| /* |
| * 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.safeguard.impl.fallback; |
| |
| import java.io.Serializable; |
| import java.lang.reflect.InvocationTargetException; |
| import java.lang.reflect.Method; |
| import java.lang.reflect.ParameterizedType; |
| import java.util.ArrayList; |
| import java.util.Arrays; |
| import java.util.Collection; |
| import java.util.Map; |
| import java.util.Set; |
| import java.util.concurrent.ConcurrentHashMap; |
| import java.util.stream.Stream; |
| |
| import javax.annotation.PreDestroy; |
| import javax.annotation.Priority; |
| import javax.enterprise.context.ApplicationScoped; |
| import javax.enterprise.context.spi.CreationalContext; |
| import javax.enterprise.inject.spi.Bean; |
| import javax.enterprise.inject.spi.BeanManager; |
| import javax.inject.Inject; |
| import javax.interceptor.AroundInvoke; |
| import javax.interceptor.Interceptor; |
| import javax.interceptor.InvocationContext; |
| |
| import org.apache.safeguard.impl.annotation.AnnotationFinder; |
| import org.apache.safeguard.impl.cdi.SafeguardExtension; |
| import org.apache.safeguard.impl.config.ConfigurationMapper; |
| import org.apache.safeguard.impl.metrics.FaultToleranceMetrics; |
| import org.eclipse.microprofile.faulttolerance.ExecutionContext; |
| import org.eclipse.microprofile.faulttolerance.Fallback; |
| import org.eclipse.microprofile.faulttolerance.FallbackHandler; |
| import org.eclipse.microprofile.faulttolerance.exceptions.FaultToleranceDefinitionException; |
| |
| // @Fallback - added through the extension since the @Target doesnt allow it |
| @Interceptor |
| @Priority(Interceptor.Priority.PLATFORM_AFTER) |
| public class FallbackInterceptor implements Serializable { |
| @Inject |
| private Cache cache; |
| |
| @AroundInvoke |
| public Object withFallback(final InvocationContext context) { |
| final Map<Method, FallbackHandler<?>> handlers = cache.getHandlers(); |
| FallbackHandler<?> handler = handlers.get(context.getMethod()); |
| if (handler == null) { |
| handler = cache.create(context); |
| handlers.putIfAbsent(context.getMethod(), handler); |
| } |
| try { |
| return context.proceed(); |
| } catch (final Throwable e) { |
| return handler.handle(new EnrichedExecutionContext() { |
| @Override |
| public Object getTarget() { |
| return context.getTarget(); |
| } |
| |
| @Override |
| public Method getMethod() { |
| return context.getMethod(); |
| } |
| |
| @Override |
| public Object[] getParameters() { |
| return context.getParameters(); |
| } |
| |
| @Override |
| public Throwable getFailure() { |
| return e; |
| } |
| }); |
| } |
| } |
| |
| @ApplicationScoped |
| public static class Cache { |
| private final Map<Method, FallbackHandler<?>> handlers = new ConcurrentHashMap<>(); |
| |
| @Inject |
| private AnnotationFinder finder; |
| |
| @Inject |
| private SafeguardExtension extension; |
| |
| @Inject |
| private BeanManager beanManager; |
| |
| @Inject |
| private FaultToleranceMetrics metrics; |
| |
| @Inject |
| private ConfigurationMapper mapper; |
| |
| private final Collection<CreationalContext<?>> contexts = new ArrayList<>(); |
| |
| @PreDestroy |
| private void release() { |
| contexts.forEach(CreationalContext::release); |
| } |
| |
| public Map<Method, FallbackHandler<?>> getHandlers() { |
| return handlers; |
| } |
| |
| public FallbackHandler<?> create(final InvocationContext context) { |
| final Fallback fallback = mapper.map(finder.findAnnotation(Fallback.class, context), context.getMethod(), Fallback.class); |
| final Class<? extends FallbackHandler<?>> value = fallback.value(); |
| final String method = fallback.fallbackMethod(); |
| if (!method.isEmpty() && value != Fallback.DEFAULT.class) { |
| throw new FaultToleranceDefinitionException("You can't set a method and handler as fallback on " + context.getMethod()); |
| } |
| |
| FallbackHandler<?> handler; |
| if (value != Fallback.DEFAULT.class) { |
| Stream.of(value.getGenericInterfaces()) |
| .filter(ParameterizedType.class::isInstance) |
| .map(ParameterizedType.class::cast) |
| .filter(it -> FallbackHandler.class == it.getRawType()) |
| .findFirst() |
| .filter(it -> it.getActualTypeArguments().length == 1) |
| .map(it -> extension.toClass(context.getMethod().getReturnType()).isAssignableFrom(extension.toClass(it.getActualTypeArguments()[0]))) |
| .orElseThrow(() -> new FaultToleranceDefinitionException("handler does not match method: " + context.getMethod())); |
| final Set<Bean<?>> beans = beanManager.getBeans(value); |
| final Bean<?> handlerBean = beanManager.resolve(beans); |
| final CreationalContext<Object> creationalContext = beanManager.createCreationalContext(null); |
| if (!beanManager.isNormalScope(handlerBean.getScope())) { |
| contexts.add(creationalContext); |
| } |
| final FallbackHandler fallbackHandler = FallbackHandler.class.cast( |
| beanManager.getReference(handlerBean, FallbackHandler.class, creationalContext)); |
| handler = fallbackHandler; |
| } else { |
| try { |
| final Method fallbackMethod = context.getTarget() |
| .getClass() |
| .getMethod(method, context.getMethod().getParameterTypes()); |
| if (!extension.toClass(context.getMethod() |
| .getReturnType()) |
| .isAssignableFrom(extension.toClass(fallbackMethod.getReturnType())) || !Arrays.equals( |
| context.getMethod() |
| .getParameterTypes(), fallbackMethod.getParameterTypes())) { |
| throw new FaultToleranceDefinitionException("handler method does not match method: " + context.getMethod()); |
| } |
| if (!fallbackMethod.isAccessible()) { |
| fallbackMethod.setAccessible(true); |
| } |
| handler = (FallbackHandler<Object>) context1 -> { |
| try { |
| return fallbackMethod.invoke(EnrichedExecutionContext.class.cast(context1) |
| .getTarget(), |
| context1.getParameters()); |
| } catch (final IllegalAccessException e) { |
| throw new IllegalStateException(e); |
| } catch (final InvocationTargetException e) { |
| throw new IllegalStateException(e.getTargetException()); |
| } |
| }; |
| } catch (final NoSuchMethodException e) { |
| throw new FaultToleranceDefinitionException("No method " + method + " in " + context.getTarget()); |
| } |
| } |
| |
| final String metricsName = "ft." + context.getMethod().getDeclaringClass().getCanonicalName() + "." |
| + context.getMethod().getName() + ".fallback.calls.total"; |
| final FaultToleranceMetrics.Counter counter = metrics.counter(metricsName, |
| "Number of times the fallback handler or method was called"); |
| return (FallbackHandler<Object>) context12 -> { |
| counter.inc(); |
| return handler.handle(context12); |
| }; |
| } |
| } |
| |
| private interface EnrichedExecutionContext extends ExecutionContext { |
| Object getTarget(); |
| } |
| } |