1   /*
    2    * Copyright (c) 2002-2007 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.ValidationAware;
   10   import com.opensymphony.xwork2.conversion.impl.XWorkConverter;
   11   import com.opensymphony.xwork2.util.ValueStack;
   12   
   13   import java.util.HashMap;
   14   import java.util.Map;
   15   
   16   
   17   /**
   18    * <!-- START SNIPPET: description -->
   19    * ConversionErrorInterceptor adds conversion errors from the ActionContext to the Action's field errors.
   20    *
   21    * <p/>
   22    * This interceptor adds any error found in the {@link ActionContext}'s conversionErrors map as a field error (provided
   23    * that the action implements {@link ValidationAware}). In addition, any field that contains a validation error has its
   24    * original value saved such that any subsequent requests for that value return the original value rather than the value
   25    * in the action. This is important because if the value "abc" is submitted and can't be converted to an int, we want to
   26    * display the original string ("abc") again rather than the int value (likely 0, which would make very little sense to
   27    * the user).
   28    *
   29    *
   30    * <!-- END SNIPPET: description -->
   31    *
   32    * <p/> <u>Interceptor parameters:</u>
   33    *
   34    * <!-- START SNIPPET: parameters -->
   35    *
   36    * <ul>
   37    *
   38    * <li>None</li>
   39    *
   40    * </ul>
   41    *
   42    * <!-- END SNIPPET: parameters -->
   43    *
   44    * <p/> <u>Extending the interceptor:</u>
   45    *
   46    * <p/>
   47    *
   48    * <!-- START SNIPPET: extending -->
   49    *
   50    * Because this interceptor is not web-specific, it abstracts the logic for whether an error should be added. This
   51    * allows for web-specific interceptors to use more complex logic in the {@link #shouldAddError} method for when a value
   52    * has a conversion error but is null or empty or otherwise indicates that the value was never actually entered by the
   53    * user.
   54    *
   55    * <!-- END SNIPPET: extending -->
   56    *
   57    * <p/> <u>Example code:</u>
   58    *
   59    * <pre>
   60    * <!-- START SNIPPET: example -->
   61    * &lt;action name="someAction" class="com.examples.SomeAction"&gt;
   62    *     &lt;interceptor-ref name="params"/&gt;
   63    *     &lt;interceptor-ref name="conversionError"/&gt;
   64    *     &lt;result name="success"&gt;good_result.ftl&lt;/result&gt;
   65    * &lt;/action&gt;
   66    * <!-- END SNIPPET: example -->
   67    * </pre>
   68    *
   69    * @author Jason Carreira
   70    */
   71   public class ConversionErrorInterceptor extends AbstractInterceptor {
   72   
   73       public static final String ORIGINAL_PROPERTY_OVERRIDE = "original.property.override";
   74   
   75       protected Object getOverrideExpr(ActionInvocation invocation, Object value) {
   76           return "'" + value + "'";
   77       }
   78   
   79       @Override
   80       public String intercept(ActionInvocation invocation) throws Exception {
   81   
   82           ActionContext invocationContext = invocation.getInvocationContext();
   83           Map<String, Object> conversionErrors = invocationContext.getConversionErrors();
   84           ValueStack stack = invocationContext.getValueStack();
   85   
   86           HashMap<Object, Object> fakie = null;
   87   
   88           for (Map.Entry<String, Object> entry : conversionErrors.entrySet()) {
   89               String propertyName = entry.getKey();
   90               Object value = entry.getValue();
   91   
   92               if (shouldAddError(propertyName, value)) {
   93                   String message = XWorkConverter.getConversionErrorMessage(propertyName, stack);
   94   
   95                   Object action = invocation.getAction();
   96                   if (action instanceof ValidationAware) {
   97                       ValidationAware va = (ValidationAware) action;
   98                       va.addFieldError(propertyName, message);
   99                   }
  100   
  101                   if (fakie == null) {
  102                       fakie = new HashMap<Object, Object>();
  103                   }
  104   
  105                   fakie.put(propertyName, getOverrideExpr(invocation, value));
  106               }
  107           }
  108   
  109           if (fakie != null) {
  110               // if there were some errors, put the original (fake) values in place right before the result
  111               stack.getContext().put(ORIGINAL_PROPERTY_OVERRIDE, fakie);
  112               invocation.addPreResultListener(new PreResultListener() {
  113                   public void beforeResult(ActionInvocation invocation, String resultCode) {
  114                       Map<Object, Object> fakie = (Map<Object, Object>) invocation.getInvocationContext().get(ORIGINAL_PROPERTY_OVERRIDE);
  115   
  116                       if (fakie != null) {
  117                           invocation.getStack().setExprOverrides(fakie);
  118                       }
  119                   }
  120               });
  121           }
  122           return invocation.invoke();
  123       }
  124   
  125       protected boolean shouldAddError(String propertyName, Object value) {
  126           return true;
  127       }
  128   }