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    1   /***************************************************************************************
    2    * Copyright (c) Jonas BonŽr, Alexandre Vasseur. All rights reserved.                 *
    3    * http://aspectwerkz.codehaus.org                                                    *
    4    * ---------------------------------------------------------------------------------- *
    5    * The software in this package is published under the terms of the LGPL license      *
    6    * a copy of which has been included with this distribution in the license.txt file.  *
    7    **************************************************************************************/
    8   package org.codehaus.aspectwerkz.transform.inlining;
    9
    10  import java.util.StringTokenizer;
    11
    12  import org.codehaus.aspectwerkz.util.ContextClassLoader;
    13  import org.codehaus.aspectwerkz.util.ContextClassLoader;
    14  import org.codehaus.aspectwerkz.transform.inlining.spi.AspectModel;
    15  import org.codehaus.aspectwerkz.definition.AspectDefinition;
    16  import org.codehaus.aspectwerkz.reflect.ClassInfo;
    17  import org.codehaus.aspectwerkz.exception.DefinitionException;
    18
    19  /***
    20   * Manages the different aspect model implementations that is registered.
    21   *
    22   * @author <a href="mailto:jboner@codehaus.org">Jonas BonŽr </a>
    23   */
    24  public class AspectModelManager {
    25
    26      public static final String ASPECT_MODELS_VM_OPTION = "aspectwerkz.extension.aspectmodels";
    27      private static final String DELIMITER = ":";
    28
    29      /***
    30       * The aspects models that are registered
    31       */
    32      private static AspectModel[] ASPECT_MODELS = new AspectModel[]{};
    33
    34      static {
    35          registerAspectModels(System.getProperty(ASPECT_MODELS_VM_OPTION, null));
    36      }
    37
    38      /***
    39       * Returns an array with all the aspect models that has been registered.
    40       *
    41       * @return an array with the aspect models
    42       */
    43      public static AspectModel[] getModels() {
    44          return ASPECT_MODELS;
    45      }
    46
    47      /***
    48       * Returns the advice model for a specific aspect model type id.
    49       *
    50       * @param type the aspect model type id
    51       * @return the aspect model
    52       */
    53      public static AspectModel getModelFor(String type) {
    54          for (int i = 0; i < ASPECT_MODELS.length; i++) {
    55              AspectModel aspectModel = ASPECT_MODELS[i];
    56              if (aspectModel.getAspectModelType().equals(type)) {
    57                  return aspectModel;
    58              }
    59          }
    60          return null;
    61      }
    62
    63      /***
    64       * Let all aspect models try to define the aspect (only one will succeed).
    65       *
    66       * @param aspectClassInfo
    67       * @param aspectDef
    68       * @param loader
    69       */
    70      public static void defineAspect(final ClassInfo aspectClassInfo,
    71                                      final AspectDefinition aspectDef,
    72                                      final ClassLoader loader) {
    73          for (int i = 0; i < ASPECT_MODELS.length; i++) {
    74              ASPECT_MODELS[i].defineAspect(aspectClassInfo, aspectDef, loader);
    75          }
    76      }
    77
    78      /***
    79       * Registers aspect models.
    80       *
    81       * @param aspectModels the class names of the aspect models to register concatenated and separated with a ':'.
    82       */
    83      private static void registerAspectModels(final String aspectModels) {
    84          if (aspectModels != null) {
    85              StringTokenizer tokenizer = new StringTokenizer(aspectModels, DELIMITER);
    86              ASPECT_MODELS = new AspectModel[tokenizer.countTokens()];
    87              for (int i = 0; i < ASPECT_MODELS.length; i++) {
    88                  final String className = tokenizer.nextToken();
    89                  try {
    90                      final Class modelClass = ContextClassLoader.forName(className);
    91                      ASPECT_MODELS[i] = (AspectModel) modelClass.newInstance();
    92                  } catch (ClassNotFoundException e) {
    93                      throw new DefinitionException(
    94                              "aspect model implementation class not found [" +
    95                              className + "]: " + e.toString()
    96                      );
    97                  } catch (Exception e) {
    98                      throw new DefinitionException(
    99                              "aspect model implementation class could not be instantiated [" +
    100                             className +
    101                             "] - make sure it has a default no argument constructor: " +
    102                             e.toString()
    103                     );
    104                 }
    105             }
    106         }
    107     }
    108 }