KuranetConfig.java

/*******************************************************************************
 * Copyright (c) 2011, 2016 Eurotech and others
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     Eurotech
 *     Red Hat Inc - Re-use SystemService for configuration
 *******************************************************************************/
package org.eclipse.kura.net.admin.visitor.linux.util;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Properties;

import org.apache.commons.io.FileUtils;
import org.eclipse.kura.KuraErrorCode;
import org.eclipse.kura.KuraException;
import org.eclipse.kura.system.SystemService;
import org.osgi.framework.BundleContext;
import org.osgi.framework.FrameworkUtil;
import org.osgi.framework.ServiceReference;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class KuranetConfig {

    private static final Logger s_logger = LoggerFactory.getLogger(KuranetConfig.class);

    private static final String KURA_DATA_DIR;
    private static final String KURANET_FILENAME;
    private static final String KURANET_TMP_FILENAME;

    static {
        final BundleContext ctx = FrameworkUtil.getBundle(KuranetConfig.class).getBundleContext();

        final ServiceReference<SystemService> systemServiceRef = ctx.getServiceReference(SystemService.class);
        if (systemServiceRef == null) {
            throw new IllegalStateException("Unable to find instance of: " + SystemService.class.getName());
        }

        final SystemService service = ctx.getService(systemServiceRef);
        if (service == null) {
            throw new IllegalStateException("Unable to get instance of: " + SystemService.class.getName());
        }

        try {
            KURA_DATA_DIR = service.getKuraDataDirectory();
            KURANET_FILENAME = KURA_DATA_DIR + "/kuranet.conf";
            KURANET_TMP_FILENAME = KURA_DATA_DIR + "/kuranet.conf.tmp";
        } finally {
            ctx.ungetService(systemServiceRef);
        }
    }

    public static Properties getProperties() {
        Properties kuraExtendedProps = null;

        s_logger.debug("Getting {}", KURANET_FILENAME);

        File kuranetFile = new File(KURANET_FILENAME);

        if (kuranetFile.exists()) {
            // found our match so load the properties
            kuraExtendedProps = new Properties();
            FileInputStream fis = null;
            try {
                fis = new FileInputStream(kuranetFile);
                kuraExtendedProps.load(fis);
            } catch (Exception e) {
                s_logger.error("Could not load {}", KURANET_FILENAME, e);
            } finally {
                if (null != fis) {
                    try {
                        fis.close();
                    } catch (IOException e) {
                        s_logger.error("Could not load {}", KURANET_FILENAME, e);
                    }
                }
            }
        } else {
            s_logger.debug("File does not exist: {}", KURANET_FILENAME);
        }

        return kuraExtendedProps;
    }

    public static String getProperty(String key) {
        String value = null;

        Properties props = KuranetConfig.getProperties();
        if (props != null) {
            value = props.getProperty(key);
            s_logger.debug("Got property " + key + " :: " + value);
        }

        return value;
    }

    public static void storeProperties(Properties props) throws IOException, KuraException {
        Properties oldProperties = KuranetConfig.getProperties();

        if (oldProperties == null || !oldProperties.equals(props)) {
            FileOutputStream fos = null;
            try {
                fos = new FileOutputStream(KURANET_TMP_FILENAME);
                props.store(fos, null);
                fos.flush();
                fos.getFD().sync();

                // move the file if we made it this far
                File tmpFile = new File(KURANET_TMP_FILENAME);
                File file = new File(KURANET_FILENAME);
                if (!FileUtils.contentEquals(tmpFile, file)) {
                    if (tmpFile.renameTo(file)) {
                        s_logger.trace("Successfully wrote kuranet props file");
                    } else {
                        s_logger.error("Failed to write kuranet props file");
                        throw new KuraException(KuraErrorCode.CONFIGURATION_ERROR,
                                "error while building up new configuration file for kuranet props");
                    }
                } else {
                    s_logger.info("Not rewriting kuranet props file because it is the same");
                }
            } finally {
                fos.close();
            }
        }
    }

    public static void setProperty(String key, String value) throws IOException, KuraException {
        s_logger.debug("Setting property " + key + " :: " + value);
        Properties properties = KuranetConfig.getProperties();

        if (properties == null) {
            properties = new Properties();
        }

        properties.setProperty(key, value);
        KuranetConfig.storeProperties(properties);
    }

    public static void deleteProperty(String key) throws IOException, KuraException {
        Properties properties = KuranetConfig.getProperties();

        if (properties != null) {
            if (properties.containsKey(key)) {
                s_logger.debug("Deleting property {}", key);
                properties.remove(key);
                KuranetConfig.storeProperties(properties);
            } else {
                s_logger.debug("Property does not exist {}", key);
            }
        }
    }
}