eu.optimis_project.monitoring.config.ConfigurationManager.java Source code

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Here is the source code for eu.optimis_project.monitoring.config.ConfigurationManager.java

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/**
 * 
 * @author Daniel Espling (<a href="mailto:espling@cs.umu.se">espling@cs.umu.se</a>)
 * Copyright (C) 2011 Umea University
 *
 * 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 3 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, see <http://www.gnu.org/licenses/>.
 */
package eu.optimis_project.monitoring.config;

import java.io.File;
import java.net.MalformedURLException;
import java.net.URL;

import org.apache.commons.configuration.Configuration;
import org.apache.commons.configuration.ConfigurationException;
import org.apache.commons.configuration.PropertiesConfiguration;
import org.apache.log4j.Logger;

/**
 * 
 * Creates and populates configuration objects based on a system property
 * (configuration.file) or the default configuration file specified.
 * 
 * Initially written for use in the RESERVOIR project
 * 
 * @author Daniel Espling <espling@cs.umu.se>
 */
public class ConfigurationManager {

    private final Logger log = Logger.getLogger(ConfigurationManager.class.getName());
    private Configuration configuration;

    /**
     * Set the default configuration file to fall back on, in case the system
     * property is not set or not working.
     * 
     */
    public ConfigurationManager(String defaultConfigFilePath, String defaultConfigFileName)
            throws ConfigurationException {
        loadConfigurationFile(defaultConfigFilePath, defaultConfigFileName);
    }

    /**
     * Load configuration file as specified in the system property, and fall
     * back on the default file if required.
     */
    private void loadConfigurationFile(String defaultConfigFilePath, String defaultConfigFileName)
            throws ConfigurationException {
        String configFilePath = System.getProperty("configuration.file.path");
        String configFileName = System.getProperty("configuration.file.name");
        String filePath = configFilePath == null ? defaultConfigFilePath : configFilePath;
        String fileName = configFileName == null ? defaultConfigFileName : configFileName;

        URL configURL;

        if (!filePath.endsWith(File.separator)) {
            filePath += File.separatorChar;
        }

        // Check if the file exists on the system, else try reading it from the
        // classpath
        File configFile = new File(filePath + fileName);
        if (configFile.exists()) {
            try {
                configURL = new URL(filePath + fileName);
            } catch (MalformedURLException e) {
                throw new ConfigurationException(e);
            }
        } else {
            configURL = this.getClass().getClassLoader().getResource(fileName);
        }

        PropertiesConfiguration config = null;
        try {
            config = new PropertiesConfiguration(configURL);
        } catch (ConfigurationException e) {
            if (defaultConfigFileName.equals(configFileName) && configFilePath.equals(defaultConfigFilePath)) {
                log.fatal("Could not find default configuration file: '" + configURL + "'", e);
                throw e;
            } else {
                // Try default file too
                try {
                    config = new PropertiesConfiguration(defaultConfigFilePath);
                } catch (ConfigurationException e2) {
                    log.warn("Could not find default file, trying same dir");
                }

                // Try file in same dir
                if (config == null) {
                    String sameDirPath = System.getProperty("user.dir") + File.separatorChar
                            + defaultConfigFileName;
                    try {
                        config = new PropertiesConfiguration(sameDirPath);
                        log.info("Using file in same directory:" + sameDirPath);
                    } catch (ConfigurationException e2) {
                        log.fatal("Could not find specified " + "configuration file: '" + configFilePath
                                + File.separatorChar + configFileName + "', could not find default "
                                + "configuration file: '" + defaultConfigFilePath + File.separatorChar
                                + defaultConfigFileName + "', and could not find file in same dir: " + sameDirPath
                                + "'", e2);
                        throw e2;
                    }
                }

                log.warn("Could not find specified " + "configuration file: '" + configFilePath + File.separatorChar
                        + configFileName + "', using default configuration at : '" + defaultConfigFilePath
                        + File.separatorChar + defaultConfigFileName + "'");
            }
        }
        config.setThrowExceptionOnMissing(true);
        this.configuration = config;
    }

    /**
     * Return a complete Configuration object, created during the
     * "loadConfiguration" call.
     */
    public Configuration getConfig() {
        return configuration;
    }
}