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| /** | |
| * <p> | |
| * 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> | |
| * There are a number of popular technologies available for creating an XML schema. | |
| * Some of the most popular ones include: | |
| * | |
| * <ul> | |
| * <li><strong>Document Type Definition (DTD)</strong> | |
| * - XML's built-in schema language. | |
| * </li> | |
| * <li><strong><a href="https://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="https://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="https://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="https://www.oasis-open.org">Organization for the Advancement | |
| * of Structured Information Standards (OASIS)</a> and is both an OASIS | |
| * and an <a href="https://www.iso.org/home.html">ISO (International Organization | |
| * for Standardization)</a> standard. | |
| * </li> | |
| * <li><strong><a href="https://standards.iso.org/ittf/PubliclyAvailableStandards/c055982_ISO_IEC_19757-3_2016.zip">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 <a href="https://standards.iso.org/ittf/PubliclyAvailableStandards/index.html">an ISO standard</a>. | |
| * </li> | |
| * </ul> | |
| * <p> | |
| * While JAXP supports validation as a feature of an XML parser, represented by | |
| * either a {@link javax.xml.parsers.SAXParser} or {@link javax.xml.parsers.DocumentBuilder} | |
| * instance, the {@code Validation} API is preferred. | |
| * | |
| * <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: | |
| * | |
| * <ul> | |
| * <li><strong>Support for additional schema languages.</strong> | |
| * The JAXP parser implementations support only 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): | |
| * | |
| * <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> | |
| * | |
| * | |
| * @since 1.5 | |
| */ | |
| package javax.xml.validation; |