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package edu.xtec.jclic.report.servlet;

import edu.xtec.jclic.report.rp.ReportsRequestProcessor;
import java.util.Enumeration;
import java.util.Properties;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;

/**
 * Web application lifecycle listener.
 * @author Francesc Busquets (fbusquets@xtec.cat)
 * @version 13.09.09
 */

public class ContextParamsReader implements ServletContextListener {

    public static final String PREFIX_ENV_KEY="PREFIX_ENV_KEY";
    public static final String PREFIX_KEY="PREFIX_KEY";
    public static final String PREFIX_SEP="_";

    public void contextInitialized(ServletContextEvent sce) {
        javax.servlet.ServletContext sc=sce.getServletContext();
        
        try{
            // Read defaut values
            ReportsRequestProcessor.loadProperties(null);
            Properties prop=ReportsRequestProcessor.getProperties();

            String prefixKey=null;

            // Try to find the name of the environment variable containing
            // the prefix key
            String prefixEnvKey=sc.getInitParameter(PREFIX_ENV_KEY);
            if(prefixEnvKey==null)
                prefixEnvKey=prop.getProperty(PREFIX_ENV_KEY);

            if(prefixEnvKey!=null)
                prefixKey=System.getenv(prefixEnvKey);
            
            // No environment variable set, then try to find the prefix key
            // directly
            if(prefixKey==null){
                prefixKey=sc.getInitParameter(PREFIX_KEY);
                if(prefixKey==null)
                    prefixKey=prop.getProperty(PREFIX_KEY);
            }

            if(prefixKey!=null && !prefixKey.endsWith(PREFIX_SEP))
                prefixKey=prefixKey+PREFIX_SEP;

            // Read properties stored in web.xml
            Enumeration en=sc.getInitParameterNames();
            while(en.hasMoreElements()){
                String key=(String)en.nextElement();
                if(prefixKey==null || key.startsWith(prefixKey) || key.indexOf(PREFIX_SEP)<0){
                    String value=sc.getInitParameter(key);
                    if(value!=null && value.length()>0){
                        String realKey = 
                                prefixKey==null || key.indexOf(PREFIX_SEP)<0
                                ? key
                                : key.substring(prefixKey.length());
                        prop.put(realKey, value);                       
                        //System.out.println("Clau: "+realKey+" - Valor: "+value);
                    }
                }
            }

            // Values stored in local properties file have always preference
            ReportsRequestProcessor.loadLocalProperties(null);

        } catch(Exception ex){
            System.err.println("Error reading initial parameters: "+ex);
        }

    }

    public void contextDestroyed(ServletContextEvent sce) {
    }
}