Package net.dryuf.onejarloader

Class OneJarLoader

java.lang.Object

java.lang.ClassLoader

net.dryuf.onejarloader.OneJarLoader

public class OneJarLoader
extends ClassLoader

The OneJarLoader implements ClassLoader which extracts the nested jar files and then allows loading classes and resources from them.

Either top level directory entries are scanned as dependencies or jar top level entries, including nested jars.

The ClassLoader supports native library with pattern os.name/os.arch/the-lib.ext and the-lib.ext

This code was written with Apache license to allow repackaging it together with commercial software.

Typical usage is as follows:

 public class JarMyApplication
 {
         public static void main(String[] args)
         {
                 OneJarLoader cl = new OneJarLoader();
                 cl.invokeMain(JarMyApplication.class.getName() + ".MyApplication", args);
         }
 }
 

VM parameters to configure logging: -DOneJarLoader.{Jar,Class,Native,Resource}.level={Level} Supported values are OFF, ERROR, WARN, INFO, DEBUG (default is ERROR)

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	OneJarLoader.Logger

Field Summary

Fields

Modifier and Type	Field	Description
static final String	SYSPROP_LOGGER_PREFIX	VM parameter prefix to configure logging.

Constructor Summary

Constructors

Constructor	Description
OneJarLoader()	Constructor with system class loader as a parent class loader.
OneJarLoader(ClassLoader parent)	Constructor.

Method Summary

Modifier and Type	Method	Description
protected Class<?>	findClass(String clazzName)
protected String	findLibrary(String name)
protected URL	findResource(String name)
Enumeration<URL>	findResources(String name)
<R> R	invokeCallable(Callable<R> callable)
void	invokeMain(String className, String[] args)	Invokes main method on a class loaded with this classloader.
<R> R	invokeStatic(String className, String method, Class<?>[] signature, Object[] args)

Methods inherited from class java.lang.ClassLoader

clearAssertionStatus, defineClass, defineClass, defineClass, defineClass, definePackage, findClass, findLoadedClass, findResource, findSystemClass, getClassLoadingLock, getDefinedPackage, getDefinedPackages, getName, getPackage, getPackages, getParent, getPlatformClassLoader, getResource, getResourceAsStream, getResources, getSystemClassLoader, getSystemResource, getSystemResourceAsStream, getSystemResources, getUnnamedModule, isRegisteredAsParallelCapable, loadClass, loadClass, registerAsParallelCapable, resolveClass, resources, setClassAssertionStatus, setDefaultAssertionStatus, setPackageAssertionStatus, setSigners

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

SYSPROP_LOGGER_PREFIX

public static final String SYSPROP_LOGGER_PREFIX

VM parameter prefix to configure logging. Full is OneJarLoader.CATEGORY.level=LEVEL

See Also:

• Constant Field Values

Constructor Details

OneJarLoader

public OneJarLoader()

Constructor with system class loader as a parent class loader.

OneJarLoader

public OneJarLoader(ClassLoader parent)

Constructor.

Parameters:

parent - class loader parent.

Method Details

invokeMain

public void invokeMain(String className,
 String[] args)
                throws Exception

Invokes main method on a class loaded with this classloader.

Parameters:

className - class name to execute

args - program parameters

Throws:

Exception - when an error occurs.

invokeStatic

public <R> R invokeStatic(String className,
 String method,
 Class<?>[] signature,
 Object[] args)
                   throws Exception

Throws:

Exception

invokeCallable

public <R> R invokeCallable(Callable<R> callable)
                     throws Exception

Throws:

Exception

findResources

public Enumeration<URL> findResources(String name)
                               throws IOException

Overrides:

findResources in class ClassLoader

Throws:

IOException

findResource

protected URL findResource(String name)

Overrides:

findResource in class ClassLoader

findLibrary

protected String findLibrary(String name)

Overrides:

findLibrary in class ClassLoader

findClass

protected Class<?> findClass(String clazzName)
                      throws ClassNotFoundException

Overrides:

findClass in class ClassLoader

Throws:

ClassNotFoundException