--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/jdk.incubator.jpackage/share/classes/jdk/incubator/jpackage/internal/RelativeFileSet.java	Fri Nov 08 14:53:03 2019 -0500
@@ -0,0 +1,80 @@
+/*
+ * Copyright (c) 2012, 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.incubator.jpackage.internal;
+
+import java.io.File;
+import java.util.Collection;
+import java.util.LinkedHashSet;
+import java.util.Set;
+
+/**
+ * RelativeFileSet
+ *
+ * A class encapsulating a directory and a set of files within it.
+ */
+class RelativeFileSet {
+
+    private File basedir;
+    private Set<String> files = new LinkedHashSet<>();
+
+    RelativeFileSet(File base, Collection<File> files) {
+        basedir = base;
+        String baseAbsolute = basedir.getAbsolutePath();
+        for (File f: files) {
+            String absolute = f.getAbsolutePath();
+            if (!absolute.startsWith(baseAbsolute)) {
+                throw new RuntimeException("File " + f.getAbsolutePath() +
+                        " does not belong to " + baseAbsolute);
+            }
+            if (!absolute.equals(baseAbsolute)) {
+                    // possible in jpackage case
+                this.files.add(absolute.substring(baseAbsolute.length()+1));
+            }
+        }
+    }
+
+    RelativeFileSet(File base, Set<File> files) {
+        this(base, (Collection<File>) files);
+    }
+
+    File getBaseDirectory() {
+        return basedir;
+    }
+
+    Set<String> getIncludedFiles() {
+        return files;
+    }
+
+    @Override
+    public String toString() {
+        if (files.size() ==  1) {
+            return "" + basedir + File.pathSeparator + files;
+        }
+        return "RelativeFileSet {basedir:" + basedir
+                + ", files: {" + files + "}";
+    }
+
+}