Package org.eclipse.jetty.webapp

Class WebAppClassLoader

java.lang.Object

java.lang.ClassLoader

java.security.SecureClassLoader

java.net.URLClassLoader

org.eclipse.jetty.webapp.WebAppClassLoader

All Implemented Interfaces:

Closeable, AutoCloseable, ClassVisibilityChecker

Direct Known Subclasses:

CachingWebAppClassLoader, OSGiWebappClassLoader

public class WebAppClassLoader
extends URLClassLoader
implements ClassVisibilityChecker

ClassLoader for HttpContext.

Specializes URLClassLoader with some utility and file mapping methods.

This loader defaults to the 2.3 servlet spec behavior where non system classes are loaded from the classpath in preference to the parent loader. Java2 compliant loading, where the parent loader always has priority, can be selected with the WebAppContext.setParentLoaderPriority(boolean) method and influenced with WebAppContext.isServerClass(Class) and WebAppContext.isSystemClass(Class).

If no parent class loader is provided, then the current thread context classloader will be used. If that is null then the classloader that loaded this class is used as the parent.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	WebAppClassLoader.Context	The Context in which the classloader operates.

Constructor Summary

Constructors

Constructor	Description
WebAppClassLoader(ClassLoader parent, WebAppClassLoader.Context context)	Constructor.
WebAppClassLoader(WebAppClassLoader.Context context)	Constructor.

Method Summary

Modifier and Type	Method	Description
void	addClassPath(String classPath)
void	addClassPath(Resource resource)
void	addJars(Resource lib)	Add elements to the class path for the context from the jar and zip files found in the specified resource.
void	addTransformer(ClassFileTransformer transformer)
void	close()
protected Class<?>	findClass(String name)
protected Class<?>	foundClass(String name, URL url)
WebAppClassLoader.Context	getContext()
String	getName()
PermissionCollection	getPermissions(CodeSource cs)
URL	getResource(String name)	Get a resource from the classloader NOTE: this method provides a convenience of hacking off a leading / should one be present.
Enumeration<URL>	getResources(String name)
boolean	isServerClass(Class<?> clazz)	Is the class a Server Class.
boolean	isSystemClass(Class<?> clazz)	Is the class a System Class.
protected Class<?>	loadAsResource(String name, boolean checkSystemResource)	Look for the classname as a resource to avoid loading a class that is potentially a system resource.
protected Class<?>	loadClass(String name, boolean resolve)
boolean	removeTransformer(ClassFileTransformer transformer)
static <T> T	runWithServerClassAccess(PrivilegedExceptionAction<T> action)	Run an action with access to ServerClasses
void	setName(String name)
String	toString()

Methods inherited from class java.net.URLClassLoader

addURL, definePackage, findResource, findResources, 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, findClass, findLibrary, findLoadedClass, findResource, findSystemClass, getClassLoadingLock, getDefinedPackage, getDefinedPackages, getPackage, getPackages, getParent, getPlatformClassLoader, getSystemClassLoader, getSystemResource, getSystemResourceAsStream, getSystemResources, getUnnamedModule, isRegisteredAsParallelCapable, loadClass, registerAsParallelCapable, resolveClass, resources, setClassAssertionStatus, setDefaultAssertionStatus, setPackageAssertionStatus, setSigners

Methods inherited from class java.lang.Object

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

Constructor Details

WebAppClassLoader

public WebAppClassLoader(WebAppClassLoader.Context context)
                  throws IOException

Constructor.

Parameters:

context - the context for this classloader

Throws:

IOException - if unable to initialize from context

WebAppClassLoader

public WebAppClassLoader(ClassLoader parent,
 WebAppClassLoader.Context context)
                  throws IOException

Constructor.

Parameters:

parent - the parent classloader

context - the context for this classloader

Throws:

IOException - if unable to initialize classloader

Method Details

runWithServerClassAccess

public static <T> T runWithServerClassAccess(PrivilegedExceptionAction<T> action)
                                      throws Exception

Run an action with access to ServerClasses

Run the passed PrivilegedExceptionAction with the classloader configured so as to allow server classes to be visible

Type Parameters:

T - The type returned by the action

T - the type of PrivilegedExceptionAction

Parameters:

action - The action to run

Returns:

The return from the action

Throws:

Exception - if thrown by the action

getName

public String getName()

Overrides:

getName in class ClassLoader

Returns:

the name of the classloader

setName

public void setName(String name)

Parameters:

name - the name of the classloader

getContext

public WebAppClassLoader.Context getContext()

addClassPath

public void addClassPath(Resource resource)
                  throws IOException

Parameters:

resource - Comma or semicolon separated path of filenames or URLs pointing to directories or jar files. Directories should end with '/'.

Throws:

IOException - if unable to add classpath from resource

addClassPath

public void addClassPath(String classPath)
                  throws IOException

Parameters:

classPath - Comma or semicolon separated path of filenames or URLs pointing to directories or jar files. Directories should end with '/'.

Throws:

IOException - if unable to add classpath

addJars

public void addJars(Resource lib)

Add elements to the class path for the context from the jar and zip files found in the specified resource.

Parameters:

lib - the resource that contains the jar and/or zip files.

getPermissions

public PermissionCollection getPermissions(CodeSource cs)

Overrides:

getPermissions in class URLClassLoader

getResources

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

Overrides:

getResources in class ClassLoader

Throws:

IOException

getResource

public URL getResource(String name)

Get a resource from the classloader NOTE: this method provides a convenience of hacking off a leading / should one be present. This is non-standard and it is recommended to not rely on this behavior

Overrides:

getResource in class ClassLoader

loadClass

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

Overrides:

loadClass in class ClassLoader

Throws:

ClassNotFoundException

addTransformer

public void addTransformer(ClassFileTransformer transformer)

removeTransformer

public boolean removeTransformer(ClassFileTransformer transformer)

loadAsResource

protected Class<?> loadAsResource(String name,
 boolean checkSystemResource)
                           throws ClassNotFoundException

Look for the classname as a resource to avoid loading a class that is potentially a system resource.

Parameters:

name - the name of the class to load

checkSystemResource - if true and the class isn't a system class we return it

Returns:

the loaded class

Throws:

ClassNotFoundException - if the class cannot be found

findClass

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

Overrides:

findClass in class URLClassLoader

Throws:

ClassNotFoundException

foundClass

protected Class<?> foundClass(String name,
 URL url)
                       throws ClassNotFoundException

Throws:

ClassNotFoundException

close

public void close()
           throws IOException

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Overrides:

close in class URLClassLoader

Throws:

IOException

toString

public String toString()

Overrides:

toString in class Object

isSystemClass

public boolean isSystemClass(Class<?> clazz)

Description copied from interface: ClassVisibilityChecker

Is the class a System Class. A System class is a class that is visible to a webapplication, but that cannot be overridden by the contents of WEB-INF/lib or WEB-INF/classes

Specified by:

isSystemClass in interface ClassVisibilityChecker

Parameters:

clazz - The fully qualified name of the class.

Returns:

True if the class is a system class.

isServerClass

public boolean isServerClass(Class<?> clazz)

Description copied from interface: ClassVisibilityChecker

Is the class a Server Class. A Server class is a class that is part of the implementation of the server and is NIT visible to a webapplication. The web application may provide it's own implementation of the class, to be loaded from WEB-INF/lib or WEB-INF/classes

Specified by:

isServerClass in interface ClassVisibilityChecker

Parameters:

clazz - The fully qualified name of the class.

Returns:

True if the class is a server class.