/*****************************************************************************
 *                                                                           *
 *  This file is part of the BeanShell Java Scripting distribution.          *
 *  Documentation and updates may be found at http://www.beanshell.org/      *
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 *  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.                                          *
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 *  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    *
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 *                                                                           *
 *  Patrick Niemeyer (pat@pat.net)                                           *
 *  Author of Learning Java, O'Reilly & Associates                           *
 *  http://www.pat.net/~pat/                                                 *
 *                                                                           *
 *****************************************************************************/

package bsh;

import java.lang.reflect.*;
import java.io.*;
import java.util.Vector;

/**
    All of the reflection API code lies here.  It is in the form
	of static utilities.  Maybe this belongs in LHS.java or a generic object 
	wrapper class.
*/
/*
	Note: This class is messy.  The method and field resolution need to be
	rewritten.  Various methods in here catch NoSuchMethod or NoSuchField
	exceptions during their searches.  These should be rewritten to avoid
	having to catch the exceptions.  Method lookups are now cached at a high 
	level so they are less important, however the logic is messy.
*/
class Reflect 
{
    /**
		Invoke method on arbitrary object.
		invocation may be static (through the object instance) or dynamic.
		Object may be a bsh scripted object (This type).
	*/
    public static Object invokeObjectMethod(
		Object object, String methodName, Object[] args, 
		Interpreter interpreter, CallStack callstack, SimpleNode callerInfo ) 
		throws ReflectError, EvalError, InvocationTargetException
	{
		// Bsh scripted object
		if ( object instanceof This && !This.isExposedThisMethod( methodName) ) 
			return ((This)object).invokeMethod( 
				methodName, args, interpreter, callstack, callerInfo,
				false/*delcaredOnly*/ );
		else 
		// Java object
		{ 
			// find the java method
			try {
				BshClassManager bcm = 
					interpreter == null ? null : interpreter.getClassManager();
				Class clas = object.getClass();

				Method method = resolveExpectedJavaMethod( 
					bcm, clas, object, methodName, args, false );

				return invokeOnMethod( method, object, args );
			} catch ( UtilEvalError e ) {
				throw e.toEvalError( callerInfo, callstack );
			}
		}
    }

    /** 
		Invoke a method known to be static.
		No object instance is needed and there is no possibility of the 
		method being a bsh scripted method.
	*/
    public static Object invokeStaticMethod(
		BshClassManager bcm, Class clas, String methodName, Object [] args )
        throws ReflectError, UtilEvalError, InvocationTargetException
    {
        Interpreter.debug("invoke static Method");
        Method method = resolveExpectedJavaMethod( 
			bcm, clas, null, methodName, args, true );
		return invokeOnMethod( method, null, args );
    }

	/**
		Invoke the Java method on the specified object.
		@param args may be null
	*/
	static Object invokeOnMethod( 
		Method method, Object object, Object[] args ) 
		throws ReflectError, InvocationTargetException
	{
		if ( args == null )
			args = new Object[0];

		if ( Interpreter.DEBUG ) 
		{
			Interpreter.debug("Invoking method (entry): "
				+method+" with args:" );
			for(int i=0; i
		This method performs Java method caching internally.

		@param onlyStatic 
			The method located must be static, the object param may be null.
		@return the method or null if no matching method was found.
		@deprecated
	*/
	/*
		Note: object is only used here for precondition... get rid of it?
	*/
    protected static Method resolveJavaMethod(
		BshClassManager bcm, Class clas, Object object, 
		String name, Object[] args, boolean onlyStatic )
        throws UtilEvalError
    {
		// Why is object in the args?
		if ( object == Primitive.NULL )
			throw new UtilTargetError( new NullPointerException(
				"Attempt to invoke method " +name+" on null value" ) );

        Class [] types = Types.getTypes(args);
		return resolveJavaMethod( bcm, clas, name, types, onlyStatic );
	}

	/*
		Notes:

		This is broken.  It finds public but less specific methods over
		non-public but more specific ones.

		findMostSpecficMethod() needs to be rewritten to eliminate 
		findAccessibleMethod.  We should implement the findMostSpecificMethod 
		that uses the publicOnly flag.  FindMostSpecificMethod should also
		operate in two passes to give standard Java assignable matches priority
		over extended bsh type matches.
	*/
    protected static Method resolveJavaMethod(
		BshClassManager bcm, Class clas, String name, 
		Class [] types, boolean onlyStatic )
        throws UtilEvalError
    {
		if ( clas == null )
			throw new InterpreterError("null class");

		Method method = null;
		if ( bcm == null ) 
			Interpreter.debug("resolveJavaMethod UNOPTIMIZED lookup");
		else {
			method = bcm.getResolvedMethod( clas, name, types, onlyStatic );
			if ( method != null )
				return method;
		}

		if ( Interpreter.DEBUG )
			Interpreter.debug( "Searching for method: "+
				StringUtil.methodString(name, types)
					+ " in '" + clas.getName() + "'" );

		/*
			First try for an accessible version of the exact match.
			This first lookup seems redundant with below, but is apparently
			needed.  This whole thing is messy.
		*/
		try {
			method  = findAccessibleMethod( clas, name, types );
		} catch ( SecurityException e ) { }

		// If not found and there are arguments to match -
		// Look for an overloaded assignable match
		// (First find the method, then find accessible version of it)
		if ( method == null && types.length > 0 ) 
		{
			// Gather all of the methods of class and parents
			Vector mv = new Vector();
			Class c = clas;
			while( c != null )
			{
				Method [] m = c.getDeclaredMethods();
				for(int i=0; i 0 ) 
		{
			Class c = (Class)classQ.firstElement();
			classQ.removeElementAt(0);

			// Is this it?
			// Is the class public or can we use accessibility?
			if ( Modifier.isPublic( c.getModifiers() )
				|| ( Capabilities.haveAccessibility() ) )
			{
				try 
				{
					meth = c.getDeclaredMethod( name, types );

					// Is the method public or are we in accessibility mode?
					if ( ( Modifier.isPublic( meth.getModifiers() )
						&& Modifier.isPublic( c.getModifiers() ) )
						|| ( Capabilities.haveAccessibility() 
							&& ReflectManager.RMSetAccessible( meth ) ) )
					{
						found = meth; // Yes, it is.
						break;
					}
					else
					{
						// Found at least one matching method but couldn't use
						inaccessibleVersion = meth;
					}
				} catch ( NoSuchMethodException e ) { 
					// ignore and move on
				}
			}
			// No, it is not.
			
			// Is this a class?
			if ( !c.isInterface() ) {
				Class superclass = c.getSuperclass();
				if ( superclass != null )
					classQ.addElement((Object)superclass);
			}

			// search all of its interfaces breadth first
			Class [] intfs = c.getInterfaces();
			for( int i=0; i< intfs.length; i++ )
				classQ.addElement((Object)intfs[i]);
		}

		if ( found != null )
			return found;

		if ( inaccessibleVersion != null )
			throw new UtilEvalError("Found non-public method: "
				+inaccessibleVersion
				+".  Use setAccessibility(true) to enable access to "
				+" private and protected members of classes." );
		
		return null; 
	}

	/**
		Primary object constructor
		This method is simpler than those that must resolve general method
		invocation because constructors are not inherited.
	*/
    static Object constructObject( Class clas, Object[] args )
        throws ReflectError, InvocationTargetException
    {
		if ( clas.isInterface() )
			throw new ReflectError(
				"Can't create instance of an interface: "+clas);

        Object obj = null;
        Class[] types = Types.getTypes(args);
        Constructor con = null;

		/* 
			Find an appropriate constructor.
			use declared here to see package and private as well
			(there are no inherited constructors to worry about) 
		*/
		Constructor[] constructors = clas.getDeclaredConstructors();
		if ( Interpreter.DEBUG ) 
			Interpreter.debug("Looking for most specific constructor: "+clas);
		con = findMostSpecificConstructor(types, constructors);

		if ( con == null )
		{
			if ( types.length == 0 )
				throw new ReflectError(
					"Can't find default constructor for: "+clas);
			else
				throw new ReflectError(
					"Can't find constructor: " 
					+ StringUtil.methodString( clas.getName(), types )
					+" in class: "+ clas.getName() );
		}

		if ( !Modifier.isPublic( con.getModifiers() )
			&& Capabilities.haveAccessibility() )
			try {
				ReflectManager.RMSetAccessible( con );
			} catch ( UtilEvalError e ) { /*ignore*/ }

        args=Primitive.unwrap( args );
        try {
            obj = con.newInstance( args );
        } catch(InstantiationException e) {
            throw new ReflectError("the class is abstract ");
        } catch(IllegalAccessException e) {
            throw new ReflectError(
				"We don't have permission to create an instance."
				+"Use setAccessibility(true) to enable access." );
        } catch(IllegalArgumentException e) {
            throw new ReflectError("the number of arguments was wrong");
        } 
		if (obj == null)
            throw new ReflectError("couldn't construct the object");

        return obj;
    }

    /**
        Implement JLS 15.11.2 for method resolution
		@return null on no match
    */
	/*
		Notes:

		This is broken.  It finds public but less specific methods over
		non-public but more specific ones.

		This method needs to be rewritten to eliminate findAccessibleMethod.
		We should implement the findMostSpecificMethod that uses the publicOnly
		flag.  FindMostSpecificMethod should also operate in two passes to give
		standard Java assignable matches priority over extended bsh type
		matches.
	*/
    static Method findMostSpecificMethod(
		String name, Class[] idealMatch, Method[] methods,
		boolean publicOnly )
    {
		// Pull out the method signatures with matching names
		Vector sigs = new Vector();
		Vector meths = new Vector();
		for(int i=0; i