bsh.classpath
Class ClassManagerImpl

java.lang.Object
  |
  +--bsh.BshClassManager
        |
        +--bsh.classpath.ClassManagerImpl

public class ClassManagerImpl

extends BshClassManager

        Manage all classloading in BeanShell.
        Allows classpath extension and class file reloading.

        This class holds the implementation of the BshClassManager so that it
        can be separated from the core package.

        This class currently relies on 1.2 for BshClassLoader and weak references.
        Is there a workaround for weak refs?  If so we could make this work
        with 1.1 by supplying our own classloader code...

        See "http://www.beanshell.org/manual/classloading.html" for details
        on the bsh classloader architecture.

        Bsh has a multi-tiered class loading architecture.  No class loader is
        used unless/until the classpath is modified or a class is reloaded.

        Note: we may need some synchronization in here

        Note on jdk1.2 dependency:

        We are forced to use weak references here to accomodate all of the
        fleeting namespace listeners.  (NameSpaces must be informed if the class
        space changes so that they can un-cache names).  I had the interesting
        thought that a way around this would be to implement BeanShell's own
        garbage collector...  Then I came to my senses and said - screw it,
        class re-loading will require 1.2.
        

Nested Class Summary

Nested classes inherited from class bsh.BshClassManager

BshClassManager.Listener

Field Summary

private BshClassPath	baseClassPath The classpath of the base loader.
private BshClassLoader	baseLoader This handles extension / modification of the base classpath The loader to use where no mapping of reloaded classes exists.
private BshClassPath	fullClassPath This is the full blown classpath including baseClassPath (extensions), user path, and java bootstrap path (rt.jar) This is lazily constructed and further (and more importantly) lazily intialized in components because mapping the full path could be expensive.
private java.util.Vector	listeners
private java.util.Map	loaderMap Map by classname of loaders to use for reloaded classes
private java.lang.ref.ReferenceQueue	refQueue

Fields inherited from class bsh.BshClassManager

absoluteClassCache, absoluteNonClasses

Constructor Summary

ClassManagerImpl()
Used by BshClassManager singleton constructor

Method Summary

void	addClassPath(java.net.URL path)
void	addListener(BshClassManager.Listener l)
protected void	classLoaderChanged() Clear global class cache and notify namespaces to clear their class caches.
void	doSuperImport() Support for "import *;" Hide details in here as opposed to NameSpace.
void	dump(java.io.PrintWriter i)
java.lang.ClassLoader	getBaseLoader()
java.lang.Class	getClassForName(java.lang.String name)
java.lang.String	getClassNameByUnqName(java.lang.String name) Return the name or null if none is found, Throw an ClassPathException containing detail if name is ambigous.
BshClassPath	getClassPath() Get the full blown classpath.
java.lang.ClassLoader	getLoaderForClass(java.lang.String name)
java.lang.Class	getPlainClassForName(java.lang.String name) Delegate for bottom level implementation of Class.forName().
private void	initBaseLoader() init the baseLoader from the baseClassPath
void	reloadAllClasses() Overlay the entire path with a new class loader.
void	reloadClasses(java.lang.String[] classNames) Reloading classes means creating a new classloader and using it whenever we are asked for classes in the appropriate space.
void	reloadPackage(java.lang.String pack) Reload all classes in the specified package: e.g.
void	removeListener(BshClassManager.Listener l)
void	reset() Clear all loaders and start over.
void	setClassPath(java.net.URL[] cp) Set a new base classpath and create a new base classloader.

Methods inherited from class bsh.BshClassManager

addCMListener, cacheClassInfo, classExists, classForName, clearCaches, getClassManager, plainClassForName, setClassLoader

Methods inherited from class java.lang.Object

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

Field Detail

baseClassPath

private BshClassPath baseClassPath

The classpath of the base loader. Initially empty. This grows as paths are added or is reset when the classpath is explicitly set. This could also be called the "extension" class path, but is not strictly confined to added path (could be set arbitrarily by setClassPath())

fullClassPath

private BshClassPath fullClassPath

This is the full blown classpath including baseClassPath (extensions), user path, and java bootstrap path (rt.jar) This is lazily constructed and further (and more importantly) lazily intialized in components because mapping the full path could be expensive. The full class path is a composite of: baseClassPath (user extension) : userClassPath : bootClassPath in that order.

listeners

private java.util.Vector listeners

refQueue

private java.lang.ref.ReferenceQueue refQueue

baseLoader

private BshClassLoader baseLoader

This handles extension / modification of the base classpath The loader to use where no mapping of reloaded classes exists. The baseLoader is initially null meaning no class loader is used.

loaderMap

private java.util.Map loaderMap

Map by classname of loaders to use for reloaded classes

Constructor Detail

ClassManagerImpl

public ClassManagerImpl()

Used by BshClassManager singleton constructor

Method Detail

getClassForName

public java.lang.Class getClassForName(java.lang.String name)

Specified by:

getClassForName in class BshClassManager

Returns:

the class or null

See Also:

BshClassManager.classForName( String )

getPlainClassForName

public java.lang.Class getPlainClassForName(java.lang.String name)
                                     throws java.lang.ClassNotFoundException

Delegate for bottom level implementation of Class.forName(). This is here solely to provide for Java version specific features. In this case - the Thread getContextClassLoader() which is required to get bsh to see user classpath when it's installed in the lib/ext directory.

Specified by:

getPlainClassForName in class BshClassManager

java.lang.ClassNotFoundException

See Also:

BshClassManager.plainClassForName()

getBaseLoader

public java.lang.ClassLoader getBaseLoader()

Specified by:

getBaseLoader in class BshClassManager

getLoaderForClass

public java.lang.ClassLoader getLoaderForClass(java.lang.String name)

Specified by:

getLoaderForClass in class BshClassManager

addClassPath

public void addClassPath(java.net.URL path)
                  throws java.io.IOException

Specified by:

addClassPath in class BshClassManager

java.io.IOException

reset

public void reset()

Clear all loaders and start over. No class loading.

Specified by:

reset in class BshClassManager

setClassPath

public void setClassPath(java.net.URL[] cp)

Set a new base classpath and create a new base classloader. This means all types change.

Specified by:

setClassPath in class BshClassManager

reloadAllClasses

public void reloadAllClasses()
                      throws ClassPathException

Overlay the entire path with a new class loader. Set the base path to the user path + base path. No point in including the boot class path (can't reload thos).

Specified by:

reloadAllClasses in class BshClassManager

ClassPathException

initBaseLoader

private void initBaseLoader()

init the baseLoader from the baseClassPath

reloadClasses

public void reloadClasses(java.lang.String[] classNames)
                   throws ClassPathException

Reloading classes means creating a new classloader and using it whenever we are asked for classes in the appropriate space. For this we use a DiscreteFilesClassLoader

Specified by:

reloadClasses in class BshClassManager

ClassPathException

reloadPackage

public void reloadPackage(java.lang.String pack)
                   throws ClassPathException

Reload all classes in the specified package: e.g. "com.sun.tools" The special package name "" can be used to refer to unpackaged classes.

Specified by:

reloadPackage in class BshClassManager

ClassPathException

getClassPath

public BshClassPath getClassPath()
                          throws ClassPathException

Get the full blown classpath.

ClassPathException

doSuperImport

public void doSuperImport()
                   throws EvalError

Support for "import *;" Hide details in here as opposed to NameSpace.

Specified by:

doSuperImport in class BshClassManager

EvalError

getClassNameByUnqName

public java.lang.String getClassNameByUnqName(java.lang.String name)
                                       throws ClassPathException

Return the name or null if none is found, Throw an ClassPathException containing detail if name is ambigous.

Specified by:

getClassNameByUnqName in class BshClassManager

ClassPathException

addListener

public void addListener(BshClassManager.Listener l)

Specified by:

addListener in class BshClassManager

removeListener

public void removeListener(BshClassManager.Listener l)

Specified by:

removeListener in class BshClassManager

classLoaderChanged

protected void classLoaderChanged()

Clear global class cache and notify namespaces to clear their class caches. The listener list is implemented with weak references so that we will not keep every namespace in existence forever.

Specified by:

classLoaderChanged in class BshClassManager

dump

public void dump(java.io.PrintWriter i)

Specified by:

dump in class BshClassManager