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https://issues.apache.org/jira/browse/HADOOP-941?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12475707
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Owen O'Malley commented on HADOOP-941:
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I think that the raw comparison functions are useful outside of Hadoop in any
application that involves sorting or merging. They provide a useful
optimization for Hadoop, but are generally useful. Therefore, I don't think it
is fair to count that code as pure Hadoop support.
(And you are right that the dependent classes do include at least Writable,
WritableComparable, WritableComparator and DataInputBuffer.)
That said, I think that a "-nohadoop" command line switch wouldn't be bad. I do
think it is pretty unreasonable to make the default behavior not support
Hadoop, since that is the primary intended audience.
> Make Hadoop Record I/O Easier to use outside Hadoop
> ---------------------------------------------------
>
> Key: HADOOP-941
> URL: https://issues.apache.org/jira/browse/HADOOP-941
> Project: Hadoop
> Issue Type: Improvement
> Components: record
> Affects Versions: 0.10.1
> Environment: All
> Reporter: Milind Bhandarkar
> Assigned To: Milind Bhandarkar
> Attachments: jute-patch.txt
>
>
> Hadoop record I/O can be used effectively outside of Hadoop. It would
> increase its utility if developers can use it without having to import hadoop
> classes, or having to depend on Hadoop jars. Following changes to the current
> translator and runtime are proposed.
> Proposed Changes:
> 1. Use java.lang.String as a native type for ustring (instead of Text.)
> 2. Provide a Buffer class as a native Java type for buffer (instead of
> BytesWritable), so that later BytesWritable could be implemented as following
> DDL:
> module org.apache.hadoop.io {
> record BytesWritable {
> buffer value;
> }
> }
> 3. Member names in generated classes should not have prefixes 'm' before
> their names. In the above example, the private member name would be 'value'
> not 'mvalue' as it is done now.
> 4. Convert getters and setters to have CamelCase. e.g. in the above example
> the getter will be:
> public Buffer getValue();
> 5. Provide a 'swiggable' C binding, so that processing the generated C code
> with swig allows it to be used in scripting languages such as Python and Perl.
> 6. The default --language="java" target would generate class code for records
> that would not have Hadoop dependency on WritableComparable interface, but
> instead would have "implements Record, Comparable". (i.e. It will not have
> write() and readFields() methods.) An additional option "--writable" will
> need to be specified on rcc commandline to generate classes that "implements
> Record, WritableComparable".
> 7. Optimize generated write() and readFields() methods, so that they do not
> have to create BinaryOutputArchive or BinaryInputArchive every time these
> methods are called on a record.
> 8. Implement ByteInStream and ByteOutStream for C++ runtime, as they will be
> needed for using Hadoop Record I/O with forthcoming C++ MapReduce framework
> (currently, only FileStreams are provided.)
> 9. Generate clone() methods for records in Java i.e. the generated classes
> should implement Cloneable.
> 10. As part of Hadoop build process, produce a tar bundle for Record I/O
> alone. This tar bundle will contain the translator classes and ant task
> (lib/rcc.jar), translator script (bin/rcc), Java runtime (recordio.jar) that
> includes org.apache.hadoop.record.*, sources for the java runtime (src/java),
> and c/c++ runtime sources with Makefiles (src/c++, src/c).
> 11. Make generated Java codes for maps and vectors use Java generics.
> These are the proposed user-visible changes. Internally, the translator will
> be restructured so that it is easier to plug-in translators for different
> targets.
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