--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/java.net.http/share/classes/java/net/http/HttpHeaders.java Tue Apr 17 08:54:17 2018 -0700
@@ -0,0 +1,168 @@
+/*
+ * 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 java.net.http;
+
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.OptionalLong;
+import static java.util.Collections.emptyList;
+import static java.util.Collections.unmodifiableList;
+import static java.util.Objects.requireNonNull;
+
+/**
+ * A read-only view of a set of HTTP headers.
+ *
+ * <p> An {@code HttpHeaders} is not created directly, but rather returned from
+ * an {@link HttpResponse HttpResponse}. Specific HTTP headers can be set for
+ * {@linkplain HttpRequest requests} through the one of the request builder's
+ * {@link HttpRequest.Builder#header(String, String) headers} methods.
+ *
+ * <p> The methods of this class ( that accept a String header name ), and the
+ * Map returned by the {@link #map() map} method, operate without regard to
+ * case when retrieving the header value.
+ *
+ * <p> {@code HttpHeaders} instances are immutable.
+ *
+ * @since 11
+ */
+public abstract class HttpHeaders {
+
+ /**
+ * Creates an HttpHeaders.
+ */
+ protected HttpHeaders() {}
+
+ /**
+ * Returns an {@link Optional} containing the first value of the given named
+ * (and possibly multi-valued) header. If the header is not present, then
+ * the returned {@code Optional} is empty.
+ *
+ * @implSpec
+ * The default implementation invokes
+ * {@code allValues(name).stream().findFirst()}
+ *
+ * @param name the header name
+ * @return an {@code Optional<String>} for the first named value
+ */
+ public Optional<String> firstValue(String name) {
+ return allValues(name).stream().findFirst();
+ }
+
+ /**
+ * Returns an {@link OptionalLong} containing the first value of the
+ * named header field. If the header is not present, then the Optional is
+ * empty. If the header is present but contains a value that does not parse
+ * as a {@code Long} value, then an exception is thrown.
+ *
+ * @implSpec
+ * The default implementation invokes
+ * {@code allValues(name).stream().mapToLong(Long::valueOf).findFirst()}
+ *
+ * @param name the header name
+ * @return an {@code OptionalLong}
+ * @throws NumberFormatException if a value is found, but does not parse as
+ * a Long
+ */
+ public OptionalLong firstValueAsLong(String name) {
+ return allValues(name).stream().mapToLong(Long::valueOf).findFirst();
+ }
+
+ /**
+ * Returns an unmodifiable List of all of the values of the given named
+ * header. Always returns a List, which may be empty if the header is not
+ * present.
+ *
+ * @implSpec
+ * The default implementation invokes, among other things, the
+ * {@code map().get(name)} to retrieve the list of header values.
+ *
+ * @param name the header name
+ * @return a List of String values
+ */
+ public List<String> allValues(String name) {
+ requireNonNull(name);
+ List<String> values = map().get(name);
+ // Making unmodifiable list out of empty in order to make a list which
+ // throws UOE unconditionally
+ return values != null ? values : unmodifiableList(emptyList());
+ }
+
+ /**
+ * Returns an unmodifiable multi Map view of this HttpHeaders.
+ *
+ * @return the Map
+ */
+ public abstract Map<String, List<String>> map();
+
+ /**
+ * Tests this HTTP headers instance for equality with the given object.
+ *
+ * <p> If the given object is not an {@code HttpHeaders} then this
+ * method returns {@code false}. Two HTTP headers are equal if each
+ * of their corresponding {@linkplain #map() maps} are equal.
+ *
+ * <p> This method satisfies the general contract of the {@link
+ * Object#equals(Object) Object.equals} method.
+ *
+ * @param obj the object to which this object is to be compared
+ * @return {@code true} if, and only if, the given object is an {@code
+ * HttpHeaders} that is equal to this HTTP headers
+ */
+ public final boolean equals(Object obj) {
+ if (!(obj instanceof HttpHeaders))
+ return false;
+ HttpHeaders that = (HttpHeaders)obj;
+ return this.map().equals(that.map());
+ }
+
+ /**
+ * Computes a hash code for this HTTP headers instance.
+ *
+ * <p> The hash code is based upon the components of the HTTP headers
+ * {@link #map() map}, and satisfies the general contract of the
+ * {@link Object#hashCode Object.hashCode} method.
+ *
+ * @return the hash-code value for this HTTP headers
+ */
+ public final int hashCode() {
+ return map().hashCode();
+ }
+
+ /**
+ * Returns this HTTP headers as a string.
+ *
+ * @return a string describing the HTTP headers
+ */
+ @Override
+ public String toString() {
+ StringBuilder sb = new StringBuilder();
+ sb.append(super.toString()).append(" { ");
+ sb.append(map());
+ sb.append(" }");
+ return sb.toString();
+ }
+}