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 * reserved comment block

 * DO NOT REMOVE OR ALTER!

 */

/*

 * Licensed to the Apache Software Foundation (ASF) under one or more

 * contributor license agreements.  See the NOTICE file distributed with

 * this work for additional information regarding copyright ownership.

 * The ASF licenses this file to You under the Apache License, Version 2.0

 * (the "License"); you may not use this file except in compliance with

 * the License.  You may obtain a copy of the License at

 *

 *      http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

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package com.sun.org.apache.xerces.internal.impl.xs.models;

import com.sun.org.apache.xerces.internal.impl.dtd.models.CMNode;

import com.sun.org.apache.xerces.internal.impl.dtd.models.CMStateSet;

import com.sun.org.apache.xerces.internal.impl.xs.XSModelGroupImpl;

/**

 *

 * Content model Bin-Op node.

 *

 * @xerces.internal

 *

 * @author Neil Graham, IBM

 */

public class XSCMBinOp extends CMNode {

    // -------------------------------------------------------------------

    //  Constructors

    // -------------------------------------------------------------------

    public XSCMBinOp(int type, CMNode leftNode, CMNode rightNode)

    {

        super(type);

        // Insure that its one of the types we require

        if ((type() != XSModelGroupImpl.MODELGROUP_CHOICE)

        &&  (type() != XSModelGroupImpl.MODELGROUP_SEQUENCE)) {

            throw new RuntimeException("ImplementationMessages.VAL_BST");

        }

        // Store the nodes and init any data that needs it

        fLeftChild = leftNode;

        fRightChild = rightNode;

    }

    // -------------------------------------------------------------------

    //  Package, final methods

    // -------------------------------------------------------------------

    final CMNode getLeft() {

        return fLeftChild;

    }

    final CMNode getRight() {

        return fRightChild;

    }

    // -------------------------------------------------------------------

    //  Package, inherited methods

    // -------------------------------------------------------------------

    public boolean isNullable() {

        //

        //  If its an alternation, then if either child is nullable then

        //  this node is nullable. If its a concatenation, then both of

        //  them have to be nullable.

        //

        if (type() == XSModelGroupImpl.MODELGROUP_CHOICE)

            return (fLeftChild.isNullable() || fRightChild.isNullable());

        else if (type() == XSModelGroupImpl.MODELGROUP_SEQUENCE)

            return (fLeftChild.isNullable() && fRightChild.isNullable());

        else

            throw new RuntimeException("ImplementationMessages.VAL_BST");

    }

    // -------------------------------------------------------------------

    //  Protected, inherited methods

    // -------------------------------------------------------------------

    protected void calcFirstPos(CMStateSet toSet) {

        if (type() == XSModelGroupImpl.MODELGROUP_CHOICE) {

            // Its the the union of the first positions of our children.

            toSet.setTo(fLeftChild.firstPos());

            toSet.union(fRightChild.firstPos());

        }

         else if (type() == XSModelGroupImpl.MODELGROUP_SEQUENCE) {

            //

            //  If our left child is nullable, then its the union of our

            //  children's first positions. Else is our left child's first

            //  positions.

            //

            toSet.setTo(fLeftChild.firstPos());

            if (fLeftChild.isNullable())

                toSet.union(fRightChild.firstPos());

        }

         else {

            throw new RuntimeException("ImplementationMessages.VAL_BST");

        }

    }

    protected void calcLastPos(CMStateSet toSet) {

        if (type() == XSModelGroupImpl.MODELGROUP_CHOICE) {

            // Its the the union of the first positions of our children.

            toSet.setTo(fLeftChild.lastPos());

            toSet.union(fRightChild.lastPos());

        }

        else if (type() == XSModelGroupImpl.MODELGROUP_SEQUENCE) {

            //

            //  If our right child is nullable, then its the union of our

            //  children's last positions. Else is our right child's last

            //  positions.

            //

            toSet.setTo(fRightChild.lastPos());

            if (fRightChild.isNullable())

                toSet.union(fLeftChild.lastPos());

        }

        else {

            throw new RuntimeException("ImplementationMessages.VAL_BST");

        }

    }

    // -------------------------------------------------------------------

    //  Private data members

    //

    //  fLeftChild

    //  fRightChild

    //      These are the references to the two nodes that are on either

    //      side of this binary operation.

    // -------------------------------------------------------------------

    private CMNode  fLeftChild;

    private CMNode  fRightChild;

} // XSCMBinOp