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.xs;


Describes a constraining facet. Enumeration and pattern facets are exposed 
via XSMultiValueFacet interface.

/**
 * Describes a constraining facet. Enumeration and pattern facets are exposed 
 * via <code>XSMultiValueFacet</code> interface.
 */
public interface XSFacet extends XSObject {
    
The name of the facet, e.g. FACET_LENGTH, FACET_TOTALDIGITS
 (see XSSimpleTypeDefinition). 

/**
     * The name of the facet, e.g. <code>FACET_LENGTH, FACET_TOTALDIGITS</code>
     *  (see <code>XSSimpleTypeDefinition</code>). 
     */
    public short getFacetKind();

    
A value of this facet. 

/**
     * A value of this facet. 
     */
    public String getLexicalFacetValue();

    
If this facet is length, minLength, maxLength, totalDigits, or
fractionDigits, and if the value can fit in "int", then return the value
of the facet as an int. If the value can't fit, return -1. Use
getActualFacetValue() to get the BigInteger representation. For all other
facets, return 0.

/**
     * If this facet is length, minLength, maxLength, totalDigits, or
     * fractionDigits, and if the value can fit in "int", then return the value
     * of the facet as an int. If the value can't fit, return -1. Use
     * getActualFacetValue() to get the BigInteger representation. For all other
     * facets, return 0.
     */
    public int getIntFacetValue();

    
If this facet is minInclusive, maxInclusive, minExclusive, or
maxExclusive, then return the actual value of the facet. If this facet
is length, minLength, maxLength, totalDigits, or fractionDigits, then
return a BigInteger representation of the value. If this facet is
whiteSpace, then return the String representation of the facet.

/**
     * If this facet is minInclusive, maxInclusive, minExclusive, or
     * maxExclusive, then return the actual value of the facet. If this facet
     * is length, minLength, maxLength, totalDigits, or fractionDigits, then
     * return a BigInteger representation of the value. If this facet is
     * whiteSpace, then return the String representation of the facet.
     */
    public Object getActualFacetValue();

    
[Facets]: check whether a facet is fixed. 

/**
     * [Facets]: check whether a facet is fixed. 
     */
    public boolean getFixed();

    
An annotation if it exists, otherwise null. If not null
then the first [annotation] from the sequence of annotations.

/**
     * An annotation if it exists, otherwise <code>null</code>. If not null
     * then the first [annotation] from the sequence of annotations.
     */
    public XSAnnotation getAnnotation();

    
A sequence of [annotations] or an empty XSObjectList.

/**
     * A sequence of [annotations] or an empty <code>XSObjectList</code>.
     */
    public XSObjectList getAnnotations();    
}