HBASE-19077 Have Region*CoprocessorEnvironment provide an ImmutableOnlineRegions

Change name of Interface OnlineRegions to MutableOnlineRegions.
Change name of Interface ImmutableOnlineRegions to OnlineRegions.
Did this since OnlineRegions is for consumer other than internals.

Add a getOnlineRegions to the RegionCoprocessorEnvironment and to
RegionServerCoprocessorEnvironment so CPs can 'access' local
Regions directly.

hbase-server/src/main/java/org/apache/hadoop/hbase/coprocessor/RegionCoprocessorEnvironment.java

@@ -27,6 +27,7 @@ import org.apache.hadoop.hbase.ServerName;
 import org.apache.hadoop.hbase.client.Connection;
 import org.apache.hadoop.hbase.client.RegionInfo;
 import org.apache.hadoop.hbase.metrics.MetricRegistry;
+import org.apache.hadoop.hbase.regionserver.OnlineRegions;
 import org.apache.hadoop.hbase.regionserver.Region;
 import org.apache.yetus.audience.InterfaceAudience;
 import org.apache.yetus.audience.InterfaceStability;
@@ -40,6 +41,11 @@ public interface RegionCoprocessorEnvironment extends CoprocessorEnvironment<Reg
   /** @return region information for the region this coprocessor is running on */
   RegionInfo getRegionInfo();
 
+  /**
+   * @return Interface to Map of regions online on this RegionServer {@link #getServerName()}}.
+   */
+  OnlineRegions getOnlineRegions();
+
   /** @return shared data between all instances of this coprocessor */
   ConcurrentMap<String, Object> getSharedData();
 

hbase-server/src/main/java/org/apache/hadoop/hbase/coprocessor/RegionServerCoprocessorEnvironment.java

@@ -23,6 +23,7 @@ import org.apache.hadoop.hbase.HBaseInterfaceAudience;
 import org.apache.hadoop.hbase.ServerName;
 import org.apache.hadoop.hbase.client.Connection;
 import org.apache.hadoop.hbase.metrics.MetricRegistry;
+import org.apache.hadoop.hbase.regionserver.OnlineRegions;
 import org.apache.yetus.audience.InterfaceAudience;
 import org.apache.yetus.audience.InterfaceStability;
 
@@ -35,6 +36,11 @@ public interface RegionServerCoprocessorEnvironment
    */
   ServerName getServerName();
 
+  /**
+   * @return Interface to Map of regions online on this RegionServer {@link #getServerName()}}.
+   */
+  OnlineRegions getOnlineRegions();
+
   /**
    * Be careful RPC'ing from a Coprocessor context.
    * RPC's will fail, stall, retry, and/or crawl because the remote side is not online, is

hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/MutableOnlineRegions.java

@@ -18,43 +18,27 @@
  */
 package org.apache.hadoop.hbase.regionserver;
 
-import java.io.IOException;
-import java.util.List;
-
-import org.apache.hadoop.hbase.HBaseInterfaceAudience;
-import org.apache.hadoop.hbase.TableName;
+import org.apache.hadoop.hbase.ServerName;
 import org.apache.yetus.audience.InterfaceAudience;
-import org.apache.yetus.audience.InterfaceStability;
 
 /**
  * Interface to Map of online regions.  In the  Map, the key is the region's
  * encoded name and the value is an {@link Region} instance.
  */
-@InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.COPROC)
-@InterfaceStability.Evolving
-public interface ImmutableOnlineRegions {
+@InterfaceAudience.Private
+public interface MutableOnlineRegions extends OnlineRegions {
 
   /**
-   * Return {@link Region} instance.
-   * Only works if caller is in same context, in same JVM. Region is not
-   * serializable.
-   * @param encodedRegionName
-   * @return Region for the passed encoded <code>encodedRegionName</code> or
-   * null if named region is not member of the online regions.
+   * Add to online regions.
+   * @param r
    */
-  Region getRegion(String encodedRegionName);
+  void addRegion(final HRegion r);
 
-   /**
-    * Get all online regions of a table in this RS.
-    * @param tableName
-    * @return List of Region
-    * @throws java.io.IOException
-    */
-   List<? extends Region> getRegions(TableName tableName) throws IOException;
-
-   /**
-    * Get all online regions in this RS.
-    * @return List of online Region
-    */
-   List<? extends Region> getRegions();
+  /**
+   * Removes the given Region from the list of onlineRegions.
+   * @param r Region to remove.
+   * @param destination Destination, if any, null otherwise.
+   * @return True if we removed a region from online list.
+   */
+  boolean removeRegion(final HRegion r, ServerName destination);
 }

hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/OnlineRegions.java

@@ -18,28 +18,43 @@
  */
 package org.apache.hadoop.hbase.regionserver;
 
-import org.apache.hadoop.hbase.ServerName;
+import java.io.IOException;
+import java.util.List;
+
+import org.apache.hadoop.hbase.HBaseInterfaceAudience;
+import org.apache.hadoop.hbase.TableName;
 import org.apache.yetus.audience.InterfaceAudience;
+import org.apache.yetus.audience.InterfaceStability;
 
 /**
- * Interface to Map of online regions.  In the  Map, the key is the region's
- * encoded name and the value is an {@link Region} instance.
+ * Provides read-only access to the Regions presently online on the
+ * current RegionServer
  */
-@InterfaceAudience.Private
-public interface OnlineRegions extends ImmutableOnlineRegions {
+@InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.COPROC)
+@InterfaceStability.Evolving
+public interface OnlineRegions {
 
   /**
-   * Add to online regions.
-   * @param r
+   * Return {@link Region} instance.
+   * Only works if caller is in same context, in same JVM. Region is not
+   * serializable.
+   * @param encodedRegionName
+   * @return Region for the passed encoded <code>encodedRegionName</code> or
+   * null if named region is not member of the online regions.
    */
-  void addRegion(final HRegion r);
+  Region getRegion(String encodedRegionName);
 
-  /**
-   * This method removes Region corresponding to hri from the Map of onlineRegions.
-   *
-   * @param r Region to remove.
-   * @param destination Destination, if any, null otherwise.
-   * @return True if we removed a region from online list.
-   */
-  boolean removeRegion(final HRegion r, ServerName destination);
+   /**
+    * Get all online regions of a table in this RS.
+    * @param tableName
+    * @return List of Region
+    * @throws java.io.IOException
+    */
+   List<? extends Region> getRegions(TableName tableName) throws IOException;
+
+   /**
+    * Get all online regions in this RS.
+    * @return List of online Region
+    */
+   List<? extends Region> getRegions();
 }

hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/RegionCoprocessorHost.java

@@ -117,6 +117,7 @@ public class RegionCoprocessorHost
     private final MetricRegistry metricRegistry;
     private final Connection connection;
     private final ServerName serverName;
+    private final OnlineRegions onlineRegions;
 
     /**
      * Constructor
@@ -132,6 +133,7 @@ public class RegionCoprocessorHost
       this.connection = services != null? services.getConnection(): null;
       this.serverName = services != null? services.getServerName(): null;
       this.sharedData = sharedData;
+      this.onlineRegions = services;
       this.metricRegistry =
           MetricsCoprocessor.createRegistryForRegionCoprocessor(impl.getClass().getName());
     }
@@ -142,6 +144,10 @@ public class RegionCoprocessorHost
       return region;
     }
 
+    public OnlineRegions getOnlineRegions() {
+      return this.onlineRegions;
+    }
+
     @Override
     public Connection getConnection() {
       return this.connection;

hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/RegionServerCoprocessorHost.java

@@ -206,6 +206,7 @@ public class RegionServerCoprocessorHost extends
     private final MetricRegistry metricRegistry;
     private final Connection connection;
     private final ServerName serverName;
+    private final OnlineRegions onlineRegions;
 
     @edu.umd.cs.findbugs.annotations.SuppressWarnings(value="BC_UNCONFIRMED_CAST",
         justification="Intentional; FB has trouble detecting isAssignableFrom")
@@ -216,12 +217,18 @@ public class RegionServerCoprocessorHost extends
       for (Service service : impl.getServices()) {
         services.registerService(service);
       }
+      this.onlineRegions = services;
       this.connection = services.getConnection();
       this.serverName = services.getServerName();
       this.metricRegistry =
           MetricsCoprocessor.createRegistryForRSCoprocessor(impl.getClass().getName());
     }
 
+    @Override
+    public OnlineRegions getOnlineRegions() {
+      return this.onlineRegions;
+    }
+
     @Override
     public ServerName getServerName() {
       return this.serverName;

hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/RegionServerServices.java

@@ -48,7 +48,7 @@ import com.google.protobuf.Service;
  * the code base.
  */
 @InterfaceAudience.Private
-public interface RegionServerServices extends Server, OnlineRegions, FavoredNodesForRegion {
+public interface RegionServerServices extends Server, MutableOnlineRegions, FavoredNodesForRegion {
 
   /** @return the WAL for a particular region. Pass null for getting the
    * default (common) WAL */

hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/handler/OpenRegionHandler.java

@@ -121,7 +121,7 @@ public class OpenRegionHandler extends EventHandler {
         return;
       }
 
-      // Successful region open, and add it to OnlineRegions
+      // Successful region open, and add it to MutableOnlineRegions
       this.rsServices.addRegion(region);
       openSuccessful = true;
 

hbase-server/src/test/java/org/apache/hadoop/hbase/security/token/TestTokenAuthentication.java

@@ -59,6 +59,7 @@ import org.apache.hadoop.hbase.ipc.SimpleRpcServer;
 import org.apache.hadoop.hbase.metrics.MetricRegistry;
 import org.apache.hadoop.hbase.protobuf.generated.AuthenticationProtos;
 import org.apache.hadoop.hbase.regionserver.HRegion;
+import org.apache.hadoop.hbase.regionserver.OnlineRegions;
 import org.apache.hadoop.hbase.regionserver.RegionServerServices;
 import org.apache.hadoop.hbase.security.SecurityInfo;
 import org.apache.hadoop.hbase.security.User;
@@ -272,6 +273,11 @@ public class TestTokenAuthentication {
         @Override
         public HRegion getRegion() { return null; }
 
+        @Override
+        public OnlineRegions getOnlineRegions() {
+          return null;
+        }
+
         @Override
         public void startup() throws IOException {}