/* 
    P/P   *  Method: org.apache.roller.weblogger.business.GuiceWebloggerProvider__static_init
          */
     1  /*
     2   * Licensed to the Apache Software Foundation (ASF) under one or more
     3   *  contributor license agreements.  The ASF licenses this file to You
     4   * under the Apache License, Version 2.0 (the "License"); you may not
     5   * 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.  For additional information regarding
    15   * copyright in this work, please see the NOTICE file in the top level
    16   * directory of this distribution.
    17   */
    18  
    19  package org.apache.roller.weblogger.business;
    20  
    21  import com.google.inject.Guice;
    22  import com.google.inject.Injector;
    23  import com.google.inject.Module;
    24  import org.apache.roller.weblogger.config.WebloggerConfig;
    25  
    26  
    27  /**
    28   * A Guice specific implementation of a WebloggerProvider.
    29   */
    30  public class GuiceWebloggerProvider implements WebloggerProvider {
    31      
    32      // Guice injector
    33      protected final Injector injector;
    34      
    35      // maintain our own singleton instance of Weblogger
    36      protected Weblogger webloggerInstance = null;
    37      
    38      
    39      /**
    40       * Instantiate a new GuiceWebloggerProvider using default guice module 
    41       * configured in WebloggerConfig via 'guice.backend.module' property.
    42       */
             /* 
    P/P       *  Method: void org.apache.roller.weblogger.business.GuiceWebloggerProvider()
              * 
              *  Preconditions:
              *    org/apache/roller/weblogger/config/WebloggerConfig.config != null
              *    org/apache/roller/weblogger/config/WebloggerConfig.log != null
              * 
              *  Presumptions:
              *    java.lang.Class:forName(...)@51 != null
              * 
              *  Postconditions:
              *    init'ed(this.injector)
              *    this.webloggerInstance == null
              */
    43      public GuiceWebloggerProvider() {
    44          
    45          String moduleClassname = WebloggerConfig.getProperty("guice.backend.module");
+   46          if(moduleClassname == null) {
    47              throw new NullPointerException("unable to lookup default guice module via property 'guice.backend.module'");
    48          }
    49          
    50          try {
    51              Class moduleClass = Class.forName(moduleClassname);
    52              Module module = (Module)moduleClass.newInstance();
    53              injector = Guice.createInjector(module);
    54          } catch (Throwable e) {                
    55              // Fatal misconfiguration, cannot recover
    56              throw new RuntimeException("Error instantiating backend module " + moduleClassname, e);
    57          }
    58      }
    59      
    60      
    61      /**
    62       * Instantiate a new GuiceWebloggerProvider using the given Guice module.
    63       *
    64       * @param moduleClassname The full classname of the Guice module to use.
    65       */
             /* 
    P/P       *  Method: void org.apache.roller.weblogger.business.GuiceWebloggerProvider(String)
              * 
              *  Preconditions:
              *    moduleClassname != null
              * 
              *  Presumptions:
              *    java.lang.Class:forName(...)@73 != null
              * 
              *  Postconditions:
              *    init'ed(this.injector)
              *    this.webloggerInstance == null
              */
    66      public GuiceWebloggerProvider(String moduleClassname) {
    67          
    68          if(moduleClassname == null) {
    69              throw new NullPointerException("moduleClassname cannot be null");
    70          }
    71          
    72          try {
    73              Class moduleClass = Class.forName(moduleClassname);
    74              Module module = (Module)moduleClass.newInstance();
    75              injector = Guice.createInjector(module);
    76          } catch (Throwable e) {                
    77              // Fatal misconfiguration, cannot recover
    78              throw new RuntimeException("Error instantiating backend module " + moduleClassname, e);
    79          }
    80      }
    81      
    82      
    83      /**
    84       * @inheritDoc
    85       */
    86      public void bootstrap() {
                 /* 
    P/P           *  Method: void bootstrap()
                  * 
                  *  Preconditions:
                  *    this.injector != null
                  * 
                  *  Postconditions:
                  *    init'ed(this.webloggerInstance)
                  */
    87          webloggerInstance =  injector.getInstance(Weblogger.class);
    88      }
    89      
    90      
    91      /**
    92       * @inheritDoc
    93       */
    94      public Weblogger getWeblogger() {
                 /* 
    P/P           *  Method: Weblogger getWeblogger()
                  * 
                  *  Preconditions:
                  *    init'ed(this.webloggerInstance)
                  * 
                  *  Postconditions:
                  *    return_value == this.webloggerInstance
                  *    init'ed(return_value)
                  */
    95          return webloggerInstance;
    96      }
    97      
    98  }