/*
 * Copyright 1999-2002,2004 The Apache Software Foundation.
 * 
 * Licensed 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,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.xerces.impl.dtd.models;

import org.apache.xerces.impl.dtd.XMLContentSpec;

/**
 * Content model Uni-Op node.
 * 
 * @xerces.internal
 *
 * @version $Id: CMUniOp.java 320090 2004-10-04 22:00:42Z mrglavas $
 */
public class CMUniOp extends CMNode
{
    // -------------------------------------------------------------------
    //  Constructors
    // -------------------------------------------------------------------
    public CMUniOp(int type, CMNode childNode) 
    {
        super(type);

        // Insure that its one of the types we require
        if ((type() != XMLContentSpec.CONTENTSPECNODE_ZERO_OR_ONE)
        &&  (type() != XMLContentSpec.CONTENTSPECNODE_ZERO_OR_MORE)
        &&  (type() != XMLContentSpec.CONTENTSPECNODE_ONE_OR_MORE))
        {
            throw new RuntimeException("ImplementationMessages.VAL_UST");
        }

        // Store the node and init any data that needs it
        fChild = childNode;
    }


    // -------------------------------------------------------------------
    //  Package, final methods
    // -------------------------------------------------------------------
    final CMNode getChild()
    {
        return fChild;
    }


    // -------------------------------------------------------------------
    //  Package, inherited methods
    // -------------------------------------------------------------------
    public boolean isNullable() 
    {
        //
        //  For debugging purposes, make sure we got rid of all non '*'
        //  repetitions. Otherwise, '*' style nodes are always nullable.
        //
        if (type() == XMLContentSpec.CONTENTSPECNODE_ONE_OR_MORE)
	    return fChild.isNullable();
	else
	    return true;
    }


    // -------------------------------------------------------------------
    //  Protected, inherited methods
    // -------------------------------------------------------------------
    protected void calcFirstPos(CMStateSet toSet) 
    {
        // Its just based on our child node's first pos
        toSet.setTo(fChild.firstPos());
    }

    protected void calcLastPos(CMStateSet toSet) 
    {
        // Its just based on our child node's last pos
        toSet.setTo(fChild.lastPos());
    }


    // -------------------------------------------------------------------
    //  Private data members
    //
    //  fChild
    //      This is the reference to the one child that we have for this
    //      unary operation.
    // -------------------------------------------------------------------
    private CMNode  fChild;
};