| /** |
| * |
| * 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 javax.availability.management; |
| |
| /** |
| * @version $Rev$ $Date$ |
| */ |
| public class AvailabilityAgentFactory { |
| |
| private static final Object LOCK = new Object(); |
| private static AvailabilityAgent agent; |
| |
| public static synchronized AvailabilityAgent instantiateAvailabilityAgent() throws AvailabilityException { |
| |
| synchronized (LOCK) { |
| |
| if (agent != null) return agent; |
| |
| String agentClassName = System.getProperty("javax.availability.management.agent"); |
| |
| if (agentClassName == null) throw new AvailabilityException("javax.availability.management.agent has not been set"); |
| |
| try { |
| Class<?> agentClass = Class.forName(agentClassName); |
| agent = (AvailabilityAgent) agentClass.newInstance(); |
| } catch (ClassNotFoundException cnfe) { |
| throw new AvailabilityException("Unable to locate class " + agentClassName, cnfe); |
| } catch (InstantiationException ie) { |
| throw new AvailabilityException("Unable to instantiate class " + agentClassName, ie); |
| } catch (IllegalAccessException iae) { |
| throw new AvailabilityException("Unable to access class " + agentClassName, iae); |
| } catch (ClassCastException cce) { |
| throw new AvailabilityException("The class " + agentClassName + " does not implement AvailabilityAgent", cce); |
| } |
| |
| return agent; |
| } |
| } |
| } |