2009/05/20 - Apache Shale has been retired.

   /*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to you under the Apache License, Version 2.0
    * (the "License"); you may not use this file except in compliance with
    * the License.  You may obtain a copy of the License at
    *
    *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package org.apache.shale.validator.faces;
  
  import java.io.IOException;
  import java.io.StringWriter;
  import javax.faces.component.UICommand;
  import javax.faces.component.UIComponent;
  import javax.faces.context.FacesContext;
  import javax.faces.context.ResponseWriter;
  import javax.faces.convert.ConverterException;
  import javax.faces.render.Renderer;
  
  /***
   * <p>This Renderer is a hybrid renderer decorator that is dynamically
   * registered by {@link ValidatorRenderKit}
   * for component renderers in the "javax.faces.Command" family.</p>
   */
  public class ValidatorCommandRenderer extends Renderer {
  
  
      /***
       * <p>The Original Renderer.</p>
       */
      private Renderer defaultRenderer = null;
  
  
      /***
       * <p>The overloaded constructor is passed the original
       * <code>Renderer</code> for the family and component type.</p>
       *
       * @param defaultRenderer The default Renderer we should delegate to
       */
      public ValidatorCommandRenderer(Renderer defaultRenderer) {
         this.defaultRenderer = defaultRenderer;
      }
  
  
      /***
       * <p>Attribute name used to override the default behavior of how the immediate
       * attribute effects the execution of client side javascript validation.</p>
       */
      public static final String OVERRIDE_IMMEDIATE = "org.apache.shale.validator.immediate";
  
      private static final int ENCODE_BEGIN = 0;
  
      private static final int ENCODE_CHILDREN = 1;
  
      private static final int ENCODE_END = 2;
  
  
      /***
       * <b>Interrogates the component's immediate property and the component's
       * immediate override attribute to determine if client side validation is
       * invoked. If either the property or attribute override is false, client
       * side validation is invoked. Otherwise, the response writer is hijacked
       * and the original render is invoked. The result is buffered and a
       * statement of javascript is injected into the onclick event which cancels
       * client side validation. The original response writer is restored and the
       * modified markup is written to the response writer. The
       * <code>encodeSwitch</code> determines if the encodeBegin, encodeChildren
       * or encodeEnd methods should be invoked on the decorated renderer.</b>
       *
       * @param context FacesContext for the current request
       * @param component UIComponent being rendered
       * @param encodeSwitch FIXME - encode switch?
       *
       * @exception IOException if an input/output error occurs
       */
      protected void encode(FacesContext context, UIComponent component,
              int encodeSwitch) throws IOException {
  
          UICommand command = (UICommand) component;
  
          // look for a override to the default
          boolean immediateOverride = true;
          String attr = (String) component.getAttributes()
                  .get(OVERRIDE_IMMEDIATE);
          if (attr != null) {
              immediateOverride = Boolean.valueOf(attr).booleanValue();
          }
  
          if (command.isImmediate() && immediateOverride) {
  
             ResponseWriter hijackedWriter = context.getResponseWriter();
             // builds a buffer to write the page to
             StringWriter writer = new StringWriter();
             // create a buffered response writer
             ResponseWriter buffResponsewriter = context.getRenderKit()
                     .createResponseWriter(writer, null,
                             hijackedWriter.getCharacterEncoding());
             // push buffered writer to the faces context
             context.setResponseWriter(buffResponsewriter);
 
             if (encodeSwitch == ENCODE_BEGIN) {
                 defaultRenderer.encodeBegin(context, component);
             } else if (encodeSwitch == ENCODE_CHILDREN) {
                 defaultRenderer.encodeChildren(context, component);
             } else {
                 defaultRenderer.encodeEnd(context, component);
             }
 
             buffResponsewriter.write(' ');
             buffResponsewriter.flush();
             buffResponsewriter.close();
             writer.flush();
             writer.close();
             StringBuffer buff = writer.getBuffer();
             int i = buff.indexOf("onclick=\"");
             if (i > 0) {
                 buff.insert(i + "onclick=\"".length(), "bCancel=true;");
             }
 
             hijackedWriter.write(buff.toString());
             context.setResponseWriter(hijackedWriter);
 
         } else {
 
             if (encodeSwitch == ENCODE_BEGIN) {
                 defaultRenderer.encodeBegin(context, component);
             } else if (encodeSwitch == ENCODE_CHILDREN) {
                 defaultRenderer.encodeChildren(context, component);
             } else {
                 defaultRenderer.encodeEnd(context, component);
             }
 
         }
 
     }
 
 
     /*** {@inheritDoc} */
     public String convertClientId(FacesContext context, String id) {
         return defaultRenderer.convertClientId(context, id);
     }
 
 
     /*** {@inheritDoc} */
     public Object getConvertedValue(FacesContext context, UIComponent component, Object o) throws ConverterException {
         return defaultRenderer.getConvertedValue(context, component, o);
     }
 
 
     /*** {@inheritDoc} */
     public void decode(FacesContext context, UIComponent component) {
         defaultRenderer.decode(context, component);
     }
 
 
     /***
      * <p>
      * Invokes the <code>encode</code> method passing
      * <code>ENCODE_BEGIN</code> for the encodeSwitch parameter.
      * </p>
      *
      * @param context FacesContext for the current request
      * @param component UIComponent being rendered
      *
      * @exception IOException if an input/output error occurs
      */
     public void encodeBegin(FacesContext context, UIComponent component)
             throws IOException {
         encode(context, component, ENCODE_BEGIN);
     }
 
 
     /***
      * <p>Invokes the <code>encode</code> method passing
      * <code>ENCODE_CHILDREN</code> for the encodeSwitch parameter.</p>
      *
      * @param context FacesContext for the current request
      * @param component UIComponent being rendered
      *
      * @exception IOException if an input/output error occurs
      */
     public void encodeChildren(FacesContext context, UIComponent component)
             throws IOException {
         encode(context, component, ENCODE_CHILDREN);
     }
 
 
     /***
      * <p>Invokes the <code>encode</code> method passing <code>ENCODE_END</code>
      * for the encodeSwitch parameter.</p>
      *
      * @param context FacesContext for the current reqauest
      * @param component UIComponent being rendered
      *
      * @exception IOException if an input/output error occurs
      */
     public void encodeEnd(FacesContext context, UIComponent component)
             throws IOException {
         encode(context, component, ENCODE_END);
     }
 
 
     /*** {@inheritDoc} */
     public boolean getRendersChildren() {
         return defaultRenderer.getRendersChildren();
     }
 
 
 }