Evaluator.java

package com.drawbridge.jsengine.ast;

import java.util.LinkedList;

import com.drawbridge.jsengine.Scope;
import com.drawbridge.jsengine.jsobjects.ExecutionException;
import com.drawbridge.jsengine.jsobjects.JSType;
import com.drawbridge.utils.Utils;
import com.google.caja.lexer.FilePosition;
import com.google.caja.parser.js.ArrayConstructor;
import com.google.caja.parser.js.AssignOperation;
import com.google.caja.parser.js.Block;
import com.google.caja.parser.js.BooleanLiteral;
import com.google.caja.parser.js.Conditional;
import com.google.caja.parser.js.ControlOperation;
import com.google.caja.parser.js.Declaration;
import com.google.caja.parser.js.ExpressionStmt;
import com.google.caja.parser.js.ForLoop;
import com.google.caja.parser.js.FunctionConstructor;
import com.google.caja.parser.js.FunctionDeclaration;
import com.google.caja.parser.js.Identifier;
import com.google.caja.parser.js.IntegerLiteral;
import com.google.caja.parser.js.Noop;
import com.google.caja.parser.js.ObjectConstructor;
import com.google.caja.parser.js.RealLiteral;
import com.google.caja.parser.js.Reference;
import com.google.caja.parser.js.ReturnStmt;
import com.google.caja.parser.js.SimpleOperation;
import com.google.caja.parser.js.SpecialOperation;
import com.google.caja.parser.js.StringLiteral;
import com.google.caja.parser.js.ValueProperty;

public abstract class Evaluator
{

	public abstract JSType evaluate() throws EvaluatorException, ExecutionException;

	public boolean compare(Evaluator e)
	{
		if (!e.getClass().equals(getClass()))
			return false;

		if (mChildren.size() != e.mChildren.size())
			return false;

		for (int i = 0; i < mChildren.size(); i++)
		{
			if (mChildren.get(i) == null || e.mChildren.get(i) == null || !mChildren.get(i).compare(e.mChildren.get(i)))
				return false;
		}

		if (e.getFilePosition().equals(getFilePosition()))
			return true;
		else
			return false;
	}

	/**
	 * Generates code interleaved with original code
	 * 
	 * @return
	 * @throws Exception
	 */
	// public abstract String generateCode() throws Exception;

	/**
	 * Returns blocks to be shown in the Visual Language Representation
	 * 
	 * @return
	 */
	public abstract LinkedList<com.drawbridge.vl.blocks.Block> getBlocks();

	private FilePosition			mFilePosition;
	public final Scope				mScope;
	public Evaluator				mParent;

	public LinkedList<Evaluator>	mChildren	= new LinkedList<Evaluator>();

	public Evaluator(Evaluator parent, Scope scope, FilePosition position) {
		mParent = parent;
		mFilePosition = position;
		this.mScope = scope;
	}

	/**
	 * Returns a new evaluator for a given AST component
	 * 
	 * @param Parent
	 *            - The parent evaluator for this object
	 * @param Scope
	 *            - The scope for this object
	 * @param Object
	 *            - The AST object we want to use
	 * @return Returns an appropriate evaluator
	 */
	public static Evaluator getEvaluator(Evaluator parent, Scope scope, Object object)
	{

		if (object instanceof SpecialOperation)
		{
			return new SpecialOperationEvaluator(parent, scope, (SpecialOperation) object);
		}
		else if (object instanceof FunctionDeclaration)
		{
			return new FunctionDeclarationEvaluator(parent, scope, (FunctionDeclaration) object);
		}
		else if (object instanceof ControlOperation)
		{
			return new ControlOperationEvaluator(parent, scope, (ControlOperation) object);
		}
		else if (object instanceof SimpleOperation)
		{
			return new SimpleOperationEvaluator(parent, scope, (SimpleOperation) object);
		}
		else if (object instanceof IntegerLiteral)
		{
			return new IntegerLiteralEvaluator(parent, scope, (IntegerLiteral) object);
		}
		else if (object instanceof RealLiteral)
		{
			return new RealLiteralEvaluator(parent, scope, (RealLiteral) object);
		}
		else if (object instanceof BooleanLiteral)
		{
			return new BooleanLiteralEvaluator(parent, scope, (BooleanLiteral) object);
		}
		else if (object instanceof Noop)
		{
			return new NoopEvaluator(parent, scope, (Noop) object);
		}
		else if (object instanceof StringLiteral)
		{
			return new StringLiteralEvaluator(parent, scope, (StringLiteral) object);
		}
		else if (object instanceof AssignOperation)
		{
			return new AssignOperationEvaluator(parent, scope, (AssignOperation) object);
		}
		else if (object instanceof ArrayConstructor)
		{
			return new ArrayConstructorEvaluator(parent, scope, (ArrayConstructor) object);
		}
		else if (object instanceof Declaration)
		{
			return new DeclarationEvaluator(parent, scope, (Declaration) object);
		}
		else if (object instanceof ReturnStmt)
		{
			return new ReturnStmtEvaluator(parent, scope, (ReturnStmt) object);
		}
		else if (object instanceof Identifier)
		{
			return new IdentifierEvaluator(parent, scope, (Identifier) object);
		}
		else if (object instanceof ForLoop)
		{
			return new ForLoopEvaluator(parent, scope, (ForLoop) object);
		}
		else if (object instanceof Conditional)
		{
			return new ConditionalEvaluator(parent, scope, (Conditional) object);
		}
		else if (object instanceof ExpressionStmt)
		{
			return new ExpressionStmtEvaluator(parent, scope, (ExpressionStmt) object);
		}
		else if (object instanceof ObjectConstructor)
		{
			return new ObjectConstructorEvaluator(parent, scope, (ObjectConstructor) object);
		}
		else if (object instanceof ValueProperty)
		{
			return new ValuePropertyEvaluator(parent, scope, (ValueProperty) object);
		}
		else if (object instanceof Reference)
		{
			return new ReferenceEvaluator(parent, scope, (Reference) object);
		}
		else if (object instanceof FunctionConstructor)
		{
			return new FunctionConstructorEvaluator(parent, scope, (FunctionConstructor) object);
		}
		else if (object instanceof Block)
		{
			return new BlockEvaluator(parent, scope, (Block) object);
		}
		else
		{
			if (object != null)
				Utils.out.println("Evaluator returned null for class of type: " + object.getClass().getName());
			else
				Utils.out.println("Evaluator returned null for class of type: null");
			return null;
		}

	}

	public FilePosition getFilePosition()
	{
		return mFilePosition;
	}

	public void setFilePosition(FilePosition f)
	{
		mFilePosition = f;
	}

	public boolean contains(int startPosInFile, int endPosInFile)
	{
		if (this.getFilePosition().startCharInFile() <= startPosInFile &&
				this.getFilePosition().endCharInFile() >= endPosInFile)
		{
			return true;
		}
		else
			return false;
	}

	/**
	 * 
	 * @param child
	 * @return -1 if not child
	 */
	public int getChildIndex(Evaluator child)
	{
		if (mChildren == null)
			return -1;
		for (int i = 0; i < mChildren.size(); i++)
		{
			if (mChildren.get(i).equals(child))
			{
				return i;
			}
		}
		return -1;
	}

	public class EvaluatorException extends Exception
	{
		private static final long	serialVersionUID	= -6787406324868348906L;

		public EvaluatorException() {
			super();
		}

		public EvaluatorException(String message) {
			super(message);
		}

		public EvaluatorException(String message, Throwable cause) {
			super(message, cause);
		}

		public EvaluatorException(Throwable cause) {
			super(cause);
		}
	}

	@Override
	public String toString()
	{
		return this.getClass().getSimpleName();
	}

}