Index: trunk/src/org/openstreetmap/josm/data/validation/OsmValidator.java
===================================================================
--- trunk/src/org/openstreetmap/josm/data/validation/OsmValidator.java	(revision 6368)
+++ trunk/src/org/openstreetmap/josm/data/validation/OsmValidator.java	(revision 6370)
@@ -39,4 +39,5 @@
 import org.openstreetmap.josm.data.validation.tests.NodesDuplicatingWayTags;
 import org.openstreetmap.josm.data.validation.tests.NodesWithSameName;
+import org.openstreetmap.josm.data.validation.tests.OpeningHourTest;
 import org.openstreetmap.josm.data.validation.tests.OverlappingAreas;
 import org.openstreetmap.josm.data.validation.tests.OverlappingWays;
@@ -114,4 +115,5 @@
         Highways.class, // ID 2701 .. 2799
         BarriersEntrances.class, // ID 2801 .. 2899
+        OpeningHourTest.class // 2901 .. 2999
     };
 
Index: trunk/src/org/openstreetmap/josm/data/validation/tests/OpeningHourTest.java
===================================================================
--- trunk/src/org/openstreetmap/josm/data/validation/tests/OpeningHourTest.java	(revision 6370)
+++ trunk/src/org/openstreetmap/josm/data/validation/tests/OpeningHourTest.java	(revision 6370)
@@ -0,0 +1,129 @@
+package org.openstreetmap.josm.data.validation.tests;
+
+import org.openstreetmap.josm.data.osm.Node;
+import org.openstreetmap.josm.data.osm.OsmPrimitive;
+import org.openstreetmap.josm.data.osm.Relation;
+import org.openstreetmap.josm.data.osm.Way;
+import org.openstreetmap.josm.data.validation.Severity;
+import org.openstreetmap.josm.data.validation.Test;
+import org.openstreetmap.josm.data.validation.TestError;
+import org.openstreetmap.josm.io.MirroredInputStream;
+import sun.org.mozilla.javascript.NativeArray;
+
+import javax.script.Invocable;
+import javax.script.ScriptEngine;
+import javax.script.ScriptEngineManager;
+import javax.script.ScriptException;
+import java.io.InputStreamReader;
+import java.text.SimpleDateFormat;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.Date;
+import java.util.List;
+import java.util.Map;
+
+import static org.openstreetmap.josm.tools.I18n.tr;
+
+/**
+ * Tests the correct usage of the opening hour syntax of the tags
+ * {@code opening_hours}, {@code collection_times}, {@code service_times} according to
+ * <a href="https://github.com/ypid/opening_hours.js">opening_hours.js</a>.
+ *
+ * @author frsantos
+ */
+public class OpeningHourTest extends Test {
+
+    public static final ScriptEngine ENGINE = new ScriptEngineManager().getEngineByName("rhino");
+
+    /**
+     * Constructs a new {@code OpeningHourTest}.
+     */
+    public OpeningHourTest() {
+        super(tr("Opening hours syntax"),
+                tr("This plugin checks for correct usage of opening hours syntax."));
+    }
+
+    @Override
+    public void initialize() throws Exception {
+        super.initialize();
+        ENGINE.eval(new InputStreamReader(new MirroredInputStream("resource://data/opening_hours.js")));
+        ENGINE.eval("var oh = function (x, y) {return new opening_hours(x, y);};");
+    }
+
+    @SuppressWarnings("unchecked")
+    protected Object parse(String value) throws ScriptException, NoSuchMethodException {
+        return ((Invocable) ENGINE).invokeFunction("oh", value);
+    }
+
+    @SuppressWarnings("unchecked")
+    protected List<Object> getList(Object obj) {
+        if (obj == null || "".equals(obj)) {
+            return Arrays.asList();
+        } else if (obj instanceof String) {
+            return Arrays.<Object>asList(((String) obj).split("\\n"));
+        } else if (obj instanceof List) {
+            return (List) obj;
+        } else {
+            throw new IllegalArgumentException("Not expecting class " + obj.getClass());
+        }
+    }
+
+    /**
+     * Checks for a correct usage of the opening hour syntax of the {@code value} given according to
+     * <a href="https://github.com/ypid/opening_hours.js">opening_hours.js</a> and returns a list containing
+     * validation errors or an empty list. Null values result in an empty list.
+     * @param value the opening hour value to be checked.
+     * @return a list of {@link TestError} or an empty list
+     */
+    public List<TestError> checkOpeningHourSyntax(final String value) {
+        if (value == null || value.trim().isEmpty()) {
+            return Collections.emptyList();
+        }
+        try {
+            final Object r = parse(value);
+            final List<TestError> errors = new ArrayList<TestError>();
+            for (final Object i : getList(((Invocable) ENGINE).invokeMethod(r, "getWarnings"))) {
+                errors.add(new TestError(this, Severity.WARNING, i.toString(), 2901, Collections.<OsmPrimitive>emptyList()));
+            }
+            return errors;
+        } catch (ScriptException ex) {
+            final String message = ex.getMessage()
+                    .replace("sun.org.mozilla.javascript.JavaScriptException: ", "")
+                    .replaceAll("\\(<Unknown source.*", "")
+                    .trim();
+            return Arrays.asList(new TestError(this, Severity.ERROR, message, 2901, Collections.<OsmPrimitive>emptyList()));
+        } catch (final Exception ex) {
+            throw new RuntimeException(ex);
+        }
+    }
+
+    protected void check(final OsmPrimitive p, final String tagValue) {
+        for (TestError e : checkOpeningHourSyntax(tagValue)) {
+            e.setPrimitives(Collections.singletonList(p));
+            errors.add(e);
+        }
+    }
+
+    protected void check(final OsmPrimitive p) {
+        check(p, p.get("opening_hours"));
+        // unsupported, cf. https://github.com/AMDmi3/opening_hours.js/issues/12
+        //check(p, p.get("collection_times"));
+        //check(p, p.get("service_times"));
+    }
+
+    @Override
+    public void visit(final Node n) {
+        check(n);
+    }
+
+    @Override
+    public void visit(final Relation r) {
+        check(r);
+    }
+
+    @Override
+    public void visit(final Way w) {
+        check(w);
+    }
+}