw new IllegalArgumentException("The searched for superclass is not a superclass of the given class.");
}
final Type type = clazz.getGenericSuperclass();
if (type instanceof ParameterizedType) {
return getTemplateTypes((ParameterizedType) type);
}
else {
throw new IllegalArgumentException("The searched for superclass is not a generic class.");
}
}
public static Class<?>[] getTemplateTypes(ParameterizedType paramterizedType) {
Class<?>[] types = new Class<?>[paramterizedType.getActualTypeArguments().length];
int i = 0;
for (Type templateArgument : paramterizedType.getActualTypeArguments()) {
assert templateArgument instanceof Class<?>;
types[i++] = (Class<?>) templateArgument;
}
return types;
}
public static Class<?>[] getTemplateTypes(Class<?> clazz) {
Type type = clazz.getGenericSuperclass();
assert (type instanceof ParameterizedType);
ParameterizedType paramterizedType = (ParameterizedType) type;
Class<?>[] types = new Class<?>[paramterizedType.getActualTypeArguments().length];
int i = 0;
for (Type templateArgument : paramterizedType.getActualTypeArguments()) {
assert (templateArgument instanceof Class<?>);
types[i++] = (Class<?>) templateArgument;
}
return types;
}
/**
* Extract the full template type information from the given type's template parameter at the
* given position.
*
* @param type type to extract the full template parameter information from
* @param templatePosition describing at which position the template type parameter is
* @return Full type information describing the template parameter's type
*/
public static FullTypeInfo getFullTemplateType(Type type, int templatePosition) {
if (type instanceof ParameterizedType) {
return getFullTemplateType(((ParameterizedType) type).getActualTypeArguments()[templatePosition]);
} else {
throw new IllegalArgumentException();
}
}
/**
* Extract the full type information from the given type.
*
* @param type to be analyzed
* @return Full type information describing the given type
*/
public static FullTypeInfo getFullTemplateType(Type type) {
if (type instanceof ParameterizedType) {
ParameterizedType parameterizedType = (ParameterizedType) type;
FullTypeInfo[] templateTypeInfos = new FullTypeInfo[parameterizedType.getActualTypeArguments().length];
for (int i = 0; i < parameterizedType.getActualTypeArguments().length; i++) {
templateTypeInfos[i] = getFullTemplateType(parameterizedType.getActualTypeArguments()[i]);
}
return new FullTypeInfo((Class<?>)parameterizedType.getRawType(), templateTypeInfos);
} else {
return new FullTypeInfo((Class<?>) type, null);
}
}
/**
* Container for the full type information of a type. This means that it contains the
* {@link Class} object and for each template parameter it contains a full type information
* describing the type.
*/
public static class FullTypeInfo {
private final Class<?> clazz;
private final FullTypeInfo[] templateTypeInfos;
public FullTypeInfo(Class<?> clazz, FullTypeInfo[] templateTypeInfos) {
this.clazz = Preconditions.checkNotNull(clazz);
this.templateTypeInfos = templateTypeInfos;
}
public Class<?> getClazz() {
return clazz;
}
public FullTypeInfo[] getTemplateTypeInfos() {
return templateTypeInfos;
}
public Iterator<Class<?>> getClazzIterator() {
UnionIterator<Class<?>> unionIterator = new UnionIterator<>();
unionIterator.add(Collections.<Class<?>>singleton(clazz).iterator());
if (templateTypeInfos != null) {
for (int i = 0; i < templateTypeInfos.length; i++) {
unionIterator.add(templateTypeInfos[i].getClazzIterator());
}
}
return unionIterator;
}
@Override
public String toString() {
StringBuilder builder = new StringBuilder();
builder.append(clazz.getSimpleName());
if (templateTypeInfos != null) {
builder.append("<");
for (int i = 0; i < templateTypeInfos.length - 1; i++) {
builder.append(templateTypeInfos[i]).append(", ");
}
builder.append(templateTypeInfos[templateTypeInfos.length - 1]);
builder.append(">");
}
return builder.toString();
}
@Override
public boolean equals(Object obj) {
if (obj instanceof FullTypeInfo) {
FullTypeInfo other = (FullTypeInfo) obj;
return clazz == other.getClazz() && Arrays.equals(templateTypeInfos, other.getTemplateTypeInfos());
} else {
return false;
}
}
}
/**
* Private constructor to prevent instantiation.
*/
private ReflectionUtil() {
throw new RuntimeException();
}
}