eu.optimis.elasticityengine.config.ConfigurationManager.java Source code

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Here is the source code for eu.optimis.elasticityengine.config.ConfigurationManager.java

Source

package eu.optimis.elasticityengine.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 (<a href="mailto:espling@cs.umu.se">espling@cs.umu.se</a>)
 *Copyright (C) 2012 Ume 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/>.
    
 */
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.pathSeparator)) {
            filePath += File.pathSeparatorChar;
        }

        // 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 (configFileName.equals(defaultConfigFileName) && configFilePath.equals(defaultConfigFilePath)) {
                log.fatal("Could not find default configuration file: '" + defaultConfigFilePath + "'", e);
                throw e;
            } else {
                // Try default file too
                try {
                    config = new PropertiesConfiguration(defaultConfigFilePath);
                } catch (ConfigurationException e2) {
                    log.fatal("Could not find specified " + "configuration file: '" + configFilePath
                            + File.pathSeparator + configFileName + "', and could not find default "
                            + "configuration file: '" + defaultConfigFilePath + "'", e2);
                    throw e2;
                }

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

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