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 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code 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 General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

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package com.sun.tools.internal.xjc.reader.relaxng;

import java.util.HashSet;

import java.util.Set;

import java.util.Stack;

import com.sun.xml.internal.rngom.digested.DAttributePattern;

import com.sun.xml.internal.rngom.digested.DChoicePattern;

import com.sun.xml.internal.rngom.digested.DDefine;

import com.sun.xml.internal.rngom.digested.DListPattern;

import com.sun.xml.internal.rngom.digested.DMixedPattern;

import com.sun.xml.internal.rngom.digested.DOneOrMorePattern;

import com.sun.xml.internal.rngom.digested.DOptionalPattern;

import com.sun.xml.internal.rngom.digested.DPatternWalker;

import com.sun.xml.internal.rngom.digested.DRefPattern;

import com.sun.xml.internal.rngom.digested.DZeroOrMorePattern;

/**

 * Fumigate the named patterns that can be bound to inheritance.

 *

 * @author Kohsuke Kawaguchi

 */

final class TypePatternBinder extends DPatternWalker {

    private boolean canInherit;

    private final Stack<Boolean> stack = new Stack<Boolean>();

    /**

     * Patterns that are determined not to be bindable to inheritance.

     */

    private final Set<DDefine> cannotBeInherited = new HashSet<DDefine>();

    void reset() {

        canInherit = true;

        stack.clear();

    }

    public Void onRef(DRefPattern p) {

        if(!canInherit) {

            cannotBeInherited.add(p.getTarget());

        } else {

            // if the whole pattern is like "A,B", we can only inherit from

            // either A or B. For now, always derive from A.

            // it might be worthwhile to have a smarter binding logic where

            // we pick A and B based on their 'usefulness' --- by taking into

            // account how many other paterns are derived from those.

            canInherit = false;

        }

        return null;

    }

    /*

        Set the flag to false if we hit a pattern that cannot include

        a <ref> to be bound as an inheritance.

        All the following code are the same

    */

    public Void onChoice(DChoicePattern p) {

        push(false);

        super.onChoice(p);

        pop();

        return null;

    }

    public Void onAttribute(DAttributePattern p) {

        push(false);

        super.onAttribute(p);

        pop();

        return null;

    }

    public Void onList(DListPattern p) {

        push(false);

        super.onList(p);

        pop();

        return null;

    }

    public Void onMixed(DMixedPattern p) {

        push(false);

        super.onMixed(p);

        pop();

        return null;

    }

    public Void onOneOrMore(DOneOrMorePattern p) {

        push(false);

        super.onOneOrMore(p);

        pop();

        return null;

    }

    public Void onZeroOrMore(DZeroOrMorePattern p) {

        push(false);

        super.onZeroOrMore(p);

        pop();

        return null;

    }

    public Void onOptional(DOptionalPattern p) {

        push(false);

        super.onOptional(p);

        pop();

        return null;

    }

    private void push(boolean v) {

        stack.push(canInherit);

        canInherit = v;

    }

    private void pop() {

        canInherit = stack.pop();

    }

}