it.grid.storm.config.ConfigReader.java Source code

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Here is the source code for it.grid.storm.config.ConfigReader.java

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/*
 * 
 * Copyright (c) Istituto Nazionale di Fisica Nucleare (INFN). 2006-2010.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */

package it.grid.storm.config;

import java.util.ArrayList;
import java.util.Iterator;

import org.apache.commons.configuration.AbstractConfiguration;
import org.apache.commons.configuration.CompositeConfiguration;
import org.apache.commons.configuration.Configuration;
import org.apache.commons.configuration.ConfigurationException;
import org.apache.commons.configuration.PropertiesConfiguration;
import org.apache.commons.configuration.reloading.FileChangedReloadingStrategy;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class ConfigReader {

    private static final Logger log = LoggerFactory.getLogger(ConfigReader.class);

    private Configuration c = makeEmptyConfiguration();

    private String configurationPathname = "";

    private int refresh = 0;

    public ConfigReader() {
        makeEmptyConfiguration();
    }

    public ConfigReader(String configurationPathname, int refresh) {

        if (configurationPathname != null) {
            if (refresh < 0)
                refresh = 0;
            this.refresh = refresh;
            this.configurationPathname = configurationPathname;
            log.info("Configuration file {}. Refresh rate: {} seconds", configurationPathname, refresh);

            try {
                FileChangedReloadingStrategy strategy = new FileChangedReloadingStrategy();
                strategy.setRefreshDelay(refresh);
                PropertiesConfiguration properties = new PropertiesConfiguration(configurationPathname);
                log.debug("Configuration properties:");
                String key;
                for (Iterator<?> i = properties.getKeys(); i.hasNext();) {
                    key = (String) i.next();
                    log.debug("{} = {}", key, properties.getProperty(key).toString());
                }
                properties.setReloadingStrategy(strategy);
                this.c = new CompositeConfiguration();
                ((CompositeConfiguration) this.c).addConfiguration(properties);
                log.info("Configuration read successfully.");
            } catch (ConfigurationException e) {
                this.c = makeEmptyConfiguration();
                log.error("Configuration parsing error: {}", e.getMessage(), e);
            }
        } else {
            throw new NullPointerException("Null configuration pathname.");
        }
    }

    /**
     * Method that returns the Apache object holding all configuration parameters!
     */
    public Configuration getConfiguration() {

        return c;
    }

    /**
     * Method that returns the directory containing the configuration files: it is
     * extrapolated from the complete pathname of the configuration file. If the
     * pathname was not setup, an empty String is returned.
     */
    public String configurationDirectory() {

        if (this.configurationPathname.equals(""))
            return "";
        int lastSlash = this.configurationPathname.lastIndexOf(java.io.File.separator);
        if (lastSlash == -1)
            return ""; // no slash!
        return this.configurationPathname.substring(0, lastSlash + 1);
    }

    /**
     * Private method that returns an Empty implementation of Apache s
     * Configuration Object, which does not contain any key, does not
     * addPropertyDirect, does not clearProperty, returns an empty Iterator for
     * getKeys, returns a primitive Object for getPropertyDirect, returns true for
     * isEmpty.
     */
    private Configuration makeEmptyConfiguration() {

        return new AbstractConfiguration() {

            protected void addPropertyDirect(String key, Object obj) {

            }

            public void clearProperty(String key) {

            }

            public boolean containsKey(String key) {

                return false;
            }

            public Iterator getKeys() {

                return new ArrayList().iterator();
            }

            protected Object getPropertyDirect(String key) {

                return new Object();
            }

            public boolean isEmpty() {

                return true;
            }

            public Object getProperty(String key) {

                return new Object();
            }
        };
    }

}