--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.truffle.api/src/com/oracle/truffle/api/instrument/ProbeListener.java	Tue Jan 27 20:24:54 2015 -0800
@@ -0,0 +1,80 @@
+/*
+ * 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.nodes.*;
+import com.oracle.truffle.api.source.*;
+
+/**
+ * An observer of events related to {@link Probe}s: creating and tagging.
+ */
+public interface ProbeListener {
+
+    /**
+     * Notifies that all registered {@link ASTProber}s are about to be applied to a newly
+     * constructed AST.
+     *
+     * @param source source code from which the AST was constructed
+     */
+    void startASTProbing(Source source);
+
+    /**
+     * Notifies that a {@link Probe} has been newly attached to an AST via {@link Node#probe()}.
+     * <p>
+     * There can be no more than one {@link Probe} at a node; this notification will only be
+     * delivered the first time {@linkplain Node#probe() probe()} is called at a particular AST
+     * node. There will also be no notification when the AST to which the Probe is attached is
+     * cloned.
+     */
+    void newProbeInserted(Probe probe);
+
+    /**
+     * Notifies that a {@link SyntaxTag} has been newly added to the set of tags associated with a
+     * {@link Probe} via {@link Probe#tagAs(SyntaxTag, Object)}.
+     * <p>
+     * The {@linkplain SyntaxTag tags} at a {@link Probe} are a <em>set</em>; this notification will
+     * only be delivered the first time a particular {@linkplain SyntaxTag tag} is added at a
+     * {@link Probe}.
+     * <p>
+     * An optional value supplied with {@linkplain Probe#tagAs(SyntaxTag, Object) tagAs(SyntaxTag,
+     * Object)} is reported to all listeners, but not stored. As a consequence, the optional value
+     * will have no effect at all if the tag had already been added.
+     *
+     * @param probe where a tag has been added
+     * @param tag the tag that has been newly added (subsequent additions of the tag are
+     *            unreported).
+     * @param tagValue an optional value associated with the tag for the purposes of reporting.
+     */
+    void probeTaggedAs(Probe probe, SyntaxTag tag, Object tagValue);
+
+    /**
+     * Notifies that the application of all registered {@link ASTProber}s to a newly constructed AST
+     * has completed.
+     *
+     * @param source source code from which the AST was constructed
+     */
+    void endASTProbing(Source source);
+
+}