Announcement - BeanShell 2.0b1
------------------------------

After several months of intense work I am pleased to announce the first beta
release of BeanShell 2.0.  With version 2.0 BeanShell becomes a fully Java
compatible scripting language.  BeanShell is now capable of interpreting 
ordinary Java source and loading .java source files from the class path.  
Although this code is still in beta I have been able to execute almost all of 
the 165 example programs from my book (Learning Java, O'Reilly & Associates) 
without modification as well as BeanShell's own ClassBrowser.java file.
The additional code to make this possible adds only about 30K to the size
of the package and the core minimal language distribution without class support
remains less than 150K.

BeanShell scripted classes are fully typed and appear to outside Java code and
via reflective inspection as ordinary classes.  However their implementation is
fully dynamic and they may include arbitrary BeanShell scripts in their bodies,
methods, and constructors.  Users may now freely mix loose, unstructured
BeanShell scripts, method closures, and full scripted classes.  BeanShell
scripted classes are "bound" in the script namespace in which they are declared
and so can freely refer to other scripted items such as scripted methods,
commands, and "global" variables of the script. e.g.

    // MyScript.bsh
    count = 5;

    class HelloWorld extends Thread {
        public void run() {
           for(i=0; i<count; i++)
              print("Hello World!");
        }     
    }

    new HelloWorld().start();

All methods and constructors of the scripted classes delegate to the BeanShell
interpreter at runtime and all typed variables appear as true class members.
Loosely typed variables and methods may still be used inside the class but are
strictly private to the class body.  

Previous limitations on the implementation of anonymous inner classes have also
been lifted, allowing BeanShell to extend arbitrary Java classes and implement
abstract base classes.

BeanShell 2.0 also brings with it two new language features:

JDK 1.5 style static class imports.  You can import the static methods and
fields of a java Class into a BeanShell namespace. e.g. 

    static import java.lang.Math.*;
    sqrt(4.0);

Instance object imports (mix-ins) with the importObject() command.  You can
import the methods and fields of a Java object instance into a BeanShell
namespace.  e.g.

    Map map = new HashMap();
    importObject( map );
    put("foo", "bar");
    print( get("foo") ); // "bar"


Version 1.3.0 Final
-------------------

In conjunction with the 2.0 beta release version 1.3.0 has been declared final. 
Version 1.3.0 fixes one major bug introduced with properties-style variable
allocation.  Additional bug fixes appear in the 2.0 code.


Getting Started
---------------

Download the bet release from http://www.beanshell.org/download.html.

You may launch a class source file containing a static main() method as you 
would any other bsh script. e.g.

  java bsh.Interpreter bsh/util/ClassBrowser.java

or, if you use the script launcher:

  bsh bsh/util/ClassBrowser.java

You may also simply source the .java files or script classes directly in your 
ordinary BeanShell scripts.

The BeanShell Users's Manual has not yet been updated for version 2.0, but
please check back soon for updates.


Known Issues with BeanShell 2.0b1
---------------------------------

- Class generation currently requires reflective accessibility security
permissions (will probably not work under a tight security policy or in an
applet).  BeanShell currently installs generated classes directly in the
current classloader by accessing the protected defineClass() method.

- In order to run a class file's main method with arguments from the command 
line the class containing your main method must be the last item in the
file.  i.e. The public class declaration must currently be the last declaration
in the file.  (You can alternately just source() the file into your script and
invoke the main() method as any other static method).

- Static final fields (constants) in interfaces are currently broken.
(BeanShell will error when you attempt to declare them).

- Non-static inner classes are currently implemented in a non-standard way
(using mix-ins) so mixing interpreted classes with their pre-compiled inner
classes will not work properly in all cases.

- Inner classes are not properly "imported" in some cases. e.g. Class A
contains one ormore inner classes.  Class B extends class A and attempt to
refer to those inner classes by their unqualified names.

- Static blocks in the class body are not yet implemented.

- If you have a source class at the wrong place in the classpath you may get a
non-fatal error when bsh attempts to load the class again.

- The existing BeanShell deficiency relating to postfix array operators comes
up more often now.  e.g. public static void main( String args [] ); will
not parse...  use "String [] args" instead.


Developer Notes
---------------

The source for BeanShell 2.0 is not yet in CVS but will be soon.

The debugClasses property can be used to save generated class files. e.g.
  -DdebugClasses=<outputDir>
However these persisted class files will not yet function outside of the
classloader in which they were created (the script body is not currently 
persisted with the class).


The ASM bytecode library
------------------------

To generate the necessary bytecode for BeanShell's dynamic classes at runtime
we have incorporated with permission a subset of the ASM bytecode library from 
Objectweb (http://asm.objectweb.org).  ASM is a remarkably efficient, fast, 
and easy to use bytecode generator that weighs in at only 22K.  (The subset
we use is only about 17K.)   If you are using BCEL or SERP please check out
ASM as a light weight alternative.


Roadmap
-------

Since the new code is fairly stable I would like to work towards finalizing
version 2.0.0 as soon as possible rather than pushing version 1.3.0 as widely 
as planned.  Your feedback and comments will help this greatly.


Thanks,
Pat Niemeyer