/*
    * 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.jetspeed.pipeline.valve.impl;
  
  import org.apache.commons.configuration.ConfigurationException;
  import org.apache.commons.configuration.PropertiesConfiguration;
  import org.apache.jetspeed.pipeline.PipelineException;
  import org.apache.jetspeed.pipeline.valve.Valve;
  import org.apache.jetspeed.pipeline.valve.ValveContext;
  import org.apache.jetspeed.request.RequestContext;
  
  /***
   * The purpose of this valve is to load a property file and make the information
   * available on the request as an attribute. The name of the attribute is the
   * key that is passed into the constructor.
   * 
   * There are 3 different ways to use this object: 1. Provide a key and a
   * PropertiesConfiguration object 2. Provide a key and a path to a properties
   * file 3. Provide a string which is used for both the key and as an environment
   * lookup to find the path to a properties file.
   * 
   * The PropertiesConfiguration object is put on the request and can be consumed
   * by anyone downstream of this valve
   * 
   * Multiple valves can be configured via Spring and put into the pipeline if
   * more than one property file is needed.
   * 
   * Spring configuration samples are shown below: <bean
   * id="ProductionConfiguration"
   * class="org.apache.commons.configuration.PropertiesConfiguration">
   * <constructor-arg> <value>/apps/jetspeed/etc/jetspeed-production.properties</value>
   * </constructor-arg> </bean>
   * 
   * <bean id="propertyLoaderValve_1"
   * class="com.fmr.portal.pipeline.impl.PropertyLoaderValve"
   * init-method="initialize"> <constructor-arg index="0"> <value>php-properties</value>
   * </constructor-arg> <constructor-arg index="1"
   * type="org.apache.commons.configuration.PropertiesConfiguration"> <ref
   * bean="ProductionConfiguration"/> </constructor-arg> </bean>
   * 
   * <bean id="propertyLoaderValve_2"
   * class="com.fmr.portal.pipeline.impl.PropertyLoaderValve"
   * init-method="initialize"> <constructor-arg index="0"> <value>php-properties</value>
   * </constructor-arg>
   * 
   * <constructor-arg index="1">
   * <value>/apps/jetspeed/etc/jetspeed-production.properties</value>
   * </constructor-arg> </bean>
   * 
   * <bean id="propertyLoaderValve_3"
   * class="com.fmr.portal.pipeline.impl.PropertyLoaderValve"
   * init-method="initialize"> <constructor-arg index="0"> <value>app.props</value>
   * </constructor-arg> </bean>
   * 
   * For this last one, an environment variable with the name "app.props" would
   * contain the file path to the properties file.
   * 
   * 
   * @author David Gurney
   * 
   */
  public class PropertyLoaderValve implements Valve
  {
      protected String m_sKey = null;
  
      protected PropertiesConfiguration m_oPropertiesConfiguration = null;
  
      protected String m_sPropertyFilePath = null;
  
      public PropertyLoaderValve(String p_sKey,
              PropertiesConfiguration p_oPropertiesConfiguration)
      {
          m_sKey = p_sKey;
          m_oPropertiesConfiguration = p_oPropertiesConfiguration;
      }
  
      public PropertyLoaderValve(String p_sKey, String p_sPropertyFilePath)
      {
          m_sKey = p_sKey;
          m_sPropertyFilePath = p_sPropertyFilePath;
      }
  
      /***
       * 
       * @param p_sEnvironmentKey -
      *            This value will be used both as the storage key and as the
      *            name to use when looking up an environment variable. The
      *            environment variable should contain the file path of the
      *            properties file to be loaded
      */
     public PropertyLoaderValve(String p_sEnvironmentKey)
     {
         m_sKey = p_sEnvironmentKey;
     }
 
     public void initialize() throws PipelineException
     {
         // Get the property file path if necessary
         if (m_sPropertyFilePath == null && m_oPropertiesConfiguration == null)
         {
             m_sPropertyFilePath = System.getProperty(m_sKey);
         }
 
         // Load the file if the path is provided
         if (m_sPropertyFilePath != null && m_oPropertiesConfiguration == null)
         {
             try
             {
                 m_oPropertiesConfiguration = new PropertiesConfiguration(
                         m_sPropertyFilePath);
             } catch (ConfigurationException e)
             {
                 throw new PipelineException(e);
             }
         }
 
         // If we still have a null, create an empty properties configuration
         // anyway
         if (m_oPropertiesConfiguration == null)
         {
             m_oPropertiesConfiguration = new PropertiesConfiguration();
         }
     }
 
     public void invoke(RequestContext p_oRequest, ValveContext p_oContext)
             throws PipelineException
     {
         p_oRequest.getRequest()
                 .setAttribute(m_sKey, m_oPropertiesConfiguration);
 
         if (p_oContext != null)
         {
             p_oContext.invokeNext(p_oRequest);
         }
     }
 }