bsh
Class BshClassManager

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

Direct Known Subclasses:

ClassManagerImpl

public 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.

Nested Class Summary

static interface

BshClassManager.Listener

Field Summary

protected java.util.Hashtable	absoluteClassCache Global cache for things we know are classes.
protected java.util.Hashtable	absoluteNonClasses Global cache for things we know are *not* classes.
protected java.util.Hashtable	resolvedObjectMethods Caches for resolved object and static methods.
protected java.util.Hashtable	resolvedStaticMethods

Constructor Summary

BshClassManager()

Method Summary

void	addClassPath(java.net.URL path)
void	addListener(BshClassManager.Listener l)
void	cacheClassInfo(java.lang.String name, java.lang.Class value) Cache info about whether name is a class or not.
void	cacheResolvedMethod(java.lang.Class clas, java.lang.Object[] args, java.lang.reflect.Method method) Cache a resolved (possibly overloaded) method based on the argument types used to invoke it, subject to classloader change.
boolean	classExists(java.lang.String name)
java.lang.Class	classForName(java.lang.String name) Load the specified class by name, taking into account added classpath and reloaded classes, etc.
protected void	classLoaderChanged()
protected void	clearCaches() Clear the caches in BshClassManager
protected static UtilEvalError	cmUnavailable()
static BshClassManager	createClassManager() Create a new instance of the class manager.
protected void	doSuperImport() Support for "import *;" Hide details in here as opposed to NameSpace.
void	dump(java.io.PrintWriter pw)
protected 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.
java.lang.reflect.Method	getResolvedMethod(java.lang.Class clas, java.lang.String methodName, java.lang.Object[] args, boolean onlyStatic) Return a previously cached resolved method.
java.net.URL	getResource(java.lang.String path) Get a resource URL using the BeanShell classpath
java.io.InputStream	getResourceAsStream(java.lang.String path) Get a resource stream using the BeanShell classpath
protected boolean	hasSuperImport() A "super import" ("import *") operation has been performed.
protected static java.lang.Error	noClassDefFound(java.lang.String className, java.lang.Error e) Annotate the NoClassDefFoundError with some info about the class we were trying to load.
java.lang.Class	plainClassForName(java.lang.String name) Perform a plain Class.forName() or call the externally provided classloader.
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	setClassLoader(java.lang.ClassLoader externalCL) Set an external class loader.
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

absoluteClassCache

protected 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 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)

resolvedObjectMethods

protected transient java.util.Hashtable resolvedObjectMethods

Caches for resolved object and static methods. We keep these maps separate to support fast lookup in the general case where the method may be either.

resolvedStaticMethods

protected transient java.util.Hashtable resolvedStaticMethods

Constructor Detail

BshClassManager

public BshClassManager()

Method Detail

createClassManager

public static BshClassManager createClassManager()

Create a new instance of the class manager. Class manager instnaces are now associated with the interpreter.

See Also:

bsh.Interpreter.getClassManager(), bsh.Interpreter.setClassLoader( ClassLoader )

classExists

public boolean classExists(java.lang.String name)

classForName

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

Perform a plain Class.forName() or call the externally provided classloader. 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:

classForName( String )

getResource

public java.net.URL getResource(java.lang.String path)

Get a resource URL using the BeanShell classpath

Parameters:

path - should be an absolute path

getResourceAsStream

public java.io.InputStream getResourceAsStream(java.lang.String path)

Get a resource stream using the BeanShell classpath

Parameters:

path - should be an absolute path

cacheClassInfo

public 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

cacheResolvedMethod

public void cacheResolvedMethod(java.lang.Class clas,
                                java.lang.Object[] args,
                                java.lang.reflect.Method method)

Cache a resolved (possibly overloaded) method based on the argument types used to invoke it, subject to classloader change. Static and Object methods are cached separately to support fast lookup in the general case where either will do.

getResolvedMethod

public java.lang.reflect.Method getResolvedMethod(java.lang.Class clas,
                                                  java.lang.String methodName,
                                                  java.lang.Object[] args,
                                                  boolean onlyStatic)

Return a previously cached resolved method.

Parameters:

onlyStatic - specifies that only a static method may be returned.

Returns:

the Method or null

clearCaches

protected void clearCaches()

Clear the caches in BshClassManager

See Also:

void #reset() for external usage

setClassLoader

public 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.

addClassPath

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

java.io.IOException

reset

public void reset()

Clear all loaders and start over. No class loading.

setClassPath

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

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

UtilEvalError

reloadAllClasses

public void reloadAllClasses()
                      throws UtilEvalError

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).

UtilEvalError

reloadClasses

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

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

UtilEvalError

reloadPackage

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

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

UtilEvalError

doSuperImport

protected void doSuperImport()
                      throws UtilEvalError

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

UtilEvalError

hasSuperImport

protected boolean hasSuperImport()

A "super import" ("import *") operation has been performed.

getClassNameByUnqName

protected java.lang.String getClassNameByUnqName(java.lang.String name)
                                          throws UtilEvalError

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

UtilEvalError

addListener

public void addListener(BshClassManager.Listener l)

removeListener

public void removeListener(BshClassManager.Listener l)

dump

public void dump(java.io.PrintWriter pw)

classLoaderChanged

protected void classLoaderChanged()

noClassDefFound

protected static java.lang.Error noClassDefFound(java.lang.String className,
                                                 java.lang.Error e)

Annotate the NoClassDefFoundError with some info about the class we were trying to load.

cmUnavailable

protected static UtilEvalError cmUnavailable()