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. 
/*
 * 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
 * limitations under the License.
 */

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

import org.apache.xerces.impl.dv.DatatypeValidator;
import org.apache.xerces.impl.dv.InvalidDatatypeValueException;
import org.apache.xerces.impl.dv.ValidationContext;
import org.apache.xerces.util.XMLChar;


IDREFDatatypeValidator - represents the IDREFS
attribute type from XML 1.0 recommendation. The
Value Space of IDREF is the set of all strings
that match the NCName production and have been
used in an XML Document as the value of an element 
or attribute of Type ID. The Lexical space of
IDREF is the set of strings that match the NCName
production.


The Value space of IDREF is scoped to a specific
instance document


Author:Jeffrey Rodriguez, IBM, Sandy Gao, IBM
@xerces.internal
Version:$Id: IDREFDatatypeValidator.java 699892 2008-09-28 21:08:27Z mrglavas $
/**
 * <P>IDREFDatatypeValidator - represents the IDREFS
 * attribute type from XML 1.0 recommendation. The
 * Value Space of IDREF is the set of all strings
 * that match the NCName production and have been
 * used in an XML Document as the value of an element 
 * or attribute of Type ID. The Lexical space of
 * IDREF is the set of strings that match the NCName
 * production.</P>
 * <P>The Value space of IDREF is scoped to a specific
 * instance document</P>
 *
 * @xerces.internal  
 * 
 * @author Jeffrey Rodriguez, IBM
 * @author Sandy Gao, IBM
 * 
 * @version $Id: IDREFDatatypeValidator.java 699892 2008-09-28 21:08:27Z mrglavas $
 */
public class IDREFDatatypeValidator implements DatatypeValidator {

    // construct an IDREF datatype validator
    public IDREFDatatypeValidator() {
    }

    
Checks that "content" string is valid IDREF value.
If invalid a Datatype validation exception is thrown.

Params:
  • content –       the string value that needs to be validated
  • context –       the validation context
Throws:
  • InvalidDatatypeException – if the content is
        invalid according to the rules for the validators
See Also:
/**
     * Checks that "content" string is valid IDREF value.
     * If invalid a Datatype validation exception is thrown.
     * 
     * @param content       the string value that needs to be validated
     * @param context       the validation context
     * @throws InvalidDatatypeException if the content is
     *         invalid according to the rules for the validators
     * @see InvalidDatatypeValueException
     */
    public void validate(String content, ValidationContext context) throws InvalidDatatypeValueException {

        //Check if is valid key-[81] EncName ::= [A-Za-z] ([A-Za-z0-9._] | '-')*
        if(context.useNamespaces()) {
            if (!XMLChar.isValidNCName(content)) {
                throw new InvalidDatatypeValueException("IDREFInvalidWithNamespaces", new Object[]{content});
            }
        }
        else {
            if (!XMLChar.isValidName(content)) {
                throw new InvalidDatatypeValueException("IDREFInvalid", new Object[]{content});
            }
        }

        context.addIdRef(content);
        
    }

}