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https://issues.apache.org/jira/browse/HBASE-7221?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13560356#comment-13560356
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Nick Dimiduk commented on HBASE-7221:
-------------------------------------
I very much agree HBase should provide a canonical tool for building things
like compound byte-arrays. Overall, I don't like the idea of a stateful utility
class, so -1.
This would be much more elegant (and less bug-prone) via a static method and an
approach similar to the format-string style. The major down-side being you'd
need a mini-language for representing these formats. The example in your class
header, under this approach, would something like {{byte[] key =
RowKey.format("%16x%4d%8d", hashVal, intVal, longVal);}}. With a {{Formatter}}
implemented, you could have an accessor static method, call it {{split}}, that
behaved similarly, ie {{byte[][] splits = RowKey.split("%16x%4d%8d", key);}}.
The key idea here being the format and split strings are of identical form.
Then the consumer can decide how to re-interpret the splits. Or maybe you get
fancy with out-parameters or something, but that doesn't seem idiomatic.
general nit: your line-lengths are well past 100 characters in some cases.
{code}
* A stateful utility class for creating rowkeys for HBase tables, particularly
composite keys. RowKey
* creates fixed length keys without the need for delimeters in between key
elements (i.e., parts of the
* rowkey), which is a best practice in HBase. A RowKey instance is
instantiated from an associated RowKeySchema,
{code}
nit: s/delimeters/delimiters
nit: RowKeySchema has superfluous imports.
nit: TestRowKey has superfluous imports.
{code}
boolean passed = true;
try {
RowKey rowkey = schema.createRowKey();
rowkey.setHash(1, intVal); // trying to set 'int' on an element that is
sized for a hash.
} catch (Exception e) {
// we are expecting a sizing exception because we are setting a
hash onto an element
// sized for an int.
passed = false;
}
if (passed) {
Assert.fail("Test did not fail!");
}
{code}
nit: forego this {{passed}} business and put your assert right inline.
> RowKey utility class for rowkey construction
> --------------------------------------------
>
> Key: HBASE-7221
> URL: https://issues.apache.org/jira/browse/HBASE-7221
> Project: HBase
> Issue Type: Improvement
> Reporter: Doug Meil
> Assignee: Doug Meil
> Priority: Minor
> Attachments: HBASE_7221.patch, hbase-common_hbase_7221_2.patch,
> hbase-common_hbase_7221_v3.patch
>
>
> A common question in the dist-lists is how to construct rowkeys, particularly
> composite keys. Put/Get/Scan specifies byte[] as the rowkey, but it's up to
> you to sensibly populate that byte-array, and that's where things tend to go
> off the rails.
> The intent of this RowKey utility class isn't meant to add functionality into
> Put/Get/Scan, but rather make it simpler for folks to construct said arrays.
> Example:
> {code}
> RowKey key = RowKey.create(RowKey.SIZEOF_MD5_HASH + RowKey.SIZEOF_LONG);
> key.addHash(a);
> key.add(b);
> byte bytes[] = key.getBytes();
> {code}
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