NonCaptureGroupTransformation.java

/*
 * Copyright (C) 2011 eXo Platform SAS.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */

package org.exoplatform.web.controller.router;

import org.exoplatform.web.controller.regexp.GroupType;
import org.exoplatform.web.controller.regexp.RENode;
import org.exoplatform.web.controller.regexp.REVisitor;

/**
 * @author <a href="mailto:julien.viet@exoplatform.com">Julien Viet</a>
 * @version $Revision$
 */
class NonCaptureGroupTransformation extends REVisitor<RuntimeException> {

    NonCaptureGroupTransformation() {
    }

    @Override
    protected void visit(RENode.Disjunction disjunction) throws RuntimeException {
        super.visit(disjunction);

        // Wrap the content of the top disjunction with a capturing group
        if (disjunction.getParent() == null) {
            if (disjunction.hasAlternative()) {
                RENode.Alternative alternative = disjunction.getAlternative();
                disjunction.clearAlternative();
                if (disjunction.hasNext()) {
                    RENode.Disjunction next = disjunction.getNext();
                    disjunction.clearNext();
                    RENode.Alternative group = new RENode.Alternative(new RENode.Group(
                            new RENode.Disjunction(alternative, next), GroupType.CAPTURING_GROUP));
                    disjunction.setAlternative(group);
                } else {
                    RENode.Alternative group = new RENode.Alternative(new RENode.Group(new RENode.Disjunction(alternative),
                            GroupType.CAPTURING_GROUP));
                    disjunction.setAlternative(group);
                }
            } else {
                if (disjunction.hasNext()) {
                    RENode.Disjunction next = disjunction.getNext();
                    disjunction.clearNext();
                    RENode.Alternative group = new RENode.Alternative(new RENode.Group(new RENode.Disjunction(next),
                            GroupType.CAPTURING_GROUP));
                    disjunction.setAlternative(group);
                } else {
                    RENode.Alternative group = new RENode.Alternative(new RENode.Group(new RENode.Disjunction(),
                            GroupType.CAPTURING_GROUP));
                    disjunction.setAlternative(group);
                }
            }
        }
    }

    @Override
    protected void visit(RENode.Group expr) throws RuntimeException {
        // We make any capturing group as non capturing
        if (expr.getType() == GroupType.CAPTURING_GROUP) {
            expr.setType(GroupType.NON_CAPTURING_GROUP);
        }

        //
        super.visit(expr);
    }
}