/jEdit/tags/jedit-4-0-pre3/bsh/BSHArrayDimensions.java

/*****************************************************************************
 *                                                                           *
 *  This file is part of the BeanShell Java Scripting distribution.          *
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 *  The contents of this file are subject to the Sun Public License Version  *
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 *  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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 *                                                                           *
 *  Patrick Niemeyer (pat@pat.net)                                           *
 *  Author of Learning Java, O'Reilly & Associates                           *
 *  http://www.pat.net/~pat/                                                 *
 *                                                                           *
 *****************************************************************************/


package bsh;

import java.lang.reflect.Array;

/**
	The name of this class is somewhat misleading.  This covers both the case
	where there is an array initializer and 
*/
class BSHArrayDimensions extends SimpleNode
{
	public Class baseType;
    private int arrayDims;

	/** The Length in each dimension.  This value set by the eval() */
	// is it ok to cache this here?
	// it can't change, right?
    /*transient?why?*/ 
	public int [] dimensions;  

    BSHArrayDimensions(int id) { super(id); }

    public void addArrayDimension() { arrayDims++; }

    public Object eval( 
			Class type, CallStack callstack, Interpreter interpreter ) 
		throws EvalError 
	{
		Interpreter.debug("array base type = "+type);
		baseType = type;
		return eval( callstack, interpreter );
	}

	/**
		Evaluate the structure of the array in one of two ways:

			a) an initializer exists, evaluate it and return
			the fully constructed array object, also record the dimensions
			of that array
			
			b) evaluate and record the lengths in each dimension and 
			return void.

		The structure of the array dims is maintained in dimensions.
	*/
    public Object eval( CallStack callstack, Interpreter interpreter )  
		throws EvalError
    {
		SimpleNode child = (SimpleNode)jjtGetChild(0);

		if (child instanceof BSHArrayInitializer)
		// evaluate the initializer and the dimensions it returns
		{
			if ( baseType == null )
				throw new EvalError( 
					"Internal Array Eval err:  unknown base type", this);

			Object initValue = ((BSHArrayInitializer)child).eval(
				baseType, arrayDims, callstack, interpreter);

			Class arrayClass = initValue.getClass();
			dimensions = new int[
				Reflect.getArrayDimensions(arrayClass) ];

			// compare with number of dimensions explicitly specified
			if (dimensions.length != arrayDims)
				throw new EvalError(
				"Incompatible initializer. Allocation calls for a " + 
				arrayDims + " dimensional array, but initializer is a " +
					dimensions.length + " dimensional array", this);

			// fill in dimensions[] lengths
			Object arraySlice = initValue;
			for(int i = 0; i < dimensions.length; i++) {
				dimensions[i] = Array.getLength( arraySlice );
				if ( dimensions[i] > 0 )
					arraySlice = Array.get(arraySlice, 0);
			}

			return initValue;
		}
		else 
		// evaluate the dimensions of the array
		{
			dimensions = new int[ jjtGetNumChildren() ];
			for(int i = 0; i < dimensions.length; i++)
			{
				try {
					Object length = ((SimpleNode)jjtGetChild(i)).eval(
						callstack, interpreter);
					dimensions[i] = ((Primitive)length).intValue();
				}
				catch(Exception e)
				{
					throw new EvalError(
						"Array index: " + i + 
						" does not evaluate to an integer", this);
				}
			}
		}

        return Primitive.VOID;
    }
}