Repository: hbase Updated Branches: refs/heads/0.98 c5522961c -> 084186836
HBASE-11865 Result implements CellScannable; rather it should BE a CellScanner Project: http://git-wip-us.apache.org/repos/asf/hbase/repo Commit: http://git-wip-us.apache.org/repos/asf/hbase/commit/08418683 Tree: http://git-wip-us.apache.org/repos/asf/hbase/tree/08418683 Diff: http://git-wip-us.apache.org/repos/asf/hbase/diff/08418683 Branch: refs/heads/0.98 Commit: 084186836318bf0cc93da611c98cb9c63b687d0b Parents: c552296 Author: stack <[email protected]> Authored: Sun Aug 31 00:11:35 2014 -0700 Committer: stack <[email protected]> Committed: Sun Aug 31 00:14:37 2014 -0700 ---------------------------------------------------------------------- .../org/apache/hadoop/hbase/client/Result.java | 60 ++++++++++++++------ .../apache/hadoop/hbase/client/TestResult.java | 27 +++++++++ 2 files changed, 69 insertions(+), 18 deletions(-) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/hbase/blob/08418683/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Result.java ---------------------------------------------------------------------- diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Result.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Result.java index 8abbcf7..68d2416 100644 --- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Result.java +++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Result.java @@ -58,20 +58,23 @@ import org.apache.hadoop.hbase.util.Bytes; * * To get the latest value for a specific family and qualifier use {@link #getValue(byte[], byte[])}. * - * A Result is backed by an array of {@link KeyValue} objects, each representing + * A Result is backed by an array of {@link Cell} objects, each representing * an HBase cell defined by the row, family, qualifier, timestamp, and value.<p> * - * The underlying {@link KeyValue} objects can be accessed through the method {@link #listCells()}. - * Each KeyValue can then be accessed through - * {@link KeyValue#getRow()}, {@link KeyValue#getFamily()}, {@link KeyValue#getQualifier()}, - * {@link KeyValue#getTimestamp()}, and {@link KeyValue#getValue()}.<p> + * The underlying {@link Cell} objects can be accessed through the method {@link #listCells()}. + * This will create a List from the internal Cell []. Better is to exploit the fact that + * a new Result instance is a primed {@link CellScanner}; just call {@link #advance()} and + * {@link #current()} to iterate over Cells as you would any {@link CellScanner}. + * Call {@link #cellScanner()} to reset should you need to iterate the same Result over again + * ({@link CellScanner}s are one-shot). * - * If you need to overwrite a Result with another Result instance -- as in the old 'mapred' RecordReader next - * invocations -- then create an empty Result with the null constructor and in then use {@link #copyFrom(Result)} + * If you need to overwrite a Result with another Result instance -- as in the old 'mapred' + * RecordReader next invocations -- then create an empty Result with the null constructor and + * in then use {@link #copyFrom(Result)} */ @InterfaceAudience.Public @InterfaceStability.Stable -public class Result implements CellScannable { +public class Result implements CellScannable, CellScanner { private Cell[] cells; private Boolean exists; // if the query was just to check existence. // We're not using java serialization. Transient here is just a marker to say @@ -85,6 +88,13 @@ public class Result implements CellScannable { private static final int PAD_WIDTH = 128; public static final Result EMPTY_RESULT = new Result(); + private final static int INITIAL_CELLSCANNER_INDEX = -1; + + /** + * Index for where we are when Result is acting as a {@link CellScanner}. + */ + private int cellScannerIndex = INITIAL_CELLSCANNER_INDEX; + /** * Creates an empty Result w/ no KeyValue payload; returns null if you call {@link #rawCells()}. * Use this to represent no results if <code>null</code> won't do or in old 'mapred' as oppposed to 'mapreduce' package @@ -180,13 +190,13 @@ public class Result implements CellScannable { } /** - * Return an cells of a Result as an array of KeyValues - * + * Return an cells of a Result as an array of KeyValues + * * WARNING do not use, expensive. This does an arraycopy of the cell[]'s value. * * Added to ease transition from 0.94 -> 0.96. - * - * @deprecated as of 0.96, use {@link #rawCells()} + * + * @deprecated as of 0.96, use {@link #rawCells()} * @return array of KeyValues, empty array if nothing in result. */ @Deprecated @@ -208,15 +218,15 @@ public class Result implements CellScannable { public List<Cell> listCells() { return isEmpty()? null: Arrays.asList(rawCells()); } - + /** - * Return an cells of a Result as an array of KeyValues - * + * Return an cells of a Result as an array of KeyValues + * * WARNING do not use, expensive. This does an arraycopy of the cell[]'s value. * * Added to ease transition from 0.94 -> 0.96. - * - * @deprecated as of 0.96, use {@link #listCells()} + * + * @deprecated as of 0.96, use {@link #listCells()} * @return all sorted List of KeyValues; can be null if no cells in the result */ @Deprecated @@ -803,7 +813,21 @@ public class Result implements CellScannable { @Override public CellScanner cellScanner() { - return CellUtil.createCellScanner(this.cells); + // Reset + this.cellScannerIndex = INITIAL_CELLSCANNER_INDEX; + return this; + } + + @Override + public Cell current() { + if (cells == null) return null; + return (cellScannerIndex < 0)? null: this.cells[cellScannerIndex]; + } + + @Override + public boolean advance() { + if (cells == null) return false; + return ++cellScannerIndex < this.cells.length; } public Boolean getExists() { http://git-wip-us.apache.org/repos/asf/hbase/blob/08418683/hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestResult.java ---------------------------------------------------------------------- diff --git a/hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestResult.java b/hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestResult.java index 74563f0..a0e1a45 100644 --- a/hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestResult.java +++ b/hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestResult.java @@ -21,6 +21,7 @@ package org.apache.hadoop.hbase.client; import static org.apache.hadoop.hbase.HBaseTestCase.assertByteEquals; +import java.io.IOException; import java.nio.ByteBuffer; import java.util.Arrays; import java.util.List; @@ -30,6 +31,7 @@ import junit.framework.TestCase; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.hadoop.hbase.Cell; +import org.apache.hadoop.hbase.CellScanner; import org.apache.hadoop.hbase.CellUtil; import org.apache.hadoop.hbase.KeyValue; import org.apache.hadoop.hbase.SmallTests; @@ -60,6 +62,31 @@ public class TestResult extends TestCase { static final byte [] family = Bytes.toBytes("family"); static final byte [] value = Bytes.toBytes("value"); + /** + * Run some tests to ensure Result acts like a proper CellScanner. + * @throws IOException + */ + public void testResultAsCellScanner() throws IOException { + Cell [] cells = genKVs(row, family, value, 1, 10); + Arrays.sort(cells, KeyValue.COMPARATOR); + Result r = Result.create(cells); + assertSame(r, cells); + // Assert I run over same result multiple times. + assertSame(r.cellScanner(), cells); + assertSame(r.cellScanner(), cells); + // Assert we are not creating new object when doing cellscanner + assertTrue(r == r.cellScanner()); + } + + private void assertSame(final CellScanner cellScanner, final Cell [] cells) throws IOException { + int count = 0; + while (cellScanner.advance()) { + assertTrue(cells[count].equals(cellScanner.current())); + count++; + } + assertEquals(cells.length, count); + } + public void testBasicGetColumn() throws Exception { KeyValue [] kvs = genKVs(row, family, value, 1, 100);
