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    1   /*
    2    * $Id: AbstractSelectModule.java 471754 2006-11-06 14:55:09Z husted $
    3    *
    4    * Licensed to the Apache Software Foundation (ASF) under one
    5    * or more contributor license agreements.  See the NOTICE file
    6    * distributed with this work for additional information
    7    * regarding copyright ownership.  The ASF licenses this file
    8    * to you under the Apache License, Version 2.0 (the
    9    * "License"); you may not use this file except in compliance
    10   * with the License.  You may obtain a copy of the License at
    11   *
    12   *  http://www.apache.org/licenses/LICENSE-2.0
    13   *
    14   * Unless required by applicable law or agreed to in writing,
    15   * software distributed under the License is distributed on an
    16   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    17   * KIND, either express or implied.  See the License for the
    18   * specific language governing permissions and limitations
    19   * under the License.
    20   */
    21  package org.apache.struts.chain.commands;
    22
    23  import org.apache.struts.Globals;
    24  import org.apache.struts.chain.contexts.ActionContext;
    25  import org.apache.struts.config.ModuleConfig;
    26  import org.apache.struts.util.MessageResources;
    27
    28  /**
    29   * <p>Cache the <code>ModuleConfig</code> and <code>MessageResources</code>
    30   * instances for the sub-application module to be used for processing this
    31   * request.</p>
    32   *
    33   * @version $Rev: 471754 $ $Date: 2005-11-12 13:01:44 -0500 (Sat, 12 Nov 2005)
    34   *          $
    35   */
    36  public abstract class AbstractSelectModule extends ActionCommandBase {
    37      // ------------------------------------------------------ Instance Variables
    38      // ---------------------------------------------------------- Public Methods
    39
    40      /**
    41       * <p>Cache the <code>ModuleConfig</code> and <code>MessageResources</code>
    42       * instances for the sub-application module to be used for processing this
    43       * request.</p>
    44       *
    45       * @param actionCtx The <code>Context</code> for the current request
    46       * @return <code>false</code> so that processing continues
    47       * @throws IllegalArgumentException if no valid ModuleConfig or
    48       *                                  MessageResources can be identified for
    49       *                                  this request
    50       * @throws Exception                if thrown by the Action class
    51       */
    52      public boolean execute(ActionContext actionCtx)
    53          throws Exception {
    54          String prefix = getPrefix(actionCtx);
    55
    56          // Cache the corresponding ModuleConfig and MessageResources instances
    57          ModuleConfig moduleConfig =
    58              (ModuleConfig) actionCtx.getApplicationScope().get(Globals.MODULE_KEY
    59                  + prefix);
    60
    61          if (moduleConfig == null) {
    62              throw new IllegalArgumentException("No module config for prefix '"
    63                  + prefix + "'");
    64          }
    65
    66          actionCtx.setModuleConfig(moduleConfig);
    67
    68          String key = Globals.MESSAGES_KEY + prefix;
    69          MessageResources messageResources =
    70              (MessageResources) actionCtx.getApplicationScope().get(key);
    71
    72          if (messageResources == null) {
    73              throw new IllegalArgumentException(
    74                  "No message resources found in application scope under " + key);
    75          }
    76
    77          actionCtx.setMessageResources(messageResources);
    78
    79          return (false);
    80      }
    81
    82      // ------------------------------------------------------- Protected Methods
    83
    84      /**
    85       * <p>Calculate and return the module prefix for the module to be selected
    86       * for this request.</p>
    87       *
    88       * @param context The <code>Context</code> for this request
    89       * @return Module prefix to be used with this request
    90       * @throws IllegalArgumentException if no valid ModuleConfig or
    91       *                                  MessageResources can be identified for
    92       *                                  this request
    93       */
    94      protected abstract String getPrefix(ActionContext context);
    95  }