http://xml.apache.org/commons/components/external/: xml-commons provides an Apache-hosted set of DOM, SAX, and JAXP interfaces for use in other xml-based projects. Our hope is that we can standardize on both a common version and packaging scheme for these critical XML standards interfaces to make the lives of both our developers and users easier. The External Components portion of xml-commons contains interfaces that are defined by external standards organizations. For DOM, that's the W3C; for SAX it's David Megginson and sax.sourceforge.net; for JAXP it's Sun. 
/*
 * 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.
 */

// $Id: Schema.java 446598 2006-09-15 12:55:40Z jeremias $

package javax.xml.validation;


Immutable in-memory representation of grammar.


This object represents a set of constraints that can be checked/
enforced against an XML document. 

 A Schema object is thread safe and applications are encouraged to share it across many parsers in many threads. 
 A Schema object is immutable in the sense that it shouldn't change the set of constraints once it is created. In other words, if an application validates the same document twice against the same Schema, it must always produce the same result. 
 A Schema object is usually created from SchemaFactory. 
 Two kinds of validators can be created from a Schema object. One is Validator, which provides highly-level validation operations that cover typical use cases. The other is ValidatorHandler, which works on top of SAX for better modularity. 
 This specification does not refine the Object.equals(Object) method. In other words, if you parse the same schema twice, you may still get !schemaA.equals(schemaB).

Author:Kohsuke Kawaguchi
See Also:
Version:$Revision: 446598 $, $Date: 2006-09-15 08:55:40 -0400 (Fri, 15 Sep 2006) $
Since:1.5
/**
 * Immutable in-memory representation of grammar.
 * 
 * <p>
 * This object represents a set of constraints that can be checked/
 * enforced against an XML document. 
 * 
 * <p>
 * A {@link Schema} object is thread safe and applications are
 * encouraged to share it across many parsers in many threads.
 * 
 * <p>
 * A {@link Schema} object is immutable in the sense that it shouldn't
 * change the set of constraints once it is created. In other words,
 * if an application validates the same document twice against the same
 * {@link Schema}, it must always produce the same result. 
 * 
 * <p>
 * A {@link Schema} object is usually created from {@link SchemaFactory}.
 * 
 * <p>
 * Two kinds of validators can be created from a {@link Schema} object.
 * One is {@link Validator}, which provides highly-level validation
 * operations that cover typical use cases. The other is
 * {@link ValidatorHandler}, which works on top of SAX for better
 * modularity.
 * 
 * <p>
 * This specification does not refine
 * the {@link java.lang.Object#equals(java.lang.Object)} method.
 * In other words, if you parse the same schema twice, you may
 * still get <code>!schemaA.equals(schemaB)</code>.
 * 
 * @author <a href="mailto:Kohsuke.Kawaguchi@Sun.com">Kohsuke Kawaguchi</a>
 * @version $Revision: 446598 $, $Date: 2006-09-15 08:55:40 -0400 (Fri, 15 Sep 2006) $
 * @see <a href="http://www.w3.org/TR/xmlschema-1/">XML Schema Part 1: Structures</a>
 * @see <a href="http://www.w3.org/TR/xml11/">Extensible Markup Language (XML) 1.1</a>
 * @see <a href="http://www.w3.org/TR/REC-xml">Extensible Markup Language (XML) 1.0 (Second Edition)</a>
 * @since 1.5
 */
public abstract class Schema {
    
    
Constructor for the derived class.


The constructor does nothing.

/**
     * Constructor for the derived class.
     * 
     * <p>
     * The constructor does nothing.
     */
    protected Schema() {
    }
    
    
Creates a new Validator for this Schema. 

A validator enforces/checks the set of constraints this object
represents.

Returns:
     Always return a non-null valid object.
/**
     * Creates a new {@link Validator} for this {@link Schema}.
     * 
     * <p>
     * A validator enforces/checks the set of constraints this object
     * represents.
     * 
     * @return

     *      Always return a non-null valid object.
     */
    public abstract Validator newValidator();
    
    
Creates a new ValidatorHandler for this Schema. 
Returns:
     Always return a non-null valid object.
/**
     * Creates a new {@link ValidatorHandler} for this {@link Schema}.
     * 
     * @return

     *      Always return a non-null valid object.
     */
    public abstract ValidatorHandler newValidatorHandler();
}