Add isBlockingWrites to pong

- Add isBlockingWrites to pong
- Cleanup and deprecate unused complexity: There is just one node and one error

9 files changed, 82 insertions, 54 deletions

diff --git a/container-search/src/main/java/com/yahoo/prelude/Ping.java b/container-search/src/main/java/com/yahoo/prelude/Ping.java
index dd14e150d95..1d5d4c92827 100644
--- a/container-search/src/main/java/com/yahoo/prelude/Ping.java
+++ b/container-search/src/main/java/com/yahoo/prelude/Ping.java
@@ -4,7 +4,7 @@ package com.yahoo.prelude;
 /**
  * A ping, typically to ask whether backend is alive.
  *
- * @author  <a href="mailto:steinar@yahoo-inc.com">Steinar Knutsen</a>
+ * @author Steinar Knutsen
  */
 public class Ping {
 
diff --git a/container-search/src/main/java/com/yahoo/prelude/Pong.java b/container-search/src/main/java/com/yahoo/prelude/Pong.java
index a60fba9a4f7..ff08d5fb33b 100644
--- a/container-search/src/main/java/com/yahoo/prelude/Pong.java
+++ b/container-search/src/main/java/com/yahoo/prelude/Pong.java
@@ -4,82 +4,102 @@ package com.yahoo.prelude;
 import com.yahoo.search.result.ErrorMessage;
 import com.yahoo.search.statistics.ElapsedTime;
 
-import java.util.ArrayList;
-import java.util.Collections;
 import java.util.List;
 import java.util.Optional;
+import java.util.stream.Collectors;
 
 /**
  * An answer from Ping.
  *
- * @author Steinar Knutsen
+ * @author bratseth
  */
 public class Pong {
 
-    private String pingInfo="";
-    private final List<ErrorMessage> errors = new ArrayList<>(1);
-    private ElapsedTime elapsed = new ElapsedTime();
+    private final ElapsedTime elapsed = new ElapsedTime();
     private final Optional<Long> activeDocuments;
+    private final boolean isBlockingWrites;
+    private final Optional<ErrorMessage> error;
 
     public Pong() {
-        this.activeDocuments = Optional.empty();
+        this(Optional.empty(), false, Optional.empty());
     }
 
     public Pong(ErrorMessage error) {
-        errors.add(error);
-        this.activeDocuments = Optional.empty();
+        this(Optional.empty(), false, Optional.of(error));
     }
 
     public Pong(long activeDocuments) {
-        this.activeDocuments = Optional.of(activeDocuments);
+        this(Optional.of(activeDocuments), false, Optional.empty());
     }
 
-    public void addError(ErrorMessage error) {
-        errors.add(error);
+    public Pong(long activeDocuments, boolean isBlockingWrites) {
+        this(Optional.of(activeDocuments), isBlockingWrites, Optional.empty());
     }
 
-    public ErrorMessage getError(int i) {
-        return errors.get(i);
+    private Pong(Optional<Long> activeDocuments, boolean isBlockingWrites, Optional<ErrorMessage> error) {
+        this.activeDocuments = activeDocuments;
+        this.isBlockingWrites = isBlockingWrites;
+        this.error = error;
     }
 
-    /** Returns the number of active documents in the backend responding in this Pong, if available */
-    public Optional<Long> activeDocuments() {
-        return activeDocuments;
+    /**
+     * @deprecated do not use. Additional errors are ignored.
+     */
+    @Deprecated
+    public void addError(ErrorMessage error) { }
+
+    /**
+     * @deprecated use error() instead
+     */
+    @Deprecated
+    public ErrorMessage getError(int i) {
+        if (i > 1) throw new IllegalArgumentException("No error at position " + i);
+        if (i == 0 && error.isEmpty()) throw new IllegalArgumentException("No error at position " + i);
+        return error.get();
     }
 
-    /** Returns the number of nodes which responded to this Pong, if available */
+    public Optional<ErrorMessage> error() { return error; }
+
+    /** Returns the number of active documents in the backend responding in this Pong, if available */
+    public Optional<Long> activeDocuments() { return activeDocuments; }
+
+    /** Returns true if the pinged node is currently blocking write operations due t being full */
+    public boolean isBlockingWrites() { return isBlockingWrites; }
+
+    /**
+     * Returns Optional.empty()
+     *
+     * @return empty
+     * @deprecated do not use. There is always one pong per node.
+     */
+    @Deprecated
     public Optional<Integer> activeNodes() {
         return Optional.empty();
     }
 
+    /**
+     * Returns a list containing 0 or 1 errors
+     *
+     * @deprecated use error() instead
+     */
+    @Deprecated
     public List<ErrorMessage> getErrors() {
-        return Collections.unmodifiableList(errors);
+        return error.stream().collect(Collectors.toList());
     }
 
     /** Returns whether there is an error or not */
-    public boolean badResponse() {
-        return ! errors.isEmpty();
-    }
+    public boolean badResponse() { return error.isPresent(); }
 
-    public ElapsedTime getElapsedTime() {
-        return elapsed;
-    }
+    public ElapsedTime getElapsedTime() { return elapsed; }
 
     /** Returns a string which included the ping info (if any) and any errors added to this */
     @Override
     public String toString() {
-        StringBuilder m = new StringBuilder("Result of pinging");
-        if (pingInfo.length() > 0) {
-            m.append(" using ");
-            m.append(pingInfo);
-        }
-        if (errors.size() > 0)
-            m.append(" ");
-        for (int i = 0; i < errors.size(); i++) {
-            m.append(errors.get(i).toString());
-            if ( i <errors.size()-1)
-                m.append(", ");
-        }
+        StringBuilder m = new StringBuilder("Ping result");
+        activeDocuments.ifPresent(docCount -> m.append(" active docs: ").append(docCount));
+        if (isBlockingWrites)
+            m.append(" blocking writes: true");
+        error.ifPresent(e -> m.append(" error: ").append(error));
         return m.toString();
     }
 
diff --git a/container-search/src/main/java/com/yahoo/prelude/query/NearItem.java b/container-search/src/main/java/com/yahoo/prelude/query/NearItem.java
index 153606e6d99..69131b6c690 100644
--- a/container-search/src/main/java/com/yahoo/prelude/query/NearItem.java
+++ b/container-search/src/main/java/com/yahoo/prelude/query/NearItem.java
@@ -8,7 +8,7 @@ import java.nio.ByteBuffer;
 
 
 /**
- * <p>A set of terms which must be near each other to match.</p>
+ * A set of terms which must be near each other to match.
  *
  * @author bratseth
  * @author havardpe
@@ -18,7 +18,7 @@ public class NearItem extends CompositeItem {
     protected int distance;
 
     /** The default distance used if none is specified: 2 */
-    public static final int defaultDistance=2;
+    public static final int defaultDistance = 2;
 
     /** Creates a NEAR item with distance 2 */
     public NearItem() {
@@ -26,8 +26,7 @@ public class NearItem extends CompositeItem {
     }
 
     /**
-     * Creates a <i>near</i> item with a limit to the distance
-     * between the words.
+     * Creates a <i>near</i> item with a limit to the distance between the words.
      *
      * @param distance the number of word position which may separate
      *        the words for this near item to match
@@ -47,14 +46,17 @@ public class NearItem extends CompositeItem {
         return distance;
     }
 
+    @Override
     public ItemType getItemType() {
         return ItemType.NEAR;
     }
 
+    @Override
     public String getName() {
         return "NEAR";
     }
 
+    @Override
     protected void encodeThis(ByteBuffer buffer) {
         super.encodeThis(buffer);
         IntegerCompressor.putCompressedPositiveNumber(distance, buffer);
@@ -67,6 +69,7 @@ public class NearItem extends CompositeItem {
     }
 
     /** Appends the heading of this string - <code>[getName()]([limit]) </code> */
+    @Override
     protected void appendHeadingString(StringBuilder buffer) {
         buffer.append(getName());
         buffer.append("(");
@@ -75,6 +78,7 @@ public class NearItem extends CompositeItem {
         buffer.append(" ");
     }
 
+    @Override
     public int hashCode() {
         return super.hashCode() + 23* distance;
     }
@@ -83,10 +87,11 @@ public class NearItem extends CompositeItem {
      * Returns whether this item is of the same class and
      * contains the same state as the given item
      */
+    @Override
     public boolean equals(Object object) {
         if (!super.equals(object)) return false;
         NearItem other = (NearItem) object; // Ensured by superclass
-        if (this.distance !=other.distance) return false;
+        if (this.distance != other.distance) return false;
         return true;
     }
 
diff --git a/container-search/src/main/java/com/yahoo/prelude/query/ONearItem.java b/container-search/src/main/java/com/yahoo/prelude/query/ONearItem.java
index 84e93d5de8f..88982195af6 100644
--- a/container-search/src/main/java/com/yahoo/prelude/query/ONearItem.java
+++ b/container-search/src/main/java/com/yahoo/prelude/query/ONearItem.java
@@ -25,10 +25,12 @@ public class ONearItem extends NearItem {
         super(distance);
     }
 
+    @Override
     public ItemType getItemType() {
         return ItemType.ONEAR;
     }
 
+    @Override
     public String getName() {
         return "ONEAR";
     }
diff --git a/container-search/src/main/java/com/yahoo/search/cluster/ClusterSearcher.java b/container-search/src/main/java/com/yahoo/search/cluster/ClusterSearcher.java
index 06cbf9a9706..20f56c86f7b 100644
--- a/container-search/src/main/java/com/yahoo/search/cluster/ClusterSearcher.java
+++ b/container-search/src/main/java/com/yahoo/search/cluster/ClusterSearcher.java
@@ -96,7 +96,7 @@ public abstract class ClusterSearcher<T> extends PingableSearcher implements Nod
         future.cancel(true);
 
         if (pong.badResponse()) {
-            monitor.failed(p, pong.getError(0));
+            monitor.failed(p, pong.error().get());
             log(LogLevel.FINE, "Failed ping - ", pong);
         } else {
             monitor.responded(p);
diff --git a/container-search/src/main/java/com/yahoo/search/dispatch/rpc/RpcPing.java b/container-search/src/main/java/com/yahoo/search/dispatch/rpc/RpcPing.java
index f2e22ba86dc..3c4735e57e2 100644
--- a/container-search/src/main/java/com/yahoo/search/dispatch/rpc/RpcPing.java
+++ b/container-search/src/main/java/com/yahoo/search/dispatch/rpc/RpcPing.java
@@ -18,6 +18,7 @@ import java.util.concurrent.LinkedBlockingQueue;
 import java.util.concurrent.TimeUnit;
 
 public class RpcPing implements Callable<Pong> {
+
     private static final String RPC_METHOD = "vespa.searchprotocol.ping";
     private static final CompressionType PING_COMPRESSION = CompressionType.NONE;
 
@@ -75,4 +76,5 @@ public class RpcPing implements Callable<Pong> {
             return new Pong(reply.getActiveDocs());
         }
     }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/dispatch/searchcluster/SearchCluster.java b/container-search/src/main/java/com/yahoo/search/dispatch/searchcluster/SearchCluster.java
index eff6ae26816..5f211c37917 100644
--- a/container-search/src/main/java/com/yahoo/search/dispatch/searchcluster/SearchCluster.java
+++ b/container-search/src/main/java/com/yahoo/search/dispatch/searchcluster/SearchCluster.java
@@ -274,7 +274,7 @@ public class SearchCluster implements NodeManager<Node> {
         futurePong.cancel(true);
 
         if (pong.badResponse()) {
-            clusterMonitor.failed(node, pong.getError(0));
+            clusterMonitor.failed(node, pong.error().get());
         } else {
             if (pong.activeDocuments().isPresent()) {
                 node.setActiveDocuments(pong.activeDocuments().get());
diff --git a/container-search/src/test/java/com/yahoo/search/cluster/test/ClusterSearcherTestCase.java b/container-search/src/test/java/com/yahoo/search/cluster/test/ClusterSearcherTestCase.java
index 2992d8ab896..8dcc25e4b3b 100644
--- a/container-search/src/test/java/com/yahoo/search/cluster/test/ClusterSearcherTestCase.java
+++ b/container-search/src/test/java/com/yahoo/search/cluster/test/ClusterSearcherTestCase.java
@@ -56,11 +56,10 @@ public class ClusterSearcherTestCase {
 
         @Override
         public Pong ping(Ping ping, Execution execution) {
-            Pong pong = new Pong();
-            if (isBlocking()) {
-                pong.addError(ErrorMessage.createTimeout("Dummy timeout"));
-            }
-            return new Pong();
+            if (isBlocking())
+                return new Pong(ErrorMessage.createTimeout("Dummy timeout"));
+            else
+                return new Pong();
         }
 
         public boolean isBlocking() {
diff --git a/container-search/src/test/java/com/yahoo/search/cluster/test/ClusteredConnectionTestCase.java b/container-search/src/test/java/com/yahoo/search/cluster/test/ClusteredConnectionTestCase.java
index c90d2774bd1..a824edd1996 100644
--- a/container-search/src/test/java/com/yahoo/search/cluster/test/ClusteredConnectionTestCase.java
+++ b/container-search/src/test/java/com/yahoo/search/cluster/test/ClusteredConnectionTestCase.java
@@ -182,10 +182,10 @@ public class ClusteredConnectionTestCase {
 
         @Override
         public Pong ping(Ping ping,Connection connection) {
-            Pong pong = new Pong();
-            if (connection.getResponse() == null)
-                pong.addError(ErrorMessage.createBackendCommunicationError("No ping response from '" + connection + "'"));
-            return pong;
+            if (connection.getResponse() != null)
+                return new Pong();
+            else
+                return new Pong(ErrorMessage.createBackendCommunicationError("No ping response from '" + connection + "'"));
         }
 
     }