| /* |
| * 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.statefun.flink.core.state; |
| |
| import java.lang.annotation.Annotation; |
| import java.lang.reflect.Field; |
| import java.lang.reflect.Modifier; |
| import java.util.ArrayList; |
| import java.util.Arrays; |
| import java.util.List; |
| import java.util.stream.Stream; |
| import javax.annotation.Nonnull; |
| import javax.annotation.Nullable; |
| import org.apache.flink.statefun.sdk.annotations.Persisted; |
| import org.apache.flink.statefun.sdk.state.ApiExtension; |
| import org.apache.flink.statefun.sdk.state.PersistedAppendingBuffer; |
| import org.apache.flink.statefun.sdk.state.PersistedStateRegistry; |
| import org.apache.flink.statefun.sdk.state.PersistedTable; |
| import org.apache.flink.statefun.sdk.state.PersistedValue; |
| |
| public final class PersistedStates { |
| |
| public static void findAndBind(@Nullable Object instance, FlinkStateBinder stateBinder) { |
| List<?> states = findReflectively(instance); |
| for (Object persisted : states) { |
| if (persisted instanceof PersistedStateRegistry) { |
| PersistedStateRegistry stateRegistry = (PersistedStateRegistry) persisted; |
| ApiExtension.bindPersistedStateRegistry(stateRegistry, stateBinder); |
| } else { |
| stateBinder.bind(persisted); |
| } |
| } |
| } |
| |
| private static List<?> findReflectively(@Nullable Object instance) { |
| PersistedStates visitor = new PersistedStates(); |
| visitor.visit(instance); |
| return visitor.getPersistedStates(); |
| } |
| |
| private final List<Object> persistedStates = new ArrayList<>(); |
| |
| private void visit(@Nullable Object instance) { |
| if (instance == null) { |
| return; |
| } |
| for (Field field : findAnnotatedFields(instance.getClass(), Persisted.class)) { |
| visitField(instance, field); |
| } |
| } |
| |
| private List<Object> getPersistedStates() { |
| return persistedStates; |
| } |
| |
| private void visitField(@Nonnull Object instance, @Nonnull Field field) { |
| if (Modifier.isStatic(field.getModifiers())) { |
| throw new IllegalArgumentException( |
| "Static persisted states are not legal in: " |
| + field.getType() |
| + " on " |
| + instance.getClass().getName()); |
| } |
| Object persistedState = getPersistedStateReflectively(instance, field); |
| if (persistedState == null) { |
| throw new IllegalStateException( |
| "The field " + field + " of a " + instance.getClass().getName() + " was not initialized"); |
| } |
| Class<?> fieldType = field.getType(); |
| if (isPersistedState(fieldType)) { |
| persistedStates.add(persistedState); |
| } else { |
| List<?> innerFields = findReflectively(persistedState); |
| persistedStates.addAll(innerFields); |
| } |
| } |
| |
| private static boolean isPersistedState(Class<?> fieldType) { |
| return fieldType == PersistedValue.class |
| || fieldType == PersistedTable.class |
| || fieldType == PersistedAppendingBuffer.class |
| || fieldType == PersistedStateRegistry.class; |
| } |
| |
| private static Object getPersistedStateReflectively(Object instance, Field persistedField) { |
| try { |
| persistedField.setAccessible(true); |
| return persistedField.get(instance); |
| } catch (IllegalAccessException e) { |
| throw new RuntimeException( |
| "Unable access field " + persistedField.getName() + " of " + instance.getClass()); |
| } |
| } |
| |
| public static Iterable<Field> findAnnotatedFields( |
| Class<?> javaClass, Class<? extends Annotation> annotation) { |
| Stream<Field> fields = |
| definedFields(javaClass).filter(field -> field.getAnnotation(annotation) != null); |
| |
| return fields::iterator; |
| } |
| |
| private static Stream<Field> definedFields(Class<?> javaClass) { |
| if (javaClass == null || javaClass == Object.class) { |
| return Stream.empty(); |
| } |
| Stream<Field> selfMethods = Arrays.stream(javaClass.getDeclaredFields()); |
| Stream<Field> superMethods = definedFields(javaClass.getSuperclass()); |
| return Stream.concat(selfMethods, superMethods); |
| } |
| } |