HBASE-18001 Extend the "count" shell command to support specified conditions

Signed-off-by: Chia-Ping Tsai <chia7712@gmail.com>

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

@@ -297,12 +297,28 @@ EOF
 
     #----------------------------------------------------------------------------------------------
     # Count rows in a table
-    def _count_internal(interval = 1000, caching_rows = 10)
+    def _count_internal(interval = 1000, scan = nil)
+
+      raise(ArgumentError, "Scan argument should be org.apache.hadoop.hbase.client.Scan") \
+        unless scan == nil || scan.kind_of?(org.apache.hadoop.hbase.client.Scan)
       # We can safely set scanner caching with the first key only filter
-      scan = org.apache.hadoop.hbase.client.Scan.new
-      scan.setCacheBlocks(false)
-      scan.setCaching(caching_rows)
-      scan.setFilter(org.apache.hadoop.hbase.filter.FirstKeyOnlyFilter.new)
+
+      if scan == nil
+        scan = org.apache.hadoop.hbase.client.Scan.new
+        scan.setCacheBlocks(false)
+        scan.setCaching(10)
+        scan.setFilter(org.apache.hadoop.hbase.filter.FirstKeyOnlyFilter.new)
+      else
+        scan.setCacheBlocks(false)
+        filter = scan.getFilter()
+        firstKeyOnlyFilter = org.apache.hadoop.hbase.filter.FirstKeyOnlyFilter.new
+        if filter == nil
+          scan.setFilter(firstKeyOnlyFilter)
+        else
+          firstKeyOnlyFilter.setReversed(filter.isReversed())
+          scan.setFilter(org.apache.hadoop.hbase.filter.FilterList.new(filter, firstKeyOnlyFilter))
+        end
+      end
 
       # Run the scanner
       scanner = @table.getScanner(scan)

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

@@ -35,6 +35,9 @@ parameter. Examples:
  hbase> count 't1', INTERVAL => 100000
  hbase> count 't1', CACHE => 1000
  hbase> count 't1', INTERVAL => 10, CACHE => 1000
+ hbase> count 't1', FILTER => "
+    (QualifierFilter (>=, 'binary:xyz')) AND (TimestampsFilter ( 123, 456))"
+ hbase> count 't1', COLUMNS => ['c1', 'c2'], STARTROW => 'abc', STOPROW => 'xyz'
 
 The same commands also can be run on a table reference. Suppose you had a reference
 t to table 't1', the corresponding commands would be:
@@ -43,6 +46,9 @@ t to table 't1', the corresponding commands would be:
  hbase> t.count INTERVAL => 100000
  hbase> t.count CACHE => 1000
  hbase> t.count INTERVAL => 10, CACHE => 1000
+ hbase> t.count FILTER => "
+    (QualifierFilter (>=, 'binary:xyz')) AND (TimestampsFilter ( 123, 456))"
+ hbase> t.count COLUMNS => ['c1', 'c2'], STARTROW => 'abc', STOPROW => 'xyz'
 EOF
       end
 
@@ -60,10 +66,11 @@ EOF
           'CACHE' => 10
         }.merge(params)
 
+        scan = table._hash_to_scan(params)
         # Call the counter method
         @start_time = Time.now
         formatter.header
-        count = table._count_internal(params['INTERVAL'].to_i, params['CACHE'].to_i) do |cnt, row|
+        count = table._count_internal(params['INTERVAL'].to_i, scan) do |cnt, row|
           formatter.row([ "Current count: #{cnt}, row: #{row}" ])
         end
         formatter.footer(count)

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

@@ -250,6 +250,31 @@ module Hbase
       assert(!rows.empty?)
     end
 
+    define_test "count should support STARTROW parameter" do
+      count = @test_table.count STARTROW => '4'
+      assert(count == 0)
+    end
+
+    define_test "count should support STOPROW parameter" do
+      count = @test_table.count STOPROW => '0'
+      assert(count == 0)
+    end
+
+    define_test "count should support COLUMNS parameter" do
+      @test_table.put(4, "x:c", "31")
+      begin
+        count = @test_table.count COLUMNS => [ 'x:c']
+        assert(count == 1)
+      ensure
+        @test_table.delete(4, "x:c")
+      end
+    end
+
+    define_test "count should support FILTER parameter" do
+      count = @test_table.count FILTER => "ValueFilter(=, 'binary:11')"
+      assert(count == 1)
+    end
+
     #-------------------------------------------------------------------------------
 
     define_test "get should work w/o columns specification" do