org.freemedsoftware.shim.Configuration.java Source code

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Here is the source code for org.freemedsoftware.shim.Configuration.java

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/*
 * $Id$
 *
 * Authors:
 *      Jeff Buchbinder <jeff@freemedsoftware.org>
 *
 * FreeMED Electronic Medical Record / Practice Management System
 * Copyright (C) 1999-2012 FreeMED Software Foundation
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Suite 500, Boston, MA 02110, USA.
 */

package org.freemedsoftware.shim;

import java.io.File;

import org.apache.commons.configuration.CompositeConfiguration;
import org.apache.commons.configuration.ConfigurationException;
import org.apache.commons.configuration.PropertiesConfiguration;
import org.apache.commons.configuration.reloading.FileChangedReloadingStrategy;
import org.apache.log4j.Logger;

public class Configuration {

    public static String DEFAULT_CONFIG = "/WEB-INF/shim-default.properties";
    public static String OVERRIDE_CONFIG = System.getProperty("shim.properties");

    protected static CompositeConfiguration compositeConfiguration = null;

    static final Logger log = Logger.getLogger(Configuration.class);

    protected static MasterControlServlet servletContext = null;

    /**
     * Get servlet object.
     * 
     * @return
     */
    public static MasterControlServlet getServletContext() {
        return servletContext;
    }

    /**
     * Store servlet object.
     * 
     * @param hS
     */
    public static void setServletContext(MasterControlServlet hS) {
        servletContext = hS;
    }

    /**
     * Get current global configuration object.
     * 
     * @return
     */
    public static CompositeConfiguration getConfiguration() {
        if (compositeConfiguration == null) {
            Configuration.loadConfiguration();
        }
        if (compositeConfiguration == null) {
            log.error("Should never be null here, configuration is failing to load!");
        }
        return compositeConfiguration;
    }

    /**
     * Load configuration from both template and override properties files.
     */
    public static void loadConfiguration() {
        log.trace("Entered loadConfiguration");
        if (servletContext == null) {
            log.error("servletContext not set!");
        }
        if (compositeConfiguration == null) {
            log.info("Configuration object not present, instantiating");
            compositeConfiguration = new CompositeConfiguration();

            PropertiesConfiguration defaults = null;
            try {
                defaults = new PropertiesConfiguration(
                        servletContext.getServletContext().getRealPath(DEFAULT_CONFIG));
                log.info("Loading default configuration from "
                        + servletContext.getServletContext().getRealPath(DEFAULT_CONFIG));
            } catch (ConfigurationException e) {
                log.error("Could not load default configuration from "
                        + servletContext.getServletContext().getRealPath(DEFAULT_CONFIG));
                // e.printStackTrace();
            }
            if (OVERRIDE_CONFIG != null) {
                PropertiesConfiguration overrides = null;
                try {
                    overrides = new PropertiesConfiguration();
                    overrides.setFile(new File(OVERRIDE_CONFIG));
                    overrides.setReloadingStrategy(new FileChangedReloadingStrategy());
                    overrides.load();
                } catch (ConfigurationException e) {
                    log.info("Could not load overrides", e);
                }
                compositeConfiguration.addConfiguration(overrides);
            }
            // Afterwards, add defaults so they're read second.
            compositeConfiguration.addConfiguration(defaults);
        }
    }

}