--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/truffle/com.oracle.truffle.api/src/com/oracle/truffle/api/instrument/SimpleInstrumentListener.java	Wed Jun 17 10:58:08 2015 +0200
@@ -0,0 +1,74 @@
+/*
+ * Copyright (c) 2015, 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 com.oracle.truffle.api.instrument;
+
+import com.oracle.truffle.api.source.*;
+
+/**
+ * A receiver of Truffle execution events that can act on behalf of an external client.
+ * <p>
+ * The {@link Probe} instance provides access to the {@link SourceSection} associated with the
+ * event, as well as any {@link SyntaxTag}s that have been applied at that program's location.
+ * <p>
+ * This is the simplest kind of listener, suitable for clients that need no other information about
+ * the program's execution state at the time of the event. Clients that require access to the AST
+ * execution state should use {@link StandardInstrumentListener}.
+ * <p>
+ * Clients are free, of course, to record additional information in the listener implementation that
+ * carries additional information about the context and reason for the particular {@link Instrument}
+ * that is to be created from the listener.
+ */
+public interface SimpleInstrumentListener {
+
+    /**
+     * Receive notification that a program location is about to be executed.
+     * <p>
+     * <strong>Synchronous</strong>: Truffle execution waits until the call returns.
+     */
+    void enter(Probe probe);
+
+    /**
+     * Receive notification that a program location's {@code void}-valued execution has just
+     * completed.
+     * <p>
+     * <strong>Synchronous</strong>: Truffle execution waits until the call returns.
+     */
+    void returnVoid(Probe probe);
+
+    /**
+     * Receive notification that a program location's execution has just completed and returned a
+     * value (boxed if primitive).
+     * <p>
+     * <strong>Synchronous</strong>: Truffle execution waits until the call returns.
+     */
+    void returnValue(Probe probe, Object result);
+
+    /**
+     * Receive notification that a program location's execution has just thrown an exception.
+     * <p>
+     * <strong>Synchronous</strong>: Truffle execution waits until the call returns.
+     */
+    void returnExceptional(Probe probe, Exception exception);
+}