[SPARK-13702][CORE][SQL][MLLIB] Use diamond operator for generic instance creation in Java code. by dongjoon-hyun · Pull Request #11541 · apache/spark

dongjoon-hyun · 2016-03-05T23:57:47Z

What changes were proposed in this pull request?

In order to make docs/examples (and other related code) more simple/readable/user-friendly, this PR replaces existing codes like the followings by using diamond operator.

- final ArrayList<Product2<Object, Object>> dataToWrite =
- new ArrayList<Product2<Object, Object>>();
+ final ArrayList<Product2<Object, Object>> dataToWrite = new ArrayList<>();

Java 7 or higher supports diamond operator which replaces the type arguments required to invoke the constructor of a generic class with an empty set of type parameters (<>). Currently, Spark Java code use mixed usage of this.

How was this patch tested?

Manual.
Pass the existing tests.

srowen · 2016-03-06T09:31:49Z

Although I personally like this change, I'm less certain about it since it does not add any functional improvement or avoid a potential bug. It does add a little readability and only touches the relatively fewer Java files. I'd like to wait for others to give an opinion.

dongjoon-hyun · 2016-03-06T10:34:44Z

Thank you for review, @srowen .
I agree. This has a little limited benefit; only small portion Java and no functional improvement.
Actually, I started this PR to improve docs/examples (28 of 61 files) for simplicity and eventually hoped to apply all code to keep it consistently.

dongjoon-hyun · 2016-03-08T08:32:46Z

The conflict will be resolved via #11567 . After #11567 is committed, I will update this.

mengxr · 2016-03-08T23:01:53Z

+1 on the code changes, which simplifies the Java code and shows some benefits from dropping Java 6, but the changes to the pom file should be discussed in a separate PR.

mengxr · 2016-03-08T23:02:03Z

add to whitelist

mengxr · 2016-03-08T23:02:07Z

ok to test

dongjoon-hyun · 2016-03-08T23:08:33Z

Thank you, @mengxr !
I will remove pom.xml and checkstyle part from this PR soon.

…ance creation in Java code. Java 7 or higher supports `diamond` operator which replaces the type arguments required to invoke the constructor of a generic class with an empty set of type parameters (<>). Currently, Spark Java code use mixed usage of this. This issue replaces existing codes to use `diamond` operator and add Checkstyle rule. ``` -List<JavaPairDStream<String, String>> kafkaStreams = new ArrayList<JavaPairDStream<String, String>>(numStreams); +List<JavaPairDStream<String, String>> kafkaStreams = new ArrayList<>(numStreams); -Set<Tuple2<Integer, Integer>> edges = new HashSet<Tuple2<Integer, Integer>>(numEdges); +Set<Tuple2<Integer, Integer>> edges = new HashSet<>(numEdges); ```

dongjoon-hyun · 2016-03-08T23:21:07Z

Hi, @mengxr .
I removed the change on build related files. Now this PR contains pure Java and md files.
Also, the description of PR/JIRA issue is updated accordingly.

SparkQA · 2016-03-09T01:47:57Z

Test build #52697 has finished for PR 11541 at commit 78e3d32.

This patch passes all tests.
This patch merges cleanly.
This patch adds no public classes.

SparkQA · 2016-03-09T02:14:36Z

Test build #52699 has finished for PR 11541 at commit 2e20843.

This patch passes all tests.
This patch merges cleanly.
This patch adds no public classes.

dongjoon-hyun · 2016-03-09T02:43:13Z

Hi, @mengxr .
The latest commit passes the test.
Could you review this again please?

SparkQA · 2016-03-09T02:46:12Z

Test build #52696 has finished for PR 11541 at commit 78e3d32.

This patch passes all tests.
This patch merges cleanly.
This patch adds no public classes.

dongjoon-hyun · 2016-03-09T03:09:42Z

The latest one is at commit 2e20843, and all three builds (including that) passes.

srowen · 2016-03-09T10:31:02Z

LGTM, merging to master. This is now just straightforward use of the diamond operator only.

dongjoon-hyun · 2016-03-09T16:28:27Z

Thank you, @srowen . Yes, it is.

…ance creation in Java code. ## What changes were proposed in this pull request? In order to make `docs/examples` (and other related code) more simple/readable/user-friendly, this PR replaces existing codes like the followings by using `diamond` operator. ``` - final ArrayList<Product2<Object, Object>> dataToWrite = - new ArrayList<Product2<Object, Object>>(); + final ArrayList<Product2<Object, Object>> dataToWrite = new ArrayList<>(); ``` Java 7 or higher supports **diamond** operator which replaces the type arguments required to invoke the constructor of a generic class with an empty set of type parameters (<>). Currently, Spark Java code use mixed usage of this. ## How was this patch tested? Manual. Pass the existing tests. Author: Dongjoon Hyun <dongjoon@apache.org> Closesapache#11541 from dongjoon-hyun/SPARK-13702.

dongjoon-hyun added 2 commits March 8, 2016 15:09

Remove Checkstyle enforcement
2e20843

asfgit closed this in c3689bcMar 9, 2016

dongjoon-hyun deleted the SPARK-13702 branch March 29, 2016 05:26

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dongjoon-hyun commented Mar 5, 2016

What changes were proposed in this pull request?

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