com.netflix.config.WebApplicationProperties.java Source code

Introduction

Here is the source code for com.netflix.config.WebApplicationProperties.java

Source

/*
 *
 *  Copyright 2012 Netflix, Inc.
 *
 *     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 com.netflix.config;

import java.io.File;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Enumeration;
import java.util.Properties;

import org.apache.commons.configuration.ConfigurationException;
import org.apache.commons.configuration.PropertiesConfiguration;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.netflix.config.util.ConfigurationUtils;

import com.netflix.config.sources.URLConfigurationSource;

/**
 * This class helps in loading properties present in a typical web appplication.
 * 
 * 1. In a series of application properties file (typically under
 * WEB-INF/conf/*) 
 * 
 * 2. Every library (JAR) located in the web application's
 * classpath i.e. WEB-INF/lib/*.jar, can contain properties in say
 * META-INF/conf/config.properties
 * 
 * This class helps load all the properties into the Default Configuration.
 * 
 * In case you would like to load these properties into another Configuration
 * instead, you can use {@link #getProperties()} to obtain the properties and
 * load these into the <code>Configuration</code> of your choice.
 * 
 * @author stonse
 * 
 */
public class WebApplicationProperties {

    private static final Logger logger = LoggerFactory.getLogger(WebApplicationProperties.class);

    static File appConfFolder = new File("."); // folder where the
    // application properties
    // files are
    static String baseConfigFileName = "config";

    static boolean loadLibraryProperties = true;

    static String libraryPropertiesResourceRelativePath = ClasspathPropertiesConfiguration.propertiesResourceRelativePath;

    /**
     * Initialize. The application should call this method once the Application
     * Folder is set using {@link #setAppConfFolder(File, String)} method.
     * 
     * @param appConfFolderFromConfig
     * @param baseConfigFileName
     * @param loadLibraryProperties
     * @param propertiesResourceRelativePath
     */
    public static void initialize(File appConfFolderFromConfig, String baseConfigFileName,
            boolean loadLibraryProperties, String propertiesResourceRelativePath) {
        WebApplicationProperties.appConfFolder = appConfFolderFromConfig;
        WebApplicationProperties.baseConfigFileName = baseConfigFileName;
        WebApplicationProperties.loadLibraryProperties = loadLibraryProperties;
        WebApplicationProperties.libraryPropertiesResourceRelativePath = propertiesResourceRelativePath;
        initialize();
    }

    /**
     * Initialize.
     * The application should call this method once the Application Folder is set using {@link #setAppConfFolder(File, String)} method.
     */
    public static void initialize() {
        try {
            initApplicationProperties();
        } catch (Exception e) {
            logger.error("Unable to load Application Properties", e);
            System.err.println("Unable to load Application Properties");
            e.printStackTrace();
        }

        // should we load the properties in the JAR files?
        if (loadLibraryProperties) {
            try {
                initClasspathPropertiesConfiguration();
            } catch (Exception e) {
                logger.error("Unable to load Library Properties", e);
                System.err.println("Unable to load Library Properties");
                e.printStackTrace();
            }
        }

        logger.debug("Properties loaded:" + getProperties());
    }

    protected static void initClasspathPropertiesConfiguration() {
        ClasspathPropertiesConfiguration.initialize();
    }

    protected static void initApplicationProperties() throws ConfigurationException, MalformedURLException {
        File appPropFile = new File(appConfFolder + "/" + baseConfigFileName + ".properties");
        File appEnvPropOverrideFile = new File(
                appConfFolder + "/" + baseConfigFileName + getEnvironment() + ".properties");

        // TODO awang, how do we add this to archaius default config?
        PropertiesConfiguration appConf = new PropertiesConfiguration(appPropFile);
        // apply env overrides
        PropertiesConfiguration overrideConf = new PropertiesConfiguration(appEnvPropOverrideFile);
        Properties overrideprops = ConfigurationUtils.getProperties(overrideConf);
        for (Object prop : overrideprops.keySet()) {
            appConf.setProperty("" + prop, overrideprops.getProperty("" + prop));
        }
        String path = appPropFile.toURI().toURL().toString();
        System.setProperty(URLConfigurationSource.CONFIG_URL, path);
        ConfigurationManager.loadPropertiesFromConfiguration(appConf);

    }

    private static String getEnvironment() {
        String env = System.getProperty("env");
        return env;
    }

    public static File getAppConfFolder() {
        return appConfFolder;
    }

    /**
     * The folder where the application's properties files are located.
     * 
     * @param appConfFolderFromConfig
     *            the folder as a <code>File</code> object where the
     *            application's properties files are located
     * @param baseConfigFileName
     *            the "base" name of the properties file. For e.g. if you have
     *            config.properties, config-test.properties, then the value to
     *            pass in is "config"
     */
    public static void setAppConfFolder(File appConfFolderFromConfig, String baseConfigFileName) {
        WebApplicationProperties.appConfFolder = appConfFolderFromConfig;
        WebApplicationProperties.baseConfigFileName = baseConfigFileName;
    }

    /**
     * Should we load the Library Properties
     */
    public static boolean shouldLoadLibraryProperties() {
        return loadLibraryProperties;
    }

    /**
     * Set this if you would like the {@link ClasspathPropertiesConfiguration}
     * to scan the JAR files in the classpath and load those proerties into the
     * default Configuration
     * 
     * @param loadLibraryProperties
     */
    public static void setLoadLibraryProperties(boolean loadLibraryProperties) {
        WebApplicationProperties.loadLibraryProperties = loadLibraryProperties;
    }

    /**
     * Returns the relative Resource Path of the properties files in the JAR files
     */
    public static String getLibraryPropertiesResourceRelativePath() {
        return libraryPropertiesResourceRelativePath;
    }

    /**
     * Please see {@link ClasspathPropertiesConfiguration} on Library Properties.
     * This methods sets the relativeResource path
     * @param libraryPropertiesResourceRelativePath
     */
    public static void setLibraryPropertiesResourceRelativePath(String libraryPropertiesResourceRelativePath) {
        WebApplicationProperties.libraryPropertiesResourceRelativePath = libraryPropertiesResourceRelativePath;
    }

    /**
     * Returns all the properties presently available
     */
    public static Properties getProperties() {
        return ConfigurationUtils.getProperties(ConfigurationManager.getConfigInstance());
    }
}