Add HTTP/2 keep-alive PING policy.

httpcore5-h2/src/main/java/org/apache/hc/core5/http2/config/H2Config.java

@@ -51,10 +51,11 @@ public class H2Config {
     private final int maxHeaderListSize;
     private final boolean compressionEnabled;
     private final int maxContinuations;
+    private final H2PingPolicy pingPolicy;
 
     H2Config(final int headerTableSize, final boolean pushEnabled, final int maxConcurrentStreams,
              final int initialWindowSize, final int maxFrameSize, final int maxHeaderListSize,
-             final boolean compressionEnabled, final int maxContinuations) {
+             final boolean compressionEnabled, final int maxContinuations, final H2PingPolicy pingPolicy) {
         super();
         this.headerTableSize = headerTableSize;
         this.pushEnabled = pushEnabled;
@@ -64,6 +65,7 @@ public class H2Config {
         this.maxHeaderListSize = maxHeaderListSize;
         this.compressionEnabled = compressionEnabled;
         this.maxContinuations = maxContinuations;
+        this.pingPolicy = pingPolicy;
     }
 
     public int getHeaderTableSize() {
@@ -98,6 +100,15 @@ public int getMaxContinuations() {
         return maxContinuations;
     }
 
+    /**
+     * Optional keep-alive PING policy.
+     *
+     * @since 5.5
+     */
+    public H2PingPolicy getPingPolicy() {
+        return pingPolicy;
+    }
+
     @Override
     public String toString() {
         final StringBuilder builder = new StringBuilder();
@@ -109,6 +120,7 @@ public String toString() {
                 .append(", maxHeaderListSize=").append(this.maxHeaderListSize)
                 .append(", compressionEnabled=").append(this.compressionEnabled)
                 .append(", maxContinuations=").append(this.maxContinuations)
+                .append(", pingPolicy=").append(this.pingPolicy)
                 .append("]");
         return builder.toString();
     }
@@ -142,7 +154,9 @@ public static H2Config.Builder copy(final H2Config config) {
                 .setInitialWindowSize(config.getInitialWindowSize())
                 .setMaxFrameSize(config.getMaxFrameSize())
                 .setMaxHeaderListSize(config.getMaxHeaderListSize())
-                .setCompressionEnabled(config.isCompressionEnabled());
+                .setCompressionEnabled(config.isCompressionEnabled())
+                .setMaxContinuations(config.getMaxContinuations())
+                .setPingPolicy(config.getPingPolicy());
     }
 
     public static class Builder {
@@ -155,6 +169,7 @@ public static class Builder {
         private int maxHeaderListSize;
         private boolean compressionEnabled;
         private int maxContinuations;
+        private H2PingPolicy pingPolicy;
 
         Builder() {
             this.headerTableSize = INIT_HEADER_TABLE_SIZE * 2;
@@ -165,6 +180,7 @@ public static class Builder {
             this.maxHeaderListSize = FrameConsts.MAX_FRAME_SIZE;
             this.compressionEnabled = true;
             this.maxContinuations = 100;
+            this.pingPolicy = null;
         }
 
         public Builder setHeaderTableSize(final int headerTableSize) {
@@ -211,14 +227,24 @@ public Builder setCompressionEnabled(final boolean compressionEnabled) {
          * Sets max limit on number of continuations.
          * <p>value zero represents no limit</p>
          *
-         * @since 5,4
+         * @since 5.4
          */
         public Builder setMaxContinuations(final int maxContinuations) {
             Args.positive(maxContinuations, "Max continuations");
             this.maxContinuations = maxContinuations;
             return this;
         }
 
+        /**
+         * Sets optional keep-alive PING policy.
+         *
+         * @since 5.5
+         */
+        public Builder setPingPolicy(final H2PingPolicy pingPolicy) {
+            this.pingPolicy = pingPolicy;
+            return this;
+        }
+
         public H2Config build() {
             return new H2Config(
                     headerTableSize,
@@ -228,7 +254,8 @@ public H2Config build() {
                     maxFrameSize,
                     maxHeaderListSize,
                     compressionEnabled,
-                    maxContinuations);
+                    maxContinuations,
+                    pingPolicy);
         }
 
     }

httpcore5-h2/src/main/java/org/apache/hc/core5/http2/config/H2PingPolicy.java

@@ -0,0 +1,103 @@
+/*
+ * ====================================================================
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ * ====================================================================
+ *
+ * This software consists of voluntary contributions made by many
+ * individuals on behalf of the Apache Software Foundation.  For more
+ * information on the Apache Software Foundation, please see
+ * <http://www.apache.org/>.
+ *
+ */
+
+package org.apache.hc.core5.http2.config;
+
+import org.apache.hc.core5.util.Args;
+import org.apache.hc.core5.util.TimeValue;
+import org.apache.hc.core5.util.Timeout;
+
+/**
+ * HTTP/2 keep-alive ping policy.
+ *
+ * @since 5.5
+ */
+public final class H2PingPolicy {
+
+    private static final H2PingPolicy DISABLED = new H2PingPolicy(Timeout.DISABLED, Timeout.DISABLED);
+
+    private final Timeout idleTime;
+    private final Timeout ackTimeout;
+
+    private H2PingPolicy(final Timeout idleTime, final Timeout ackTimeout) {
+        this.idleTime = idleTime;
+        this.ackTimeout = ackTimeout;
+    }
+
+    public static H2PingPolicy disabled() {
+        return DISABLED;
+    }
+
+    public static Builder custom() {
+        return new Builder();
+    }
+
+    public Timeout getIdleTime() {
+        return idleTime;
+    }
+
+    public Timeout getAckTimeout() {
+        return ackTimeout;
+    }
+
+    public boolean isEnabled() {
+        return isActive(idleTime) && isActive(ackTimeout);
+    }
+
+    private static boolean isActive(final Timeout timeout) {
+        return timeout != null && timeout.isEnabled() && TimeValue.isPositive(timeout);
+    }
+
+    public static final class Builder {
+
+        private Timeout idleTime;
+        private Timeout ackTimeout;
+
+        private Builder() {
+            this.idleTime = Timeout.DISABLED;
+            this.ackTimeout = Timeout.DISABLED;
+        }
+
+        public Builder setIdleTime(final Timeout idleTime) {
+            this.idleTime = Args.notNull(idleTime, "idleTime");
+            return this;
+        }
+
+        public Builder setAckTimeout(final Timeout ackTimeout) {
+            this.ackTimeout = Args.notNull(ackTimeout, "ackTimeout");
+            return this;
+        }
+
+        public H2PingPolicy build() {
+            if (isActive(idleTime)) {
+                Args.check(isActive(ackTimeout), "ackTimeout must be positive when idleTime is enabled");
+            }
+            return new H2PingPolicy(idleTime, ackTimeout);
+        }
+    }
+
+}