add example of watch files

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

@@ -275,9 +275,9 @@ public class FilerClient {
         try {
             FilerProto.CreateEntryResponse createEntryResponse =
                     filerGrpcClient.getBlockingStub().createEntry(FilerProto.CreateEntryRequest.newBuilder()
-                    .setDirectory(parent)
-                    .setEntry(entry)
-                    .build());
+                            .setDirectory(parent)
+                            .setEntry(entry)
+                            .build());
             if (Strings.isNullOrEmpty(createEntryResponse.getError())) {
                 return true;
             }
@@ -333,4 +333,13 @@ public class FilerClient {
         return true;
     }
 
+    public Iterator<FilerProto.SubscribeMetadataResponse> watch(String prefix, String clientName, long sinceNs) {
+        return filerGrpcClient.getBlockingStub().subscribeMetadata(FilerProto.SubscribeMetadataRequest.newBuilder()
+                .setPathPrefix(prefix)
+                .setClientName(clientName)
+                .setSinceNs(sinceNs)
+                .build()
+        );
+    }
+
 }

other/java/examples/src/main/java/com/example/test/Example.java → other/java/examples/src/main/java/com/seaweedfs/examples/UnzipFile.java

@@ -1,4 +1,4 @@
-package com.example.test;
+package com.seaweedfs.examples;
 
 import seaweed.hdfs.SeaweedInputStream;
 import seaweedfs.client.FilerClient;
@@ -10,22 +10,20 @@ import java.io.InputStream;
 import java.util.zip.ZipEntry;
 import java.util.zip.ZipInputStream;
 
-public class Example {
-
-    public static FilerClient filerClient = new FilerClient("localhost", 18888);
-    public static FilerGrpcClient filerGrpcClient = new FilerGrpcClient("localhost", 18888);
+public class UnzipFile {
 
     public static void main(String[] args) throws IOException {
 
+        FilerGrpcClient filerGrpcClient = new FilerGrpcClient("localhost", 18888);
+        FilerClient filerClient = new FilerClient(filerGrpcClient);
+
         long startTime = System.currentTimeMillis();
-        // 本地模式，速度很快
         parseZip("/Users/chris/tmp/test.zip");
 
         long startTime2 = System.currentTimeMillis();
 
         long localProcessTime = startTime2 - startTime;
 
-        // swfs读取，慢
         SeaweedInputStream seaweedInputStream = new SeaweedInputStream(
                 filerGrpcClient,
                 new org.apache.hadoop.fs.FileSystem.Statistics(""),

other/java/examples/src/main/java/com/seaweedfs/examples/WatchFiles.java

@@ -0,0 +1,42 @@
+package com.seaweedfs.examples;
+
+import seaweedfs.client.FilerClient;
+import seaweedfs.client.FilerGrpcClient;
+import seaweedfs.client.FilerProto;
+
+import java.io.IOException;
+import java.util.Iterator;
+
+public class WatchFiles {
+
+    public static void main(String[] args) throws IOException {
+        FilerGrpcClient filerGrpcClient = new FilerGrpcClient("localhost", 18888);
+        FilerClient filerClient = new FilerClient(filerGrpcClient);
+
+        Iterator<FilerProto.SubscribeMetadataResponse> watch = filerClient.watch(
+                "/buckets",
+                "exampleClient",
+                System.currentTimeMillis() * 1000000L
+        );
+
+        while (watch.hasNext()) {
+            FilerProto.SubscribeMetadataResponse event = watch.next();
+            FilerProto.EventNotification notification = event.getEventNotification();
+            if (notification.getNewParentPath() != null) {
+                // move an entry to a new directory, possibly with a new name
+                if (notification.hasOldEntry() && notification.hasNewEntry()) {
+                    System.out.println("move " + event.getDirectory() + "/" + notification.getOldEntry().getName() + " to " + notification.getNewParentPath() + "/" + notification.getNewEntry().getName());
+                } else {
+                    System.out.println("this should not happen.");
+                }
+            } else if (notification.hasNewEntry() && !notification.hasOldEntry()) {
+                System.out.println("create entry " + event.getDirectory() + "/" + notification.getNewEntry().getName());
+            } else if (!notification.hasNewEntry() && notification.hasOldEntry()) {
+                System.out.println("delete entry " + event.getDirectory() + "/" + notification.getOldEntry().getName());
+            } else if (notification.hasNewEntry() && notification.hasOldEntry()) {
+                System.out.println("updated entry " + event.getDirectory() + "/" + notification.getNewEntry().getName());
+            }
+        }
+
+    }
+}