org.opengis.cite.geotiff11.util.ValidationUtils Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of ets-geotiff11 Show documentation
Describe purpose of test suite.
The newest version!
package org.opengis.cite.geotiff11.util;

import java.io.File;
import java.io.IOException;
import java.net.URI;
import java.net.URL;
import java.util.Arrays;
import java.util.HashSet;
import java.util.Set;
import java.util.logging.Level;

import javax.xml.XMLConstants;
import javax.xml.namespace.QName;
import javax.xml.stream.XMLEventReader;
import javax.xml.stream.XMLInputFactory;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.events.Attribute;
import javax.xml.stream.events.StartElement;
import javax.xml.transform.Source;
import javax.xml.transform.stream.StreamSource;

import org.apache.xerces.util.XMLCatalogResolver;
import org.opengis.cite.geotiff11.Namespaces;
import org.opengis.cite.validation.SchematronValidator;
import org.w3c.dom.ls.LSResourceResolver;

/**
 * A utility class that provides convenience methods to support schema validation.
 */
public class ValidationUtils {

	static final String ROOT_PKG = "/org/opengis/cite/geotiff11/";

	private static final XMLCatalogResolver SCH_RESOLVER = initCatalogResolver();

	private static XMLCatalogResolver initCatalogResolver() {
		return (XMLCatalogResolver) createSchemaResolver(Namespaces.SCH);
	}

	/**
	 * Creates a resource resolver suitable for locating schemas using an entity catalog.
	 * In effect, local copies of standard schemas are returned instead of retrieving them
	 * from external repositories.
	 * @param schemaLanguage A URI that identifies a schema language by namespace name.
	 * @return A {@code LSResourceResolver} object that is configured to use an OASIS
	 * entity catalog.
	 */
	public static LSResourceResolver createSchemaResolver(URI schemaLanguage) {
		String catalogFileName;
		if (schemaLanguage.equals(Namespaces.XSD)) {
			catalogFileName = "schema-catalog.xml";
		}
		else {
			catalogFileName = "schematron-catalog.xml";
		}
		URL catalogURL = ValidationUtils.class.getResource(ROOT_PKG + catalogFileName);
		XMLCatalogResolver resolver = new XMLCatalogResolver();
		resolver.setCatalogList(new String[] { catalogURL.toString() });
		return resolver;
	}

	/**
	 * Constructs a SchematronValidator that will check an XML resource against the rules
	 * defined in a Schematron schema. An attempt is made to resolve the schema reference
	 * using an entity catalog; if this fails the reference is used as given.
	 * @param schemaRef A reference to a Schematron schema; this is expected to be a
	 * relative or absolute URI value, possibly matching the system identifier for some
	 * entry in an entity catalog.
	 * @param phase The name of the phase to invoke.
	 * @return A SchematronValidator instance, or {@code null} if the validator cannot be
	 * constructed (e.g. invalid schema reference or phase name).
	 */
	public static SchematronValidator buildSchematronValidator(String schemaRef, String phase) {
		Source source = null;
		try {
			String catalogRef = SCH_RESOLVER.resolveSystem(schemaRef.toString());
			if (null != catalogRef) {
				source = new StreamSource(URI.create(catalogRef).toString());
			}
			else {
				source = new StreamSource(schemaRef);
			}
		}
		catch (IOException x) {
			TestSuiteLogger.log(Level.WARNING, "Error reading Schematron schema catalog.", x);
		}
		SchematronValidator validator = null;
		try {
			validator = new SchematronValidator(source, phase);
		}
		catch (Exception e) {
			TestSuiteLogger.log(Level.WARNING, "Error creating Schematron validator.", e);
		}
		return validator;
	}

	/**
	 * Extracts a set of XML Schema references from a source XML document. The document
	 * element is expected to include the standard xsi:schemaLocation attribute.
	 * @param source The source instance to read from; its base URI (systemId) should be
	 * set.
	 * @param baseURI An alternative base URI to use if the source does not have a system
	 * identifier set or if its system id is a {@code file} URI. This will usually be the
	 * URI used to retrieve the resource; it may be null.
	 * @return A Set containing absolute URI references that specify the locations of XML
	 * Schema resources.
	 * @throws javax.xml.stream.XMLStreamException If an error occurs while reading the
	 * source instance.
	 */
	public static Set extractSchemaReferences(Source source, String baseURI) throws XMLStreamException {
		XMLInputFactory factory = XMLInputFactory.newInstance();
		XMLEventReader reader = factory.createXMLEventReader(source);
		// advance to document element
		StartElement docElem = reader.nextTag().asStartElement();
		Attribute schemaLoc = docElem
			.getAttributeByName(new QName(XMLConstants.W3C_XML_SCHEMA_INSTANCE_NS_URI, "schemaLocation"));
		if (null == schemaLoc) {
			throw new RuntimeException("No xsi:schemaLocation attribute found. See ISO 19136, A.3.1.");
		}
		String[] uriValues = schemaLoc.getValue().split("\\s+");
		if (uriValues.length % 2 != 0) {
			throw new RuntimeException("xsi:schemaLocation attribute contains an odd number of URI values:\n"
					+ Arrays.toString(uriValues));
		}
		Set schemaURIs = new HashSet();
		// one or more pairs of [namespace name] [schema location]
		for (int i = 0; i < uriValues.length; i += 2) {
			URI schemaURI = null;
			if (!URI.create(uriValues[i + 1]).isAbsolute() && (null != source.getSystemId())) {
				String schemaRef = URIUtils.resolveRelativeURI(source.getSystemId(), uriValues[i + 1]).toString();
				if (schemaRef.startsWith("file") && !new File(schemaRef).exists() && (null != baseURI)) {
					schemaRef = URIUtils.resolveRelativeURI(baseURI, uriValues[i + 1]).toString();
				}
				schemaURI = URI.create(schemaRef);
			}
			else {
				schemaURI = URI.create(uriValues[i + 1]);
			}
			schemaURIs.add(schemaURI);
		}
		return schemaURIs;
	}

}