/*
 * 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.activemq.artemis.jndi;

import javax.naming.Context;
import javax.naming.Name;
import javax.naming.NamingException;
import javax.naming.Reference;
import javax.naming.StringRefAddr;
import javax.naming.spi.ObjectFactory;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Properties;


/**
 * Converts objects implementing JNDIStorable into a property fields so they can be
 * stored and regenerated from JNDI
 *
 * @since 1.0
 */
public class JNDIReferenceFactory implements ObjectFactory {

   /**
    * This will be called by a JNDIprovider when a Reference is retrieved from
    * a JNDI store - and generates the original instance
    *
    * @param object
    *      the Reference object
    * @param name
    *      the JNDI name
    * @param nameCtx
    *      the context
    * @param environment
    *      the environment settings used by JNDI
    *
    * @return the instance built from the Reference object
    *
    * @throws Exception
    *       if building the instance from Reference fails (usually class not found)
    */
   @Override
   public Object getObjectInstance(Object object, Name name, Context nameCtx, Hashtable<?, ?> environment)
         throws Exception {
      Object result = null;
      if (object instanceof Reference) {
         Reference reference = (Reference) object;
         Class<?> theClass = loadClass(this, reference.getClassName());
         if (JNDIStorable.class.isAssignableFrom(theClass)) {
            JNDIStorable store = (JNDIStorable) theClass.getDeclaredConstructor().newInstance();
            store.setProperties(getProperties(reference));
            result = store;
         }
      } else {
         throw new RuntimeException("Object " + object + " is not a reference");
      }
      return result;
   }

   public static Properties getProperties(Reference reference) {
      Properties properties = new Properties();
      for (Enumeration iter = reference.getAll(); iter.hasMoreElements();) {
         StringRefAddr addr = (StringRefAddr)iter.nextElement();
         properties.put(addr.getType(), (addr.getContent() == null) ? "" : addr.getContent());
      }
      return properties;
   }

   /**
    * Create a Reference instance from a JNDIStorable object
    *
    * @param instanceClassName
    *     The name of the class that is being created.
    * @param po
    *     The properties object to use when configuring the new instance.
    *
    * @return Reference
    *
    * @throws NamingException if an error occurs while creating the new instance.
    */
   public static Reference createReference(String instanceClassName, JNDIStorable po) throws NamingException {
      Reference result = new Reference(instanceClassName, JNDIReferenceFactory.class.getName(), null);
      try {
         Properties props = po.getProperties();
         for (Enumeration iter = props.propertyNames(); iter.hasMoreElements();) {
            String key = (String)iter.nextElement();
            result.add(new StringRefAddr(key, props.getProperty(key)));
         }
      } catch (Exception e) {
         throw new NamingException(e.getMessage());
      }
      return result;
   }

   /**
    * Retrieve the class loader for a named class
    *
    * @param thisObj
    *     Local object to use when doing the lookup.
    * @param className
    *     The name of the class being loaded.
    *
    * @return the class that was requested.
    *
    * @throws ClassNotFoundException if a matching class cannot be created.
    */
   public static Class<?> loadClass(Object thisObj, String className) throws ClassNotFoundException {
      // try local ClassLoader first.
      ClassLoader loader = thisObj.getClass().getClassLoader();
      Class<?> theClass;
      if (loader != null) {
         theClass = loader.loadClass(className);
      } else {
         // Will be null in jdk1.1.8
         // use default classLoader
         theClass = Class.forName(className);
      }
      return theClass;
   }
}
