feat(objectionary#889): first optimization round

src/main/java/org/eolang/jeo/representation/xmir/XmlNode.java

@@ -46,7 +46,7 @@ public final class XmlNode {
     /**
      * Parent node.
      */
-    private final XML node;
+    private final Node node;
 
     /**
      * Constructor.
@@ -56,27 +56,19 @@ public XmlNode(final String xml) {
         this(new XMLDocument(xml).node().getFirstChild());
     }
 
-    /**
-     * Constructor.
-     * @param parent XML document
-     */
-    public XmlNode(final Node parent) {
-        this(new XMLDocument(parent));
-    }
-
     /**
      * Constructor.
      * @param parent Parent node.
      */
-    public XmlNode(final XML parent) {
+    public XmlNode(final Node parent) {
         this.node = parent;
     }
 
     @Override
     public boolean equals(final Object obj) {
         final boolean res;
         if (obj instanceof XmlNode) {
-            res = this.node.equals(((XmlNode) obj).node);
+            res = new XMLDocument(this.node).equals(new XMLDocument(((XmlNode) obj).node));
         } else {
             res = false;
         }
@@ -106,7 +98,7 @@ public Stream<XmlNode> children() {
      * @return Text content.
      */
     public String text() {
-        return this.node.node().getTextContent();
+        return this.node.getTextContent();
     }
 
     /**
@@ -116,7 +108,7 @@ public String text() {
      */
     public Optional<String> attribute(final String name) {
         final Optional<String> result;
-        final NamedNodeMap attrs = this.node.node().getAttributes();
+        final NamedNodeMap attrs = this.node.getAttributes();
         if (attrs == null) {
             result = Optional.empty();
         } else {
@@ -140,7 +132,7 @@ XmlNode child(final String name) {
      * @return List of elements.
      */
     List<String> xpath(final String xpath) {
-        return this.node.xpath(xpath);
+        return new XMLDocument(this.node).xpath(xpath);
     }
 
     /**
@@ -206,7 +198,7 @@ boolean hasAttribute(final String name, final String value) {
      * @return Class.
      */
     XmlClass toClass() {
-        return new XmlClass(this.node.node());
+        return new XmlClass(this.node);
     }
 
     /**
@@ -233,9 +225,14 @@ XmlBytecodeEntry toEntry() {
      */
     private Optional<XmlNode> optchild(final String name) {
         Optional<XmlNode> result = Optional.empty();
-        final List<XML> nodes = this.node.nodes(name);
-        if (!nodes.isEmpty()) {
-            result = Optional.of(new XmlNode(nodes.get(0)));
+        final NodeList children = this.node.getChildNodes();
+        final int length = children.getLength();
+        for (int index = 0; index < length; ++index) {
+            final Node current = children.item(index);
+            if (current.getNodeName().equals(name)) {
+                result = Optional.of(new XmlNode(current));
+                break;
+            }
         }
         return result;
     }
@@ -260,7 +257,7 @@ private IllegalStateException notFound(final String name) {
      * @return Stream of class objects.
      */
     private Stream<Node> objects() {
-        final NodeList children = this.node.node().getChildNodes();
+        final NodeList children = this.node.getChildNodes();
         final List<Node> res = new ArrayList<>(children.getLength());
         for (int index = 0; index < children.getLength(); ++index) {
             final Node child = children.item(index);

src/test/java/org/eolang/jeo/representation/XmirRepresentationTest.java

@@ -160,7 +160,8 @@ void failsToOpenBrokenXmirRepresentationFromFile(@TempDir final Path dir) throws
      * This is a performance test, which is disabled by default.
      * It is used to measure the performance of the conversion of the EO object
      * into the bytecode representation and back.
-     * Timings before the optimization were: 21s, 23s, 21s, 21s (500 attempts)
+     * 1) Timings before the optimization were: 21s, 23s, 21s, 21s (500 attempts)
+     * 2) `XMLDocument` -> `org.w3c.Node` optimization: 11s, 10s, 11s, 10s (500 attempts)
      */
     @Test
     @Disabled