HV-1577 Move from JAXB to Stax for XML configuration

Author: marko-bekhta

engine/src/main/java/org/hibernate/validator/internal/engine/ConfigurationImpl.java

@@ -49,8 +49,8 @@
 import org.hibernate.validator.internal.util.privilegedactions.GetClassLoader;
 import org.hibernate.validator.internal.util.privilegedactions.GetInstancesFromServiceLoader;
 import org.hibernate.validator.internal.util.privilegedactions.SetContextClassLoader;
-import org.hibernate.validator.internal.xml.ValidationBootstrapParameters;
-import org.hibernate.validator.internal.xml.ValidationXmlParser;
+import org.hibernate.validator.internal.xml.config.ValidationBootstrapParameters;
+import org.hibernate.validator.internal.xml.config.ValidationXmlParser;
 import org.hibernate.validator.messageinterpolation.ResourceBundleMessageInterpolator;
 import org.hibernate.validator.resourceloading.PlatformResourceBundleLocator;
 import org.hibernate.validator.spi.resourceloading.ResourceBundleLocator;

engine/src/main/java/org/hibernate/validator/internal/util/logging/Log.java

@@ -841,4 +841,7 @@ ValidationException getUnableToAccessMethodException(Lookup lookup, @FormatWith(
 	@LogMessage(level = DEBUG)
 	@Message(id = 240, value = "Constraint validator payload set to %1$s.")
 	void logConstraintValidatorPayload(Object payload);
+
+	@Message(id = 241, value = "Encountered unsupported element %1$s while parsing the XML configuration.")
+	ValidationException logUnknownElementInXmlConfiguration(String tag);
 }

engine/src/main/java/org/hibernate/validator/internal/xml/AbstractStaxBuilder.java

@@ -0,0 +1,88 @@
+/*
+ * Hibernate Validator, declare and validate application constraints
+ *
+ * License: Apache License, Version 2.0
+ * See the license.txt file in the root directory or <http://www.apache.org/licenses/LICENSE-2.0>.
+ */
+package org.hibernate.validator.internal.xml;
+
+import java.util.Optional;
+
+import javax.xml.namespace.QName;
+import javax.xml.stream.XMLEventReader;
+import javax.xml.stream.XMLStreamException;
+import javax.xml.stream.events.Attribute;
+import javax.xml.stream.events.StartElement;
+import javax.xml.stream.events.XMLEvent;
+
+/**
+ * Other Stax xml builders should extend from this one.
+ * Provides some common functionality like reading an attribute value
+ * or value of a simple tag.
+ *
+ * @author Marko Bekhta
+ */
+public abstract class AbstractStaxBuilder {
+
+	protected abstract String getAcceptableQName();
+
+	/**
+	 * Checks if the given {@link XMLEvent} is a {@link StartElement} and if the
+	 * corresponding xml tag can be processed based on a tag name.
+	 *
+	 * @param xmlEvent an event to check
+	 *
+	 * @return {@code true} if corresponding event can be processed by current builder,
+	 * 		{@code false} otherwise
+	 */
+	protected boolean accept(XMLEvent xmlEvent) {
+		return xmlEvent.isStartElement() && xmlEvent.asStartElement().getName().getLocalPart().equals( getAcceptableQName() );
+	}
+
+	public boolean process(XMLEventReader xmlEventReader, XMLEvent xmlEvent) {
+		if ( accept( xmlEvent ) ) {
+			try {
+				add( xmlEventReader, xmlEvent );
+			}
+			catch (XMLStreamException e) {
+				throw new IllegalStateException( e );
+			}
+			return true;
+		}
+		return false;
+	}
+
+	protected abstract void add(XMLEventReader xmlEventReader, XMLEvent xmlEvent) throws XMLStreamException;
+
+	/**
+	 * Reads a value between a simple tag element. In case of a {@code <someTag>some-value</someTag>} will
+	 * return {@code some-value} as a string.
+	 *
+	 * @param xmlEventReader a current {@link XMLEventReader}
+	 *
+	 * @return a value of a current xml tag as a string
+	 */
+	protected String readSingleElement(XMLEventReader xmlEventReader) throws XMLStreamException {
+		// trimming the string value as it might contain leading/trailing spaces or \n
+		XMLEvent xmlEvent = xmlEventReader.nextEvent();
+		StringBuilder stringBuilder = new StringBuilder( xmlEvent.asCharacters().getData() );
+		while ( xmlEventReader.peek().isCharacters() ) {
+			xmlEvent = xmlEventReader.nextEvent();
+			stringBuilder.append( xmlEvent.asCharacters().getData() );
+		}
+		return stringBuilder.toString().trim();
+	}
+
+	/**
+	 * Reads a value of an attribute of a given element.
+	 *
+	 * @param startElement an element to get an attribute from
+	 * @param qName a {@link QName} of an attribute to read
+	 *
+	 * @return a value of an attribute if it is present, {@link Optional#empty()} otherwise
+	 */
+	protected Optional<String> readAttribute(StartElement startElement, QName qName) {
+		Attribute attribute = startElement.getAttributeByName( qName );
+		return Optional.ofNullable( attribute ).map( Attribute::getValue );
+	}
+}

engine/src/main/java/org/hibernate/validator/internal/xml/CloseIgnoringInputStream.java

@@ -17,7 +17,7 @@
  *
  * @author Guillaume Smet
  */
-class CloseIgnoringInputStream extends FilterInputStream {
+public class CloseIgnoringInputStream extends FilterInputStream {
 
 	public CloseIgnoringInputStream(InputStream in) {
 		super( in );