HBASE-4903 Return a result from RegionObserver.preIncrement (Daniel Gómez Ferro)

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1208952 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -736,6 +736,8 @@ Release 0.92.0 - Unreleased
    HBASE-4779  TestHTablePool, TestScanWithBloomError, TestRegionSplitCalculator are
                not tagged and TestPoolMap should not use TestSuite (N Keywal)
    HBASE-4805  Allow better control of resource consumption in HTable (Lars H)
+   HBASE-4903  Return a result from RegionObserver.preIncrement
+               (Daniel Gómez Ferro via Lars H)
 
   TASKS
    HBASE-3559  Move report of split to master OFF the heartbeat channel

src/main/java/org/apache/hadoop/hbase/coprocessor/BaseRegionObserver.java

@@ -186,13 +186,15 @@ public abstract class BaseRegionObserver implements RegionObserver {
   }
 
   @Override
-  public void preAppend(final ObserverContext<RegionCoprocessorEnvironment> e,
+  public Result preAppend(final ObserverContext<RegionCoprocessorEnvironment> e,
-      final Append append, final Result result) throws IOException {
+      final Append append) throws IOException {
+    return null;
   }
 
   @Override
-  public void postAppend(final ObserverContext<RegionCoprocessorEnvironment> e,
+  public Result postAppend(final ObserverContext<RegionCoprocessorEnvironment> e,
       final Append append, final Result result) throws IOException {
+    return result;
   }
 
   @Override
@@ -211,13 +213,15 @@ public abstract class BaseRegionObserver implements RegionObserver {
   }
 
   @Override
-  public void preIncrement(final ObserverContext<RegionCoprocessorEnvironment> e,
+  public Result preIncrement(final ObserverContext<RegionCoprocessorEnvironment> e,
-      final Increment increment, final Result result) throws IOException {
+      final Increment increment) throws IOException {
+    return null;
   }
 
   @Override
-  public void postIncrement(final ObserverContext<RegionCoprocessorEnvironment> e,
+  public Result postIncrement(final ObserverContext<RegionCoprocessorEnvironment> e,
       final Increment increment, final Result result) throws IOException {
+    return result;
   }
 
   @Override

src/main/java/org/apache/hadoop/hbase/coprocessor/RegionObserver.java

@@ -16,20 +16,19 @@
 
 package org.apache.hadoop.hbase.coprocessor;
 
+import java.io.IOException;
 import java.util.List;
-import java.util.Map;
 
-import com.google.common.collect.ImmutableList;
 import org.apache.hadoop.hbase.Coprocessor;
 import org.apache.hadoop.hbase.HRegionInfo;
 import org.apache.hadoop.hbase.KeyValue;
 import org.apache.hadoop.hbase.client.Append;
 import org.apache.hadoop.hbase.client.Delete;
 import org.apache.hadoop.hbase.client.Get;
+import org.apache.hadoop.hbase.client.Increment;
 import org.apache.hadoop.hbase.client.Put;
 import org.apache.hadoop.hbase.client.Result;
 import org.apache.hadoop.hbase.client.Scan;
-import org.apache.hadoop.hbase.client.Increment;
 import org.apache.hadoop.hbase.filter.CompareFilter.CompareOp;
 import org.apache.hadoop.hbase.filter.WritableByteArrayComparable;
 import org.apache.hadoop.hbase.regionserver.HRegion;
@@ -40,7 +39,7 @@ import org.apache.hadoop.hbase.regionserver.StoreFile;
 import org.apache.hadoop.hbase.regionserver.wal.HLogKey;
 import org.apache.hadoop.hbase.regionserver.wal.WALEdit;
 
-import java.io.IOException;
+import com.google.common.collect.ImmutableList;
 
 /**
  * Coprocessors implement this interface to observe and mediate client actions
@@ -467,13 +466,11 @@ public interface RegionObserver extends Coprocessor {
    * coprocessors
    * @param c the environment provided by the region server
    * @param append Append object
-   * @param result The result to return to the client if default processing
+   * @return result to return to the client if bypassing default processing
-   * is bypassed. Can be modified. Will not be used if default processing
-   * is not bypassed.
    * @throws IOException if an error occurred on the coprocessor
    */
-  void preAppend(final ObserverContext<RegionCoprocessorEnvironment> c,
+  Result preAppend(final ObserverContext<RegionCoprocessorEnvironment> c,
-      final Append append, final Result result)
+      final Append append)
     throws IOException;
 
   /**
@@ -483,10 +480,11 @@ public interface RegionObserver extends Coprocessor {
    * coprocessors
    * @param c the environment provided by the region server
    * @param append Append object
-   * @param result the result returned by increment, can be modified
+   * @param result the result returned by increment
+   * @return the result to return to the client
    * @throws IOException if an error occurred on the coprocessor
    */
-  void postAppend(final ObserverContext<RegionCoprocessorEnvironment> c,
+  Result postAppend(final ObserverContext<RegionCoprocessorEnvironment> c,
       final Append append, final Result result)
     throws IOException;
 
@@ -499,13 +497,11 @@ public interface RegionObserver extends Coprocessor {
    * coprocessors
    * @param c the environment provided by the region server
    * @param increment increment object
-   * @param result The result to return to the client if default processing
+   * @return result to return to the client if bypassing default processing
-   * is bypassed. Can be modified. Will not be used if default processing
-   * is not bypassed.
    * @throws IOException if an error occurred on the coprocessor
    */
-  void preIncrement(final ObserverContext<RegionCoprocessorEnvironment> c,
+  Result preIncrement(final ObserverContext<RegionCoprocessorEnvironment> c,
-      final Increment increment, final Result result)
+      final Increment increment)
     throws IOException;
 
   /**
@@ -515,10 +511,11 @@ public interface RegionObserver extends Coprocessor {
    * coprocessors
    * @param c the environment provided by the region server
    * @param increment increment object
-   * @param result the result returned by increment, can be modified
+   * @param result the result returned by increment
+   * @return the result to return to the client
    * @throws IOException if an error occurred on the coprocessor
    */
-  void postIncrement(final ObserverContext<RegionCoprocessorEnvironment> c,
+  Result postIncrement(final ObserverContext<RegionCoprocessorEnvironment> c,
       final Increment increment, final Result result)
     throws IOException;
 

src/main/java/org/apache/hadoop/hbase/regionserver/HRegionServer.java

@@ -3052,7 +3052,7 @@ public class HRegionServer implements HRegionInterface, HBaseRPCErrorHandler,
       resVal = region.increment(incVal, lock,
           increment.getWriteToWAL());
       if (region.getCoprocessorHost() != null) {
-        region.getCoprocessorHost().postIncrement(incVal, resVal);
+        resVal = region.getCoprocessorHost().postIncrement(incVal, resVal);
       }
       return resVal;
     } catch (IOException e) {

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

@@ -954,13 +954,13 @@ public class RegionCoprocessorHost
   public Result preAppend(Append append)
       throws IOException {
     boolean bypass = false;
-    Result result = new Result();
+    Result result = null;
     ObserverContext<RegionCoprocessorEnvironment> ctx = null;
     for (RegionEnvironment env: coprocessors) {
       if (env.getInstance() instanceof RegionObserver) {
         ctx = ObserverContext.createAndPrepare(env, ctx);
         try {
-          ((RegionObserver)env.getInstance()).preAppend(ctx, append, result);
+          result = ((RegionObserver)env.getInstance()).preAppend(ctx, append);
         } catch (Throwable e) {
           handleCoprocessorThrowable(env, e);
         }
@@ -982,13 +982,13 @@ public class RegionCoprocessorHost
   public Result preIncrement(Increment increment)
       throws IOException {
     boolean bypass = false;
-    Result result = new Result();
+    Result result = null;
     ObserverContext<RegionCoprocessorEnvironment> ctx = null;
     for (RegionEnvironment env: coprocessors) {
       if (env.getInstance() instanceof RegionObserver) {
         ctx = ObserverContext.createAndPrepare(env, ctx);
         try {
-          ((RegionObserver)env.getInstance()).preIncrement(ctx, increment, result);
+          result = ((RegionObserver)env.getInstance()).preIncrement(ctx, increment);
         } catch (Throwable e) {
           handleCoprocessorThrowable(env, e);
         }
@@ -1029,14 +1029,14 @@ public class RegionCoprocessorHost
    * @param result the result returned by postIncrement
    * @throws IOException if an error occurred on the coprocessor
    */
-  public void postIncrement(final Increment increment, Result result)
+  public Result postIncrement(final Increment increment, Result result)
       throws IOException {
     ObserverContext<RegionCoprocessorEnvironment> ctx = null;
     for (RegionEnvironment env: coprocessors) {
       if (env.getInstance() instanceof RegionObserver) {
         ctx = ObserverContext.createAndPrepare(env, ctx);
         try {
-          ((RegionObserver)env.getInstance()).postIncrement(ctx, increment, result);
+          result = ((RegionObserver)env.getInstance()).postIncrement(ctx, increment, result);
         } catch (Throwable e) {
           handleCoprocessorThrowable(env, e);
         }
@@ -1045,6 +1045,7 @@ public class RegionCoprocessorHost
         }
       }
     }
+    return result;
   }
 
   /**

src/test/java/org/apache/hadoop/hbase/coprocessor/SimpleRegionObserver.java

@@ -371,15 +371,17 @@ public class SimpleRegionObserver extends BaseRegionObserver {
   }
 
   @Override
-  public void preIncrement(final ObserverContext<RegionCoprocessorEnvironment> c,
+  public Result preIncrement(final ObserverContext<RegionCoprocessorEnvironment> c,
-      final Increment increment, final Result result) throws IOException {
+      final Increment increment) throws IOException {
     hadPreIncrement = true;
+    return null;
   }
 
   @Override
-  public void postIncrement(final ObserverContext<RegionCoprocessorEnvironment> c,
+  public Result postIncrement(final ObserverContext<RegionCoprocessorEnvironment> c,
       final Increment increment, final Result result) throws IOException {
     hadPostIncrement = true;
+    return result;
   }
 
   public boolean hadPreGet() {