add volume id cache

other/java/client/src/main/java/seaweedfs/client/ChunkCache.java

@@ -15,7 +15,6 @@ public class ChunkCache {
         }
         this.cache = CacheBuilder.newBuilder()
                 .maximumSize(maxEntries)
-                .weakValues()
                 .expireAfterAccess(1, TimeUnit.HOURS)
                 .build();
     }

other/java/client/src/main/java/seaweedfs/client/SeaweedRead.java

@@ -19,6 +19,7 @@ public class SeaweedRead {
     private static final Logger LOG = LoggerFactory.getLogger(SeaweedRead.class);
 
     static ChunkCache chunkCache = new ChunkCache(4);
+    static VolumeIdCache volumeIdCache = new VolumeIdCache(4 * 1024);
 
     // returns bytesRead
     public static long read(FilerGrpcClient filerGrpcClient, List<VisibleInterval> visibleIntervals,
@@ -30,13 +31,19 @@ public class SeaweedRead {
         FilerProto.LookupVolumeRequest.Builder lookupRequest = FilerProto.LookupVolumeRequest.newBuilder();
         for (ChunkView chunkView : chunkViews) {
             String vid = parseVolumeId(chunkView.fileId);
+            if (volumeIdCache.getLocations(vid)==null){
                 lookupRequest.addVolumeIds(vid);
             }
+        }
 
+        if (lookupRequest.getVolumeIdsCount()>0){
             FilerProto.LookupVolumeResponse lookupResponse = filerGrpcClient
                     .getBlockingStub().lookupVolume(lookupRequest.build());
-
             Map<String, FilerProto.Locations> vid2Locations = lookupResponse.getLocationsMapMap();
+            for (Map.Entry<String,FilerProto.Locations> entry : vid2Locations.entrySet()) {
+                volumeIdCache.setLocations(entry.getKey(), entry.getValue());
+            }
+        }
 
         //TODO parallel this
         long readCount = 0;
@@ -50,7 +57,7 @@ public class SeaweedRead {
                 startOffset += gap;
             }
 
-            FilerProto.Locations locations = vid2Locations.get(parseVolumeId(chunkView.fileId));
+            FilerProto.Locations locations = volumeIdCache.getLocations(parseVolumeId(chunkView.fileId));
             if (locations == null || locations.getLocationsCount() == 0) {
                 LOG.error("failed to locate {}", chunkView.fileId);
                 // log here!

other/java/client/src/main/java/seaweedfs/client/VolumeIdCache.java

@@ -0,0 +1,36 @@
+package seaweedfs.client;
+
+import com.google.common.cache.Cache;
+import com.google.common.cache.CacheBuilder;
+
+import java.util.concurrent.TimeUnit;
+
+public class VolumeIdCache {
+
+    private Cache<String, FilerProto.Locations> cache = null;
+
+    public VolumeIdCache(int maxEntries) {
+        if (maxEntries == 0) {
+            return;
+        }
+        this.cache = CacheBuilder.newBuilder()
+                .maximumSize(maxEntries)
+                .expireAfterAccess(1, TimeUnit.HOURS)
+                .build();
+    }
+
+    public FilerProto.Locations getLocations(String volumeId) {
+        if (this.cache == null) {
+            return null;
+        }
+        return this.cache.getIfPresent(volumeId);
+    }
+
+    public void setLocations(String volumeId, FilerProto.Locations locations) {
+        if (this.cache == null) {
+            return;
+        }
+        this.cache.put(volumeId, locations);
+    }
+
+}