--- /dev/null	2017-11-09 09:38:01.297999907 +0100
+++ new/src/jdk.jfr/share/classes/jdk/jfr/internal/handlers/EventHandler.java	2018-04-09 16:13:27.278098623 +0200
@@ -0,0 +1,117 @@
+/*
+ * Copyright (c) 2016, 2018, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package jdk.jfr.internal.handlers;
+
+import java.io.IOException;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+
+import jdk.jfr.EventType;
+import jdk.jfr.internal.EventControl;
+import jdk.jfr.internal.JVM;
+import jdk.jfr.internal.PlatformEventType;
+import jdk.jfr.internal.PrivateAccess;
+import jdk.jfr.internal.StringPool;
+
+// Users should not be subclass for security reasons.
+public abstract class EventHandler {
+    // Accessed by generated sub class
+    protected final PlatformEventType platformEventType;
+
+    private final EventType eventType;
+    private final EventControl eventControl;
+
+    // Accessed by generated sub class
+    EventHandler(boolean registered, EventType eventType, EventControl eventControl) {
+        this.eventType = eventType;
+        this.platformEventType = PrivateAccess.getInstance().getPlatformEventType(eventType);
+        this.eventControl = eventControl;
+        platformEventType.setRegistered(registered);
+    }
+
+    final protected StringPool createStringFieldWriter() {
+        return new StringPool();
+    }
+
+    // Accessed by generated code in event class
+    public final boolean shouldCommit(long duration) {
+        return isEnabled() && duration >= platformEventType.getThresholdTicks();
+    }
+
+    // Accessed by generated code in event class
+    // Accessed by generated sub class
+    public final boolean isEnabled() {
+        return platformEventType.isCommitable();
+    }
+
+    public final EventType getEventType() {
+        return eventType;
+    }
+
+    public final PlatformEventType getPlatformEventType() {
+        return platformEventType;
+    }
+
+    public final EventControl getEventControl() {
+        return eventControl;
+    }
+
+    public static long timestamp() {
+        return JVM.counterTime();
+    }
+
+    public static long duration(long startTime) {
+        if (startTime == 0) {
+            // User forgot to invoke begin, or instrumentation was
+            // added after the user invoked begin.
+            // Returning 0 will make it an instant event
+            return 0;
+        }
+        return timestamp() - startTime;
+    }
+
+    // Prevent a malicious user from instantiating a generated event handlers.
+    @Override
+    public final Object clone() throws java.lang.CloneNotSupportedException {
+        throw new CloneNotSupportedException();
+    }
+
+    private final void writeObject(ObjectOutputStream out) throws IOException {
+        throw new IOException("Object cannot be serialized");
+    }
+
+    private final void readObject(ObjectInputStream in) throws IOException {
+        throw new IOException("Class cannot be deserialized");
+    }
+
+    public boolean isRegistered() {
+        return platformEventType.isRegistered();
+    }
+
+    public boolean setRegistered(boolean registered) {
+       return platformEventType.setRegistered(registered);
+    }
+}