Java tutorial
/** * Copyright 2015 Netflix, Inc. * * 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. */ package com.netflix.hystrix.contrib.javanica.cache; import com.netflix.hystrix.contrib.javanica.cache.annotation.CacheRemove; import com.netflix.hystrix.contrib.javanica.cache.annotation.CacheResult; import com.netflix.hystrix.contrib.javanica.command.MetaHolder; import com.netflix.hystrix.contrib.javanica.command.MethodExecutionAction; import com.netflix.hystrix.contrib.javanica.exception.HystrixCachingException; import org.apache.commons.lang3.StringUtils; import java.lang.reflect.Method; import static com.netflix.hystrix.contrib.javanica.utils.AopUtils.getDeclaredMethod; /** * Factory to create certain {@link CacheInvocationContext}. * * @author dmgcodevil */ public class CacheInvocationContextFactory { /** * Create {@link CacheInvocationContext} parametrized with {@link CacheResult} annotation. * * @param metaHolder the meta holder, see {@link com.netflix.hystrix.contrib.javanica.command.MetaHolder} * @return initialized and configured {@link CacheInvocationContext} */ public static CacheInvocationContext<CacheResult> createCacheResultInvocationContext(MetaHolder metaHolder) { Method method = metaHolder.getMethod(); if (method.isAnnotationPresent(CacheResult.class)) { CacheResult cacheResult = method.getAnnotation(CacheResult.class); MethodExecutionAction cacheKeyMethod = createCacheKeyAction(cacheResult.cacheKeyMethod(), metaHolder); return new CacheInvocationContext<CacheResult>(cacheResult, cacheKeyMethod, metaHolder.getObj(), method, metaHolder.getArgs()); } return null; } /** * Create {@link CacheInvocationContext} parametrized with {@link CacheRemove} annotation. * * @param metaHolder the meta holder, see {@link com.netflix.hystrix.contrib.javanica.command.MetaHolder} * @return initialized and configured {@link CacheInvocationContext} */ public static CacheInvocationContext<CacheRemove> createCacheRemoveInvocationContext(MetaHolder metaHolder) { Method method = metaHolder.getMethod(); if (method.isAnnotationPresent(CacheRemove.class)) { CacheRemove cacheRemove = method.getAnnotation(CacheRemove.class); MethodExecutionAction cacheKeyMethod = createCacheKeyAction(cacheRemove.cacheKeyMethod(), metaHolder); return new CacheInvocationContext<CacheRemove>(cacheRemove, cacheKeyMethod, metaHolder.getObj(), method, metaHolder.getArgs()); } return null; } private static MethodExecutionAction createCacheKeyAction(String method, MetaHolder metaHolder) { MethodExecutionAction cacheKeyAction = null; if (StringUtils.isNotBlank(method)) { Method cacheKeyMethod = getDeclaredMethod(metaHolder.getObj().getClass(), method, metaHolder.getMethod().getParameterTypes()); if (cacheKeyMethod == null) { throw new HystrixCachingException("method with name '" + method + "' doesn't exist in class '" + metaHolder.getObj().getClass() + "'"); } if (!cacheKeyMethod.getReturnType().equals(String.class)) { throw new HystrixCachingException("return type of cacheKey method must be String. Method: '" + method + "', Class: '" + metaHolder.getObj().getClass() + "'"); } MetaHolder cMetaHolder = MetaHolder.builder().obj(metaHolder.getObj()).method(cacheKeyMethod) .args(metaHolder.getArgs()).build(); cacheKeyAction = new MethodExecutionAction(cMetaHolder.getObj(), cacheKeyMethod, cMetaHolder.getArgs(), cMetaHolder); } return cacheKeyAction; } }