1 files changed, 92 insertions, 0 deletions
diff --git a/container-search/src/main/java/com/yahoo/fs4/PongPacket.java b/container-search/src/main/java/com/yahoo/fs4/PongPacket.java
new file mode 100644
index 00000000000..37aaf7067a9
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+++ b/container-search/src/main/java/com/yahoo/fs4/PongPacket.java
@@ -0,0 +1,92 @@
+// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.fs4;
+
+import java.nio.ByteBuffer;
+import java.util.Optional;
+
+/**
+ * A pong packet for FS4. It maps to PCODE_MONITORRESULTX
+ * in the C++ implementation of the protocol.
+ *
+ * @author Steinar Knutsen
+ */
+public class PongPacket extends BasicPacket {
+
+    private int dispatchTimestamp;
+
+    @SuppressWarnings("unused")
+    private int totalNodes; // configured nodes
+    private Optional<Integer> activeNodes = Optional.empty(); // number of nodes that are up
+    @SuppressWarnings("unused")
+    private int totalPartitions; // configured partitions
+    private Optional<Integer> activePartitions = Optional.empty(); // number of partitions that are up
+
+    private Optional<Long> activeDocuments = Optional.empty(); // how many documents are searchable (sum)
+
+    public PongPacket() {
+    }
+
+    /** For testing */
+    public PongPacket(long activeDocuments) {
+        this.activeDocuments = Optional.of(activeDocuments);
+    }
+
+    private int code;
+    protected void codeDecodedHook(int code) { this.code = code; }
+    public int getCode() { return code; }
+
+    public void decodeBody(ByteBuffer buffer) {
+        int features = buffer.getInt();
+        buffer.getInt();  // Unused lowPartitionId
+        dispatchTimestamp = buffer.getInt();
+        if ((features & MRF_MLD) != 0) {
+            totalNodes = buffer.getInt();
+            activeNodes = Optional.of(buffer.getInt());
+            totalPartitions = buffer.getInt();
+            activePartitions = Optional.of(buffer.getInt());
+        }
+        if ((features & MRF_RFLAGS) != 0) {
+            buffer.getInt(); // ignore rflags (historical field)
+        }
+        if ((features & MRF_ACTIVEDOCS) != 0) {
+            activeDocuments = Optional.of(Long.valueOf(buffer.getLong()));
+        }
+    }
+
+    public static PongPacket create() {
+        return new PongPacket();
+    }
+
+    /**
+     * Return current docstamp for backend to make cache invalidation
+     * possible.
+     * */
+    public int getDocstamp() {
+        return dispatchTimestamp;
+    }
+
+    /**
+     * retrieve the reported number of active (searchable) documents
+     * in the monitored backend.
+     **/
+    public Optional<Long> getActiveDocuments() {
+        return activeDocuments;
+    }
+
+    public Optional<Integer> getActiveNodes() {
+        return activeNodes;
+    }
+
+    public Optional<Integer> getActivePartitions() {
+        return activePartitions;
+    }
+
+    /** feature bits, taken from searchlib/common/transport.h */
+    static final int MRF_MLD        = 0x00000001;
+    static final int MRF_RFLAGS     = 0x00000008;
+    static final int MRF_ACTIVEDOCS = 0x00000010;
+
+    /** packet codes, taken from searchlib/common/transport.h */
+    static final int PCODE_MONITORRESULTX    = 221;
+
+}