HBASE-13100 Shell command to retrieve table splits

hbase-shell/src/main/ruby/hbase/table.rb

@@ -678,5 +678,16 @@ EOF
         column[1] = parts[0]
       end
     end
+
+    #----------------------------------------------------------------------------------------------
+    # Get the split points for the table
+    def _get_splits_internal()
+      locator = @table.getRegionLocator()
+      splits = locator.getAllRegionLocations().
+          map{|i| Bytes.toStringBinary(i.getRegionInfo().getStartKey)}.delete_if{|k| k == ""}
+      locator.close()
+      puts("Total number of splits = %s" % [splits.size + 1])
+      return splits
+    end
   end
 end

hbase-shell/src/main/ruby/shell.rb

@@ -301,6 +301,7 @@ Shell.load_command_group(
     truncate
     truncate_preserve
     append
+    get_splits
   ]
 )
 

hbase-shell/src/main/ruby/shell/commands/get_splits.rb

@@ -0,0 +1,46 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+module Shell
+  module Commands
+    class GetSplits < Command
+      def help
+        return <<-EOF
+Get the splits of the named table:
+  hbase> get_splits 't1'
+  hbase> get_splits 'ns1:t1'
+
+The same commands also can be run on a table reference. Suppose you had a reference
+t to table 't1', the corresponding command would be:
+
+  hbase> t.get_splits
+EOF
+      end
+
+      def command(table)
+        get_splits(table(table))
+      end
+
+      def get_splits(table)
+        table._get_splits_internal()
+      end
+    end
+  end
+end
+
+::Hbase::Table.add_shell_command("get_splits")

hbase-shell/src/test/ruby/hbase/table_test.rb

@@ -611,5 +611,22 @@ module Hbase
       end
     end
 
+    define_test "Split count for a table" do
+      @testTableName = "tableWithSplits"
+      create_test_table_with_splits(@testTableName, SPLITS => ['10', '20', '30', '40'])
+      @table = table(@testTableName)
+      splits = @table._get_splits_internal()
+      #Total splits is 5 but here count is 4 as we ignore implicit empty split.
+      assert_equal(4, splits.size)
+      assert_equal(["10", "20", "30", "40"], splits)
+      drop_test_table(@testTableName)
+    end
+
+    define_test "Split count for a empty table" do
+      splits = @test_table._get_splits_internal()
+      #Empty split should not be part of this array.
+      assert_equal(0, splits.size)
+      assert_equal([], splits)
+    end
   end
 end

hbase-shell/src/test/ruby/test_helper.rb

@@ -85,6 +85,18 @@ module Hbase
       end
     end
 
+    def create_test_table_with_splits(name, splits)
+      # Create the table if needed
+      unless admin.exists?(name)
+        admin.create name, 'f1', splits
+      end
+
+      # Enable the table if needed
+      unless admin.enabled?(name)
+        admin.enable(name)
+      end
+    end
+
     def drop_test_table(name)
       return unless admin.exists?(name)
       begin