fix #1411 add Element parse method

src/main/java/org/jsoup/nodes/Element.java

@@ -86,6 +86,36 @@ public Element(Tag tag, @Nullable String baseUri) {
         this(tag, baseUri, null);
     }
 
+    private Element() {
+        this("-");
+    }
+
+    /**
+     * Parse HTML String into an Element
+     * <p>
+     * Use examples:
+     * <ul>
+     *     <li><code>Element e = Element.parse("<div></div>");</code></li>
+     *     <li><code>Element e = Element.parse("<div><span>Some stuff</span><span>Second part</span></div>");</code></li>
+     *     <li><code>Element e = Element.parse("<ul><li>item1</li><li>item2</li></ul>");</code></li>
+     * </ul>
+     * </p>
+     * @param html  HTML to parse
+     * @return an Element
+     */
+    public static Element parse(String html) {
+        Element dummyElement = new Element().html(html);
+        if (dummyElement.childNodeSize() > 1) {
+            throw new IllegalArgumentException("Element syntax error: Number of outer element must be one");
+        }
+        if (dummyElement.childNodeSize() == 0) {
+            throw new IllegalArgumentException("Element syntax error: No legal element detected");
+        }
+        Element e = dummyElement.child(0);
+        e.parentNode = null;
+        return e;
+    }
+
     /**
      Internal test to check if a nodelist object has been created.
      */

src/test/java/org/jsoup/nodes/ElementTest.java

@@ -729,7 +729,7 @@ public void testWrapNoop() {
 
     @Test
     public void testWrapOnOrphan() {
-        Element orphan = new Element("span").text("Hello!");
+        Element orphan = Element.parse("<span>Hello!</span>");
         assertFalse(orphan.hasParent());
         Element wrapped = orphan.wrap("<div></div> There!");
         assertSame(orphan, wrapped);
@@ -1445,8 +1445,8 @@ public void testShadowElementsAreUpdated() {
         assertEquals(2, els.size()); // the two Ps
         assertEquals(3, nodes.size()); // the "Three" textnode
 
-        Element p3 = new Element("p").text("P3");
-        Element p4 = new Element("p").text("P4");
+        Element p3 = Element.parse("<p>P3</p>");
+        Element p4 = Element.parse("<p>P4</p>");
         div.insertChildren(1, p3);
         div.insertChildren(3, p4);
         Elements els2 = div.children();
@@ -1839,8 +1839,8 @@ public void doesntDeleteZWJWhenNormalizingText() {
     public void testReparentSeperateNodes() {
         String html = "<div><p>One<p>Two";
         Document doc = Jsoup.parse(html);
-        Element new1 = new Element("p").text("Three");
-        Element new2 = new Element("p").text("Four");
+        Element new1 = Element.parse("<p>Three</p>");
+        Element new2 = Element.parse("<p>Four</p>");
 
         doc.body().insertChildren(-1, new1, new2);
         assertEquals("<div><p>One</p><p>Two</p></div><p>Three</p><p>Four</p>", TextUtil.stripNewlines(doc.body().html()));
@@ -1863,14 +1863,14 @@ public void testNotActuallyAReparent() {
         String html = "<div>";
         Document doc = Jsoup.parse(html);
         Element div = doc.selectFirst("div");
-        Element new1 = new Element("p").text("One");
-        Element new2 = new Element("p").text("Two");
+        Element new1 = Element.parse("<p>One</p>");
+        Element new2 = Element.parse("<p>Two</p>");
         div.addChildren(new1, new2);
 
         assertEquals("<div><p>One</p><p>Two</p></div>", TextUtil.stripNewlines(div.outerHtml()));
 
         // and the issue setup:
-        Element new3 = new Element("p").text("Three");
+        Element new3 = Element.parse("<p>Three</p>");
         Element wrap = new Element("nav");
         wrap.addChildren(0, new1, new3);
 
@@ -2099,4 +2099,21 @@ public void childNodesAccessorDoesNotVivify() {
         p.removeAttr("foo");
         assertEquals(0, p.attributesSize());
     }
+
+    @Test void parseFromHtmlOneElementSuccess() {
+        Element e = Element.parse("<div><text>test</text></div>");
+        assertEquals(e.tagName(), "div");
+        assertEquals(e.child(0).tagName(), "text");
+        assertEquals(e.child(0).text(), "test");
+    }
+
+    @Test void parseFromHtmlMultiElementsError() {
+        Throwable exception = assertThrows(IllegalArgumentException.class, () -> Element.parse("<li>item1</li><li>item2</li>"));
+        assertEquals("Element syntax error: Number of outer element must be one", exception.getMessage());
+    }
+
+    @Test void parseFromHtmlNoElementError() {
+        Throwable exception = assertThrows(IllegalArgumentException.class, () -> Element.parse(""));
+        assertEquals("Element syntax error: No legal element detected", exception.getMessage());
+    }
 }