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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 *
* allow use of your version of this file only under the terms of the LGPL *
* and not to allow others to use your version of this file under the SPL, *
* indicate your decision by deleting the provisions above and replace *
* them with the notice and other provisions required by the LGPL. If you *
* do not delete the provisions above, a recipient may use your version of *
* this file under either the SPL or the LGPL. *
* *
* Patrick Niemeyer (pat@pat.net) *
* Author of Learning Java, O'Reilly & Associates *
* http://www.pat.net/~pat/ *
* *
*****************************************************************************/
package bsh;
import java.util.Vector;
/**
A ClassNameSpace represents the body a scripted class definition or
scripted class instance. In the case of the class definition it serves as
the Class object and holds the class initializer method (called before the
constructor).
<p/>
When serving as a class definition, only static members are visible and
attempting to access an instance member will cause a "can't reach instance
from static context" exception.
<p/>
When serving as a class instance static members are dissallowed (except
by the initializer) and are ignored, allowing them to be seen in the class
definition.
<p/>
Class instances also serve as the top scope of instance variables declared
within the class (by the initializer).
*/
/*
This would obviously be cleaner if we made a second subclass of NameSpace:
ClassInstanceNameSpace.
*/
public class ClassNameSpace extends NameSpace
{
/** Java class for this class static body */
Class javaClass;
/** Java instance object for this class instance */
Object javaObject;
public ClassNameSpace(
NameSpace parent, String name, Class javaClass )
throws EvalError
{
super( parent, name );
this.javaClass = javaClass;
}
/**
Instance constructor
*/
public ClassNameSpace( ClassNameSpace parent, Object javaObject )
throws EvalError
{
super( parent, parent.getName() );
this.javaObject = javaObject;
}
public This constructClassInstance( Object[] args,
Interpreter interpreter, CallStack callstack, SimpleNode callerInfo )
throws EvalError
{
ClassNameSpace classNameSpace = this;
String className = classNameSpace.getName();
BshMethod classInitializer = null;
try {
classInitializer =
classNameSpace.getMethod(
BSHClassDeclaration.CLASSINITNAME, new Class[0] );
} catch ( UtilEvalError e ) { // shouldn't happen
throw e.toEvalError(
"Error getting class initializer", callerInfo, callstack );
}
if ( classInitializer == null )
throw new EvalError("Unable to find initializer for class.",
callerInfo, callstack);
// Get the (non-initializer) constructor, if any
Class [] sig = Types.getTypes( args );
BshMethod constructor = null;
try {
constructor =
classNameSpace.getMethod( className, sig );
} catch ( UtilEvalError e ) { // shouldn't happen
throw e.toEvalError(
"Error getting constructor", callerInfo, callstack );
}
// No constructor found
if ( constructor == null )
{
// args constructor not found
if ( args.length > 0 )
throw new EvalError("Constructor not found: "+
StringUtil.methodString( className, sig ),
callerInfo, callstack );
else
// no args constructor missing. Ok if no other constructors exist
{
BshMethod [] methods = classNameSpace.getMethods();
for(int i=0; i<methods.length; i++)
if ( methods[i].getName().equals( className ) )
throw new EvalError(
"Default (no args) constructor not found: "+
StringUtil.methodString( className, sig ),
callerInfo, callstack );
}
}
// Invoke the constructors
// Recurse to handle superclasses
NameSpace superNameSpace = null;
if ( classNameSpace.getParent() instanceof ClassNameSpace
&& ((ClassNameSpace)classNameSpace.getParent()).isClass()
)
{
// Call the superClass's default constructor
// Note: this isn't always right -
// We need to allow super() in the constructor()
This superInstance =
((ClassNameSpace)classNameSpace.getParent())
.constructClassInstance(
new Object[0], interpreter, callstack, callerInfo );
superNameSpace = superInstance.getNameSpace();
}
// Chain the instance namespaces
NameSpace instanceNameSpace;
// REMOVE or put back
/*
if ( superNameSpace != null )
instanceNameSpace = new ClassNameSpace(
superNameSpace, className, INSTANCE );
else
instanceNameSpace = new ClassNameSpace( classNameSpace );
*/
instanceNameSpace = null;
callstack.push( instanceNameSpace );
// Invoke the class initializer method
try {
classInitializer.invoke(
new Object[0], interpreter, callstack, callerInfo,
true/*overrideNameSpace*/ );
} catch ( EvalError e ) {
e.reThrow("Exception in default constructor: "+e);
}
// Call the specific constructor if any
if ( constructor != null )
{
try {
constructor.invoke(
args, interpreter, callstack, callerInfo,
true/*overrideNameSpace*/ );
} catch ( EvalError e ) {
e.reThrow("Exception in constructor: "+e);
}
}
callstack.pop();
// return the initialized object
This instance = instanceNameSpace.getThis( interpreter );
return instance;
}
public String toString()
{
return "Scripted Class "
+(isClassInstance() ? "Instance " : "")
+" : " +super.toString();
}
public boolean isClassInstance() { return javaObject != null; }
public boolean isClass() { return javaClass != null; }
}
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