--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/java.net.http/share/classes/jdk/internal/net/http/HeaderFilter.java	Wed Feb 07 21:45:37 2018 +0000
@@ -0,0 +1,45 @@
+/*
+ * Copyright (c) 2015, 2018, 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.internal.net.http;
+
+import java.io.IOException;
+
+/**
+ * A header filter that can examine or modify, typically system headers for
+ * requests before they are sent, and responses before they are returned to the
+ * user. Some ability to resend requests is provided.
+ */
+interface HeaderFilter {
+
+    void request(HttpRequestImpl r, MultiExchange<?> e) throws IOException;
+
+    /**
+     * Returns null if response ok to be given to user.  Non null is a request
+     * that must be resent and its response given to user. If impl throws an
+     * exception that is returned to user instead.
+     */
+    HttpRequestImpl response(Response r) throws IOException;
+}