1   /*
    2    * Copyright (c) 2002-2006 by OpenSymphony
    3    * All rights reserved.
    4    */
    5   package com.opensymphony.xwork2.interceptor;
    6   
    7   import com.opensymphony.xwork2.ActionContext;
    8   import com.opensymphony.xwork2.ActionInvocation;
    9   import com.opensymphony.xwork2.ObjectFactory;
   10   import com.opensymphony.xwork2.XWorkException;
   11   import com.opensymphony.xwork2.config.entities.ActionConfig;
   12   import com.opensymphony.xwork2.inject.Inject;
   13   
   14   import java.lang.reflect.Method;
   15   import java.util.Map;
   16   
   17   /**
   18    * <!-- START SNIPPET: description -->
   19    *
   20    * An interceptor that enables scoped model-driven actions.
   21    *
   22    * <p/>This interceptor only activates on actions that implement the {@link ScopedModelDriven} interface.  If
   23    * detected, it will retrieve the model class from the configured scope, then provide it to the Action.
   24    *  
   25    * <!-- END SNIPPET: description -->
   26    *
   27    * <p/> <u>Interceptor parameters:</u>
   28    *
   29    * <!-- START SNIPPET: parameters -->
   30    *
   31    * <ul>
   32    *
   33    * <li>className - The model class name.  Defaults to the class name of the object returned by the getModel() method.</li>
   34    *            
   35    * <li>name - The key to use when storing or retrieving the instance in a scope.  Defaults to the model
   36    *            class name.</li>
   37    *
   38    * <li>scope - The scope to store and retrieve the model.  Defaults to 'request' but can also be 'session'.</li>
   39    * </ul>
   40    *
   41    * <!-- END SNIPPET: parameters -->
   42    *
   43    * <p/> <u>Extending the interceptor:</u>
   44    *
   45    * <p/>
   46    *
   47    * <!-- START SNIPPET: extending -->
   48    *
   49    * There are no known extension points for this interceptor.
   50    *
   51    * <!-- END SNIPPET: extending -->
   52    *
   53    * <p/> <u>Example code:</u>
   54    *
   55    * <pre>
   56    * <!-- START SNIPPET: example -->
   57    * 
   58    * &lt;-- Basic usage --&gt;
   59    * &lt;interceptor name="scopedModelDriven" class="com.opensymphony.interceptor.ScopedModelDrivenInterceptor" /&gt;
   60    * 
   61    * &lt;-- Using all available parameters --&gt;
   62    * &lt;interceptor name="gangsterForm" class="com.opensymphony.interceptor.ScopedModelDrivenInterceptor"&gt;
   63    *      &lt;param name="scope"&gt;session&lt;/param&gt;
   64    *      &lt;param name="name"&gt;gangsterForm&lt;/param&gt;
   65    *      &lt;param name="className"&gt;com.opensymphony.example.GangsterForm&lt;/param&gt;
   66    *  &lt;/interceptor&gt;
   67    * 
   68    * <!-- END SNIPPET: example -->
   69    * </pre>
   70    */
   71   public class ScopedModelDrivenInterceptor extends AbstractInterceptor {
   72   
   73       private static final String GET_MODEL = "getModel";
   74       private String scope;
   75       private String name;
   76       private String className;
   77       private ObjectFactory objectFactory;
   78       
   79       @Inject
   80       public void setObjectFactory(ObjectFactory factory) {
   81           this.objectFactory = factory;
   82       }
   83       
   84       protected Object resolveModel(ObjectFactory factory, ActionContext actionContext, String modelClassName, String modelScope, String modelName) throws Exception {
   85           Object model = null;
   86           Map<String, Object> scopeMap = actionContext.getContextMap();
   87           if ("session".equals(modelScope)) {
   88               scopeMap = actionContext.getSession();
   89           }
   90           
   91           model = scopeMap.get(modelName);
   92           if (model == null) {
   93               model = factory.buildBean(modelClassName, null);
   94               scopeMap.put(modelName, model);
   95           }
   96           return model;
   97       }
   98   
   99       @Override
  100       public String intercept(ActionInvocation invocation) throws Exception {
  101           Object action = invocation.getAction();
  102   
  103           if (action instanceof ScopedModelDriven) {
  104               ScopedModelDriven modelDriven = (ScopedModelDriven) action;
  105               if (modelDriven.getModel() == null) {
  106                   ActionContext ctx = ActionContext.getContext();
  107                   ActionConfig config = invocation.getProxy().getConfig();
  108                   
  109                   String cName = className;
  110                   if (cName == null) {
  111                       try {
  112                           Method method = action.getClass().getMethod(GET_MODEL, new Class[0]);
  113                           Class cls = method.getReturnType();
  114                           cName = cls.getName();
  115                       } catch (NoSuchMethodException e) {
  116                           throw new XWorkException("The " + GET_MODEL + "() is not defined in action " + action.getClass() + "", config);
  117                       }
  118                   }
  119                   String modelName = name;
  120                   if (modelName == null) {
  121                       modelName = cName;
  122                   }
  123                   Object model = resolveModel(objectFactory, ctx, cName, scope, modelName);
  124                   modelDriven.setModel(model);
  125                   modelDriven.setScopeKey(modelName);
  126               }
  127           }
  128           return invocation.invoke();
  129       }
  130   
  131       /**
  132        * @param className the className to set
  133        */
  134       public void setClassName(String className) {
  135           this.className = className;
  136       }
  137   
  138       /**
  139        * @param name the name to set
  140        */
  141       public void setName(String name) {
  142           this.name = name;
  143       }
  144   
  145       /**
  146        * @param scope the scope to set
  147        */
  148       public void setScope(String scope) {
  149           this.scope = scope;
  150       }    
  151   }