EDIT

// $Id$

/**

 * Copyright (C) 2009 EDIT

 * European Distributed Institute of Taxonomy

 * http://www.e-taxonomy.eu

 *

 * The contents of this file are subject to the Mozilla Public License Version 1.1

 * See LICENSE.TXT at the top of this package for the full license terms.

 */

package eu.etaxonomy.cdm.remote.config;

import java.io.FileInputStream;

import java.io.IOException;

import java.io.InputStream;

import java.util.ArrayList;

import java.util.List;

import java.util.Properties;

import org.apache.log4j.Logger;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.context.ApplicationContext;

import org.springframework.web.context.WebApplicationContext;

import eu.etaxonomy.cdm.common.CdmUtils;

/**

 * @author a.kohlbecker

 * @date 20.07.2010

 *

 */

public abstract class AbstractWebApplicationConfigurer {

    public static final Logger logger = Logger.getLogger(AbstractWebApplicationConfigurer.class);

    private static final String CDMLIB_REMOTE_PROPERTIES = "cdmlib-remote.properties";

    /**

     * see also <code>eu.etaxonomy.cdm.server.instance.SharedAttributes</code>

     */

    private static final String ATTRIBUTE_ERROR_MESSAGES = "cdm.errorMessages";

    WebApplicationContext webApplicationContext;

    static Properties userDefinedProperties = null;

    static {

        if(userDefinedProperties == null) {

            userDefinedProperties = new Properties();

            try {

                InputStream in = new FileInputStream(

                            CdmUtils.perUserCdmFolder

                            + java.io.File.separator

                            + CDMLIB_REMOTE_PROPERTIES

                    );

                if (in != null) {

                    userDefinedProperties.load(in);

                }

            } catch (IOException e) {

                logger.debug("No per user " + CDMLIB_REMOTE_PROPERTIES + " found.");

            }

        }

    }

    @Autowired

    public void setApplicationContext(ApplicationContext applicationContext){

        if(WebApplicationContext.class.isAssignableFrom(applicationContext.getClass())) {

            this.webApplicationContext = (WebApplicationContext)applicationContext;

        } else {

            logger.error("The " + this.getClass().getSimpleName() + " only can be used within a WebApplicationContext");

        }

    }

    /**

     * Find a property primarily in the ServletContext and secondarily

     * in the environment variables of the OS. So a property can be set

     * by three means:

     * <ol>

     * <li>As attribute to the ServletContext (the cdm-server makes use of this method)</li>

     * <li>as system property e.g. by setting the jvm commandline option like for example

     * <code>-Dcdm.rootpathprefix=my/cdm/remote-instance<code></li>

     * <li>In a per user Java properties file {@code ~/.cdmLibrary/cdmlib-remote.properties}</li>

     * </ol>

     *

     * @param property usually a string constant defined in a subclass of

     * 		<code>AbstractWebApplicationConfigurer</code> names <code>ATTRIBUTE_*</code>

     * @param required

     * @return

     */

    protected String findProperty(String property, boolean required) {

        // 1. look for the property in the ServletContext

        Object obj = webApplicationContext.getServletContext().getAttribute(property);

        String value = (String)obj;

        // 2. look for the property in environment variables of the OS

        if(value == null){

            value = System.getProperty(property);

        }

        if(value == null && userDefinedProperties != null){

            value = userDefinedProperties.getProperty(property);

        }

        if(value == null && required){

            logger.error("property {" + property + "} not found.");

            logger.error("--> This property can be set in two ways:");

            logger.error("--> 		1. as attribute to the ServletContext");

            logger.error("--> 		2. as system property e.g. -D" + property);

            logger.error("--> 		3. in ~/.cdmLibrary/cdmlib-remote.properties");

            logger.error("Stopping application ...");

            System.exit(-1);

        }

        return value;

    }

    protected void addErrorMessageToServletContextAttributes(String errorMessage) {

        Object o = webApplicationContext.getServletContext().getAttribute(ATTRIBUTE_ERROR_MESSAGES);

        List<String> messages;

        if(o != null  && o instanceof List<?>){

            messages = (List<String>) o;

        } else {

            messages = new ArrayList<String>();

        }

        messages.add(errorMessage);

        webApplicationContext.getServletContext().setAttribute(ATTRIBUTE_ERROR_MESSAGES, messages);

    }

}