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BeanShell is a small, free, embeddable Java source interpreter with object scripting language features,
written in Java. BeanShell dynamically executes standard Java syntax and extends it with common scripting
conveniences such as loose types, commands, and method closures like those in Perl and JavaScript.
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/*****************************************************************************
* *
* This file is part of the BeanShell Java Scripting distribution. *
* Documentation and updates may be found at http://www.beanshell.org/ *
* *
* Sun Public License Notice: *
* *
* The contents of this file are subject to the Sun Public License Version *
* 1.0 (the "License"); you may not use this file except in compliance with *
* the License. A copy of the License is available at http://www.sun.com *
* *
* The Original Code is BeanShell. The Initial Developer of the Original *
* Code is Pat Niemeyer. Portions created by Pat Niemeyer are Copyright *
* (C) 2000. All Rights Reserved. *
* *
* GNU Public License Notice: *
* *
* Alternatively, the contents of this file may be used under the terms of *
* the GNU Lesser General Public License (the "LGPL"), in which case the *
* provisions of LGPL are applicable instead of those above. If you wish to *
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* indicate your decision by deleting the provisions above and replace *
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* do not delete the provisions above, a recipient may use your version of *
* this file under either the SPL or the LGPL. *
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* Patrick Niemeyer ([email protected]) *
* Author of Learning Java, O'Reilly & Associates *
* http://www.pat.net/~pat/ *
* *
*****************************************************************************/
package bsh;
import java.lang.reflect.Array;
import java.lang.reflect.InvocationTargetException;
/**
New object, new array, or inner class style allocation with body.
*/
class BSHAllocationExpression extends SimpleNode
{
BSHAllocationExpression(int id) { super(id); }
private static int innerClassCount = 0;
public Object eval( CallStack callstack, Interpreter interpreter)
throws EvalError
{
// type is either a class name or a primitive type
SimpleNode type = (SimpleNode)jjtGetChild(0);
// args is either constructor arguments or array dimensions
SimpleNode args = (SimpleNode)jjtGetChild(1);
if ( type instanceof BSHAmbiguousName )
{
BSHAmbiguousName name = (BSHAmbiguousName)type;
if (args instanceof BSHArguments)
return objectAllocation(name, (BSHArguments)args,
callstack, interpreter );
else
return objectArrayAllocation(name, (BSHArrayDimensions)args,
callstack, interpreter );
}
else
return primitiveArrayAllocation((BSHPrimitiveType)type,
(BSHArrayDimensions)args, callstack, interpreter );
}
private Object objectAllocation(
BSHAmbiguousName nameNode, BSHArguments argumentsNode,
CallStack callstack, Interpreter interpreter
)
throws EvalError
{
NameSpace namespace = callstack.top();
Object[] args = argumentsNode.getArguments( callstack, interpreter );
if ( args == null)
throw new EvalError( "Null args in new.", this, callstack );
// Look for scripted class object
Object obj = nameNode.toObject(
callstack, interpreter, false/* force class*/ );
// Try regular class
obj = nameNode.toObject(
callstack, interpreter, true/*force class*/ );
Class type = null;
if ( obj instanceof ClassIdentifier )
type = ((ClassIdentifier)obj).getTargetClass();
else
throw new EvalError(
"Unknown class: "+nameNode.text, this, callstack );
// Is an inner class style object allocation
boolean hasBody = jjtGetNumChildren() > 2;
if ( hasBody )
{
BSHBlock body = (BSHBlock)jjtGetChild(2);
if ( type.isInterface() )
return constructWithInterfaceBody(
type, args, body, callstack, interpreter );
else
return constructWithClassBody(
type, args, body, callstack, interpreter );
} else
return constructObject( type, args, callstack );
}
private Object constructObject(
Class type, Object[] args, CallStack callstack )
throws EvalError
{
Object obj;
try {
obj = Reflect.constructObject( type, args );
} catch ( ReflectError e) {
throw new EvalError(
"Constructor error: " + e.getMessage(), this, callstack );
} catch(InvocationTargetException e) {
// No need to wrap this debug
Interpreter.debug("The constructor threw an exception:\n\t" +
e.getTargetException());
throw new TargetError(
"Object constructor", e.getTargetException(),
this, callstack, true);
}
String className = type.getName();
// Is it an inner class?
if ( className.indexOf("$") == -1 )
return obj;
// Temporary hack to support inner classes
// If the obj is a non-static inner class then import the context...
// This is not a sufficient emulation of inner classes.
// Replace this later...
// work through to class 'this'
This ths = callstack.top().getThis( null );
NameSpace instanceNameSpace =
Name.getClassNameSpace( ths.getNameSpace() );
// Change the parent (which was the class static) to the class instance
// We really need to check if we're a static inner class here first...
// but for some reason Java won't show the static modifier on our
// fake inner classes... could generate a flag field.
if ( instanceNameSpace != null
&& className.startsWith( instanceNameSpace.getName() +"$")
)
{
try {
ClassGenerator.getClassGenerator().setInstanceNameSpaceParent(
obj, className, instanceNameSpace );
} catch ( UtilEvalError e ) {
throw e.toEvalError( this, callstack );
}
}
return obj;
}
// TODO
/*
This is totally broken...
need to construct a real inner class block here...
*/
private Object constructWithClassBody(
Class type, Object[] args, BSHBlock block,
CallStack callstack, Interpreter interpreter )
throws EvalError
{
//throw new InterpreterError("constructWithClassBody unimplemented");
String name = callstack.top().getName() + "$" + (++innerClassCount);
Modifiers modifiers = new Modifiers();
modifiers.addModifier( Modifiers.CLASS, "public" );
Class clas;
try {
clas = ClassGenerator.getClassGenerator() .generateClass(
name, modifiers, null/*interfaces*/, type/*superClass*/,
// block is not innerClassBlock here!!!
block, false/*isInterface*/, callstack, interpreter );
} catch ( UtilEvalError e ) {
throw e.toEvalError( this, callstack );
}
try {
return Reflect.constructObject( clas, args );
} catch ( Exception e ) {
if ( e instanceof InvocationTargetException )
e = (Exception)((InvocationTargetException)e)
.getTargetException();
if ( Interpreter.DEBUG )
e.printStackTrace();
throw new EvalError(
"Error constructing inner class instance: "+e, this, callstack
);
}
}
private Object constructWithInterfaceBody(
Class type, Object[] args, BSHBlock body,
CallStack callstack, Interpreter interpreter )
throws EvalError
{
NameSpace namespace = callstack.top();
NameSpace local = new NameSpace(namespace, "AnonymousBlock");
callstack.push(local);
body.eval( callstack, interpreter, true/*overrideNamespace*/ );
callstack.pop();
// statical import fields from the interface so that code inside
// can refer to the fields directly (e.g. HEIGHT)
local.importStatic( type );
try {
return local.getThis(interpreter).getInterface( type );
} catch ( UtilEvalError e ) {
throw e.toEvalError( this, callstack );
}
}
private Object objectArrayAllocation(
BSHAmbiguousName nameNode, BSHArrayDimensions dimensionsNode,
CallStack callstack, Interpreter interpreter
)
throws EvalError
{
NameSpace namespace = callstack.top();
Class type = nameNode.toClass( callstack, interpreter );
if ( type == null )
throw new EvalError( "Class " + nameNode.getName(namespace)
+ " not found.", this, callstack );
return arrayAllocation( dimensionsNode, type, callstack, interpreter );
}
private Object primitiveArrayAllocation(
BSHPrimitiveType typeNode, BSHArrayDimensions dimensionsNode,
CallStack callstack, Interpreter interpreter
)
throws EvalError
{
Class type = typeNode.getType();
return arrayAllocation( dimensionsNode, type, callstack, interpreter );
}
private Object arrayAllocation(
BSHArrayDimensions dimensionsNode, Class type,
CallStack callstack, Interpreter interpreter )
throws EvalError
{
/*
dimensionsNode can return either a fully intialized array or VOID.
when VOID the prescribed array dimensions (defined and undefined)
are contained in the node.
*/
Object result = dimensionsNode.eval( type, callstack, interpreter );
if ( result != Primitive.VOID )
return result;
else
return arrayNewInstance( type, dimensionsNode, callstack );
}
/**
Create an array of the dimensions specified in dimensionsNode.
dimensionsNode may contain a number of "undefined" as well as "defined"
dimensions.
Background: in Java arrays are implemented in arrays-of-arrays style
where, for example, a two dimensional array is a an array of arrays of
some base type. Each dimension-type has a Java class type associated
with it... so if foo = new int[5][5] then the type of foo is
int [][] and the type of foo[0] is int[], etc. Arrays may also be
specified with undefined trailing dimensions - meaning that the lower
order arrays are not allocated as objects. e.g.
if foo = new int [5][]; then foo[0] == null //true; and can later be
assigned with the appropriate type, e.g. foo[0] = new int[5];
(See Learning Java, O'Reilly & Associates more background).
To create an array with undefined trailing dimensions using the
reflection API we must use an array type to represent the lower order
(undefined) dimensions as the "base" type for the array creation...
Java will then create the correct type by adding the dimensions of the
base type to specified allocated dimensions yielding an array of
dimensionality base + specified with the base dimensons unallocated.
To create the "base" array type we simply create a prototype, zero
length in each dimension, array and use it to get its class
(Actually, I think there is a way we could do it with Class.forName()
but I don't trust this). The code is simpler than the explanation...
see below.
*/
private Object arrayNewInstance(
Class type, BSHArrayDimensions dimensionsNode, CallStack callstack )
throws EvalError
{
if ( dimensionsNode.numUndefinedDims > 0 )
{
Object proto = Array.newInstance(
type, new int [dimensionsNode.numUndefinedDims] ); // zeros
type = proto.getClass();
}
try {
return Array.newInstance(
type, dimensionsNode.definedDimensions);
} catch( NegativeArraySizeException e1 ) {
throw new TargetError( e1, this, callstack );
} catch( Exception e ) {
throw new EvalError("Can't construct primitive array: " +
e.getMessage(), this, callstack);
}
}
}