HBASE-1106 Expose getClosestRowBefore in HTable

git-svn-id: https://svn.apache.org/repos/asf/hadoop/hbase/trunk@731178 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -202,6 +202,8 @@ Release 0.19.0 - Unreleased
    HBASE-1062  Compactions at (re)start on a large table can overwhelm DFS
    HBASE-1102  boolean HTable.exists()
    HBASE-1105  Remove duplicated code in HCM, add javadoc to RegionState, etc.
+   HBASE-1106  Expose getClosestRowBefore in HTable
+               (Michael Gottesman via Stack)
 
   NEW FEATURES
    HBASE-875   Use MurmurHash instead of JenkinsHash [in bloomfilters]

src/java/org/apache/hadoop/hbase/client/HTable.java

@@ -618,6 +618,19 @@ public class HTable {
     );
   }
 
+  public RowResult getClosestRowBefore(final byte[] row, final byte[] columnFamily)
+  throws IOException {
+    return connection.getRegionServerWithRetries(
+      new ServerCallable<RowResult>(connection,tableName,row) {
+        public RowResult call() throws IOException {
+          return server.getClosestRowBefore(
+              location.getRegionInfo().getRegionName(), row, columnFamily
+            );
+          }
+        }
+      );
+    }
+
   /** 
    * Get a scanner on the current table starting at first row.
    * Return the specified columns.

src/test/org/apache/hadoop/hbase/client/TestHTable.java

@@ -259,4 +259,57 @@ public class TestHTable extends HBaseClusterTestCase implements HConstants {
     }
   }
   
+  public void testGetClosestRowBefore() throws IOException {
+    HColumnDescriptor column2 =
+      new HColumnDescriptor(Bytes.toBytes("info2:"));
+    HBaseAdmin admin = new HBaseAdmin(conf);
+    HTableDescriptor testTableADesc =
+      new HTableDescriptor(tableAname);
+    testTableADesc.addFamily(column);
+    testTableADesc.addFamily(column2);
+    admin.createTable(testTableADesc);
+    
+    byte[] firstRow = Bytes.toBytes("ro");
+    byte[] beforeFirstRow = Bytes.toBytes("rn");
+    byte[] beforeSecondRow = Bytes.toBytes("rov");
+    
+    HTable table = new HTable(conf, tableAname);
+    BatchUpdate batchUpdate = new BatchUpdate(firstRow);
+    BatchUpdate batchUpdate2 = new BatchUpdate(row);
+    byte[] zero = new byte[]{0};
+    byte[] one = new byte[]{1};
+    byte[] columnFamilyBytes = Bytes.toBytes(COLUMN_FAMILY_STR);
+    
+    batchUpdate.put(COLUMN_FAMILY_STR,zero);
+    batchUpdate2.put(COLUMN_FAMILY_STR,one);
+    
+    table.commit(batchUpdate);
+    table.commit(batchUpdate2);
+    
+    RowResult result = null;
+    
+    // Test before first that null is returned
+    result = table.getClosestRowBefore(beforeFirstRow, columnFamilyBytes);
+    assertTrue(result == null);
+    
+    // Test at first that first is returned
+    result = table.getClosestRowBefore(firstRow, columnFamilyBytes);
+    assertTrue(result.containsKey(COLUMN_FAMILY_STR));
+    assertTrue(Bytes.equals(result.get(COLUMN_FAMILY_STR).getValue(), zero));
+    
+    // Test inbetween first and second that first is returned
+    result = table.getClosestRowBefore(beforeSecondRow, columnFamilyBytes);
+    assertTrue(result.containsKey(COLUMN_FAMILY_STR));
+    assertTrue(Bytes.equals(result.get(COLUMN_FAMILY_STR).getValue(), zero));
+    
+    // Test at second make sure second is returned
+    result = table.getClosestRowBefore(row, columnFamilyBytes);
+    assertTrue(result.containsKey(COLUMN_FAMILY_STR));
+    assertTrue(Bytes.equals(result.get(COLUMN_FAMILY_STR).getValue(), one));
+    
+    // Test after second, make sure second is returned
+    result = table.getClosestRowBefore(Bytes.add(row,one), columnFamilyBytes);
+    assertTrue(result.containsKey(COLUMN_FAMILY_STR));
+    assertTrue(Bytes.equals(result.get(COLUMN_FAMILY_STR).getValue(), one));
+  }
 }