private void load(File jarFile) {
ClassLoader loader;
try {
loader =
URLClassLoader.newInstance(
new URL[] {jarFile.toURI().toURL()}, getClass().getClassLoader());
} catch (MalformedURLException e) {
Application.LOGGER.error(
"Error while loading plugin file - " + jarFile.getAbsolutePath(), e);
return;
}
InputStream stream = loader.getResourceAsStream(MANIFEST_FILE);
Properties properties = new Properties();
try {
properties.load(stream);
} catch (IOException e) {
Application.LOGGER.error(
"Manifest file - "
+ MANIFEST_FILE
+ " not found in the plugin jar - "
+ jarFile.getAbsolutePath(),
e);
return;
}
String pluginClassName = properties.getProperty("plugin.class");
if (!properties.containsKey("plugin.class")) {
Application.LOGGER.error(
"plugin.class not defined in the manifest file in the plugin jar - "
+ jarFile.getAbsolutePath());
return;
}
Class<?> clazz;
try {
clazz = Class.forName(pluginClassName, true, loader);
} catch (ClassNotFoundException e) {
Application.LOGGER.error(
"Plugin main class - "
+ pluginClassName
+ " defined in manifest not found in the plugin jar - "
+ jarFile.getAbsolutePath(),
e);
return;
}
if (!Plugin.class.isAssignableFrom(clazz)) {
Application.LOGGER.error(
"Plugin class - "
+ clazz
+ " is not a Plugin, in the plugin jar - "
+ jarFile.getAbsolutePath());
}
load((Class<? extends Plugin>) clazz, properties);
}
private void load(Class<? extends Plugin> pluginClass, Properties properties) {
// A plugin can be instantiated only once
if (PLUGINS.containsKey(pluginClass)) {
Application.LOGGER.error("Plugin for " + pluginClass + " is already loaded");
return;
}
Plugin plugin;
try {
plugin = pluginClass.newInstance();
} catch (InstantiationException e) {
Application.LOGGER.error("Error while instantiating plugin from " + pluginClass, e);
return;
} catch (IllegalAccessException e) {
Application.LOGGER.error(
"Plugin class default constructor not accessible for " + pluginClass, e);
return;
}
// register the plugin
PLUGINS.put(pluginClass, plugin);
// Load the properties if available
if (properties != null) {
plugin.name = properties.getProperty("plugin.name");
plugin.version = Version.parse(properties.getProperty("plugin.version"));
plugin.description = properties.getProperty("plugin.description");
} else {
// in case the application is loading the plugin directly
plugin.name = pluginClass.getSimpleName();
plugin.version = null;
plugin.description = null;
}
// Let the plugin initialize
Application.LOGGER.trace(
"Initializing Plugin - " + plugin.name + " - " + pluginClass.getCanonicalName());
plugin.onInit(app);
}
void loadPlugins() {
// go through all the jar files within the plugin folder
File folder = new File(pluginFolder);
if (folder.isDirectory()) {
for (File jarFile : folder.listFiles()) {
if (jarFile.isFile() && jarFile.getName().endsWith(".jar")) {
load(jarFile);
}
}
} else {
Application.LOGGER.error("Error loading plugins - " + pluginFolder + " is not a directory");
}
}