8245095: Implementation of JEP 408: Simple Web Server

Co-authored-by: Julia Boes <jboes@openjdk.org>
Co-authored-by: Chris Hegarty <chegar@openjdk.org>
Co-authored-by: Michael McMahon <michaelm@openjdk.org>
Co-authored-by: Daniel Fuchs <dfuchs@openjdk.org>
Co-authored-by: Jan Lahoda <jlahoda@openjdk.org>
Co-authored-by: Ivan Šipka <isipka@openjdk.org>
Reviewed-by: ihse, jlaskey, michaelm, chegar, dfuchs

make/CreateJmods.gmk

@@ -1,5 +1,5 @@
 #
-# Copyright (c) 2014, 2020, Oracle and/or its affiliates. All rights reserved.
+# Copyright (c) 2014, 2021, 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
@@ -196,6 +196,11 @@ else # not java.base
   endif
 endif
 
+# Set main class of jdk.httpserver module
+ifeq ($(MODULE), jdk.httpserver)
+    JMOD_FLAGS += --main-class sun.net.httpserver.simpleserver.Main
+endif
+
 # Changes to the jmod tool itself should also trigger a rebuild of all jmods.
 # The variable JMOD_CMD could contain an environment variable assignment before
 # the actual command. Filter that out using wildcard before adding to DEPS.

make/langtools/src/classes/build/tools/symbolgenerator/CreateSymbols.java

@@ -123,6 +123,7 @@
 import com.sun.tools.classfile.InnerClasses_attribute.Info;
 import com.sun.tools.classfile.Method;
 import com.sun.tools.classfile.MethodParameters_attribute;
+import com.sun.tools.classfile.ModuleMainClass_attribute;
 import com.sun.tools.classfile.ModuleResolution_attribute;
 import com.sun.tools.classfile.ModuleTarget_attribute;
 import com.sun.tools.classfile.Module_attribute;
@@ -928,6 +929,12 @@ private void addAttributes(ModuleDescription md,
             attributes.put(Attribute.ModuleTarget,
                            new ModuleTarget_attribute(attrIdx, targetIdx));
         }
+        if (header.moduleMainClass != null) {
+            int attrIdx = addString(cp, Attribute.ModuleMainClass);
+            int targetIdx = addString(cp, header.moduleMainClass);
+            attributes.put(Attribute.ModuleMainClass,
+                           new ModuleMainClass_attribute(attrIdx, targetIdx));
+        }
         int attrIdx = addString(cp, Attribute.Module);
         attributes.put(Attribute.Module,
                        new Module_attribute(attrIdx,
@@ -2294,6 +2301,13 @@ private boolean readAttribute(ClassFile cf, FeatureDescription feature, Attribut
                 chd.isSealed = true;
                 break;
             }
+            case Attribute.ModuleMainClass: {
+                ModuleMainClass_attribute moduleMainClass = (ModuleMainClass_attribute) attr;
+                assert feature instanceof ModuleHeaderDescription;
+                ModuleHeaderDescription mhd = (ModuleHeaderDescription) feature;
+                mhd.moduleMainClass = moduleMainClass.getMainClassName(cf.constant_pool);
+                break;
+            }
             default:
                 throw new IllegalStateException("Unhandled attribute: " +
                                                 attrName);
@@ -2731,6 +2745,7 @@ static class ModuleHeaderDescription extends HeaderDescription {
         List<ProvidesDescription> provides = new ArrayList<>();
         Integer moduleResolution;
         String moduleTarget;
+        String moduleMainClass;
 
         @Override
         public int hashCode() {
@@ -2743,6 +2758,7 @@ public int hashCode() {
             hash = 83 * hash + Objects.hashCode(this.provides);
             hash = 83 * hash + Objects.hashCode(this.moduleResolution);
             hash = 83 * hash + Objects.hashCode(this.moduleTarget);
+            hash = 83 * hash + Objects.hashCode(this.moduleMainClass);
             return hash;
         }
 
@@ -2781,6 +2797,10 @@ public boolean equals(Object obj) {
                                 other.moduleResolution)) {
                 return false;
             }
+            if (!Objects.equals(this.moduleMainClass,
+                                other.moduleMainClass)) {
+                return false;
+            }
             return true;
         }
 
@@ -2818,6 +2838,8 @@ public void write(Appendable output, String baselineVersion,
                 output.append(" resolution " +
                               quote(Integer.toHexString(moduleResolution),
                                     true));
+            if (moduleMainClass != null)
+                output.append(" moduleMainClass " + quote(moduleMainClass, true));
             writeAttributes(output);
             output.append("\n");
             writeInnerClasses(output, baselineVersion, version);
@@ -2862,6 +2884,8 @@ public boolean read(LineBasedReader reader) throws IOException {
                 moduleResolution = Integer.parseInt(resolutionFlags, 16);
             }
 
+            moduleMainClass = reader.attributes.get("moduleMainClass");
+
             readAttributes(reader);
             reader.moveNext();
             readInnerClasses(reader);

make/modules/jdk.httpserver/Gensrc.gmk

@@ -0,0 +1,41 @@
+#
+# Copyright (c) 2021, 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.
+#
+
+include GensrcCommonJdk.gmk
+include GensrcProperties.gmk
+include Modules.gmk
+
+################################################################################
+
+# Use wildcard so as to avoid getting non-existing directories back
+SIMPLESERVER_RESOURCES_DIRS := $(wildcard $(addsuffix /sun/net/httpserver/simpleserver/resources, \
+    $(call FindModuleSrcDirs, jdk.httpserver)))
+
+$(eval $(call SetupCompileProperties, SIMPLESERVER_PROPERTIES, \
+    SRC_DIRS := $(SIMPLESERVER_RESOURCES_DIRS), \
+    CLASS := ListResourceBundle, \
+))
+
+TARGETS += $(SIMPLESERVER_PROPERTIES)

src/jdk.httpserver/share/classes/com/sun/net/httpserver/Filter.java

@@ -28,10 +28,13 @@
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
+import java.net.URI;
 import java.util.List;
 import java.util.ListIterator;
 import java.util.Objects;
 import java.util.function.Consumer;
+import java.util.function.UnaryOperator;
+import sun.net.httpserver.DelegatingHttpExchange;
 
 /**
  * A filter used to pre- and post-process incoming requests. Pre-processing occurs
@@ -134,7 +137,6 @@ public void doFilter (HttpExchange exchange) throws IOException {
      */
     public abstract void doFilter (HttpExchange exchange, Chain chain)
         throws IOException;
-
     /**
      * Returns a short description of this {@code Filter}.
      *
@@ -252,4 +254,64 @@ public String description() {
             }
         };
     }
+
+    /**
+     * Returns a
+     * {@linkplain Filter#beforeHandler(String, Consumer) pre-processing Filter}
+     * that inspects and possibly adapts the request state.
+     *
+     * The {@code Request} returned by the {@link UnaryOperator requestOperator}
+     * will be the effective request state of the exchange. It is executed for
+     * each {@code HttpExchange} before invoking either the next filter in the
+     * chain or the exchange handler (if this is the final filter in the chain).
+     * Exceptions thrown by the {@code requestOperator} are not handled by the
+     * filter.
+     *
+     * @apiNote
+     * When the returned filter is invoked, it first invokes the
+     * {@code requestOperator} with the given exchange, {@code ex}, in order to
+     * retrieve the <i>adapted request state</i>. It then invokes the next
+     * filter in the chain or the exchange handler, passing an exchange
+     * equivalent to {@code ex} with the <i>adapted request state</i> set as the
+     * effective request state.
+     *
+     * <p> Example of adding the {@code "Foo"} request header to all requests:
+     * <pre>{@code
+     *     var filter = Filter.adaptRequest("Add Foo header", r -> r.with("Foo", List.of("Bar")));
+     *     httpContext.getFilters().add(filter);
+     * }</pre>
+     *
+     * @param description the string to be returned from {@link #description()}
+     * @param requestOperator the request operator
+     * @return a filter that adapts the request state before the exchange is handled
+     * @throws NullPointerException if any argument is null
+     * @since 18
+     */
+    public static Filter adaptRequest(String description,
+                                      UnaryOperator<Request> requestOperator) {
+        Objects.requireNonNull(description);
+        Objects.requireNonNull(requestOperator);
+
+        return new Filter() {
+            @Override
+            public void doFilter(HttpExchange exchange, Chain chain) throws IOException {
+                var request = requestOperator.apply(exchange);
+                var newExchange =  new DelegatingHttpExchange(exchange) {
+                    @Override
+                    public URI getRequestURI() { return request.getRequestURI(); }
+
+                    @Override
+                    public String getRequestMethod() { return request.getRequestMethod(); }
+
+                    @Override
+                    public Headers getRequestHeaders() { return request.getRequestHeaders(); }
+                };
+                chain.doFilter(newExchange);
+            }
+            @Override
+            public String description() {
+                return description;
+            }
+        };
+    }
 }

src/jdk.httpserver/share/classes/com/sun/net/httpserver/Headers.java

@@ -25,6 +25,7 @@
 
 package com.sun.net.httpserver;
 
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.LinkedList;
@@ -33,6 +34,8 @@
 import java.util.Objects;
 import java.util.Set;
 import java.util.function.BiFunction;
+import java.util.stream.Collectors;
+import sun.net.httpserver.UnmodifiableHeaders;
 
 /**
  * HTTP request and response headers are represented by this class which
@@ -65,6 +68,14 @@
  *     value given overwriting any existing values in the value list.
  * </ul>
  *
+ * <p> An instance of {@code Headers} is either <i>mutable</i> or <i>immutable</i>.
+ * A <i>mutable headers</i> allows to add, remove, or modify header names and
+ * values, e.g. the instance returned by {@link HttpExchange#getResponseHeaders()}.
+ * An <i>immutable headers</i> disallows any modification to header names or
+ * values, e.g. the instance returned by {@link HttpExchange#getRequestHeaders()}.
+ * The mutator methods for an immutable headers instance unconditionally throw
+ * {@code UnsupportedOperationException}.
+ *
  * <p> All methods in this class reject {@code null} values for keys and values.
  * {@code null} keys will never be present in HTTP request or response headers.
  * @since 1.6
@@ -78,6 +89,25 @@ public class Headers implements Map<String,List<String>> {
      */
     public Headers() {map = new HashMap<>(32);}
 
+    /**
+     * Creates a mutable {@code Headers} from the given {@code headers} with
+     * the same header names and values.
+     *
+     * @param headers a map of header names and values
+     * @throws NullPointerException if {@code headers} or any of its names or
+     *                              values are null, or if any value contains
+     *                              null.
+     * @since 18
+     */
+    public Headers(Map<String,List<String>> headers) {
+        Objects.requireNonNull(headers);
+        var h = headers.entrySet().stream()
+                .collect(Collectors.toUnmodifiableMap(
+                        Entry::getKey, e -> new LinkedList<>(e.getValue())));
+        map = new HashMap<>(32);
+        this.putAll(h);
+    }
+
     /**
      * Normalize the key by converting to following form.
      * First {@code char} upper case, rest lower case.
@@ -254,4 +284,55 @@ public String toString() {
         sb.append(" }");
         return sb.toString();
     }
+
+    /**
+     * Returns an immutable {@code Headers} with the given name value pairs as
+     * its set of headers.
+     *
+     * <p> The supplied {@code String} instances must alternate as header names
+     * and header values. To add several values to the same name, the same name
+     * must be supplied with each new value. If the supplied {@code headers} is
+     * empty, then an empty {@code Headers} is returned.
+     *
+     * @param headers the list of name value pairs
+     * @return an immutable headers with the given name value pairs
+     * @throws NullPointerException     if {@code headers} or any of its
+     *                                  elements are null.
+     * @throws IllegalArgumentException if the number of supplied strings is odd.
+     * @since 18
+     */
+    public static Headers of(String... headers) {
+        Objects.requireNonNull(headers);
+        if (headers.length == 0) {
+            return new UnmodifiableHeaders(new Headers());
+        }
+        if (headers.length % 2 != 0) {
+            throw new IllegalArgumentException("wrong number, %d, of elements"
+                    .formatted(headers.length));
+        }
+        Arrays.stream(headers).forEach(Objects::requireNonNull);
+
+        var h = new Headers();
+        for (int i = 0; i < headers.length; i += 2) {
+            String name  = headers[i];
+            String value = headers[i + 1];
+            h.add(name, value);
+        }
+        return new UnmodifiableHeaders(h);
+    }
+
+    /**
+     * Returns an immutable {@code Headers} from the given {@code headers} with
+     * the same header names and values.
+     *
+     * @param headers a map of header names and values
+     * @return an immutable headers
+     * @throws NullPointerException if {@code headers} or any of its names or
+     *                              values are null, or if any value contains
+     *                              null.
+     * @since 18
+     */
+    public static Headers of(Map<String,List<String>> headers) {
+        return new UnmodifiableHeaders(new Headers(headers));
+    }
 }

src/jdk.httpserver/share/classes/com/sun/net/httpserver/HttpExchange.java

@@ -69,7 +69,7 @@
  * @since 1.6
  */
 
-public abstract class HttpExchange implements AutoCloseable {
+public abstract class HttpExchange implements AutoCloseable, Request {
 
     /**
      * Constructor for subclasses to call.
@@ -78,19 +78,8 @@ protected HttpExchange() {
     }
 
     /**
-     * Returns an immutable {@link Headers} containing the HTTP headers that
-     * were included with this request.
-     *
-     * <p> The keys in this {@code Headers} are the header names, while the
-     * values are a {@link java.util.List} of
-     * {@linkplain java.lang.String Strings} containing each value that was
-     * included in the request, in the order they were included. Header fields
-     * appearing multiple times are represented as multiple string values.
-     *
-     * <p> The keys in {@code Headers} are case-insensitive.
-     *
-     * @return a read-only {@code Headers} which can be used to access request
-     *         headers.
+     * {@inheritDoc}
+     * @return {@inheritDoc}
      */
     public abstract Headers getRequestHeaders();
 
@@ -111,16 +100,14 @@ protected HttpExchange() {
     public abstract Headers getResponseHeaders();
 
     /**
-     * Returns the request {@link URI}.
-     *
-     * @return the request {@code URI}
+     * {@inheritDoc}
+     * @return {@inheritDoc}
      */
     public abstract URI getRequestURI();
 
     /**
-     * Returns the request method.
-     *
-     * @return the request method
+     * {@inheritDoc}
+     * @return {@inheritDoc}
      */
     public abstract String getRequestMethod();