package org.apache.ojb.broker.metadata.fieldaccess;
   
   /* Copyright 2003-2005 The Apache Software Foundation
    *
    * Licensed 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.
   */
  
  import java.lang.reflect.Field;
  import java.util.ArrayList;
  import java.util.List;
  
  import org.apache.commons.lang.StringUtils;
  import org.apache.commons.lang.SystemUtils;
  import org.apache.commons.lang.builder.ToStringBuilder;
  import org.apache.ojb.broker.metadata.MetadataException;
  import org.apache.ojb.broker.util.logging.Logger;
  import org.apache.ojb.broker.util.logging.LoggerFactory;
  
  /**
   * Abstract {@link PersistentField} base implementation class.
   *
   * @author <a href="mailto:armin@codeAuLait.de">Armin Waibel</a>
   * @version $Id: PersistentFieldBase.java,v 1.1 2007-08-24 22:17:35 ewestfal Exp $
   */
  public abstract class PersistentFieldBase implements PersistentField
  {
      public static final String PATH_TOKEN = "::";
  
      private String fieldName;
      protected Class rootObjectType;
  
      /**
       * For internal use only!!
       * TODO: Default constructor only needed to support
       * PersistentFieldFactory#usesAccessorsAndMutators()
       * method - find a better solution. Make 'public' to
       * allow helper class to instantiate class.
       */
      public PersistentFieldBase()
      {
      }
  
      public PersistentFieldBase(Class clazz, String fieldname)
      {
          this.rootObjectType = clazz;
          this.fieldName = fieldname;
      }
  
      /**
       * A value of true indicates that this field should
       * suppress Java language access checking when it is used.
       */
      protected abstract boolean makeAccessible();
  
      public String getName()
      {
          return fieldName;
      }
  
      public Class getDeclaringClass()
      {
          return rootObjectType;
      }
  
      protected List getFieldGraph(boolean makeAccessible)
      {
          List result = new ArrayList();
          String[] fields = StringUtils.split(getName(), PATH_TOKEN);
          Field fld = null;
          for (int i = 0; i < fields.length; i++)
          {
              String fieldName = fields[i];
              try
              {
                  if (fld == null)
                  {
                      fld = getFieldRecursive(rootObjectType, fieldName);
                  }
                  else
                  {
                      fld = getFieldRecursive(fld.getType(), fieldName);
                  }
                  if (makeAccessible)
                  {
                      fld.setAccessible(true);
                  }
              }
              catch (NoSuchFieldException e)
              {
                 throw new MetadataException("Can't find member '"
                         + fieldName + "' in class " + (fld != null ? fld.getDeclaringClass() : rootObjectType), e);
             }
             result.add(fld);
         }
         return result;
     }
 
     /**
      * try to find a field in class c, recurse through class hierarchy if necessary
      *
      * @throws NoSuchFieldException if no Field was found into the class hierarchy
      */
     private Field getFieldRecursive(Class c, String name) throws NoSuchFieldException
     {
         try
         {
             return c.getDeclaredField(name);
         }
         catch (NoSuchFieldException e)
         {
             // if field  could not be found in the inheritance hierarchy, signal error
             if ((c == Object.class) || (c.getSuperclass() == null) || c.isInterface())
             {
                 throw e;
             }
             // if field could not be found in class c try in superclass
             else
             {
                 return getFieldRecursive(c.getSuperclass(), name);
             }
         }
     }
 
     protected Logger getLog()
     {
         return LoggerFactory.getLogger("PersistentField");
     }
 
     public String toString()
     {
         ToStringBuilder buf = new ToStringBuilder(this);
         buf.append("rootType", rootObjectType);
         buf.append("fieldName", fieldName);
         return buf.toString();
     }
 
     /**
      * Build a String representation of given arguments.
      */
     protected String buildErrorSetMsg(Object obj, Object value, Field aField)
     {
         String eol = SystemUtils.LINE_SEPARATOR;
         StringBuffer buf = new StringBuffer();
         buf
                 .append(eol + "[try to set 'object value' in 'target object'")
                 .append(eol + "target obj class: " + (obj != null ? obj.getClass().getName() : null))
                 .append(eol + "target field name: " + (aField != null ? aField.getName() : null))
                 .append(eol + "target field type: " + (aField != null ? aField.getType() : null))
                 .append(eol + "target field declared in: " + (aField != null ? aField.getDeclaringClass().getName() : null))
                 .append(eol + "object value class: " + (value != null ? value.getClass().getName() : null))
                 .append(eol + "object value: " + (value != null ? value : null))
                 .append(eol + "]");
         return buf.toString();
     }
 
     /**
      * Build a String representation of given arguments.
      */
     protected String buildErrorGetMsg(Object obj, Field aField)
     {
         String eol = SystemUtils.LINE_SEPARATOR;
         StringBuffer buf = new StringBuffer();
         buf
                 .append(eol + "[try to read from source object")
                 .append(eol + "source obj class: " + (obj != null ? obj.getClass().getName() : null))
                 .append(eol + "target field name: " + (aField != null ? aField.getName() : null))
                 .append(eol + "target field type: " + (aField != null ? aField.getType() : null))
                 .append(eol + "target field declared in: " + (aField != null ? aField.getDeclaringClass().getName() : null))
                 .append(eol + "]");
         return buf.toString();
     }
 }