code: /** 
   * Test "must pass one"
   * @throws Exception
   */
  public void testMPONE() throws Exception {
    List<Filter> filters=new ArrayList<Filter>();
    filters.add(new PageFilter(MAX_PAGES));
    filters.add(new WhileMatchFilter(new PrefixFilter(Bytes.toBytes("yyy"))));
    Filter filterMPONE=new FilterList(FilterList.Operator.MUST_PASS_ONE,filters);
    filterMPONE.reset();
    assertFalse(filterMPONE.filterAllRemaining());
    byte[] rowkey=Bytes.toBytes("yyyyyyyyy");
    for (int i=0; i < MAX_PAGES - 1; i++) {
      assertFalse(filterMPONE.filterRowKey(rowkey,0,rowkey.length));
      assertFalse(filterMPONE.filterRow());
      KeyValue kv=new KeyValue(rowkey,rowkey,Bytes.toBytes(i),Bytes.toBytes(i));
      assertTrue(Filter.ReturnCode.INCLUDE == filterMPONE.filterKeyValue(kv));
    }
    rowkey=Bytes.toBytes("z");
    assertFalse(filterMPONE.filterRowKey(rowkey,0,rowkey.length));
    assertFalse(filterMPONE.filterRow());
    KeyValue kv=new KeyValue(rowkey,rowkey,Bytes.toBytes(0),Bytes.toBytes(0));
    assertTrue(Filter.ReturnCode.INCLUDE == filterMPONE.filterKeyValue(kv));
    rowkey=Bytes.toBytes("yyy");
    assertFalse(filterMPONE.filterRowKey(rowkey,0,rowkey.length));
    assertFalse(filterMPONE.filterRow());
    kv=new KeyValue(rowkey,rowkey,Bytes.toBytes(0),Bytes.toBytes(0));
    assertTrue(Filter.ReturnCode.INCLUDE == filterMPONE.filterKeyValue(kv));
    rowkey=Bytes.toBytes("z");
    assertTrue(filterMPONE.filterRowKey(rowkey,0,rowkey.length));
    assertTrue(filterMPONE.filterRow());
    assertTrue(filterMPONE.filterAllRemaining());
  }
  