/*
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 1999 The Apache Software Foundation.  All rights 
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer. 
 *
 * 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 end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:  
 *       "This product includes software developed by the 
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 *
 * 4. The names "The Jakarta Project", "Tomcat", and "Apache Software
 *    Foundation" must not be used to endorse or promote products derived
 *    from this software without prior written permission. For written 
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache"
 *    nor may "Apache" appear in their names without prior written
 *    permission of the Apache Group.
 *
 * THIS SOFTWARE IS PROVIDED ``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 THE APACHE SOFTWARE FOUNDATION 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.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 */ 

package org.apache.commons.el;

import java.beans.BeanInfo;
import java.beans.EventSetDescriptor;
import java.beans.IndexedPropertyDescriptor;
import java.beans.IntrospectionException;
import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.text.MessageFormat;
import java.util.HashMap;
import java.util.Map;
import javax.servlet.jsp.el.ELException;

/**
 *
 * <p>Manages the BeanInfo for one class - contains the BeanInfo, and
 * also a mapping from property name to BeanInfoProperty.  There are
 * also static methods for accessing the BeanInfoManager for a class -
 * those mappings are cached permanently so that once the
 * BeanInfoManager is calculated, it doesn't have to be calculated
 * again.
 * 
 * @author Nathan Abramson - Art Technology Group
 * @version $Change: 181181 $$DateTime: 2001/06/26 09:55:09 $$Author: luehe $
 **/

public class BeanInfoManager
{
  //-------------------------------------
  // Properties
  //-------------------------------------
  // property beanClass

  Class mBeanClass;
  public Class getBeanClass ()
  { return mBeanClass; }

  //-------------------------------------
  // Member variables
  //-------------------------------------

  // The BeanInfo
  BeanInfo mBeanInfo;

  // Mapping from property name to BeanInfoProperty
  Map mPropertyByName;

  // Mapping from property name to BeanInfoIndexedProperty
  Map mIndexedPropertyByName;

  // Mapping from event set name to event set descriptor
  Map mEventSetByName;

  // Flag if this is initialized
  boolean mInitialized;

  // The global mapping from class to BeanInfoManager
  static Map mBeanInfoManagerByClass = new HashMap ();

  //-------------------------------------
  /**
   *
   * Constructor
   **/
  BeanInfoManager (Class pBeanClass)
  {
    mBeanClass = pBeanClass;
  }

  //-------------------------------------
  /**
   *
   * Returns the BeanInfoManager for the specified class
   **/
  public static BeanInfoManager getBeanInfoManager (Class pClass)
  {
    BeanInfoManager ret = (BeanInfoManager) 
      mBeanInfoManagerByClass.get (pClass);
    if (ret == null) {
      ret = createBeanInfoManager (pClass);
    }
    return ret;
  }

  //-------------------------------------
  /**
   *
   * Creates and registers the BeanInfoManager for the given class if
   * it isn't already registered.
   **/
  static synchronized BeanInfoManager createBeanInfoManager (Class pClass)
  {
    // Because this method is synchronized statically, the
    // BeanInfoManager is not initialized at this time (otherwise it
    // could end up being a bottleneck for the entire system).  It is
    // put into the map in an uninitialized state.  The first time
    // someone tries to use it, it will be initialized (with proper
    // synchronizations in place to make sure it is only initialized
    // once).

    BeanInfoManager ret = (BeanInfoManager) 
      mBeanInfoManagerByClass.get (pClass);
    if (ret == null) {
      ret = new BeanInfoManager (pClass);
      mBeanInfoManagerByClass.put (pClass, ret);
    }
    return ret;
  }

  //-------------------------------------
  /**
   *
   * Returns the BeanInfoProperty for the specified property in the
   * given class, or null if not found.
   **/
  public static BeanInfoProperty getBeanInfoProperty
    (Class pClass,
     String pPropertyName,
     Logger pLogger)
    throws ELException
  {
    return getBeanInfoManager (pClass).getProperty (pPropertyName, pLogger);
  }

  //-------------------------------------
  /**
   *
   * Returns the BeanInfoIndexedProperty for the specified property in
   * the given class, or null if not found.
   **/
  public static BeanInfoIndexedProperty getBeanInfoIndexedProperty
    (Class pClass,
     String pIndexedPropertyName,
     Logger pLogger)
    throws ELException
  {
    return getBeanInfoManager 
      (pClass).getIndexedProperty (pIndexedPropertyName, pLogger);
  }

  //-------------------------------------
  /**
   *
   * Makes sure that this class has been initialized, and synchronizes
   * the initialization if it's required.
   **/
  void checkInitialized (Logger pLogger)
    throws ELException
  {
    if (!mInitialized) {
      synchronized (this) {
	if (!mInitialized) {
	  initialize (pLogger);
	  mInitialized = true;
	}
      }
    }
  }

  //-------------------------------------
  /**
   *
   * Initializes by mapping property names to BeanInfoProperties
   **/
  void initialize (Logger pLogger)
    throws ELException
  {
    try {
      mBeanInfo = Introspector.getBeanInfo (mBeanClass);

      mPropertyByName = new HashMap ();
      mIndexedPropertyByName = new HashMap ();
      PropertyDescriptor [] pds = mBeanInfo.getPropertyDescriptors ();
      for (int i = 0; pds != null && i < pds.length; i++) {
	// Treat as both an indexed property and a normal property
	PropertyDescriptor pd = pds [i];
	if (pd instanceof IndexedPropertyDescriptor) {
	  IndexedPropertyDescriptor ipd = (IndexedPropertyDescriptor) pd;
	  Method readMethod = getPublicMethod (ipd.getIndexedReadMethod ());
	  Method writeMethod = getPublicMethod (ipd.getIndexedWriteMethod ());
	  BeanInfoIndexedProperty property = new BeanInfoIndexedProperty
	    (readMethod,
	     writeMethod,
	     ipd);

	  mIndexedPropertyByName.put (ipd.getName (), property);
	}

	Method readMethod = getPublicMethod (pd.getReadMethod ());
	Method writeMethod = getPublicMethod (pd.getWriteMethod ());
	BeanInfoProperty property = new BeanInfoProperty
	  (readMethod,
	   writeMethod,
	   pd);

	mPropertyByName.put (pd.getName (), property);
      }

      mEventSetByName = new HashMap ();
      EventSetDescriptor [] esds = mBeanInfo.getEventSetDescriptors ();
      for (int i = 0; esds != null && i < esds.length; i++) {
	EventSetDescriptor esd = esds [i];
	mEventSetByName.put (esd.getName (), esd);
      }
    }
    catch (IntrospectionException exc) {
      if (pLogger.isLoggingWarning ()) {
	pLogger.logWarning
	  (Constants.EXCEPTION_GETTING_BEANINFO,
	   exc,
	   mBeanClass.getName ());
      }
    }
  }

  //-------------------------------------
  /**
   *
   * Returns the BeanInfo for the class
   **/
  BeanInfo getBeanInfo (Logger pLogger)
    throws ELException
  {
    checkInitialized (pLogger);
    return mBeanInfo;
  }

  //-------------------------------------
  /**
   *
   * Returns the BeanInfoProperty for the given property name, or null
   * if not found.
   **/
  public BeanInfoProperty getProperty (String pPropertyName,
				       Logger pLogger)
    throws ELException
  {
    checkInitialized (pLogger);
    return (BeanInfoProperty) mPropertyByName.get (pPropertyName);
  }

  //-------------------------------------
  /**
   *
   * Returns the BeanInfoIndexedProperty for the given property name,
   * or null if not found.
   **/
  public BeanInfoIndexedProperty getIndexedProperty 
    (String pIndexedPropertyName,
     Logger pLogger)
    throws ELException
  {
    checkInitialized (pLogger);
    return (BeanInfoIndexedProperty) 
      mIndexedPropertyByName.get (pIndexedPropertyName);
  }

  //-------------------------------------
  /**
   *
   * Returns the EventSetDescriptor for the given event set name, or
   * null if not found.
   **/
  public EventSetDescriptor getEventSet (String pEventSetName,
					 Logger pLogger)
    throws ELException
  {
    checkInitialized (pLogger);
    return (EventSetDescriptor) mEventSetByName.get (pEventSetName);
  }

  //-------------------------------------
  // Finding the public version of a method - if a PropertyDescriptor
  // is obtained for a non-public class that implements a public
  // interface, the read/write methods will be for the class, and
  // therefore inaccessible.  To correct this, a version of the same
  // method must be found in a superclass or interface.
  //-------------------------------------
  /**
   *
   * Returns a publicly-accessible version of the given method, by
   * searching for a public declaring class.
   **/
  static Method getPublicMethod (Method pMethod)
  {
    if (pMethod == null) {
      return null;
    }

    // See if the method is already available from a public class
    Class cl = pMethod.getDeclaringClass ();
    if (Modifier.isPublic (cl.getModifiers ())) {
      return pMethod;
    }

    // Otherwise, try to find a public class that declares the method
    Method ret = getPublicMethod (cl, pMethod);
    if (ret != null) {
      return ret;
    }
    else {
      return pMethod;
    }
  }

  //-------------------------------------
  /**
   *
   * If the given class is public and has a Method that declares the
   * same name and arguments as the given method, then that method is
   * returned.  Otherwise the superclass and interfaces are searched
   * recursively.
   **/
  static Method getPublicMethod (Class pClass,
				 Method pMethod)
  {
    // See if this is a public class declaring the method
    if (Modifier.isPublic (pClass.getModifiers ())) {
      try {
        Method m;
        try {
	  m = pClass.getDeclaredMethod (pMethod.getName (),
					     pMethod.getParameterTypes ());
        } catch (java.security.AccessControlException ex) {
	  // kludge to accommodate J2EE RI's default settings
	  // TODO: see if we can simply replace
          //       getDeclaredMethod() with getMethod() ...?
          m = pClass.getMethod(pMethod.getName (),
                                             pMethod.getParameterTypes ());
        }
	if (Modifier.isPublic (m.getModifiers ())) {
	  return m;
	}
      }
      catch (NoSuchMethodException exc) {}
    }

    // Search the interfaces
    {
      Class [] interfaces = pClass.getInterfaces ();
      if (interfaces != null) {
	for (int i = 0; i < interfaces.length; i++) {
	  Method m = getPublicMethod (interfaces [i], pMethod);
	  if (m != null) {
	    return m;
	  }
	}
      }
    }

    // Search the superclass
    {
      Class superclass = pClass.getSuperclass ();
      if (superclass != null) {
	Method m = getPublicMethod (superclass, pMethod);
	if (m != null) {
	  return m;
	}
      }
    }

    return null;
  }

  //-------------------------------------
}