/*
    * Copyright 2001-2005 (C) MetaStuff, Ltd. All Rights Reserved.
    *
    * This software is open source.
    * See the bottom of this file for the licence.
    */
   
   package org.dom4j.bean;
   
  import java.beans.BeanInfo;
  import java.beans.IntrospectionException;
  import java.beans.Introspector;
  import java.beans.PropertyDescriptor;
  import java.lang.reflect.Method;
  import java.util.HashMap;
  import java.util.Map;
  
  import org.dom4j.DocumentFactory;
  import org.dom4j.QName;
  
  /***
   * <p>
   * <code>BeanMetaData</code> contains metadata about a bean class.
   * </p>
   * 
   * @author <a href="mailto:james.strachan@metastuff.com">James Strachan </a>
   * @version $Revision: 1.10 $
   */
  public class BeanMetaData {
      /*** Empty arguments for reflection calls */
      protected static final Object[] NULL_ARGS = {};
  
      /*** Singleton cache */
      private static Map singletonCache = new HashMap();
  
      private static final DocumentFactory DOCUMENT_FACTORY = BeanDocumentFactory
              .getInstance();
  
      /*** The class of the bean */
      private Class beanClass;
  
      /*** Property descriptors for the bean */
      private PropertyDescriptor[] propertyDescriptors;
  
      /*** QNames for the attributes */
      private QName[] qNames;
  
      /*** Read methods used for getting properties */
      private Method[] readMethods;
  
      /*** Write methods used for setting properties */
      private Method[] writeMethods;
  
      /*** Index of names and QNames to indices */
      private Map nameMap = new HashMap();
  
      public BeanMetaData(Class beanClass) {
          this.beanClass = beanClass;
  
          if (beanClass != null) {
              try {
                  BeanInfo beanInfo = Introspector.getBeanInfo(beanClass);
                  propertyDescriptors = beanInfo.getPropertyDescriptors();
              } catch (IntrospectionException e) {
                  handleException(e);
              }
          }
  
          if (propertyDescriptors == null) {
              propertyDescriptors = new PropertyDescriptor[0];
          }
  
          int size = propertyDescriptors.length;
          qNames = new QName[size];
          readMethods = new Method[size];
          writeMethods = new Method[size];
  
          for (int i = 0; i < size; i++) {
              PropertyDescriptor propertyDescriptor = propertyDescriptors[i];
              String name = propertyDescriptor.getName();
              QName qName = DOCUMENT_FACTORY.createQName(name);
              qNames[i] = qName;
              readMethods[i] = propertyDescriptor.getReadMethod();
              writeMethods[i] = propertyDescriptor.getWriteMethod();
  
              Integer index = new Integer(i);
              nameMap.put(name, index);
              nameMap.put(qName, index);
          }
      }
  
      /***
       * Static helper method to find and cache meta data objects for bean types
       * 
       * @param beanClass
       *            DOCUMENT ME!
       * 
       * @return DOCUMENT ME!
       */
     public static BeanMetaData get(Class beanClass) {
         BeanMetaData answer = (BeanMetaData) singletonCache.get(beanClass);
 
         if (answer == null) {
             answer = new BeanMetaData(beanClass);
             singletonCache.put(beanClass, answer);
         }
 
         return answer;
     }
 
     /***
      * DOCUMENT ME!
      * 
      * @return the number of attribtutes for this bean type
      */
     public int attributeCount() {
         return propertyDescriptors.length;
     }
 
     public BeanAttributeList createAttributeList(BeanElement parent) {
         return new BeanAttributeList(parent, this);
     }
 
     public QName getQName(int index) {
         return qNames[index];
     }
 
     public int getIndex(String name) {
         Integer index = (Integer) nameMap.get(name);
 
         return (index != null) ? index.intValue() : (-1);
     }
 
     public int getIndex(QName qName) {
         Integer index = (Integer) nameMap.get(qName);
 
         return (index != null) ? index.intValue() : (-1);
     }
 
     public Object getData(int index, Object bean) {
         try {
             Method method = readMethods[index];
 
             return method.invoke(bean, NULL_ARGS);
         } catch (Exception e) {
             handleException(e);
 
             return null;
         }
     }
 
     public void setData(int index, Object bean, Object data) {
         try {
             Method method = writeMethods[index];
             Object[] args = {data};
             method.invoke(bean, args);
         } catch (Exception e) {
             handleException(e);
         }
     }
 
     // Implementation methods
     // -------------------------------------------------------------------------
     protected void handleException(Exception e) {
         // ignore introspection exceptions
     }
 }
 
 /*
  * Redistribution and use of this software and associated documentation
  * ("Software"), with or without modification, are permitted provided that the
  * following conditions are met:
  * 
  * 1. Redistributions of source code must retain copyright statements and
  * notices. Redistributions must also contain a copy of this document.
  * 
  * 2. Redistributions in binary form must reproduce the above copyright notice,
  * this list of conditions and the following disclaimer in the documentation
  * and/or other materials provided with the distribution.
  * 
  * 3. The name "DOM4J" must not be used to endorse or promote products derived
  * from this Software without prior written permission of MetaStuff, Ltd. For
  * written permission, please contact dom4j-info@metastuff.com.
  * 
  * 4. Products derived from this Software may not be called "DOM4J" nor may
  * "DOM4J" appear in their names without prior written permission of MetaStuff,
  * Ltd. DOM4J is a registered trademark of MetaStuff, Ltd.
  * 
  * 5. Due credit should be given to the DOM4J Project - http://www.dom4j.org
  * 
  * THIS SOFTWARE IS PROVIDED BY METASTUFF, LTD. AND CONTRIBUTORS ``AS IS'' AND
  * ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED. IN NO EVENT SHALL METASTUFF, LTD. OR ITS CONTRIBUTORS BE
  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  * POSSIBILITY OF SUCH DAMAGE.
  * 
  * Copyright 2001-2005 (C) MetaStuff, Ltd. All Rights Reserved.
  */