https://xerces.apache.org/xerces2-j/: Xerces2 is the next generation of high performance, fully compliant XML parsers in the Apache Xerces family. This new version of Xerces introduces the Xerces Native Interface (XNI), a complete framework for building parser components and configurations that is extremely modular and easy to program. The Apache Xerces2 parser is the reference implementation of XNI but other parser components, configurations, and parsers can be written using the Xerces Native Interface. For complete design and implementation documents, refer to the XNI Manual. Xerces2 is a fully conforming XML Schema 1.0 processor. A partial experimental implementation of the XML Schema 1.1 Structures and Datatypes Working Drafts (December 2009) and an experimental implementation of the XML Schema Definition Language (XSD): Component Designators (SCD) Candidate Recommendation (January 2010) are provided for evaluation. For more information, refer to the XML Schema page. Xerces2 also provides a complete implementation of the Document Object Model Level 3 Core and Load/Save W3C Recommendations and provides a complete implementation of the XML Inclusions (XInclude) W3C Recommendation. It also provides support for OASIS XML Catalogs v1.1. Xerces2 is able to parse documents written according to the XML 1.1 Recommendation, except that it does not yet provide an option to enable normalization checking as described in section 2.13 of this specification. It also handles namespaces according to the XML Namespaces 1.1 Recommendation, and will correctly serialize XML 1.1 documents if the DOM level 3 load/save APIs are in use. 
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 * 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,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
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package org.apache.xerces.impl.xs.models;

import org.apache.xerces.impl.dtd.models.CMNode;
import org.apache.xerces.impl.dtd.models.CMStateSet;
import org.apache.xerces.impl.xs.XSParticleDecl;


Content model Uni-Op node.

Author:Neil Graham, IBM
@xerces.internal
Version:$Id: XSCMUniOp.java 476309 2006-11-17 20:49:31Z mrglavas $
/**
 *
 * Content model Uni-Op node.
 *
 * @xerces.internal 
 *
 * @author Neil Graham, IBM
 * @version $Id: XSCMUniOp.java 476309 2006-11-17 20:49:31Z mrglavas $
 */
public class XSCMUniOp extends CMNode {
    // -------------------------------------------------------------------
    //  Constructors
    // -------------------------------------------------------------------
    public XSCMUniOp(int type, CMNode childNode) {
        super(type);

        // Insure that its one of the types we require
        if ((type() != XSParticleDecl.PARTICLE_ZERO_OR_ONE)
        &&  (type() != XSParticleDecl.PARTICLE_ZERO_OR_MORE)
        &&  (type() != XSParticleDecl.PARTICLE_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() == XSParticleDecl.PARTICLE_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;
} // XSCMUniOp