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The following page has been changed by JimKellerman:
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New page:
= How to Contribute to HBase =

This page describes the mechanics of ''how'' to contribute software to HBase.  
For ideas about ''what'' you might contribute, please see the open issues in 
the [https://issues.apache.org/jira/browse/HBASE Hbase JIRA].

=== Getting the source code ===

First of all, you need the Hadoop source code.[[BR]]

Get the source code on your local drive using 
[http://svn.apache.org/viewvc/hadoop/hbase SVN]. Most development is done on 
the "trunk":

{{{
svn checkout http://svn.apache.org/viewvc/hadoop/hbase/trunk hadoop-core-trunk
}}}

If you prefer to use Eclipse for development, there are instructions for 
setting up SVN access from within Eclipse at EclipseEnvironment.

=== Making Changes ===

Before you start, send a message to the [[MailTo(hbase-dev AT SPAMFREE hadoop 
DOT apache DOT org)]] HBase developer mailing list, or file a bug report in 
[https://issues.apache.org/jira/browse/HBASE Hbase JIRA].  Describe your 
proposed changes and check that they fit in with what others are doing and have 
planned for the project.  Be patient, it may take folks a while to understand 
your requirements.

Modify the source code and add some (very) nice features using your favorite 
IDE.[[BR]]

But take care about the following points
 * All public classes and methods should have informative 
[http://java.sun.com/j2se/javadoc/writingdoccomments/ Javadoc comments].
  * Do not use @author tags.
 * Code should be formatted according to [http://java.sun.com/docs/codeconv/ 
Sun's conventions], with two exceptions:
  1. Indent two spaces per level, not four.
  2. Use spaces and not tabs.
 * Contributions must pass existing unit tests.
 * New unit tests should be provided to demonstrate bugs and fixes.  
[http://www.junit.org JUnit] is our test framework:
  * You must implement a class that extends {{{junit.framework.TestCase}}}, 
{{{org.apache.hadoop.hbase.HBaseTestCase}}} or 
{{{org.apache.hadoop.HBaseClusterTestCase}}} and whose class name starts with 
{{{Test}}}.
  * Define methods within your class whose names begin with {{{test}}}, and 
call JUnit's many assert methods to verify conditions; these methods will be 
executed when you run {{{ant test}}}.
  * By default, do not let tests write any temporary files to {{{/tmp}}}.  
Instead, the tests should write to the location specified by the 
{{{test.build.data}}} system property.
  * If a HBase cluster is needed by your test, either subclass 
{{{org.apache.hadoop.hbase.HBaseClusterTestCase}}} or use 
{{{org.apache.hadoop.hbase.MiniHBaseCluster}}}. If you also need to use a 
!MapReduce cluster, use {{{org.apache.hadoop.MiniMRCluster}}}.
  * Place your class in the {{{src/test}}} tree.
  * you can run all the unit test with the command {{{ant test}}}, or you can 
run a specific unit test with the command {{{ant test -Dtestcase=<ClassName>}}} 
(For example {{{ant test -Dtestcase=TestHBaseCluster}}})

=== Generating a patch ===

==== Unit Tests ====

Please make sure that all unit tests succeed before constructing your patch and 
that no new javac compiler warnings are introduced by your patch.

{{{
> cd hadoop-trunk
> ant -Djavac.args="-Xlint -Xmaxwarns 1000" clean test tar
}}}
After a while, if you see
{{{
BUILD SUCCESSFUL
}}}
all is ok, but if you see
{{{
BUILD FAILED
}}}
then please examine error messages in {{{build/test}}} and fix things before 
proceeding.

==== Javadoc ====

Please also check the javadoc.

{{{
> ant javadoc
> firefox build/docs/api/index.html
}}}

Examine all public classes you've changed to see that documentation is complete 
and informative.  Your patch must not generate any javadoc warnings.

==== Creating a patch ====
Check to see what files you have modified with:
{{{
svn stat
}}}

Add any new files with:
{{{
svn add src/.../MyNewClass.java
}}}

Edit the ''CHANGES.txt'' file, adding a description of your change, including 
the bug number it fixes. If this is a new feature, or other enhancement that 
doesn't currently have a ticket please create one for it, then use it's number 
when adding your note to CHANGES.txt. You'll need this ticket to submit your 
patch anyway.

In order to create a patch, just type:

{{{
svn diff > myBeautifulPatch.patch
}}}

This will report all modifications done on Hadoop sources on your local disk 
and save them into the ''myBeautifulPath.patch'' file.  Read the patch file.  
Make sure it includes ONLY the modifications required to fix a single issue.

Please do not:
 * reformat code unrelated to the bug being fixed: formatting changes should be 
separate patches/commits.
 * comment out code that is now obsolete: just remove it.  
 * insert comments around each change, marking the change: folks can use 
subversion to figure out what's changed and by whom.
 * make things public which are not required by end users.

Please do:
 * try to adhere to the coding style of files you edit;
 * comment code whose function or rationale is not obvious;
 * update documentation (e.g., ''package.html'' files, this wiki, etc.)

==== Applying a patch ====

To apply a patch either you generated or found from JIRA, you can issue 
{{{
patch -p0 <cool_patch.patch
}}}
if you just want to check whether the patch applies you can run patch with 
--dry-run option
{{{
patch -p0 --dry-run <cool_patch.patch
}}}

If you are an Eclipse user, you can apply a patch by : 1. Right click project 
name in Package Explorer , 2. Team -> Apply Patch 

=== Contributing your work ===

Finally, patches should be ''attached'' to a bug report in 
[https://issues.apache.org/jira/browse/HBASE HBase JIRA] via the '''Attach 
File''' link on the jira. Please add a comment that asks for a code review 
following our [:CodeReviewChecklist: code review checklist]. Please note that 
the attachment should be granted license to ASF for inclusion in ASF works (as 
per the [http://www.apache.org/licenses/LICENSE-2.0 Apache License] §5). 

When you believe that your patch is ready to be committed, select the 'Submit 
Patch' link from the 'Available Workflow Actions' section in Jira.  Submitted 
patches will be automatically tested against "trunk" by 
[http://hudson.zones.apache.org/hudson/ Hudson], the project's continuous 
integration engine.  Upon test completion, Hudson will add a success ("+1") 
message or failure ("-1") to your bug report in Jira.  If your issue contains 
multiple patch versions, Hudson tests the last patch uploaded.

Folks should run 'ant clean test javadoc before selecting 'Submit Patch'.  
Tests should all pass.  Javadoc should report no warnings or errors. Hudson's 
tests should only double-check things, and not be used as a primary patch 
tester, which would create too much noise on the mailing list and in Jira.  
Submitting patches that fail Hudson testing is frowned on, (unless the failure 
is not actually due to the patch).

If your patch involves performance optimizations, they should be validated by 
benchmarks that demonstrate an improvement.

Once a "+1" comment is received from the automated patch testing system and a 
"+1, code reviewed" comment is received from a code reviewer, a committer 
should then evaluate it within a few days and either: commit it; or reject it 
with an explanation.

Please be patient.  Committers are busy people too.  If no one responds to your 
patch after a few days, please make friendly reminders.  Please incorporate 
other's suggestions into into your patch if you think they're reasonable.  
Finally, remember that even a patch that is not committed is useful to the 
community.

Should your patch earn a -1 on the Hudson test, set the issue status to 'Resume 
Progress', upload a patch with necessary fixes and then set the status to 
'Submit Patch' again.

Committers: for non-trivial changes, it is __'''required'''__ to get another 
committer to review your patches before commit.  Use "Submit Patch" like other 
contributors, and then wait for a "+1" from another committer before 
committing.  Please also try to frequently review things in the patch queue.

== Jira Guidelines ==

Please comment on issues in Jira, making their concerns known.  Please also 
vote for issues that are a high priority for you.

Please refrain from editing descriptions and comments if possible, as edits 
spam the mailing list and clutter Jira's "All" display, which is otherwise very 
useful.  Instead, preview descriptions and comments using the preview button 
(on the right) before posting them.  Keep descriptions brief and save more 
elaborate proposals for comments, since descriptions are included in Jira's 
automatically sent messages.  If you change your mind, note this in a new 
comment, rather than editing an older comment.  The issue should preserve this 
history of the discussion.

== Stay involved ==

Contributors should join the developer's mailing list [[MailTo(hbase-dev AT 
SPAMFREE hadoop DOT apache DOT org)]], the user's mailing list 
[[MailTo(hbase-user AT SPAMFREE hadoop DOT apache DOT org)]] and the commit's 
mailing list [[MailTo(hbase-commits AT SPAMFREE hadoop DOT apache DOT org)]].

== See Also ==

 * [http://www.apache.org/dev/contributors.html Apache contributor 
documentation]
 * [http://www.apache.org/foundation/voting.html Apache voting documentation]

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