AbstractPropertiesFactory.java

/*
 * JBoss, Home of Professional Open Source.
 * Copyright 2014, Red Hat, Inc., and individual contributors
 * as indicated by the @author tags. See the copyright.txt file in the
 * distribution for a full listing of individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package com.arjuna.common.util.propertyservice;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.Enumeration;
import java.util.Properties;

import com.arjuna.common.logging.commonLogger;
import com.arjuna.common.util.ConfigurationInfo;

/*
 * Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003
 *
 * Arjuna Technologies Ltd.
 * Newcastle upon Tyne,
 * Tyne and Wear,
 * UK.
 *
 */

/**
 * This class loads properties according to the file location, substitution and override rules described in the docs.
 *
 * @author Richard A. Begg (richard.begg@arjuna.com)
 * @author <a href="mailto:gytis@redhat.com">Gytis Trikleris</a>
 */
public abstract class AbstractPropertiesFactory {
    private volatile Properties defaultProperties = null;

    /**
     * Returns the systems default properties, as read from the configuration file.
     * @return the configuration Properties
     */
    public Properties getDefaultProperties() {
        if(defaultProperties == null) {
            // TODO: pick and document new standard for global config file name property. For now use 'common' module value.
            initDefaultProperties("com.arjuna.ats.arjuna.common.propertiesFile");
        }

        return defaultProperties;
    }

    /**
     * Returns the config properties read from a specified location.
     *
     * @param propertyFileName the file name. If relative, this is located using the FileLocator algorithm.
     * @return the Properties loaded from the specified source.
     */
    public Properties getPropertiesFromFile(String propertyFileName, ClassLoader classLoader) {
        String propertiesSourceUri = null;
        try
        {
            // This is the point where the search path is applied - user.dir (pwd), user.home, java.home, classpath
            propertiesSourceUri = com.arjuna.common.util.propertyservice.FileLocator.locateFile(propertyFileName, classLoader);
        }
        catch(FileNotFoundException fileNotFoundException)
        {
            // try falling back to a default file built into the .jar
            // Note the default- prefix on the name, to avoid finding it from the .jar at the previous stage
            // in cases where the .jar comes before the etc dir on the classpath.
            URL url = AbstractPropertiesFactory.class.getResource("/default-"+propertyFileName);
            if(url == null) {
            	commonLogger.i18NLogger.warn_could_not_find_config_file(url);
            } else {
                propertiesSourceUri = url.toString();
            }
        }
        catch (IOException e)
        {
            throw new RuntimeException("invalid property file "+propertiesSourceUri, e);
        }

        Properties properties = null;

        try {
        	if (propertiesSourceUri != null) {
        		properties = loadFromFile(propertiesSourceUri);
        	}
            properties = applySystemProperties(properties);

        } catch(Exception e) {
            throw new RuntimeException("unable to load properties from "+propertiesSourceUri, e);
        }

        return properties;
    }

    /**
     * System properties take precedence over ones from the file.
     *
     * @param inputProperties
     * @return
     */
    private Properties applySystemProperties(Properties inputProperties) {
        Properties outputProperties = new Properties(inputProperties);
        Enumeration enumeration = System.getProperties().propertyNames();
        while(enumeration.hasMoreElements()) {
            String key = (String)enumeration.nextElement();
            outputProperties.setProperty(key, System.getProperty(key));
        }
        return outputProperties;
    }

    /**
     * Standard java.util.Properties xml format, with JBossAS style substitution post-processing.
     *
     * @param uri
     * @return
     * @throws IOException
     */
    private Properties loadFromFile(String uri) throws IOException {
        InputStream inputStream = null;
        Properties inputProperties = new Properties();
        Properties outputProperties = new Properties();

        if( new File(uri).exists() ) {
            inputStream = new FileInputStream(uri);
        } else {
            // it's probably a file embedded in a .jar
            inputStream = new URL(uri).openStream();
        }

        try {
            loadFromXML(inputProperties,inputStream);
        } finally {
            inputStream.close();
        }


        Enumeration namesEnumeration = inputProperties.propertyNames();
        while(namesEnumeration.hasMoreElements()) {
            String propertyName = (String)namesEnumeration.nextElement();
            String propertyValue = inputProperties.getProperty(propertyName);

            propertyValue = propertyValue.trim();

            // perform JBossAS style property substitutions. JBTM-369
            propertyValue = StringPropertyReplacer.replaceProperties(propertyValue);

            outputProperties.setProperty(propertyName, propertyValue);
        }

        return outputProperties;
    }

    private synchronized void initDefaultProperties(String fileNamePropertyKey) {
        if(defaultProperties != null) {
            return;
        }

        // This is where the properties loading takes place. The algorithm is as follows:

        // If the specified fileNamePropertyKey exists as a key is the system properties, take the value of that property as
        // the location of the module's properties file. This allows file location to be overriden easily.
        String propertyFileName = System.getProperty(fileNamePropertyKey);

        // If the system property is not set, try to load the build time properties. Build time properties
        // are not the module properties! These are optional and so loading may fail. That's not considered an error.
        // If the properties file name is defined by the build time properties, use that.
        // (In JBossTS it mostly does exist - the build scripts put build time properties into the .jars manifest file.)
        if (propertyFileName == null) {
            propertyFileName = ConfigurationInfo.getPropertiesFile();
        }

        // Bail out if it has not been possible to get a file name by either of these method.
        if(propertyFileName == null) {
            throw new RuntimeException("Unable to resolve property file name");
        }

        defaultProperties = getPropertiesFromFile(propertyFileName, PropertiesFactoryStax.class.getClassLoader());
    }

    protected abstract Properties loadFromXML(Properties p, InputStream is) throws IOException;
}