Examples of org.apache.hadoop.hbase.client.Scan

org.apache.hadoop.hbase.client.Scan
Used to perform Scan operations.
All operations are identical to {@link Get} with the exception ofinstantiation. Rather than specifying a single row, an optional startRow and stopRow may be defined. If rows are not specified, the Scanner will iterate over all rows.
To scan everything for each row, instantiate a Scan object.
To modify scanner caching for just this scan, use {@link #setCaching(int) setCaching}. If caching is NOT set, we will use the caching value of the hosting {@link HTable}. See {@link HTable#setScannerCaching(int)}.
To further define the scope of what to get when scanning, perform additional methods as outlined below.
To get all columns from specific families, execute {@link #addFamily(byte[]) addFamily}for each family to retrieve.
To get specific columns, execute {@link #addColumn(byte[],byte[]) addColumn}for each column to retrieve.
To only retrieve columns within a specific range of version timestamps, execute {@link #setTimeRange(long,long) setTimeRange}.
To only retrieve columns with a specific timestamp, execute {@link #setTimeStamp(long) setTimestamp}.
To limit the number of versions of each column to be returned, execute {@link #setMaxVersions(int) setMaxVersions}.
To limit the maximum number of values returned for each call to next(), execute {@link #setBatch(int) setBatch}.
To add a filter, execute {@link #setFilter(org.apache.hadoop.hbase.filter.Filter) setFilter}.
Expert: To explicitly disable server-side block caching for this scan, execute {@link #setCacheBlocks(boolean)}.

        KeyValueTestUtil.create("R2", "cf", "a", 20, KeyValue.Type.Put, "dont-care")
    };
    KeyValueScanner [] scanners = new KeyValueScanner[] {
        new KeyValueScanFixture(KeyValue.COMPARATOR, kvs)
    };
    Scan scanSpec = new Scan(Bytes.toBytes("R1"));
    StoreScanner scan =
      new StoreScanner(scanSpec, CF, Long.MAX_VALUE, KeyValue.COMPARATOR,
          getCols("a"), scanners);


    List<KeyValue> results = new ArrayList<KeyValue>();

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    KeyValueScanner [] scanners = new KeyValueScanner[] {
        new KeyValueScanFixture(KeyValue.COMPARATOR, kvs1),
        new KeyValueScanFixture(KeyValue.COMPARATOR, kvs2)
    };
    StoreScanner scan =
      new StoreScanner(new Scan(Bytes.toBytes("R1")), CF, Long.MAX_VALUE, KeyValue.COMPARATOR,
          getCols("a"), scanners);
    List<KeyValue> results = new ArrayList<KeyValue>();
    // the two put at ts=now will be masked by the 1 delete, and
    // since the scan default returns 1 version we'll return the newest
    // key, which is kvs[2], now-100.

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    };
    KeyValueScanner [] scanners = new KeyValueScanner[] {
        new KeyValueScanFixture(KeyValue.COMPARATOR, kvs1),
        new KeyValueScanFixture(KeyValue.COMPARATOR, kvs2)
    };
    Scan scanSpec = new Scan(Bytes.toBytes("R1")).setMaxVersions(2);
    StoreScanner scan =
      new StoreScanner(scanSpec, CF, Long.MAX_VALUE, KeyValue.COMPARATOR,
          getCols("a"), scanners);
    List<KeyValue> results = new ArrayList<KeyValue>();
    assertEquals(true, scan.next(results));

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    };
    KeyValueScanner [] scanners = new KeyValueScanner[] {
        new KeyValueScanFixture(KeyValue.COMPARATOR, kvs)
    };
    StoreScanner scan =
      new StoreScanner(new Scan(Bytes.toBytes("R1")), CF, Long.MAX_VALUE, KeyValue.COMPARATOR,
          null, scanners);
    List<KeyValue> results = new ArrayList<KeyValue>();
    assertEquals(true, scan.next(results));
    assertEquals(2, results.size());
    assertEquals(kvs[0], results.get(0));

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    };
    KeyValueScanner [] scanners = new KeyValueScanner[] {
        new KeyValueScanFixture(KeyValue.COMPARATOR, kvs)
    };
    StoreScanner scan =
      new StoreScanner(new Scan().setMaxVersions(2), CF, Long.MAX_VALUE, KeyValue.COMPARATOR,
          null, scanners);
    List<KeyValue> results = new ArrayList<KeyValue>();
    assertEquals(true, scan.next(results));
    assertEquals(5, results.size());
    assertEquals(kvs[0], results.get(0));

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    };
    KeyValueScanner [] scanners = new KeyValueScanner[] {
        new KeyValueScanFixture(KeyValue.COMPARATOR, kvs)
    };
    StoreScanner scan =
      new StoreScanner(new Scan().setMaxVersions(Integer.MAX_VALUE), CF, Long.MAX_VALUE, KeyValue.COMPARATOR,
          null, scanners);
    List<KeyValue> results = new ArrayList<KeyValue>();
    assertEquals(true, scan.next(results));
    assertEquals(0, results.size());
    assertEquals(true, scan.next(results));

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    };
    KeyValueScanner [] scanners = new KeyValueScanner[] {
        new KeyValueScanFixture(KeyValue.COMPARATOR, kvs),
    };
    StoreScanner scan =
      new StoreScanner(new Scan(), CF, Long.MAX_VALUE, KeyValue.COMPARATOR,
          null, scanners);
    List<KeyValue> results = new ArrayList<KeyValue>();
    assertEquals(true, scan.next(results));
    assertEquals(1, results.size());
    assertEquals(kvs[3], results.get(0));

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    };
    KeyValueScanner [] scanners = new KeyValueScanner[] {
        new KeyValueScanFixture(KeyValue.COMPARATOR, kvs)
    };
    StoreScanner scan =
      new StoreScanner(new Scan(), CF, Long.MAX_VALUE, KeyValue.COMPARATOR,
          getCols("a", "d"), scanners);


    List<KeyValue> results = new ArrayList<KeyValue>();
    assertEquals(true, scan.next(results));
    assertEquals(2, results.size());

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        KeyValueTestUtil.create("R2", "cf", "c", now-1000, KeyValue.Type.Put, "dont-care")
    };
    KeyValueScanner [] scanners = new KeyValueScanner[] {
        new KeyValueScanFixture(KeyValue.COMPARATOR, kvs)
    };
    Scan scan = new Scan();
    scan.setMaxVersions(1);
    StoreScanner scanner =
      new StoreScanner(scan, CF, 500, KeyValue.COMPARATOR,
          null, scanners);


    List<KeyValue> results = new ArrayList<KeyValue>();

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      new HashMap<HRegionInfo, Result>();
    List<byte []> emptyRows = new ArrayList<byte []>();
    int rows = 0;
    try {
      regionServer = master.connection.getHRegionConnection(region.getServer());
      Scan s = new Scan().addFamily(HConstants.CATALOG_FAMILY);
      // Make this scan do a row at a time otherwise, data can be stale.
      s.setCaching(1);
      scannerId = regionServer.openScanner(region.getRegionName(), s);
      while (true) {
        Result values = regionServer.next(scannerId);
        if (values == null || values.size() == 0) {
          break;

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