bsh
Class BshClassManager

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

Direct Known Subclasses:

ClassManagerImpl

public abstract class BshClassManager

extends java.lang.Object

BshClassManager manages all classloading in BeanShell. It also supports a dynamically loaded extension (bsh.classpath package) which allows classpath extension and class file reloading. Currently the extension relies on 1.2 for BshClassLoader and weak references. 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: currently class loading features affect all instances of the Interpreter. However the basic design of this class will allow for per instance class management in the future if it is desired.

Nested Class Summary

static interface

BshClassManager.Listener

Field Summary

protected static java.util.Hashtable	absoluteClassCache Global cache for things we know are classes.
protected static java.util.Hashtable	absoluteNonClasses Global cache for things we know are *not* classes.
private static boolean	checkedForManager
private static java.lang.ClassLoader	externalClassLoader An external classloader supplied by the setClassLoader() command.
private static BshClassManager	manager Singleton class manager
private static java.lang.Object	NOVALUE

Constructor Summary

BshClassManager()

Method Summary

abstract void	addClassPath(java.net.URL path)
static void	addCMListener(BshClassManager.Listener l) Add a BshClassManager.Listener to the class manager.
abstract void	addListener(BshClassManager.Listener l)
static void	cacheClassInfo(java.lang.String name, java.lang.Class value) Cache info about whether name is a class or not.
static boolean	classExists(java.lang.String name)
static java.lang.Class	classForName(java.lang.String name) Load the specified class by name, taking into account added classpath and reloaded classes, etc.
protected abstract void	classLoaderChanged()
protected void	clearCaches() Clear the static caches in BshClassManager
abstract void	doSuperImport() Support for "import *;" Hide details in here as opposed to NameSpace.
abstract void	dump(java.io.PrintWriter pw)
abstract java.lang.ClassLoader	getBaseLoader()
abstract java.lang.Class	getClassForName(java.lang.String name)
static BshClassManager	getClassManager()
abstract 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.
abstract java.lang.ClassLoader	getLoaderForClass(java.lang.String name)
abstract java.lang.Class	getPlainClassForName(java.lang.String name) Delegate for plainClassForName.
static java.lang.Class	plainClassForName(java.lang.String name) Perform a plain Class.forName() or call the externally provided class loader.
abstract void	reloadAllClasses() Overlay the entire path with a new class loader.
abstract 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.
abstract void	reloadPackage(java.lang.String pack) Reload all classes in the specified package: e.g.
abstract void	removeListener(BshClassManager.Listener l)
abstract void	reset() Clear all loaders and start over.
static void	setClassLoader(java.lang.ClassLoader externalCL) Set an external class loader.
abstract void	setClassPath(java.net.URL[] cp) Set a new base classpath and create a new base classloader.

Methods inherited from class java.lang.Object

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

Field Detail

manager

private static BshClassManager manager

Singleton class manager

checkedForManager

private static boolean checkedForManager

NOVALUE

private static java.lang.Object NOVALUE

externalClassLoader

private static java.lang.ClassLoader externalClassLoader

An external classloader supplied by the setClassLoader() command.

absoluteClassCache

protected static transient java.util.Hashtable absoluteClassCache

Global cache for things we know are classes. Note: these should probably be re-implemented with Soft references. (as opposed to strong or Weak)

absoluteNonClasses

protected static transient java.util.Hashtable absoluteNonClasses

Global cache for things we know are *not* classes. Note: these should probably be re-implemented with Soft references. (as opposed to strong or Weak)

Constructor Detail

BshClassManager

public BshClassManager()

Method Detail

getClassManager

public static BshClassManager getClassManager()

Returns:

the BshClassManager singleton or null, indicating no class manager is available.

classExists

public static boolean classExists(java.lang.String name)

classForName

public static java.lang.Class classForName(java.lang.String name)

Load the specified class by name, taking into account added classpath and reloaded classes, etc.

Returns:

the class or null

plainClassForName

public static java.lang.Class plainClassForName(java.lang.String name)
                                         throws java.lang.ClassNotFoundException

Perform a plain Class.forName() or call the externally provided class loader. If a BshClassManager implementation is loaded the call will be delegated to it, to allow for additional hooks. This simply wraps that bottom level class lookup call and provides a central point for monitoring and handling certain Java version dependent bugs, etc.

Returns:

the class

java.lang.ClassNotFoundException

See Also:

getPlainClassForName( String )

cacheClassInfo

public static void cacheClassInfo(java.lang.String name,
                                  java.lang.Class value)

Cache info about whether name is a class or not.

Parameters:

value - if value is non-null, cache the class if value is null, set the flag that it is *not* a class to speed later resolution

clearCaches

protected void clearCaches()

Clear the static caches in BshClassManager

addCMListener

public static void addCMListener(BshClassManager.Listener l)

Add a BshClassManager.Listener to the class manager. The listener is informed upon changes to the classpath. This is a static convenience form of BshClassManager addListener(). If there is no class manager the listener will be ignored.

setClassLoader

public static void setClassLoader(java.lang.ClassLoader externalCL)

Set an external class loader. BeanShell will use this at the same point it would otherwise use the plain Class.forName(). i.e. if no explicit classpath management is done from the script (addClassPath(), setClassPath(), reloadClasses()) then BeanShell will only use the supplied classloader. If additional classpath management is done then BeanShell will perform that in addition to the supplied external classloader. However BeanShell is not currently able to reload classes supplied through the external classloader.

getClassForName

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

See Also:

classForName( String )

getPlainClassForName

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

Delegate for plainClassForName.

java.lang.ClassNotFoundException

See Also:

plainClassForName( String )

getBaseLoader

public abstract java.lang.ClassLoader getBaseLoader()

getLoaderForClass

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

addClassPath

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

java.io.IOException

reset

public abstract void reset()

Clear all loaders and start over. No class loading.

setClassPath

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

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

reloadAllClasses

public abstract 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).

ClassPathException

reloadClasses

public abstract 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

ClassPathException

reloadPackage

public abstract 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.

ClassPathException

doSuperImport

public abstract void doSuperImport()
                            throws EvalError

Support for "import *;" Hide details in here as opposed to NameSpace. Note: this used to be package private...

EvalError

getClassNameByUnqName

public abstract 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. Note: this used to be package private...

ClassPathException

addListener

public abstract void addListener(BshClassManager.Listener l)

removeListener

public abstract void removeListener(BshClassManager.Listener l)

dump

public abstract void dump(java.io.PrintWriter pw)

classLoaderChanged

protected abstract void classLoaderChanged()