HBASE-22833 MultiRowRangeFilter should provide a method for creating… (#493)
* HBASE-22833: MultiRowRangeFilter should provide a method for creating a filter which is functionally equivalent to multiple prefix filters * Delete superfluous comments * Add description for MultiRowRangeFilter constructor * Add null check for rowKeyPrefixes * Fix checkstyle Signed-off-by: huzheng <openinx@gmail.com>
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@ -17,6 +17,8 @@
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*/
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package org.apache.hadoop.hbase.client;
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import java.util.Arrays;
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import org.apache.hadoop.hbase.HConstants;
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import org.apache.hadoop.hbase.classification.InterfaceAudience;
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import org.apache.hadoop.hbase.util.Bytes;
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@ -31,4 +33,46 @@ public class ClientUtil {
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public static Cursor createCursor(byte[] row) {
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return new Cursor(row);
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}
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/**
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* <p>When scanning for a prefix the scan should stop immediately after the the last row that
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* has the specified prefix. This method calculates the closest next rowKey immediately following
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* the given rowKeyPrefix.</p>
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* <p><b>IMPORTANT: This converts a rowKey<u>Prefix</u> into a rowKey</b>.</p>
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* <p>If the prefix is an 'ASCII' string put into a byte[] then this is easy because you can
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* simply increment the last byte of the array.
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* But if your application uses real binary rowids you may run into the scenario that your
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* prefix is something like:</p>
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* <b>{ 0x12, 0x23, 0xFF, 0xFF }</b><br/>
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* Then this stopRow needs to be fed into the actual scan<br/>
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* <b>{ 0x12, 0x24 }</b> (Notice that it is shorter now)<br/>
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* This method calculates the correct stop row value for this usecase.
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*
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* @param rowKeyPrefix the rowKey<u>Prefix</u>.
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* @return the closest next rowKey immediately following the given rowKeyPrefix.
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*/
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public static byte[] calculateTheClosestNextRowKeyForPrefix(byte[] rowKeyPrefix) {
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// Essentially we are treating it like an 'unsigned very very long' and doing +1 manually.
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// Search for the place where the trailing 0xFFs start
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int offset = rowKeyPrefix.length;
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while (offset > 0) {
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if (rowKeyPrefix[offset - 1] != (byte) 0xFF) {
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break;
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}
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offset--;
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}
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if (offset == 0) {
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// We got an 0xFFFF... (only FFs) stopRow value which is
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// the last possible prefix before the end of the table.
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// So set it to stop at the 'end of the table'
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return HConstants.EMPTY_END_ROW;
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}
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// Copy the right length of the original
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byte[] newStopRow = Arrays.copyOfRange(rowKeyPrefix, 0, offset);
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// And increment the last one
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newStopRow[newStopRow.length - 1]++;
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return newStopRow;
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}
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}
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@ -21,7 +21,6 @@ package org.apache.hadoop.hbase.client;
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import java.io.IOException;
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import java.util.ArrayList;
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import java.util.Arrays;
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import java.util.HashMap;
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import java.util.List;
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import java.util.Map;
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@ -530,53 +529,11 @@ public class Scan extends Query {
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setStopRow(HConstants.EMPTY_END_ROW);
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} else {
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this.setStartRow(rowPrefix);
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this.setStopRow(calculateTheClosestNextRowKeyForPrefix(rowPrefix));
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this.setStopRow(ClientUtil.calculateTheClosestNextRowKeyForPrefix(rowPrefix));
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}
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return this;
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}
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/**
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* <p>When scanning for a prefix the scan should stop immediately after the the last row that
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* has the specified prefix. This method calculates the closest next rowKey immediately following
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* the given rowKeyPrefix.</p>
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* <p><b>IMPORTANT: This converts a rowKey<u>Prefix</u> into a rowKey</b>.</p>
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* <p>If the prefix is an 'ASCII' string put into a byte[] then this is easy because you can
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* simply increment the last byte of the array.
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* But if your application uses real binary rowids you may run into the scenario that your
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* prefix is something like:</p>
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* <b>{ 0x12, 0x23, 0xFF, 0xFF }</b><br/>
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* Then this stopRow needs to be fed into the actual scan<br/>
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* <b>{ 0x12, 0x24 }</b> (Notice that it is shorter now)<br/>
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* This method calculates the correct stop row value for this usecase.
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*
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* @param rowKeyPrefix the rowKey<u>Prefix</u>.
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* @return the closest next rowKey immediately following the given rowKeyPrefix.
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*/
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private byte[] calculateTheClosestNextRowKeyForPrefix(byte[] rowKeyPrefix) {
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// Essentially we are treating it like an 'unsigned very very long' and doing +1 manually.
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// Search for the place where the trailing 0xFFs start
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int offset = rowKeyPrefix.length;
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while (offset > 0) {
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if (rowKeyPrefix[offset - 1] != (byte) 0xFF) {
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break;
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}
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offset--;
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}
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if (offset == 0) {
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// We got an 0xFFFF... (only FFs) stopRow value which is
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// the last possible prefix before the end of the table.
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// So set it to stop at the 'end of the table'
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return HConstants.EMPTY_END_ROW;
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}
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// Copy the right length of the original
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byte[] newStopRow = Arrays.copyOfRange(rowKeyPrefix, 0, offset);
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// And increment the last one
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newStopRow[newStopRow.length - 1]++;
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return newStopRow;
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}
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/**
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* Get all available versions.
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* @return this
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@ -28,6 +28,7 @@ import org.apache.hadoop.hbase.HConstants;
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import org.apache.hadoop.hbase.KeyValueUtil;
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import org.apache.hadoop.hbase.classification.InterfaceAudience;
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import org.apache.hadoop.hbase.classification.InterfaceStability;
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import org.apache.hadoop.hbase.client.ClientUtil;
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import org.apache.hadoop.hbase.exceptions.DeserializationException;
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import org.apache.hadoop.hbase.protobuf.generated.FilterProtos;
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import org.apache.hadoop.hbase.util.ByteStringer;
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@ -77,6 +78,33 @@ public class MultiRowRangeFilter extends FilterBase {
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this.ranges = new RangeIteration(rangeList);
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}
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/**
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* Constructor for creating a <code>MultiRowRangeFilter</code> from multiple rowkey prefixes.
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*
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* As <code>MultiRowRangeFilter</code> javadoc says (See the solution 1 of the first statement),
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* if you try to create a filter list that scans row keys corresponding to given prefixes (e.g.,
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* <code>FilterList</code> composed of multiple <code>PrefixFilter</code>s), this constructor
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* provides a way to avoid creating an inefficient one.
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*
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* @param rowKeyPrefixes the array of byte array
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*/
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public MultiRowRangeFilter(byte[][] rowKeyPrefixes) throws IOException {
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this(createRangeListFromRowKeyPrefixes(rowKeyPrefixes));
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}
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private static List<RowRange> createRangeListFromRowKeyPrefixes(byte[][] rowKeyPrefixes) {
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if (rowKeyPrefixes == null) {
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throw new IllegalArgumentException("Invalid rowkey prefixes");
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}
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List<RowRange> list = new ArrayList<>();
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for (byte[] rowKeyPrefix: rowKeyPrefixes) {
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byte[] stopRow = ClientUtil.calculateTheClosestNextRowKeyForPrefix(rowKeyPrefix);
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list.add(new RowRange(rowKeyPrefix, true, stopRow, false));
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}
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return list;
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}
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public List<RowRange> getRowRanges() {
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// Used by hbase-rest
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return this.rangeList;
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@ -28,6 +28,7 @@ import org.apache.commons.logging.Log;
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import org.apache.commons.logging.LogFactory;
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import org.apache.hadoop.hbase.Cell;
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import org.apache.hadoop.hbase.HBaseTestingUtility;
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import org.apache.hadoop.hbase.HConstants;
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import org.apache.hadoop.hbase.client.HTable;
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import org.apache.hadoop.hbase.client.Put;
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import org.apache.hadoop.hbase.client.Result;
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@ -69,6 +70,61 @@ public class TestMultiRowRangeFilter {
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TEST_UTIL.shutdownMiniCluster();
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}
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@Test
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public void testRowKeyPrefixWithEmptyPrefix() throws IOException {
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byte[] prefix = {};
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byte[][] rowKeyPrefixes = new byte[1][];
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rowKeyPrefixes[0] = prefix;
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MultiRowRangeFilter filter = new MultiRowRangeFilter(rowKeyPrefixes);
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List<RowRange> actualRanges = filter.getRowRanges();
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List<RowRange> expectedRanges = new ArrayList<>();
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expectedRanges.add(
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new RowRange(HConstants.EMPTY_START_ROW, true, HConstants.EMPTY_END_ROW, false)
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);
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assertRangesEqual(expectedRanges, actualRanges);
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}
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@Test
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public void testRowKeyPrefixWithLastIncrementablePrefix() throws IOException {
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byte[] prefix = {(byte) 0x12, (byte) 0x23, (byte) 0xFF, (byte) 0xFE};
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byte[][] rowKeyPrefixes = new byte[1][];
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rowKeyPrefixes[0] = prefix;
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MultiRowRangeFilter filter = new MultiRowRangeFilter(rowKeyPrefixes);
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List<RowRange> actualRanges = filter.getRowRanges();
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List<RowRange> expectedRanges = new ArrayList<>();
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final byte[] expectedStop = {(byte) 0x12, (byte) 0x23, (byte) 0xFF, (byte) 0xFF};
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expectedRanges.add(new RowRange(prefix, true, expectedStop , false));
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assertRangesEqual(expectedRanges, actualRanges);
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}
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@Test
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public void testRowKeyPrefixWithoutLastIncrementablePrefix() throws IOException {
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byte[] prefix = {(byte) 0x12, (byte) 0x23, (byte) 0xFF, (byte) 0xFF};
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byte[][] rowKeyPrefixes = new byte[1][];
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rowKeyPrefixes[0] = prefix;
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MultiRowRangeFilter filter = new MultiRowRangeFilter(rowKeyPrefixes);
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List<RowRange> actualRanges = filter.getRowRanges();
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List<RowRange> expectedRanges = new ArrayList<>();
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final byte[] expectedStop = {(byte) 0x12, (byte) 0x24};
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expectedRanges.add(new RowRange(prefix, true, expectedStop , false));
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assertRangesEqual(expectedRanges, actualRanges);
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}
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@Test
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public void testRowKeyPrefixWithMergablePrefix() throws IOException {
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byte[] prefix1 = {(byte) 0x12, (byte) 0x23, (byte) 0xFF, (byte) 0xFE};
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byte[] prefix2 = {(byte) 0x12, (byte) 0x23, (byte) 0xFF, (byte) 0xFF};
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byte[][] rowKeyPrefixes = new byte[2][];
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rowKeyPrefixes[0] = prefix1;
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rowKeyPrefixes[1] = prefix2;
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MultiRowRangeFilter filter = new MultiRowRangeFilter(rowKeyPrefixes);
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List<RowRange> actualRanges = filter.getRowRanges();
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List<RowRange> expectedRanges = new ArrayList<>();
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final byte[] expectedStop = {(byte) 0x12, (byte) 0x24};
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expectedRanges.add(new RowRange(prefix1, true, expectedStop , false));
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assertRangesEqual(expectedRanges, actualRanges);
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}
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@Test
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public void testRanges() throws IOException {
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byte[] key1Start = new byte[] {-3};
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