--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.truffle.api/src/com/oracle/truffle/api/instrument/impl/LineLocationToProbeCollectionMap.java	Mon Aug 18 14:36:12 2014 -0700
@@ -0,0 +1,121 @@
+/*
+ * Copyright (c) 2013, 2014, 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.impl;
+
+import java.util.*;
+
+import com.oracle.truffle.api.instrument.*;
+import com.oracle.truffle.api.source.*;
+
+/**
+ * This class maintains a mapping from {@link LineLocation} to a collection of {@link Probe}s to be
+ * used by debugging tools.
+ *
+ */
+public class LineLocationToProbeCollectionMap implements ProbeListener {
+    /**
+     * Map: Source line ==> probes associated with source sections starting on the line.
+     */
+    private final Map<LineLocation, Collection<Probe>> lineToProbesMap = new HashMap<>();
+
+    public LineLocationToProbeCollectionMap() {
+    }
+
+    /**
+     * Adds the current wrapper's child's line location and probe to this map.
+     */
+    public void newProbeInserted(SourceSection source, Probe probe) {
+        final LineLocation line = source.getLineLocation();
+        this.addProbeToLine(line, probe);
+    }
+
+    /**
+     * Does nothing.
+     */
+    public void probeTaggedAs(Probe probe, SyntaxTag tag) {
+
+    }
+
+    /**
+     * Returns the {@link Probe}, if any, associated with source that starts on a specified line; if
+     * there are more than one, return the one with the first character location.
+     */
+    public Probe findLineProbe(LineLocation lineLocation) {
+        Probe probe = null;
+        final Collection<Probe> probes = getProbesAtLine(lineLocation);
+        for (Probe probeOnLine : probes) {
+            if (probe == null) {
+                probe = probeOnLine;
+            } else if (probeOnLine.getSourceLocation().getCharIndex() < probe.getSourceLocation().getCharIndex()) {
+                probe = probeOnLine;
+            }
+        }
+        return probe;
+    }
+
+    /**
+     * Adds a probe to the given line.
+     * <p>
+     * If the line already exists in the internal {@link #lineToProbesMap}, this probe will be added
+     * to the existing collection. If no line already exists in the internal map, then a new key is
+     * added along with a new collection containing the probe.
+     * <p>
+     * This class requires that each added line/probe pair hasn't been previously added. However,
+     * attaching the same probe to a new line location is allowed.
+     *
+     * @param line The {@link LineLocation} to attach the probe to.
+     * @param probe The {@link Probe} to attach for that line location.
+     */
+    private void addProbeToLine(LineLocation line, Probe probe) {
+
+        if (!lineToProbesMap.containsKey(line)) {
+            // Key does not exist, add new probe list
+            final ArrayList<Probe> newProbeList = new ArrayList<>(2);
+            newProbeList.add(probe);
+            lineToProbesMap.put(line, newProbeList);
+        } else {
+            // Probe list exists, add to existing
+            final Collection<Probe> existingProbeList = lineToProbesMap.get(line);
+            assert !existingProbeList.contains(probe);
+            existingProbeList.add(probe);
+        }
+    }
+
+    /**
+     * Returns a collection of {@link Probe}s at the given {@link LineLocation}. If there are no
+     * probes at that line, an empty list is returned.
+     *
+     * @param line The line to check.
+     * @return A iterable collection of probes at the given line.
+     */
+    private Collection<Probe> getProbesAtLine(LineLocation line) {
+        Collection<Probe> probeList = lineToProbesMap.get(line);
+
+        if (probeList == null)
+            probeList = new ArrayList<>(2);
+
+        return probeList;
+    }
+}