001 /*
002 * Copyright (C) 2012 eXo Platform SAS.
003 *
004 * This is free software; you can redistribute it and/or modify it
005 * under the terms of the GNU Lesser General Public License as
006 * published by the Free Software Foundation; either version 2.1 of
007 * the License, or (at your option) any later version.
008 *
009 * This software is distributed in the hope that it will be useful,
010 * but WITHOUT ANY WARRANTY; without even the implied warranty of
011 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
012 * Lesser General Public License for more details.
013 *
014 * You should have received a copy of the GNU Lesser General Public
015 * License along with this software; if not, write to the Free
016 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
017 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
018 */
019 package org.crsh.shell.impl.command.spi;
020
021 import org.crsh.plugin.CRaSHPlugin;
022 import org.crsh.plugin.PluginContext;
023
024 import java.lang.reflect.Constructor;
025 import java.util.HashMap;
026 import java.util.Set;
027 import java.util.concurrent.atomic.AtomicReference;
028
029 /**
030 * A command manager that is able to load a command manager via reflection.
031 *
032 * @author Julien Viet
033 */
034 public class CommandManagerProxy extends CRaSHPlugin<CommandManager> implements CommandManager {
035
036 /** . */
037 private final AtomicReference<CommandManager> real = new AtomicReference<CommandManager>();
038
039 /** . */
040 private final String name;
041
042 /** . */
043 private final String className;
044
045 /** . */
046 private final Set<String> ext;
047
048 public CommandManagerProxy(String name, String className, Set<String> ext) {
049 this.name = name;
050 this.className = className;
051 this.ext = ext;
052 }
053
054 @Override
055 public CommandManager getImplementation() {
056 return this;
057 }
058
059 @Override
060 public void init() {
061 try {
062 Class<CommandManager> mgrClass = (Class<CommandManager>)CommandManagerProxy.class.getClassLoader().loadClass(className);
063 Constructor<CommandManager> mgrCtor = mgrClass.getConstructor(PluginContext.class);
064 CommandManager mgr = mgrCtor.newInstance(getContext());
065 real.set(mgr);
066 }
067 catch (Exception e) {
068 log.info("Plugin is inactive");
069 }
070 catch (NoClassDefFoundError e) {
071 log.info("Plugin is inactive");
072 }
073 }
074
075 @Override
076 public boolean isActive() {
077 return real.get() != null;
078 }
079
080 @Override
081 public Set<String> getExtensions() {
082 return ext;
083 }
084
085 @Override
086 public CommandResolution resolveCommand(String name, byte[] source) throws CommandCreationException, NullPointerException {
087 CommandManager mgr = real.get();
088 if (mgr != null) {
089 return mgr.resolveCommand(name, source);
090 } else {
091 throw new IllegalStateException(name + " command manager is not available");
092 }
093 }
094
095 @Override
096 public void init(HashMap<String, Object> session) {
097 CommandManager mgr = real.get();
098 if (mgr != null) {
099 mgr.init(session);
100 } else {
101 throw new IllegalStateException(name + " command manager is not available");
102 }
103 }
104
105 @Override
106 public void destroy(HashMap<String, Object> session) {
107 CommandManager mgr = real.get();
108 if (mgr != null) {
109 mgr.destroy(session);
110 } else {
111 throw new IllegalStateException(name + " command manager is not available");
112 }
113 }
114
115 @Override
116 public String doCallBack(HashMap<String, Object> session, String name, String defaultValue) {
117 CommandManager mgr = real.get();
118 if (mgr != null) {
119 return mgr.doCallBack(session, name, defaultValue);
120 } else {
121 throw new IllegalStateException(name + " command manager is not available");
122 }
123 }
124 }