Java tutorial
/** * * 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.hadoop.hbase.client; import java.lang.reflect.Constructor; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.hbase.HConstants; import org.apache.hadoop.hbase.classification.InterfaceAudience; /** * Factory implementation to provide the {@link ConnectionImplementation} with * the implementation of the {@link RetryingCallerInterceptor} that we would use * to intercept the {@link RpcRetryingCaller} during the course of their calls. * */ @InterfaceAudience.Private class RetryingCallerInterceptorFactory { private static final Log LOG = LogFactory.getLog(RetryingCallerInterceptorFactory.class); private Configuration conf; private final boolean failFast; public static final RetryingCallerInterceptor NO_OP_INTERCEPTOR = new NoOpRetryableCallerInterceptor(null); public RetryingCallerInterceptorFactory(Configuration conf) { this.conf = conf; failFast = conf.getBoolean(HConstants.HBASE_CLIENT_FAST_FAIL_MODE_ENABLED, HConstants.HBASE_CLIENT_ENABLE_FAST_FAIL_MODE_DEFAULT); } /** * This builds the implementation of {@link RetryingCallerInterceptor} that we * specify in the conf and returns the same. * * To use {@link PreemptiveFastFailInterceptor}, set HBASE_CLIENT_ENABLE_FAST_FAIL_MODE to true. * HBASE_CLIENT_FAST_FAIL_INTERCEPTOR_IMPL is defaulted to {@link PreemptiveFastFailInterceptor} * * @return The factory build method which creates the * {@link RetryingCallerInterceptor} object according to the * configuration. */ public RetryingCallerInterceptor build() { RetryingCallerInterceptor ret = NO_OP_INTERCEPTOR; if (failFast) { try { Class<?> c = conf.getClass(HConstants.HBASE_CLIENT_FAST_FAIL_INTERCEPTOR_IMPL, PreemptiveFastFailInterceptor.class); Constructor<?> constructor = c.getDeclaredConstructor(Configuration.class); constructor.setAccessible(true); ret = (RetryingCallerInterceptor) constructor.newInstance(conf); } catch (Exception e) { ret = new PreemptiveFastFailInterceptor(conf); } } LOG.trace("Using " + ret.toString() + " for intercepting the RpcRetryingCaller"); return ret; } }