Implemented a HashTag version of SCAN methods for Redis Cluster (#1335)

Based on http://www.paluch.biz/blog/162-iterate-over-all-keys-in-a-redis-cluster.html.
This implementation supports scanning for "Hash Tag" prefixed based patterns ( i.e. {TAG}* )

*NOTE* Changes on Jungtaek Lim <kabhwan@gmail.com>

* Fix conflicts
* Moved scan() interface from JedisClusterCommands to MultiKeyJedisClusterCommands
  * JedisClusterCommands is not available for 2.9
  * since we treat scan as multikey operation, it should be applied to master, too

Author: sheinbergon

.gitignore

@@ -2,6 +2,7 @@
 *.iml
 *.ipr
 *.iws
+nb*
 .project
 .settings/
 .gradle/

src/main/java/redis/clients/jedis/BinaryJedisCluster.java

@@ -14,6 +14,8 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import org.apache.commons.pool2.impl.GenericObjectPoolConfig;
+import redis.clients.util.JedisClusterHashTagUtil;
 
 public class BinaryJedisCluster implements BasicCommands, BinaryJedisClusterCommands,
     MultiKeyBinaryJedisClusterCommands, JedisClusterBinaryScriptingCommands, Closeable {
@@ -1951,7 +1953,30 @@ public List<GeoRadiusResponse> execute(Jedis connection) {
       }
     }.runBinary(key);
   }
+  
+  @Override
+  public ScanResult<byte[]> scan(final byte[] cursor, final ScanParams params) {
 
+    String matchPattern = null;
+
+    if (params == null || (matchPattern = params.match()) == null || matchPattern.isEmpty()) {
+      throw new IllegalArgumentException(BinaryJedisCluster.class.getSimpleName() + " only supports SCAN commands with non-empty MATCH patterns");
+    }
+
+    if (JedisClusterHashTagUtil.isClusterCompliantMatchPattern(matchPattern)) {
+
+      return new JedisClusterCommand< ScanResult<byte[]>>(connectionHandler,
+              maxRedirections) {
+        @Override
+        public ScanResult<byte[]> execute(Jedis connection) {
+          return connection.scan(cursor, params);
+        }
+      }.runBinary(SafeEncoder.encode(matchPattern));
+    } else {
+      throw new IllegalArgumentException(BinaryJedisCluster.class.getSimpleName() + " only supports SCAN commands with MATCH patterns containing hash-tags ( curly-brackets enclosed strings )");
+    }
+  }
+  
   @Override
   public ScanResult<Map.Entry<byte[], byte[]>> hscan(final byte[] key, final byte[] cursor) {
     return new JedisClusterCommand<ScanResult<Map.Entry<byte[], byte[]>>>(connectionHandler,

src/main/java/redis/clients/jedis/BinaryJedisClusterCommands.java

@@ -261,6 +261,8 @@ List<GeoRadiusResponse> georadius(byte[] key, double longitude, double latitude,
   List<GeoRadiusResponse> georadiusByMember(byte[] key, byte[] member, double radius, GeoUnit unit,
       GeoRadiusParam param);
 
+  ScanResult<byte[]> scan(final byte[] cursor, final ScanParams params);
+  
   ScanResult<Map.Entry<byte[], byte[]>> hscan(byte[] key, byte[] cursor);
 
   ScanResult<Map.Entry<byte[], byte[]>> hscan(byte[] key, byte[] cursor, ScanParams params);

src/main/java/redis/clients/jedis/JedisCluster.java

@@ -13,6 +13,8 @@
 import java.util.Set;
 
 import org.apache.commons.pool2.impl.GenericObjectPoolConfig;
+import redis.clients.util.JedisClusterHashTagUtil;
+import redis.clients.util.SafeEncoder;
 
 public class JedisCluster extends BinaryJedisCluster implements JedisCommands,
     MultiKeyJedisClusterCommands, JedisClusterScriptingCommands {
@@ -1236,6 +1238,29 @@ public Long execute(Jedis connection) {
     }.run(key);
   }
 
+  @Override
+  public ScanResult<String> scan(final String cursor, final ScanParams params) {
+
+    String matchPattern = null;
+
+    if (params == null || (matchPattern = params.match()) == null || matchPattern.isEmpty()) {
+      throw new IllegalArgumentException(JedisCluster.class.getSimpleName() + " only supports SCAN commands with non-empty MATCH patterns");
+    }
+
+    if (JedisClusterHashTagUtil.isClusterCompliantMatchPattern(matchPattern)) {
+
+      return new JedisClusterCommand< ScanResult<String>>(connectionHandler,
+              maxRedirections) {
+        @Override
+        public ScanResult<String> execute(Jedis connection) {
+          return connection.scan(cursor, params);
+        }
+      }.runBinary(SafeEncoder.encode(matchPattern));
+    } else {
+      throw new IllegalArgumentException(JedisCluster.class.getSimpleName() + " only supports SCAN commands with MATCH patterns containing hash-tags ( curly-brackets enclosed strings )");
+    }
+  }
+  
   @Override
   public Long bitpos(final String key, final boolean value) {
     return new JedisClusterCommand<Long>(connectionHandler, maxRedirections) {

src/main/java/redis/clients/jedis/JedisClusterCommands.java

@@ -63,4 +63,6 @@ public interface MultiKeyJedisClusterCommands {
   String pfmerge(final String destkey, final String... sourcekeys);
 
   long pfcount(final String... keys);
+
+  ScanResult<String> scan(final String cursor, final ScanParams params);
 }