| /* |
| * 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.chukwa.datacollection.agent; |
| |
| |
| import org.apache.hadoop.chukwa.datacollection.adaptor.Adaptor; |
| import org.apache.log4j.Logger; |
| |
| /** |
| * Produces new unconfigured adaptors, given the class name of the appender type. |
| * Will try the name both in the default package, and then with |
| * 'org.apache.hadoop.chukwa.datacollection.adaptor' prepended. |
| * |
| */ |
| public class AdaptorFactory { |
| public static final String PREPENDED_PACKAGE = "org.apache.hadoop.chukwa.datacollection.adaptor."; |
| static Logger log = Logger.getLogger(ChukwaAgent.class); |
| |
| /** |
| * Instantiate an adaptor that can be added by the {@link ChukwaAgent} |
| * |
| * @param className the name of the {@link Adaptor} class to instantiate |
| * @return an Adaptor of the specified type |
| */ |
| static public Adaptor createAdaptor(String className) { |
| Object obj = null; |
| try { |
| // the following reflection business for type checking is probably |
| // unnecessary |
| // since it will just throw a ClassCastException on error anyway. |
| obj = Class.forName(className).newInstance(); |
| if (Adaptor.class.isInstance(obj)) { |
| return (Adaptor) obj; |
| } else |
| return null; |
| } catch (Exception e1) { |
| log.debug("Error instantiating new adaptor by class name, " |
| + "attempting again, but with default chukwa package prepended, i.e. " |
| + PREPENDED_PACKAGE + className |
| + ". " + e1); |
| try { |
| // if failed, try adding default class prefix |
| Object obj2 = Class.forName( |
| PREPENDED_PACKAGE + className) |
| .newInstance(); |
| if (Adaptor.class.isInstance(obj2)) { |
| log.debug("Succeeded in finding class by adding default adaptor " |
| + "namespace prefix to class name profided"); |
| return (Adaptor) obj2; |
| } else |
| return null; |
| } catch (Exception e2) { |
| log.warn("Error instantiating new adaptor "+ className + " by classname" |
| + " and also with \"o.a.h.c.datacollection.adaptor\" prefix added", e2); |
| return null; |
| } |
| } |
| } |
| |
| } |