i18n/ImplementationLoader.java

   1 /*
   2  * Copyright (C) 2007-2012 Mathieu Baudier
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *         http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16 package org.argeo.demo.i18n;
  17
  18 import java.text.MessageFormat;
  19
  20 /**
  21  * This class enable single sourcing between RAP and RCP. For this to run
  22  * correctly, following conventions must be respected:
  23  * <ul>
  24  * <li>Given the fact that a common interface named Xxx is defined in package
  25  * aa.bb.cc, corresponding implementation named XxxImpl must be found in package
  26  * aa.bb.cc.specific of both RAP and RCP UI bundles.
  27  *
  28  * thanks to {@link http
  29  * ://eclipsesource.com/en/info/rcp-rap-single-sourcing-guideline/}, chapter 7
  30  */
  31
  32 public class ImplementationLoader {
  33         // private final static Log log = LogFactory
  34         // .getLog(ImplementationLoader.class);
  35
  36         public static Object newInstance(
  37                         @SuppressWarnings("rawtypes") final Class type) {
  38                 String name = type.getName();
  39                 // manually construct the implementation name for the given interface,
  40                 // assuming that convention have been respected.
  41                 String cName = type.getCanonicalName();
  42                 String pName = cName.substring(0, cName.lastIndexOf('.') + 1);
  43                 String sName = cName.substring(cName.lastIndexOf('.') + 1);
  44                 String implName = pName + "specific." + sName + "Impl";
  45                 // String implName = cName + "Impl";
  46                 Object result = null;
  47                 try {
  48                         result = type.getClassLoader().loadClass(implName).newInstance();
  49                 } catch (Throwable throwable) {
  50                         String txt = "Could not load implementation for {0}";
  51                         String msg = MessageFormat.format(txt, new Object[] { name });
  52                         throw new RuntimeException(msg, throwable);
  53                 }
  54                 return result;
  55         }
  56 }