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https://issues.apache.org/jira/browse/HADOOP-941?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12475809
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Milind Bhandarkar commented on HADOOP-941:
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David,
Thanks for testing the patch. Since I have moved record I/O tests from the
org.apache.hadoop.record.test package to o.a.h.r package (to remove instances
that needed to be public only because of tests, and since moving (i.e.
renaming) files does not work very well with the patch process (rename is
treated as remove followed by an add), such problems occur.
Other points are well taken (3,4,5). I will provide more tests and do the
refactoring in the future patch. As you can guess, just the read methods were
in in WritableUtils (Owen, add one more dependency of static methods only to
your list), they were moved to record.Utils, and so it seems like an awkward
way of doing things. Now that they are in record.Utils, and eferred to only
from the generated code, I can make them more amenable to "doing the right
thing" rather than trying to keep the brain-dead backward compatibility.
> 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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