#1 XML.xslt() works

pom.xml

@@ -109,4 +109,18 @@
             <scope>provided</scope>
         </dependency>
     </dependencies>
+    <build>
+        <plugins>
+            <plugin>
+                <artifactId>maven-site-plugin</artifactId>
+                <dependencies>
+                    <dependency>
+                        <groupId>org.apache.maven.doxia</groupId>
+                        <artifactId>doxia-module-markdown</artifactId>
+                        <version>1.3</version>
+                    </dependency>
+                </dependencies>
+            </plugin>
+        </plugins>
+    </build>
 </project>

src/main/java/com/jcabi/xml/XML.java

@@ -32,6 +32,8 @@
 import java.util.List;
 import javax.validation.constraints.NotNull;
 import javax.xml.namespace.NamespaceContext;
+import javax.xml.transform.Source;
+import javax.xml.transform.TransformerException;
 import org.w3c.dom.Node;
 
 /**
@@ -143,4 +145,12 @@ public interface XML {
      */
     Node node();
 
+    /**
+     * Transform to another XML using provided XSL.
+     * @param xsl XSL stylesheet
+     * @return XML document
+     * @throws TransformerException If fails to transform
+     */
+    XML xslt(Source xsl) throws TransformerException;
+
 }

src/main/java/com/jcabi/xml/XMLDocument.java

@@ -39,11 +39,15 @@
 import java.util.List;
 import javax.validation.constraints.NotNull;
 import javax.xml.namespace.NamespaceContext;
+import javax.xml.parsers.DocumentBuilderFactory;
+import javax.xml.parsers.ParserConfigurationException;
 import javax.xml.transform.Source;
+import javax.xml.transform.Transformer;
 import javax.xml.transform.TransformerConfigurationException;
 import javax.xml.transform.TransformerException;
 import javax.xml.transform.TransformerFactory;
 import javax.xml.transform.dom.DOMResult;
+import javax.xml.transform.dom.DOMSource;
 import javax.xml.xpath.XPath;
 import javax.xml.xpath.XPathConstants;
 import javax.xml.xpath.XPathExpressionException;
@@ -52,6 +56,7 @@
 import org.apache.commons.io.FileUtils;
 import org.apache.commons.io.IOUtils;
 import org.apache.commons.lang3.CharEncoding;
+import org.w3c.dom.Document;
 import org.w3c.dom.Node;
 import org.w3c.dom.NodeList;
 
@@ -66,8 +71,27 @@
  */
 @EqualsAndHashCode(of = "dom")
 @Loggable(Loggable.DEBUG)
+@SuppressWarnings("PMD.ExcessiveImports")
 public final class XMLDocument implements XML {
 
+    /**
+     * XPath factory.
+     */
+    private static final XPathFactory XFACTORY =
+        XPathFactory.newInstance();
+
+    /**
+     * Transformer factory.
+     */
+    private static final TransformerFactory TFACTORY =
+        TransformerFactory.newInstance();
+
+    /**
+     * Document Factory.
+     */
+    private static final DocumentBuilderFactory DFACTORY =
+        DocumentBuilderFactory.newInstance();
+
     /**
      * Namespace context to use.
      */
@@ -217,13 +241,27 @@ public Node node() {
         return this.dom;
     }
 
+    @Override
+    @NotNull
+    public XML xslt(final Source xsl) throws TransformerException {
+        final Transformer trans = XMLDocument.TFACTORY.newTransformer(xsl);
+        final Document target;
+        try {
+            target = XMLDocument.DFACTORY.newDocumentBuilder().newDocument();
+        } catch (ParserConfigurationException ex) {
+            throw new IllegalStateException(ex);
+        }
+        trans.transform(new DOMSource(this.dom), new DOMResult(target));
+        return new XMLDocument(target, this.context);
+    }
+
     @Override
     @NotNull
     public List<String> xpath(@NotNull final String query) {
         final NodeList nodes = this.nodelist(query);
         final List<String> items = new ArrayList<String>(nodes.getLength());
         for (int idx = 0; idx < nodes.getLength(); ++idx) {
-            final short type = nodes.item(idx).getNodeType();
+            final int type = (int) nodes.item(idx).getNodeType();
             if (type != Node.TEXT_NODE && type != Node.ATTRIBUTE_NODE
                 && type != Node.CDATA_SECTION_NODE) {
                 throw new IllegalArgumentException(
@@ -277,7 +315,7 @@ public XML merge(@NotNull final NamespaceContext ctx) {
     private NodeList nodelist(final String query) {
         final NodeList nodes;
         try {
-            final XPath xpath = XPathFactory.newInstance().newXPath();
+            final XPath xpath = XMLDocument.XFACTORY.newXPath();
             xpath.setNamespaceContext(this.context);
             nodes = (NodeList) xpath.evaluate(
                 query,
@@ -301,9 +339,7 @@ private NodeList nodelist(final String query) {
     private static Node transform(final Source source) {
         final DOMResult result = new DOMResult();
         try {
-            TransformerFactory.newInstance()
-                .newTransformer()
-                .transform(source, result);
+            XMLDocument.TFACTORY.newTransformer().transform(source, result);
         } catch (TransformerConfigurationException ex) {
             throw new IllegalStateException(ex);
         } catch (TransformerException ex) {

src/site/site.xml

@@ -55,6 +55,10 @@
             <item name="Test coverage" href="./cobertura/index.html"/>
             <item name="Release History" href="./changes-report.html"/>
         </menu>
+        <menu name="Examples">
+            <item name="Parsing XML" href="example-parsing.html"/>
+            <item name="XSL Transforming" href="example-xslt.html"/>
+        </menu>
         <menu ref="reports"/>
     </body>
 </project>

src/test/java/com/jcabi/xml/XMLDocumentTest.java

@@ -29,16 +29,18 @@
  */
 package com.jcabi.xml;
 
+import com.google.common.io.Files;
 import com.rexsl.test.XhtmlMatchers;
 import java.io.File;
+import javax.xml.transform.stream.StreamSource;
+import org.apache.commons.io.Charsets;
 import org.apache.commons.io.FileUtils;
 import org.apache.commons.io.IOUtils;
 import org.apache.commons.lang3.CharEncoding;
+import org.apache.commons.lang3.StringUtils;
 import org.hamcrest.MatcherAssert;
 import org.hamcrest.Matchers;
-import org.junit.Rule;
 import org.junit.Test;
-import org.junit.rules.TemporaryFolder;
 import org.w3c.dom.Node;
 
 /**
@@ -49,13 +51,6 @@
 @SuppressWarnings("PMD.TooManyMethods")
 public final class XMLDocumentTest {
 
-    /**
-     * Temporary folder.
-     * @checkstyle VisibilityModifier (3 lines)
-     */
-    @Rule
-    public transient TemporaryFolder temp = new TemporaryFolder();
-
     /**
      * XMLDocument can find nodes with XPath.
      * @throws Exception If something goes wrong inside
@@ -101,7 +96,7 @@ public void findsWithXpathAndNamespaces() throws Exception {
      */
     @Test
     public void findsWithXpathWithCustomNamespace() throws Exception {
-        final File file = this.temp.newFile("temp-1.xml");
+        final File file = new File(Files.createTempDir(), "x.xml");
         FileUtils.writeStringToFile(
             file,
             "<a xmlns='urn:foo'><b>\u0433!</b></a>",
@@ -210,4 +205,25 @@ public void preservesProcessingInstructions() throws Exception {
         );
     }
 
+    /**
+     * XMLDocument can make XSL transformations.
+     * @throws Exception If something goes wrong inside
+     */
+    @Test
+    public void makesXslTransformations() throws Exception {
+        final String xsl = StringUtils.join(
+            "<xsl:stylesheet",
+            " xmlns:xsl='http://www.w3.org/1999/XSL/Transform'",
+            " version='2.0'>",
+            "<xsl:template match='/'><done/>",
+            "</xsl:template></xsl:stylesheet>"
+        );
+        MatcherAssert.assertThat(
+            new XMLDocument("<?xml version='1.0'?><a/>").xslt(
+                new StreamSource(IOUtils.toInputStream(xsl, Charsets.UTF_8))
+            ),
+            XhtmlMatchers.hasXPath("/done")
+        );
+    }
+
 }