org.wings.util.PropertyDiscovery Maven / Gradle / Ivy
/*
* Copyright 2000,2005 wingS development team.
*
* This file is part of wingS (http://wingsframework.org).
*
* wingS 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.
*
* Please see COPYING for the complete licence.
*/
package org.wings.util;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.wings.session.SessionManager;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.Enumeration;
import java.util.Properties;
/**
* Utility class to discover all properties that can be found in retrievable files either via Classpath loader or as file in the
* WEB-INF directory.
*/
public final class PropertyDiscovery {
private final static Logger log = LoggerFactory.getLogger(PropertyDiscovery.class);
private static final String WEB_INF = "WEB-INF/";
/**
* Loads all properties from either the class path or with modified name in the WEB-INF directory. Requires something to be found.
*
* First looks in the classPath for the file. Then replace all path-separators with . and look for a named file in the WEB-INF
* directory. Throws an exception if nothings was found and required is true! Example: org/wings/myprops.properties
* first checks for that file on the classpath and then for a file WEB-INF/org.wings.myprops.properties.
*
* @param propertyPath the name of the properties file i.e. org/wings/myprops.properties
* @return The Properties loaded
* @throws java.io.IOException if something fails or nothing was found
*/
public static Properties loadRequiredProperties(String propertyPath) throws IOException {
return loadProperties(propertyPath, true);
}
/**
* Loads all properties from either the class path or with modified name in the WEB-INF directory.
*
* First looks in the classPath for the file. Then replace all path-separators with . and look for a named file in the WEB-INF
* directory. Throws an exception if nothings was found and required is true! Example: org/wings/myprops.properties
* first checks for that file on the classpath and then for a file WEB-INF/org.wings.myprops.properties.
*
* @param propertyPath the name of the properties file i.e. org/wings/myprops.properties
* @return The Properties loaded
*/
public static Properties loadOptionalProperties(String propertyPath) {
try {
return loadProperties(propertyPath, false);
} catch (IOException e) {
log.info("Error", e);
return new Properties();
}
}
private static Properties loadProperties(String propertyPath, boolean required) throws IOException {
final Properties properties = new Properties();
// first load defaults from classpath, and if it fails, throw Exception
boolean somethingFound = loadPropertiesFromClasspath(properties, propertyPath);
// now load from webapp folder, log if fails.
String webappUrl = WEB_INF + propertyPath.replace('/', '.');
somethingFound |= (loadPropertiesFromContainer(properties, webappUrl));
if (required && !somethingFound) {
throw new IOException("No properties found under: " + propertyPath);
}
return properties;
}
/**
* Loads a file from the webapp's dir into a properties file.
*
* @param webappUrl the file's url
* @return true if something was found
*/
private static boolean loadPropertiesFromContainer(final Properties properties, final String webappUrl) {
try {
InputStream in = SessionManager.getSession().getServletContext().getResourceAsStream(webappUrl);
properties.load(in);
in.close();
if (log.isDebugEnabled()) {
log.debug("Loaded properties from servlet container file '" + webappUrl + '\'');
}
} catch (Exception e) {
log.debug("No custom " + webappUrl + "found. Using defaults.");
return false;
}
return true;
}
/**
* Loads a file from the webapp's classpath into a properties file.
*
* @param propertyFileClasspath the file's classpath
* @return true if something was found and loaded
*/
private static boolean loadPropertiesFromClasspath(final Properties properties,
final String propertyFileClasspath) throws IOException {
final ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
final Enumeration filesFound = classLoader.getResources(propertyFileClasspath);
boolean somethingLoaded = false;
while (filesFound.hasMoreElements()) {
final URL propertyFile = filesFound.nextElement();
try {
InputStream content = propertyFile.openStream();
properties.load(content);
content.close();
somethingLoaded = true;
if (log.isDebugEnabled()) {
log.debug("Loaded properties from classpath file '" + propertyFileClasspath + '\'');
}
} catch (Exception e) {
final String error = "Unable to open " + propertyFile.toExternalForm() +
" from classpath due " + e + ". Please check deployment!";
throw new IOException(error);
}
}
return somethingLoaded;
}
}