/*
 * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

/*
 * 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 com.sun.faces.el.impl;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

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.util.HashMap;
import java.util.Map;


/**
 * <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: rlubke $
 */

public class BeanInfoManager {

    //-------------------------------------
    // Constants
    //-------------------------------------
    private static Log log = LogFactory.getLog(BeanInfoManager.class);
    
    //-------------------------------------
    // 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)
        throws ElException {
        return getBeanInfoManager(pClass).getProperty(pPropertyName);
    }

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

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

    //-------------------------------------
    /**
     * Initializes by mapping property names to BeanInfoProperties
     */
    void initialize()
        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 (log.isWarnEnabled()) {
                log.warn(
                    MessageUtil.getMessageWithArgs(
                        Constants.EXCEPTION_GETTING_BEANINFO,
                        mBeanClass.getName()),
                    exc);
            }
        }
    }

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

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

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

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

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