Implemented Element.is()

jhy · jhy · commit 4f707008353e · 2016-10-29T14:41:34.000-07:00
diff --git a/CHANGES b/CHANGES
@@ -4,6 +4,8 @@ jsoup changelog
  * Improved startup time, particularly on Android, by reducing garbage generation and CPU execution time when loading
    the HTML entity files. About 1.72x faster in this area.
 
+ * Added Element.is(query) to check if an element matches this CSS query.
+
  * Bugfix: a "SYSTEM" flag in doctype tags would be incorrectly removed.
    <https://github.com/jhy/jsoup/issues/408>
 
diff --git a/src/main/java/org/jsoup/nodes/Element.java b/src/main/java/org/jsoup/nodes/Element.java
@@ -10,6 +10,7 @@
 import org.jsoup.select.Evaluator;
 import org.jsoup.select.NodeTraversor;
 import org.jsoup.select.NodeVisitor;
+import org.jsoup.select.QueryParser;
 import org.jsoup.select.Selector;
 
 import java.io.IOException;
@@ -286,6 +287,19 @@ public List<DataNode> dataNodes() {
     public Elements select(String cssQuery) {
         return Selector.select(cssQuery, this);
     }
+
+    /**
+     * Check if this element matches the given {@link Selector} CSS query.
+     * @param cssQuery a {@link Selector} CSS query
+     * @return if this element matches the query
+     */
+    public boolean is(String cssQuery) {
+        return is(QueryParser.parse(cssQuery));
+    }
+
+    public boolean is(Evaluator evaluator) {
+        return evaluator.matches(this.ownerDocument(), this);
+    }
     
     /**
      * Add a node child node to this element.
diff --git a/src/main/java/org/jsoup/select/Elements.java b/src/main/java/org/jsoup/select/Elements.java
@@ -440,8 +440,12 @@ public Elements eq(int index) {
      * @return true if at least one element in the list matches the query.
      */
     public boolean is(String query) {
-        Elements children = select(query);
-        return !children.isEmpty();
+        Evaluator eval = QueryParser.parse(query);
+        for (Element e : this) {
+            if (e.is(eval))
+                return true;
+        }
+        return false;
     }
 
     /**
diff --git a/src/main/java/org/jsoup/select/QueryParser.java b/src/main/java/org/jsoup/select/QueryParser.java
@@ -12,7 +12,7 @@
 /**
  * Parses a CSS selector into an Evaluator tree.
  */
-class QueryParser {
+public class QueryParser {
     private final static String[] combinators = {",", ">", "+", "~", " "};
     private static final String[] AttributeEvals = new String[]{"=", "!=", "^=", "$=", "*=", "~="};
 
diff --git a/src/test/java/org/jsoup/nodes/ElementTest.java b/src/test/java/org/jsoup/nodes/ElementTest.java
@@ -972,4 +972,27 @@ public void testChainedRemoveAttributes() {
             .removeAttr("five");
         assertEquals("<a>Text</a>", a.outerHtml());
     }
+
+    @Test
+    public void testIs() {
+        String html = "<div><p>One <a class=big>Two</a> Three</p><p>Another</p>";
+        Document doc = Jsoup.parse(html);
+        Element p = doc.select("p").first();
+
+        assertTrue(p.is("p"));
+        assertFalse(p.is("div"));
+        assertTrue(p.is("p:has(a)"));
+        assertTrue(p.is("p:first-child"));
+        assertFalse(p.is("p:last-child"));
+        assertTrue(p.is("*"));
+        assertTrue(p.is("div p"));
+
+        Element q = doc.select("p").last();
+        assertTrue(q.is("p"));
+        assertTrue(q.is("p ~ p"));
+        assertTrue(q.is("p + p"));
+        assertTrue(q.is("p:last-child"));
+        assertFalse(q.is("p a"));
+        assertFalse(q.is("a"));
+    }
 }
