Examples of org.apache.accumulo.core.iterators.user.WholeRowIterator

Package org.apache.accumulo.core.iterators.user

Examples of org.apache.accumulo.core.iterators.user.WholeRowIterator

org.apache.accumulo.core.iterators.user.WholeRowIterator
The WholeRowIterator is designed to provide row-isolation so that queries see mutations as atomic. It does so by encapsulating an entire row of key/value pairs into a single key/value pair, which is returned through the client as an atomic operation.
One caveat is that when seeking in the WholeRowIterator using a range that starts at a non-inclusive first key in a row, (e.g. seek(new Range(new Key(new Text("row")),false,...),...)) this iterator will skip to the next row. This is done in order to prevent repeated scanning of the same row when system automatically creates ranges of that form, which happens in the case of the client calling continueScan, or in the case of the tablet server continuing a scan after swapping out sources.
To regain the original key/value pairs of the row, call the decodeRow function on the key/value pair that this iterator returned. @see RowFilter

        trueCount++;
        map2.put(k, map.get(k));
      }
    }
    SortedMapIterator source = new SortedMapIterator(map);
    WholeRowIterator iter = new WholeRowIterator(source);
    SortedMap<Key,Value> resultMap = new TreeMap<Key,Value>();
    iter.seek(new Range(), new ArrayList<ByteSequence>(), false);
    int numRows = 0;
    while (iter.hasTop()) {
      numRows++;
      Key rowKey = iter.getTopKey();
      Value rowValue = iter.getTopValue();
      resultMap.putAll(WholeRowIterator.decodeRow(rowKey, rowValue));
      iter.next();
    }
    assertTrue(numRows == 5);
    assertEquals(resultMap, map);
    
    WholeRowIterator iter2 = new WholeRowIterator(source) {
      @Override
      public boolean filter(Text row, List<Key> keys, List<Value> values) {
        return toInclude.get(row);
      }
    };
    resultMap.clear();
    iter2.seek(new Range(), new ArrayList<ByteSequence>(), false);
    numRows = 0;
    while (iter2.hasTop()) {
      numRows++;
      Key rowKey = iter2.getTopKey();
      Value rowValue = iter2.getTopValue();
      resultMap.putAll(WholeRowIterator.decodeRow(rowKey, rowValue));
      iter2.next();
    }
    assertTrue(numRows == trueCount);
    assertEquals(resultMap, map2);
  }

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    map.putAll(map1);
    map.putAll(map2);
    map.putAll(map3);
    
    SortedMapIterator source = new SortedMapIterator(map);
    WholeRowIterator iter = new WholeRowIterator(source);
    
    Range range = new Range(new Text("row1"), true, new Text("row2"), true);
    iter.seek(range, new ArrayList<ByteSequence>(), false);
    
    assertTrue(iter.hasTop());
    assertEquals(map1, WholeRowIterator.decodeRow(iter.getTopKey(), iter.getTopValue()));
    
    // simulate something continuing using the last key from the iterator
    // this is what client and server code will do
    range = new Range(iter.getTopKey(), false, range.getEndKey(), range.isEndKeyInclusive());
    iter.seek(range, new ArrayList<ByteSequence>(), false);
    
    assertTrue(iter.hasTop());
    assertEquals(map2, WholeRowIterator.decodeRow(iter.getTopKey(), iter.getTopValue()));
    
    iter.next();
    
    assertFalse(iter.hasTop());
    
  }

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    map.putAll(map1);
    map.putAll(map2);
    
    MultiIterator source = new MultiIterator(Collections.singletonList((SortedKeyValueIterator<Key,Value>) new SortedMapIterator(map)), new Range(null, true,
        new Text("row1"), true));
    WholeRowIterator iter = new WholeRowIterator(source);
    
    Range range = new Range(new Text("row1"), true, new Text("row2"), true);
    iter.seek(range, new ArrayList<ByteSequence>(), false);
    
    assertTrue(iter.hasTop());
    assertEquals(map1, WholeRowIterator.decodeRow(iter.getTopKey(), iter.getTopValue()));
    
    // simulate something continuing using the last key from the iterator
    // this is what client and server code will do
    range = new Range(iter.getTopKey(), false, range.getEndKey(), range.isEndKeyInclusive());
    iter.seek(range, new ArrayList<ByteSequence>(), false);
    
    assertFalse(iter.hasTop());
    
  }

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