OoasTools

/**

  *

  *                      OOAS Compiler

  *

  *       Copyright 2015, AIT Austrian Institute of Technology.

  * This code is based on the C# Version of the OOAS Compiler, which is

  * copyright 2015 by the Institute of Software Technology, Graz University

  * of Technology with portions copyright by the AIT Austrian Institute of

  * Technology. All rights reserved.

  *

  * SEE THE "LICENSE" FILE FOR THE TERMS UNDER WHICH THIS FILE IS PROVIDED.

  *

  * If you modify the file please update the list of contributors below to in-

  * clude your name. Please also stick to the coding convention of using TABs

  * to do the basic (block-level) indentation and spaces for anything after

  * that. (Enable the display of special chars and it should be pretty obvious

  * what this means.) Also, remove all trailing whitespace.

  *

  * Contributors:

  *               Willibald Krenn (AIT)

  *               Stephan Zimmerer (AIT)

  *               Markus Demetz (AIT)

  *               Christoph Czurda (AIT)

  *

  */

package org.momut.ooas.visitors.optimisation;

import org.momut.ooas.ast.identifiers.MainModule;

import org.momut.ooas.parser.ParserState;

import org.momut.ooas.visitors.OoaEmptyVisitor;

/**

 * Iteratively applies the remove trivial Prioritized/Nondet/Seq visitors until

 * we've reached a fixed point and no more changes can be done.

 *

 * @author willibald

 */

public final class OoaRemoveTrivialBlocksVisitor extends OoaEmptyVisitor {

        final ParserState m_state;

        private boolean removePrio(MainModule m) {

                final OoaRemoveTrivialPrioritizedCompositionVisitor vis = new OoaRemoveTrivialPrioritizedCompositionVisitor(m_state);

                vis.visit(m);

                return vis.changedAst();

        }

        private boolean removeNonDet(MainModule m) {

                final OoaRemoveTrivialNondetChoiceCompositionVisitor vis = new OoaRemoveTrivialNondetChoiceCompositionVisitor(m_state);

                vis.visit(m);

                return vis.changedAst();

        }

        private boolean removeSeq(MainModule m) {

                final OoaRemoveTrivialSequentialCompositionVisitor vis = new OoaRemoveTrivialSequentialCompositionVisitor(m_state);

                vis.visit(m);

                return vis.changedAst();

        }

        private boolean joinSeq(MainModule m) {

                final OoaJoinSequentialCompositionBlocksVisitor vis = new OoaJoinSequentialCompositionBlocksVisitor(m_state);

                vis.visit(m);

                return vis.changedAst();

        }

        @Override

        public void visit(MainModule mainModule)

        {

                boolean changes = true;

                while (changes) {

                        changes = false;

                        changes |= removePrio(mainModule);

                        changes |= removeNonDet(mainModule);

                        changes |= removeSeq(mainModule);

                        changes |= joinSeq(mainModule);

                }

        }

        public OoaRemoveTrivialBlocksVisitor(ParserState aState)

        {

                m_state = aState;

        }

}