/jEdit/tags/jedit-4-2-pre4/bsh/BSHEnhancedForStatement.java

package bsh;

// Just testing...
import java.util.*;

/**
	 Implementation of the enhanced for(:) statement.  
	 This statement uses BshIterable to support iteration over a wide variety
	 of iterable types.  Under JDK 1.1 this statement supports primitive and 
	 Object arrays, Vectors, and enumerations.  Under JDK 1.2 and later it 
	 additionally supports collections.

	 @author Daniel Leuck 
	 @author Pat Niemeyer
*/
class BSHEnhancedForStatement extends SimpleNode implements ParserConstants 
{
	String varName;

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

    public Object eval( CallStack callstack , Interpreter interpreter )
		throws EvalError 
	{
		Class elementType = null;
		SimpleNode expression, statement=null;

		NameSpace enclosingNameSpace = callstack.top();
		SimpleNode firstNode =((SimpleNode)jjtGetChild(0));
		int nodeCount = jjtGetNumChildren();
		
		if ( firstNode instanceof BSHType ) 
		{
			elementType=((BSHType)firstNode).getType( callstack, interpreter );
			expression=((SimpleNode)jjtGetChild(1));
			if ( nodeCount>2 )
				statement=((SimpleNode)jjtGetChild(2));
		} else 
		{
			expression=firstNode;
			if ( nodeCount>1 )
				statement=((SimpleNode)jjtGetChild(1));
		}

		BlockNameSpace eachNameSpace = new BlockNameSpace( enclosingNameSpace );
		callstack.swap( eachNameSpace );

		final Object iteratee = expression.eval( callstack, interpreter );

		if ( iteratee == Primitive.NULL )
			throw new EvalError("The collection, array, map, iterator, or " +
				"enumeration portion of a for statement cannot be null.", 
				this, callstack );

		CollectionManager cm = CollectionManager.getCollectionManager();
		if ( !cm.isBshIterable( iteratee ) )
			throw new EvalError("Can't iterate over type: "
				+iteratee.getClass(), this, callstack );
		BshIterator iterator = cm.getBshIterator( iteratee );
		
		Object returnControl = Primitive.VOID;
        while( iterator.hasNext() )
        {
			try {
			if ( elementType != null )
				eachNameSpace.setTypedVariable(
					varName, elementType, iterator.next(), false );
			else
				eachNameSpace.setVariable( varName, iterator.next(), false );
			} catch ( UtilEvalError e ) {
				throw e.toEvalError(
					"for loop iterator variable:"+ varName, this, callstack );
			}

            boolean breakout = false; // switch eats a multi-level break here?
            if ( statement != null ) // not empty statement
            {
                Object ret = statement.eval( callstack, interpreter );

                if (ret instanceof ReturnControl)
                {
                    switch(((ReturnControl)ret).kind)
                    {
                        case RETURN:
							returnControl = ret;
							breakout = true;
                            break;

                        case CONTINUE:
                            break;

                        case BREAK:
                            breakout = true;
                            break;
                    }
                }
            }

            if (breakout)
                break;
        }

		callstack.swap(enclosingNameSpace);
        return returnControl;
    }
}