/*
    * Copyright 2012-2013 smartics, Kronseder & Reiner GmbH
    *
    * 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.
   */
  package de.smartics.properties.impl.config.jndi;
  
  import java.io.IOException;
  import java.io.ObjectInputStream;
  import java.util.HashMap;
  import java.util.Map;
  
  import javax.annotation.concurrent.ThreadSafe;
  import javax.naming.Context;
  import javax.naming.InitialContext;
  import javax.naming.NameClassPair;
  import javax.naming.NamingEnumeration;
  import javax.naming.NamingException;
  
  import de.smartics.properties.api.config.domain.Property;
  import de.smartics.properties.api.config.domain.PropertyCollection;
  import de.smartics.properties.api.config.domain.PropertyProvider;
  import de.smartics.properties.api.config.domain.PropertyStoreAccessor;
  import de.smartics.properties.api.config.domain.SerializableConfigurationPropertiesManagement;
  import de.smartics.properties.api.config.domain.key.ConfigurationKey;
  import de.smartics.properties.api.core.app.JndiContext;
  import de.smartics.properties.api.core.domain.PropertyDescriptorRegistry;
  import de.smartics.properties.api.core.security.PropertyValueSecurity;
  import de.smartics.properties.spi.config.support.AbstractConfigurationPropertiesManagement;
  import de.smartics.properties.spi.config.support.NativePropertyCollection;
  import de.smartics.properties.spi.config.support.SerializableConfigurationPropertiesManagementSpi;
  import de.smartics.util.lang.NullArgumentException;
  
  /**
   * Implementation based on JNDI.
   */
  @ThreadSafe
  public final class JndiConfigurationProperties extends
      AbstractConfigurationPropertiesManagement implements
      SerializableConfigurationPropertiesManagement,
      SerializableConfigurationPropertiesManagementSpi
  { // NOPMD
    // ********************************* Fields *********************************
  
    // --- constants ------------------------------------------------------------
  
    /**
     * The class version identifier.
     */
    private static final long serialVersionUID = 1L;
  
    // --- members --------------------------------------------------------------
  
    /**
     * The reference to the configuration within the JNDI context.
     */
    private transient JndiContext context;
  
    /**
     * The helper to access properties in a property store directly.
     *
     * @serial
     */
    private final PropertyStoreAccessor propertyStoreAccessor =
        new JndiPropertyStoreAccessor();
  
    // ****************************** Initializer *******************************
  
    // ****************************** Constructors ******************************
  
    /**
     * Default constructor.
     *
     * @param key the key that identifies the configuration.
     * @param registry the registry to resolve property descriptors.
     * @param decrypter the helper to decrypt secured property values.
     * @throws NullArgumentException if {@code key}, {@code registry} or
     *           {@code decrypter} is <code>null</code>.
     * @throws NamingException if the JNDI context cannot be created.
     * @throws IllegalArgumentException on any problem accessing the JNDI context.
     */
    public JndiConfigurationProperties(final ConfigurationKey<?> key,
        final PropertyDescriptorRegistry registry,
        final PropertyValueSecurity decrypter) throws NullArgumentException,
      NamingException, IllegalArgumentException
    {
      super(key, registry, decrypter);
  
      this.context = initContext(key);
   }
 
   // ****************************** Inner Classes *****************************
 
   /**
    * Provides direct access to the properties in the property store.
    */
   private final class JndiPropertyStoreAccessor implements
       PropertyStoreAccessor
   {
     /**
      * The class version identifier.
      * <p>
      * The value of this constant is {@value}.
      * </p>
      */
     private static final long serialVersionUID = 1L;
 
     @Override
     public Property getPropertyFromStore(final String name)
       throws JndiPropertyStoreException
     {
       try
       {
         final String value = context.lookup(name);
         final Property property =
             new Property(context.getSourceId(), name, value);
         return property;
       }
       catch (final NamingException e)
       {
         throw new JndiPropertyStoreException(new JndiPropertyStoreMessageBean(
             JndiPropertyStoreCode.CANNOT_GET_PROPERTY, e, getKey(), name));
       }
     }
 
     @Override
     public Property setPropertyToStore(final String name, final String value)
       throws JndiPropertyStoreException
     {
       try
       {
         final Property oldProperty = getPropertyFromStore(name);
         context.set(name, value);
         return oldProperty;
       }
       catch (final NamingException e)
       {
         throw new JndiPropertyStoreException(new JndiPropertyStoreMessageBean(
             JndiPropertyStoreCode.CANNOT_SET_PROPERTY, e, getKey(), name));
       }
     }
 
     @Override
     public Property deletePropertyInStore(final String name)
       throws JndiPropertyStoreException
     {
       try
       {
         final Property oldProperty = getPropertyFromStore(name);
         context.set(name, null);
         return oldProperty;
       }
       catch (final NamingException e)
       {
         throw new JndiPropertyStoreException(new JndiPropertyStoreMessageBean(
             JndiPropertyStoreCode.CANNOT_DELETE_PROPERTY, e, getKey(), name));
       }
     }
 
     @Override
     public PropertyCollection getPropertyCollectionFromStore()
       throws JndiPropertyStoreException
     {
       try
       {
         final Map<String, Property> properties =
             new HashMap<String, Property>();
         final NamingEnumeration<NameClassPair> list = context.list();
         while (list.hasMore())
         {
           final NameClassPair pair = list.next();
           final String name = pair.getName();
           final Property property = getPropertyFromStore(name);
           properties.put(name, property);
         }
 
         return new NativePropertyCollection(properties);
       }
       catch (final NamingException e)
       {
         throw new JndiPropertyStoreException(
             JndiPropertyStoreMessageBean.collection(e, getKey()));
       }
     }
   }
 
   // ********************************* Methods ********************************
 
   // --- init -----------------------------------------------------------------
 
   private static JndiContext initContext(final ConfigurationKey<?> key)
     throws NamingException, IllegalArgumentException
   {
     final Context jndi = new InitialContext();
     final JndiContext context = JndiContext.config(jndi, key.toString());
     return context;
   }
 
   // --- get&set --------------------------------------------------------------
 
   @Override
   public PropertyStoreAccessor getPropertyStoreAccessor()
   {
     return propertyStoreAccessor;
   }
 
   // --- business -------------------------------------------------------------
 
   @Override
   protected void setPropertiesToStore(final PropertyProvider provider)
     throws JndiPropertyStoreException
   {
     String name = "<unknown>";
     try
     {
       for (final Property property : provider.getProperties())
       {
         name = property.getName();
         final String value = property.getValue();
         context.set(name, value);
       }
     }
     catch (final NamingException e)
     {
       throw new JndiPropertyStoreException(new JndiPropertyStoreMessageBean(
           JndiPropertyStoreCode.CANNOT_SET_PROPERTY, e, getKey(), name));
     }
   }
 
   /**
    * {@inheritDoc}
    *
    * @impl since JNDI values are currently not persisted.
    * @todo check JNDI configuration for persistence.
    */
   @Override
   protected void addDefinitionsToStore(final PropertyProvider properties)
     throws JndiPropertyStoreException
   {
     setPropertiesToStore(properties);
   }
 
   @Override
   public SerializableConfigurationPropertiesManagement toSerializable()
   {
     return this;
   }
 
   // --- object basics --------------------------------------------------------
 
   /**
    * Reads the object from the given stream.
    *
    * @param in the stream to read from.
    * @throws IOException on read problems or if the JNDI context cannot be
    *           established.
    * @throws ClassNotFoundException if a class cannot be found.
    */
   private void readObject(final ObjectInputStream in) throws IOException,
     ClassNotFoundException
   {
     in.defaultReadObject();
 
     try
     {
       this.context = initContext(getKey());
     }
     catch (final NamingException e)
     {
       throw new IOException("Cannot reestablish the JNDI context.", e);
     }
     catch (final IllegalArgumentException e)
     {
       throw new IOException("Cannot reestablish the JNDI context.", e);
     }
   }
 }