--- /dev/null	2018-06-17 23:18:20.806999507 +0800
+++ new/src/share/classes/jdk/jfr/EventSettings.java	2019-01-29 10:58:36.810397990 +0800
@@ -0,0 +1,141 @@
+/*
+ * Copyright (c) 2016, 2019, 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;
+
+import java.time.Duration;
+import java.util.Map;
+
+/**
+ * Convenience class for applying event settings to a recording.
+ * <p>
+ * An event setting object for a recording can be obtained by invoking
+ * the {@link Recording#enable(String)} method which is configured using method
+ * chaining.
+ * <p>
+ * The following example shows how to use the {@code EventSetting} class.
+ * <pre>
+ * {@code
+ * Recording r = new Recording();
+ * r.enable("com.oracle.jdk.CPULoad")
+ *    .withPeriod(Duration.ofSeconds(1));
+ * r.enable("com.oracle.jdk.FileWrite")
+ *    .withoutStackTrace()
+ *    .withThreshold(Duration.ofNanos(10));
+ * r.start();
+ * Thread.sleep(10_000);
+ * r.stop();
+ * r.dump(Files.createTempFile("recording", ".jfr"));
+ *
+ * }
+ * </pre>
+ * @since 9
+ */
+public abstract class EventSettings {
+
+    // package private
+    EventSettings() {
+    }
+
+    /**
+     * Enables stack traces for the event that is associated with this event setting.
+     *
+     * Equivalent to invoking the {@code with("stackTrace", "true")} method.
+     *
+     * @return event settings object for further configuration, not {@code null}
+     */
+    final public EventSettings withStackTrace() {
+        return with(StackTrace.NAME, "true");
+    }
+
+    /**
+     * Disables stack traces for the event that is associated with this event setting.
+     *
+     * Equivalent to invoking the {@code with("stackTrace", "false")} method.
+     *
+     * @return event settings object for further configuration, not {@code null}
+     */
+    final public EventSettings withoutStackTrace() {
+        return with(StackTrace.NAME, "false");
+    }
+
+    /**
+     * Specifies that a threshold is not used.
+     * <p>
+     * This is a convenience method, equivalent to invoking the
+     * {@code with("threshold", "0 s")} method.
+     *
+     * @return event settings object for further configuration, not {@code null}
+     */
+    final public EventSettings withoutThreshold() {
+        return with(Threshold.NAME, "0 s");
+    }
+
+    /**
+     * Sets the interval for the event that is associated with this event setting.
+     *
+     * @param duration the duration, not {@code null}
+     *
+     * @return event settings object for further configuration, not {@code null}
+     */
+    final public EventSettings withPeriod(Duration duration) {
+        return with(Period.NAME, duration.toNanos() + " ns");
+    }
+
+    /**
+     * Sets the threshold for the event that is associated with this event setting.
+     *
+     * @param duration the duration, or {@code null} if no duration is used
+     *
+     * @return event settings object for further configuration, not {@code null}
+     */
+    final public EventSettings withThreshold(Duration duration) {
+        if (duration == null) {
+            return with(Threshold.NAME, "0 ns");
+        } else {
+            return with(Threshold.NAME, duration.toNanos() + " ns");
+        }
+    }
+
+    /**
+     * Sets a setting value for the event that is associated with this event setting.
+     *
+     * @param name the name of the setting (for example, {@code "threshold"})
+     *
+     * @param value the value to set (for example {@code "20 ms"} not
+     *        {@code null})
+     *
+     * @return event settings object for further configuration, not {@code null}
+     */
+    abstract public EventSettings with(String name, String value);
+
+    /**
+     * Creates a settings {@code Map} for the event that is associated with this
+     * event setting.
+     *
+     * @return a settings {@code Map}, not {@code null}
+     */
+    abstract Map<String, String> toMap();
+}