Content of file ReflectionUtils.java

/*
 * *********************************************************************************************************************
 *
 * SteelBlue: DCI User Interfaces
 * http://tidalwave.it/projects/steelblue
 *
 * Copyright (C) 2015 - 2021 by Tidalwave s.a.s. (http://tidalwave.it)
 *
 * *********************************************************************************************************************
 *
 * Licensed 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.
 *
 * *********************************************************************************************************************
 *
 * git clone https://bitbucket.org/tidalwave/steelblue-src
 * git clone https://github.com/tidalwave-it/steelblue-src
 *
 * *********************************************************************************************************************
 */
package it.tidalwave.role.ui.javafx.impl.util;

import lombok.experimental.UtilityClass;
import lombok.extern.slf4j.Slf4j;
import javax.annotation.CheckForNull;
import javax.annotation.Nonnull;
import java.lang.reflect.Array;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.GenericArrayType;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.lang.reflect.TypeVariable;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.inject.Inject;
import static java.util.stream.Collectors.toList;
import static it.tidalwave.role.spi.impl.LogUtil.*;

/***********************************************************************************************************************
 *
 * Just slightly adapted from http://www.artima.com/weblogs/viewpost.jsp?thread=208860
 *
 * TODO: Consider incorporating this in TFT.
Consider incorporating this in TFT.
* * @author Fabrizio Giudici * @author based on code of Ian Robertson * **********************************************************************************************************************/ @Slf4j @UtilityClass public class ReflectionUtils { /******************************************************************************************************************* * * * ******************************************************************************************************************/ public static void injectDependencies (@Nonnull final Object object, @Nonnull final Map<Class<?>, Object> beans) { for (final Field field : object.getClass().getDeclaredFields()) { if (field.getAnnotation(Inject.class) != null) { field.setAccessible(true); final Class<?> type = field.getType(); final Object dependency = beans.get(type); if (dependency == null) { throw new RuntimeException("Can't inject " + object + "." + field.getName()); } try { field.set(object, dependency); } catch (IllegalArgumentException | IllegalAccessException e) { throw new RuntimeException(e); } } } } /******************************************************************************************************************* * * Instantiates an object of the given class performing dependency injections through the constructor. * * @param <T> the generic type of the object to instantiate * @param type the dynamic type of the object to instantiate; it is expected to have a single constructor * @param beans the pool of objects to instantiate * @return the new instance * @throws RuntimeException if something fails * ******************************************************************************************************************/ public static <T> T instantiateWithDependencies (@Nonnull final Class<T> type, @Nonnull final Map<Class<?>, Object> beans) { try { log.debug("instantiateWithDependencies({}, {})", shortName(type), shortIds(beans.values())); final Constructor<?>[] constructors = type.getConstructors(); if (constructors.length > 1) { throw new RuntimeException("Multiple constructors in " + type); } final List<Object> parameters = Arrays.stream(constructors[0].getParameterTypes()).map(beans::get).collect(toList()); log.trace(">>>> ctor arguments: {}", shortIds(parameters)); return type.cast(constructors[0].newInstance(parameters.toArray())); } catch (InstantiationException | IllegalAccessException | InvocationTargetException e) { throw new RuntimeException(e); } } /******************************************************************************************************************* * * Get the actual type arguments a child class has used to extend a generic base class. * * @param baseClass the base class * @param childClass the child class * @return a list of the raw classes for the actual type arguments. * ******************************************************************************************************************/ public static <T> List<Class<?>> getTypeArguments (@Nonnull final Class<T> baseClass, @Nonnull final Class<? extends T> childClass) { final Map<Type, Type> resolvedTypes = new HashMap<>(); Type type = childClass; // start walking up the inheritance hierarchy until we hit baseClass while (!getClass(type).equals(baseClass)) { if (type instanceof Class<?>) { // there is no useful information for us in raw types, so just keep going. type = ((Class<?>)type).getGenericSuperclass(); } else { final ParameterizedType parameterizedType = (ParameterizedType) type; final Class<?> rawType = (Class) parameterizedType.getRawType(); final Type[] actualTypeArguments = parameterizedType.getActualTypeArguments(); final TypeVariable<?>[] typeParameters = rawType.getTypeParameters(); for (int i = 0; i < actualTypeArguments.length; i++) { resolvedTypes.put(typeParameters[i], actualTypeArguments[i]); } if (!rawType.equals(baseClass)) { type = rawType.getGenericSuperclass(); } } } // finally, for each actual type argument provided to baseClass, determine (if possible) // the raw class for that type argument. final Type[] actualTypeArguments; if (type instanceof Class) { actualTypeArguments = ((Class)type).getTypeParameters(); } else { actualTypeArguments = ((ParameterizedType)type).getActualTypeArguments(); } final List<Class<?>> typeArgumentsAsClasses = new ArrayList<>(); // resolve types by chasing down type variables. for (Type baseType : actualTypeArguments) { while (resolvedTypes.containsKey(baseType)) { baseType = resolvedTypes.get(baseType); } typeArgumentsAsClasses.add(getClass(baseType)); } return typeArgumentsAsClasses; } /******************************************************************************************************************* * * * ******************************************************************************************************************/ @CheckForNull public static Class<?> getClass (@Nonnull final Type type) { if (type instanceof Class<?>) { return (Class<?>)type; } else if (type instanceof ParameterizedType) { return getClass(((ParameterizedType)type).getRawType()); } else if (type instanceof GenericArrayType) { final Type componentType = ((GenericArrayType)type).getGenericComponentType(); final Class<?> componentClass = getClass(componentType); if (componentClass == null) { return null; } return Array.newInstance(componentClass, 0).getClass(); } else { return null; } } }