org.openmrs.module

Class ModuleClassLoader

java.lang.Object

java.lang.ClassLoader

java.security.SecureClassLoader

java.net.URLClassLoader

org.openmrs.module.ModuleClassLoader

All Implemented Interfaces:

Closeable, AutoCloseable

public class ModuleClassLoader
extends URLClassLoader

Standard implementation of module class loader.
Code adapted from the Java Plug-in Framework (JPF) - LGPL - Copyright (C)
2004-2006 Dmitry Olshansky

Constructor Summary

Constructors

Modifier	Constructor and Description
	ModuleClassLoader(Module module, ClassLoader parent) Creates class instance configured to load classes and resources for given module.
protected	ModuleClassLoader(Module module, List<URL> urls)
protected	ModuleClassLoader(Module module, List<URL> urls, ClassLoader parent)
protected	ModuleClassLoader(Module module, List<URL> urls, ClassLoader parent, URLStreamHandlerFactory factory)

Method Summary

Modifier and Type	Method and Description
void	addAdditionalPackage(String additionalPackage) Convenience method to add another package name to the list of packages provided by this module
void	addAllAdditionalPackages(Collection<String> providedPackages) Convenience method to add a bunch of package names to the list of packages provided by this module
protected File	cacheLibrary(URL libUrl, String libname) Saves the given library in the openmrs cache.
protected void	checkClassVisibility(Class<?> cls, ModuleClassLoader requestor) Checking the given class's visibility in this module
protected void	collectFilters() Get and cache the filters for this module (not currently implemented)
protected static Module[]	collectRequiredModuleImports(Module module) Get and cache the imports for this module.
void	dispose()
protected String	findLibrary(String name)
URL	findResource(String name) If a resource is found within a jar, that jar URL is converted to a temporary file and a URL to that is returned
protected URL	findResource(String name, ModuleClassLoader requestor, Set<String> seenModules) Find a resource (image, file, etc) in the module structure
protected void	findResources(List<URL> result, String name, ModuleClassLoader requestor, Set<String> seenModules) Find all occurrences of a resource (image, file, etc) in the module structure
Enumeration<URL>	findResources(String name)
Set<String>	getAdditionalPackages() Package names that this module should try to load.
static File	getLibCacheFolderForModule(Module module) Get the library cache folder for the given module.
Module	getModule()
protected boolean	isResourceVisible(String name, URL url, ModuleClassLoader requestor) Check if the given resource (image, file, etc) is visible by this classloader
protected Class<?>	loadClass(String name, boolean resolve)
protected Class<?>	loadClass(String name, boolean resolve, ModuleClassLoader requestor, Set<String> seenModules) Custom loadClass implementation to allow for loading from a given ModuleClassLoader and skip the modules that have been tried already
protected void	modulesSetChanged()
void	setAdditionalPackages(Set<String> additionalPackages)
void	setProbeParentLoaderLast(boolean value) Allow the probe parent loader last variable to be set.
String	toString()

Methods inherited from class java.net.URLClassLoader

addURL, close, definePackage, findClass, getPermissions, getResourceAsStream, getURLs, newInstance, newInstance

Methods inherited from class java.security.SecureClassLoader

defineClass, defineClass

Methods inherited from class java.lang.ClassLoader

clearAssertionStatus, defineClass, defineClass, defineClass, defineClass, definePackage, findLoadedClass, findSystemClass, getClassLoadingLock, getPackage, getPackages, getParent, getResource, getResources, getSystemClassLoader, getSystemResource, getSystemResourceAsStream, getSystemResources, loadClass, registerAsParallelCapable, resolveClass, setClassAssertionStatus, setDefaultAssertionStatus, setPackageAssertionStatus, setSigners

Methods inherited from class java.lang.Object

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

Constructor Detail

ModuleClassLoader

protected ModuleClassLoader(Module module,
                            List<URL> urls,
                            ClassLoader parent,
                            URLStreamHandlerFactory factory)

Parameters:

module - Module

urls - resources "managed" by this class loader

parent - parent class loader

factory - URL stream handler factory

See Also:

URLClassLoader(java.net.URL[], java.lang.ClassLoader, java.net.URLStreamHandlerFactory)

ModuleClassLoader

protected ModuleClassLoader(Module module,
                            List<URL> urls,
                            ClassLoader parent)

Parameters:

module - the Module to load

urls - List of the resources "managed" by this class loader

parent - parent ClassLoader

See Also:

URLClassLoader(java.net.URL[], java.lang.ClassLoader)

ModuleClassLoader

protected ModuleClassLoader(Module module,
                            List<URL> urls)

Parameters:

module - the Module to load

urls - List of thee resources "managed" by this class loader

See Also:

URLClassLoader(java.net.URL[])

ModuleClassLoader

public ModuleClassLoader(Module module,
                         ClassLoader parent)

Creates class instance configured to load classes and resources for given module.

Parameters:

module - the Module to load

parent - parent ClassLoader

Method Detail

getModule

public Module getModule()

Returns:

returns this classloader's module

getLibCacheFolderForModule

public static File getLibCacheFolderForModule(Module module)

Get the library cache folder for the given module. Each module has a different cache folder to ease cleanup when unloading a module while openmrs is running

Parameters:

module - Module which the cache will be used for

Returns:

File directory where the files will be placed

collectRequiredModuleImports

protected static Module[] collectRequiredModuleImports(Module module)

Get and cache the imports for this module. The imports should just be the modules that set as "required" by this module

collectFilters

protected void collectFilters()

Get and cache the filters for this module (not currently implemented)

modulesSetChanged

protected void modulesSetChanged()

See Also:

modulesSetChanged()

dispose

public void dispose()

See Also:

ModuleFactory.stopModule(Module,boolean)

setProbeParentLoaderLast

public void setProbeParentLoaderLast(boolean value)

Allow the probe parent loader last variable to be set. Usually this is set to true to allow modules to override and create their own classes

Parameters:

value - boolean true/false whether or not to look at the parent classloader last

loadClass

protected Class<?> loadClass(String name,
                             boolean resolve)
                      throws ClassNotFoundException

Overrides:

loadClass in class ClassLoader

Throws:

ClassNotFoundException

See Also:

ClassLoader.loadClass(java.lang.String, boolean)

loadClass

protected Class<?> loadClass(String name,
                             boolean resolve,
                             ModuleClassLoader requestor,
                             Set<String> seenModules)
                      throws ClassNotFoundException

Custom loadClass implementation to allow for loading from a given ModuleClassLoader and skip the modules that have been tried already

Parameters:

name - String path and name of the class to load

resolve - boolean whether or not to resolve this class before returning

requestor - ModuleClassLoader with which to try loading

seenModules - Set moduleIds that have been tried already

Returns:

Class that has been loaded or null if none

Throws:

ClassNotFoundException - if no class found

checkClassVisibility

protected void checkClassVisibility(Class<?> cls,
                                    ModuleClassLoader requestor)
                             throws ClassNotFoundException

Checking the given class's visibility in this module

Parameters:

cls - Class to check

requestor - ModuleClassLoader to check against

Throws:

ClassNotFoundException

findLibrary

protected String findLibrary(String name)

Overrides:

findLibrary in class ClassLoader

See Also:

ClassLoader.findLibrary(java.lang.String)

cacheLibrary

protected File cacheLibrary(URL libUrl,
                            String libname)

Saves the given library in the openmrs cache. This prevents locking of jars/files by servlet container

Parameters:

libUrl - URL to the library/jar file

libname - name of the jar that will be the name of the cached file

Returns:

file that is now copied and cached

findResource

public URL findResource(String name)

If a resource is found within a jar, that jar URL is converted to a temporary file and a URL to that is returned

Overrides:

findResource in class URLClassLoader

See Also:

ClassLoader.findResource(java.lang.String)

findResources

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

Overrides:

findResources in class URLClassLoader

Throws:

IOException

See Also:

ClassLoader.findResources(java.lang.String)

findResource

protected URL findResource(String name,
                           ModuleClassLoader requestor,
                           Set<String> seenModules)

Find a resource (image, file, etc) in the module structure

Parameters:

name - String path and name of the file

requestor - ModuleClassLoader in which to look

seenModules - Set modules that have been checked already

Returns:

URL to resource

See Also:

findResource(String)

findResources

protected void findResources(List<URL> result,
                             String name,
                             ModuleClassLoader requestor,
                             Set<String> seenModules)
                      throws IOException

Find all occurrences of a resource (image, file, etc) in the module structure

Parameters:

result - URL of the file found

name - String path and name of the file to find

requestor - ModuleClassLoader in which to start

seenModules - Set moduleIds that have been checked already

Throws:

IOException

See Also:

findResources(String), findResource(String, ModuleClassLoader, Set)

isResourceVisible

protected boolean isResourceVisible(String name,
                                    URL url,
                                    ModuleClassLoader requestor)

Check if the given resource (image, file, etc) is visible by this classloader

Parameters:

name - String path and name to check

url - URL of the library file

requestor - ModuleClassLoader in which to look

Returns:

true/false whether this resource is visibile by this classloader

getAdditionalPackages

public Set<String> getAdditionalPackages()

Package names that this module should try to load. All classes/packages within the omod and the lib folder are already checked, this method/variable are used for extreme circumstances where an omod needs to know about another after being loaded

Returns:

the additionalPackages

setAdditionalPackages

public void setAdditionalPackages(Set<String> additionalPackages)

Parameters:

additionalPackages - the package names to set that this module contains that are outside the normal omod and omod/lib folders

addAdditionalPackage

public void addAdditionalPackage(String additionalPackage)

Convenience method to add another package name to the list of packages provided by this module

Parameters:

additionalPackage - string package name

See Also:

#setProvidedPackages(Set)

addAllAdditionalPackages

public void addAllAdditionalPackages(Collection<String> providedPackages)

Convenience method to add a bunch of package names to the list of packages provided by this module

Parameters:

providedPackages - list/set of strings that are package names

See Also:

#setProvidedPackages(Set)

toString

public String toString()

Overrides:

toString in class Object

See Also:

Object.toString()