Mercurial > hg > openjdk > jdk9 > jaxp
view src/java.xml/share/classes/javax/xml/validation/package.html @ 1129:e6d6c8126a36
8180385: Fix HTML5 issues in the java.xml module
Reviewed-by: joehw, lancea
author | jjg |
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date | Tue, 16 May 2017 17:36:12 -0700 |
parents | 2bfaf29cc90b |
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<!doctype html> <!-- Copyright (c) 2003, 2017, Oracle and/or its affiliates. All rights reserved. DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. This code is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License version 2 only, as published by the Free Software Foundation. Oracle designates this particular file as subject to the "Classpath" exception as provided by Oracle in the LICENSE file that accompanied this code. This code is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License version 2 for more details (a copy is included in the LICENSE file that accompanied this code). You should have received a copy of the GNU General Public License version 2 along with this work; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA or visit www.oracle.com if you need additional information or have any questions. --> <html> <head> <title>javax.xml.validation</title> <meta name="CVS" content="$Id: package.html,v 1.2 2005/06/10 03:50:43 jeffsuttor Exp $" /> <meta name="AUTHOR" content="Jeff.Suttor@Sun.com" /> </head> <body> <p> This package provides an API for validation of XML documents. <em>Validation</em> is the process of verifying that an XML document is an instance of a specified XML <em>schema</em>. An XML schema defines the content model (also called a <em>grammar</em> or <em>vocabulary</em>) that its instance documents will represent. </p> <p> There are a number of popular technologies available for creating an XML schema. Some of the most popular include: </p> <ul> <li><strong>Document Type Definition (DTD)</strong> - XML's built-in schema language.</li> <li><strong><a href="http://www.w3.org/XML/Schema">W3C XML Schema (WXS)</a></strong> - an object-oriented XML schema language. WXS also provides a type system for constraining the character data of an XML document. WXS is maintained by the <a href="http://www.w3.org">World Wide Web Consortium (W3C)</a> and is a W3C Recommendation (that is, a ratified W3C standard specification).</li> <li><strong><a href="http://www.relaxng.org">RELAX NG (RNG)</a></strong> - a pattern-based, user-friendly XML schema language. RNG schemas may also use types to constrain XML character data. RNG is maintained by the <a href="http://www.oasis-open.org">Organization for the Advancement of Structured Information Standards (OASIS)</a> and is both an OASIS and an <a href="http://www.iso.org">ISO (International Organization for Standardization)</a> standard.</li> <li><strong><a href="http://www.schematron.com/">Schematron</a></strong> - a rules-based XML schema language. Whereas DTD, WXS, and RNG are designed to express the structure of a content model, Schematron is designed to enforce individual rules that are difficult or impossible to express with other schema languages. Schematron is intended to supplement a schema written in structural schema language such as the aforementioned. Schematron is in the process of becoming an ISO standard.</li> </ul> <p> Previous versions of JAXP supported validation as a feature of an XML parser, represented by either a {@link javax.xml.parsers.SAXParser} or {@link javax.xml.parsers.DocumentBuilder} instance. </p> <p> The JAXP validation API decouples the validation of an instance document from the parsing of an XML document. This is advantageous for several reasons, some of which are: </p> <ul> <li><strong>Support for additional schema langauges.</strong> As of JDK 1.5, the two most popular JAXP parser implementations, Crimson and Xerces, only support a subset of the available XML schema languages. The Validation API provides a standard mechanism through which applications may take of advantage of specialization validation libraries which support additional schema languages.</li> <li><strong>Easy runtime coupling of an XML instance and schema.</strong> Specifying the location of a schema to use for validation with JAXP parsers can be confusing. The Validation API makes this process simple (see <a href="#example-1">example</a> below).</li> </ul> <p> <a id="example-1"><strong>Usage example</strong>.</a> The following example demonstrates validating an XML document with the Validation API (for readability, some exception handling is not shown): </p> <pre> // parse an XML document into a DOM tree DocumentBuilder parser = DocumentBuilderFactory.newInstance().newDocumentBuilder(); Document document = parser.parse(new File("instance.xml")); // create a SchemaFactory capable of understanding WXS schemas SchemaFactory factory = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI); // load a WXS schema, represented by a Schema instance Source schemaFile = new StreamSource(new File("mySchema.xsd")); Schema schema = factory.newSchema(schemaFile); // create a Validator instance, which can be used to validate an instance document Validator validator = schema.newValidator(); // validate the DOM tree try { validator.validate(new DOMSource(document)); } catch (SAXException e) { // instance document is invalid! } </pre> <p> The JAXP parsing API has been integrated with the Validation API. Applications may create a {@link javax.xml.validation.Schema} with the validation API and associate it with a {@link javax.xml.parsers.DocumentBuilderFactory} or a {@link javax.xml.parsers.SAXParserFactory} instance by using the {@link javax.xml.parsers.DocumentBuilderFactory#setSchema(Schema)} and {@link javax.xml.parsers.SAXParserFactory#setSchema(Schema)} methods. <strong>You should not</strong> both set a schema and call <code>setValidating(true)</code> on a parser factory. The former technique will cause parsers to use the new validation API; the latter will cause parsers to use their own internal validation facilities. <strong>Turning on both of these options simultaneously will cause either redundant behavior or error conditions.</strong> </p> </body> </html>