/*
    * 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.mina.integration.ognl;
  
  import java.util.Map;
  
  import ognl.ObjectPropertyAccessor;
  import ognl.OgnlContext;
  import ognl.OgnlException;
  import ognl.OgnlRuntime;
  import ognl.PropertyAccessor;
  
  /**
   * An abstract OGNL {@link PropertyAccessor} for MINA constructs.
   * 
   * @author <a href="http://mina.apache.org">Apache MINA Project</a>
   */
  public abstract class AbstractPropertyAccessor extends ObjectPropertyAccessor {
  
      static final Object READ_ONLY_MODE = new Object();
  
      static final Object QUERY = new Object();
  
      @Override
      public final boolean hasGetProperty(OgnlContext context, Object target, Object oname) throws OgnlException {
          if (oname == null) {
              return false;
          }
  
          if (hasGetProperty0(context, target, oname.toString())) {
              return true;
          } else {
              return super.hasGetProperty(context, target, oname);
          }
      }
  
      @Override
      public final boolean hasSetProperty(OgnlContext context, Object target, Object oname) throws OgnlException {
          if (context.containsKey(READ_ONLY_MODE)) {
              // Return true to trigger setPossibleProperty to throw an exception.
              return true;
          }
  
          if (oname == null) {
              return false;
          }
  
          if (hasSetProperty0(context, target, oname.toString())) {
              return true;
          } else {
              return super.hasSetProperty(context, target, oname);
          }
      }
  
      @Override
      public final Object getPossibleProperty(Map context, Object target, String name) throws OgnlException {
          Object answer = getProperty0((OgnlContext) context, target, name);
          if (answer == OgnlRuntime.NotFound) {
              answer = super.getPossibleProperty(context, target, name);
          }
          return answer;
      }
  
      @Override
      public final Object setPossibleProperty(Map context, Object target, String name, Object value) throws OgnlException {
          if (context.containsKey(READ_ONLY_MODE)) {
              throw new OgnlException("Expression must be read-only: " + context.get(QUERY));
          }
  
          Object answer = setProperty0((OgnlContext) context, target, name, value);
          if (answer == OgnlRuntime.NotFound) {
              answer = super.setPossibleProperty(context, target, name, value);
          }
          return answer;
      }
  
      protected abstract boolean hasGetProperty0(OgnlContext context, Object target, String name) throws OgnlException;
  
      protected abstract boolean hasSetProperty0(OgnlContext context, Object target, String name) throws OgnlException;
  
      protected abstract Object getProperty0(OgnlContext context, Object target, String name) throws OgnlException;
  
      protected abstract Object setProperty0(OgnlContext context, Object target, String name, Object value)
              throws OgnlException;
  }