Something similar was asked in another thread, but I figured others may find
this helpful.
I wanted to automatically bind my interfaces and implementations of my numerous
DAOs in my AppModule. It's pretty easy, so here is what I idd. This is called
from the bind static method. Obviously you'd need to change the package names.
My naming convention is to put the implementation packages in a sub ".impl"
package, e.g. com.myasd.db.dao.impl in my case. Classes then are suffixed with
"Impl" to make Eclipse's package auto-complete suggestions work better. I've
been using this for a few years, at lest.
@SuppressWarnings({ "unchecked", "rawtypes" })
static void bindDAOs(ServiceBinder binder) {
try {
ClassLoader contextClassLoader =
Thread.currentThread().getContextClassLoader();
List<Class<?>> daos =
PackageEnumerator.getClassesForPackage("com.myasd.db.dao");
for (Class<?> dao : daos) {
String pkg = dao.getPackage().getName();
String cls = dao.getSimpleName();
try {
Class impl =
contextClassLoader.loadClass(pkg+".impl."+cls+"Impl");
binder.bind(dao, impl).scope(ScopeConstants.PERTHREAD);
} catch (ClassNotFoundException e) {
// Ignore, we just won't bind that class.
}
}
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
}
Helper method borrowed from who-knows-where:
public static List<Class<?>> getClassesForPackage(String packageName)
throws ClassNotFoundException {
// This will hold a list of directories matching the pckgname.
// There may be more than one if a package is split over multiple
// jars/paths
List<Class<?>> classes = new ArrayList<Class<?>>();
ArrayList<File> directories = new ArrayList<File>();
try {
ClassLoader cld = Thread.currentThread().getContextClassLoader();
if (cld == null) {
throw new ClassNotFoundException("Can't get class loader.");
}
// Ask for all resources for the path
Enumeration<URL> resources =
cld.getResources(packageName.replace('.', '/'));
while (resources.hasMoreElements()) {
URL res = resources.nextElement();
if (res.getProtocol().equalsIgnoreCase("jar")) {
JarURLConnection conn = (JarURLConnection)
res.openConnection();
JarFile jar = conn.getJarFile();
for (JarEntry e : Collections.list(jar.entries())) {
if (e.getName().startsWith(packageName.replace('.',
'/')) && e.getName().endsWith(".class")
&& !e.getName().contains("$")) {
String className = e.getName().replace("/",
".").substring(0, e.getName().length() - 6);
System.out.println(className);
classes.add(Class.forName(className));
}
}
} else
directories.add(new File(URLDecoder.decode(res.getPath(),
"UTF-8")));
}
} catch (NullPointerException x) {
throw new ClassNotFoundException(packageName + " does not appear to
be "
+ "a valid package (Null pointer exception)");
} catch (UnsupportedEncodingException encex) {
throw new ClassNotFoundException(packageName + " does not appear to
be "
+ "a valid package (Unsupported encoding)");
} catch (IOException ioex) {
throw new ClassNotFoundException("IOException was thrown when
trying " + "to get all resources for "
+ packageName);
}
// For every directory identified capture all the .class files
for (File directory : directories) {
if (directory.exists()) {
// Get the list of the files contained in the package
String[] files = directory.list();
for (String file : files) {
// we are only interested in .class files
if (file.endsWith(".class")) {
// removes the .class extension
classes.add(Class.forName(packageName + '.' +
file.substring(0, file.length() - 6)));
}
}
} else {
throw new ClassNotFoundException(packageName + " (" +
directory.getPath()
+ ") does not appear to be a valid package");
}
}
return classes;
}
Norman Franke
Answering Service for Directors, Inc.
www.myasd.com
