1   /*
    2    * $Id: TilesContextELResolver.java 816924 2009-09-19 13:45:40Z apetrelli $
    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.tiles.el;
   22   
   23   import java.beans.FeatureDescriptor;
   24   import java.util.Iterator;
   25   
   26   import javax.el.BeanELResolver;
   27   import javax.el.ELContext;
   28   
   29   import org.apache.tiles.TilesApplicationContext;
   30   import org.apache.tiles.context.TilesRequestContext;
   31   import org.apache.tiles.util.CombinedBeanInfo;
   32   
   33   /**
   34    * Resolves properties of {@link TilesRequestContext} and
   35    * {@link TilesApplicationContext}.
   36    *
   37    * @version $Rev: 816924 $ $Date: 2009-09-19 15:45:40 +0200 (sab, 19 set 2009) $
   38    * @since 2.2.1
   39    */
   40   public class TilesContextELResolver extends BeanELResolver {
   41   
   42       /**
   43        * The beaninfos about {@link TilesRequestContext} and {@link TilesApplicationContext}.
   44        */
   45       private CombinedBeanInfo requestBeanInfo = new CombinedBeanInfo(
   46               TilesRequestContext.class, TilesApplicationContext.class);
   47   
   48       /** {@inheritDoc} */
   49       @Override
   50       public Class<?> getCommonPropertyType(ELContext context, Object base) {
   51           // only resolve at the root of the context
   52           if (base != null) {
   53               return null;
   54           }
   55   
   56           return String.class;
   57       }
   58   
   59       /** {@inheritDoc} */
   60       @Override
   61       public Iterator<FeatureDescriptor> getFeatureDescriptors(ELContext context,
   62               Object base) {
   63           // only resolve at the root of the context
   64           if (base != null) {
   65               return null;
   66           }
   67   
   68           return requestBeanInfo.getDescriptors().iterator();
   69       }
   70   
   71       /** {@inheritDoc} */
   72       @Override
   73       public Class<?> getType(ELContext context, Object base, Object property) {
   74           // only resolve at the root of the context
   75           if (base != null) {
   76               return null;
   77           }
   78   
   79           Class<?> retValue = null;
   80           if (requestBeanInfo.getProperties(TilesRequestContext.class).contains(property)) {
   81               TilesRequestContext request = (TilesRequestContext) context
   82                       .getContext(TilesRequestContext.class);
   83               retValue = super.getType(context, request, property);
   84           } else if (requestBeanInfo.getProperties(TilesApplicationContext.class).contains(property)) {
   85               TilesApplicationContext applicationContext = (TilesApplicationContext) context
   86                       .getContext(TilesApplicationContext.class);
   87               retValue = super.getType(context, applicationContext, property);
   88           }
   89   
   90           if (retValue != null) {
   91               context.setPropertyResolved(true);
   92           }
   93   
   94           return retValue;
   95       }
   96   
   97       /** {@inheritDoc} */
   98       @Override
   99       public Object getValue(ELContext context, Object base, Object property) {
  100           // only resolve at the root of the context
  101           if (base != null) {
  102               return null;
  103           }
  104   
  105           Object retValue = null;
  106   
  107           if (requestBeanInfo.getProperties(TilesRequestContext.class).contains(property)) {
  108               TilesRequestContext request = (TilesRequestContext) context
  109                       .getContext(TilesRequestContext.class);
  110               retValue = super.getValue(context, request, property);
  111           } else if (requestBeanInfo.getProperties(TilesApplicationContext.class)
  112                   .contains(property)) {
  113               TilesApplicationContext applicationContext = (TilesApplicationContext) context
  114                       .getContext(TilesApplicationContext.class);
  115               retValue = super.getValue(context, applicationContext, property);
  116           }
  117   
  118           if (retValue != null) {
  119               context.setPropertyResolved(true);
  120           }
  121   
  122           return retValue;
  123       }
  124   
  125       /** {@inheritDoc} */
  126       @Override
  127       public boolean isReadOnly(ELContext context, Object base, Object property) {
  128           if (context == null) {
  129               throw new NullPointerException();
  130           }
  131   
  132           return true;
  133       }
  134   
  135       /** {@inheritDoc} */
  136       @Override
  137       public void setValue(ELContext context, Object base, Object property,
  138               Object value) {
  139           // Does nothing for the moment.
  140       }
  141   }