HBASE-13299 Add setReturnResults() to Increment, like Append has

Signed-off-by: stack <stack@apache.org>

hbase-client/src/main/java/org/apache/hadoop/hbase/client/Increment.java

@@ -53,6 +53,8 @@ import org.apache.hadoop.hbase.util.ClassSize;
 public class Increment extends Mutation implements Comparable<Row> {
   private static final long HEAP_OVERHEAD =  ClassSize.REFERENCE + ClassSize.TIMERANGE;
 
+  private static final String RETURN_RESULTS = "_rr_";
+
   private TimeRange tr = new TimeRange();
 
   /**
@@ -161,6 +163,24 @@ public class Increment extends Mutation implements Comparable<Row> {
     tr = new TimeRange(minStamp, maxStamp);
     return this;
   }
+  
+  /**
+   * @param returnResults True (default) if the increment operation should return the results. A
+   *          client that is not interested in the result can save network bandwidth setting this
+   *          to false.
+   */
+  public Increment setReturnResults(boolean returnResults) {
+    setAttribute(RETURN_RESULTS, Bytes.toBytes(returnResults));
+    return this;
+  }
+
+  /**
+   * @return current value for returnResults
+   */
+  public boolean isReturnResults() {
+    byte[] v = getAttribute(RETURN_RESULTS);
+    return v == null ? true : Bytes.toBoolean(v);
+  }
 
   /**
    * Method for retrieving the number of families to increment from

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

@@ -7097,8 +7097,7 @@ public class HRegion implements HeapSize, PropagatingConfigurationObserver, Regi
       // Request a cache flush.  Do it outside update lock.
       requestFlush();
     }
-
-    return Result.create(allKVs);
+    return increment.isReturnResults() ? Result.create(allKVs) : null;
   }
 
   //

hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/wal/TestDurability.java

@@ -19,6 +19,7 @@
 package org.apache.hadoop.hbase.regionserver.wal;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
 
 import java.io.IOException;
 
@@ -192,6 +193,28 @@ public class TestDurability {
     assertEquals(3, Bytes.toLong(res.getValue(FAMILY, col3)));
     verifyWALCount(wals, wal, 2);
   }
+  
+  /*
+   * Test when returnResults set to false in increment it should not return the result instead it
+   * resturn null.
+   */
+  @Test
+  public void testIncrementWithReturnResultsSetToFalse() throws Exception {
+    byte[] row1 = Bytes.toBytes("row1");
+    byte[] col1 = Bytes.toBytes("col1");
+
+    // Setting up region
+    final WALFactory wals = new WALFactory(CONF, null, "testIncrementWithReturnResultsSetToFalse");
+    byte[] tableName = Bytes.toBytes("testIncrementWithReturnResultsSetToFalse");
+    final WAL wal = wals.getWAL(tableName);
+    HRegion region = createHRegion(tableName, "increment", wal, Durability.USE_DEFAULT);
+
+    Increment inc1 = new Increment(row1);
+    inc1.setReturnResults(false);
+    inc1.addColumn(FAMILY, col1, 1);
+    Result res = region.increment(inc1);
+    assertNull(res);
+  }
 
   private Put newPut(Durability durability) {
     Put p = new Put(ROW);