[COLLECTIONS-795] Add a new Iterator to allowing zipping over two iterators of different types

[anantdamle]

[COLLECTIONS-795] Add a new Iterator to allowing zipping over two iterators of different types.

[anantdamle]

The CI flagged failing tests are not stemming from any code that I have touched, How to resolve?

[XenoAmess]

The CI flagged failing tests are not stemming from any code that I have touched, How to resolve?

checkstyles fails.

https://travis-ci.com/github/apache/commons-collections/jobs/508633787

[ERROR] src/main/java/org/apache/commons/collections4/IterableUtils.java:[574,21] (whitespace) WhitespaceAfter: ',' is not followed by whitespace. [ERROR] src/main/java/org/apache/commons/collections4/IterableUtils.java:[574,46] (whitespace) WhitespaceAfter: ',' is not followed by whitespace. [ERROR] src/main/java/org/apache/commons/collections4/IterableUtils.java:[578,47] (whitespace) WhitespaceAfter: ',' is not followed by whitespace. [ERROR] src/main/java/org/apache/commons/collections4/IterableUtils.java:[580,41] (whitespace) WhitespaceAfter: ',' is not followed by whitespace. [ERROR] src/main/java/org/apache/commons/collections4/iterators/PairedIterator.java:[74,7] (indentation) Indentation: 'ctor def' child has incorrect indentation level 6, expected level should be 8. [ERROR] src/main/java/org/apache/commons/collections4/iterators/PairedIterator.java:[75,7] (indentation) Indentation: 'ctor def' child has incorrect indentation level 6, expected level should be 8. [ERROR] src/main/java/org/apache/commons/collections4/iterators/PairedIterator.java:[88,7] (indentation) Indentation: 'method def' child has incorrect indentation level 6, expected level should be 8. [ERROR] src/main/java/org/apache/commons/collections4/iterators/PairedIterator.java:[101,7] (indentation) Indentation: 'method def' child has incorrect indentation level 6, expected level should be 8. [ERROR] src/main/java/org/apache/commons/collections4/iterators/PairedIterator.java:[114,7] (indentation) Indentation: 'method def' child has incorrect indentation level 6, expected level should be 8. [ERROR] src/main/java/org/apache/commons/collections4/iterators/PairedIterator.java:[125,7] (indentation) Indentation: 'if' has incorrect indentation level 6, expected level should be 8. [ERROR] src/main/java/org/apache/commons/collections4/iterators/PairedIterator.java:[126,9] (indentation) Indentation: 'if' child has incorrect indentation level 8, expected level should be 12. [ERROR] src/main/java/org/apache/commons/collections4/iterators/PairedIterator.java:[127,7] (indentation) Indentation: 'if rcurly' has incorrect indentation level 6, expected level should be 8. [ERROR] src/main/java/org/apache/commons/collections4/iterators/PairedIterator.java:[129,7] (indentation) Indentation: 'method def' child has incorrect indentation level 6, expected level should be 8. [ERROR] src/main/java/org/apache/commons/collections4/iterators/PairedIterator.java:[140,5] (indentation) Indentation: 'member def modifier' has incorrect indentation level 4, expected level should be 8. [ERROR] src/main/java/org/apache/commons/collections4/iterators/PairedIterator.java:[142,5] (indentation) Indentation: 'member def modifier' has incorrect indentation level 4, expected level should be 8. [ERROR] src/main/java/org/apache/commons/collections4/iterators/PairedIterator.java:[144,5] (indentation) Indentation: 'ctor def modifier' has incorrect indentation level 4, expected level should be 8. [ERROR] src/main/java/org/apache/commons/collections4/iterators/PairedIterator.java:[145,7] (indentation) Indentation: 'ctor def' child has incorrect indentation level 6, expected level should be 12. [ERROR] src/main/java/org/apache/commons/collections4/iterators/PairedIterator.java:[146,7] (indentation) Indentation: 'ctor def' child has incorrect indentation level 6, expected level should be 12. [ERROR] src/main/java/org/apache/commons/collections4/iterators/PairedIterator.java:[147,5] (indentation) Indentation: 'ctor def rcurly' has incorrect indentation level 4, expected level should be 8. [ERROR] src/main/java/org/apache/commons/collections4/iterators/PairedIterator.java:[156,5] (indentation) Indentation: 'method def modifier' has incorrect indentation level 4, expected level should be 8. [ERROR] src/main/java/org/apache/commons/collections4/iterators/PairedIterator.java:[157,7] (indentation) Indentation: 'method def' child has incorrect indentation level 6, expected level should be 12. [ERROR] src/main/java/org/apache/commons/collections4/iterators/PairedIterator.java:[158,5] (indentation) Indentation: 'method def rcurly' has incorrect indentation level 4, expected level should be 8. [ERROR] src/main/java/org/apache/commons/collections4/iterators/PairedIterator.java:[160,5] (indentation) Indentation: 'method def modifier' has incorrect indentation level 4, expected level should be 8. [ERROR] src/main/java/org/apache/commons/collections4/iterators/PairedIterator.java:[161,7] (indentation) Indentation: 'method def' child has incorrect indentation level 6, expected level should be 12. [ERROR] src/main/java/org/apache/commons/collections4/iterators/PairedIterator.java:[162,5] (indentation) Indentation: 'method def rcurly' has incorrect indentation level 4, expected level should be 8. [ERROR] src/main/java/org/apache/commons/collections4/iterators/PairedIterator.java:[164,5] (indentation) Indentation: 'method def modifier' has incorrect indentation level 4, expected level should be 8. [ERROR] src/main/java/org/apache/commons/collections4/iterators/PairedIterator.java:[165,7] (indentation) Indentation: 'method def' child has incorrect indentation level 6, expected level should be 12. [ERROR] src/main/java/org/apache/commons/collections4/iterators/PairedIterator.java:[166,5] (indentation) Indentation: 'method def rcurly' has incorrect indentation level 4, expected level should be 8. [ERROR] src/main/java/org/apache/commons/collections4/iterators/PairedIterator.java:[168,5] (indentation) Indentation: 'method def modifier' has incorrect indentation level 4, expected level should be 8. [ERROR] src/main/java/org/apache/commons/collections4/iterators/PairedIterator.java:[170,7] (indentation) Indentation: 'method def' child has incorrect indentation level 6, expected level should be 12. [ERROR] src/main/java/org/apache/commons/collections4/iterators/PairedIterator.java:[171,5] (indentation) Indentation: 'method def rcurly' has incorrect indentation level 4, expected level should be 8. [ERROR] src/main/java/org/apache/commons/collections4/iterators/PairedIterator.java:[172,3] (indentation) Indentation: 'class def rcurly' has incorrect indentation level 2, expected level should be 4. [ERROR] src/main/java/org/apache/commons/collections4/IteratorUtils.java:[921,21] (whitespace) WhitespaceAfter: ',' is not followed by whitespace. [ERROR] src/main/java/org/apache/commons/collections4/IteratorUtils.java:[921,41] (whitespace) WhitespaceAfter: ',' is not followed by whitespace. [ERROR] src/main/java/org/apache/commons/collections4/PairedIterable.java:[85,21] (whitespace) WhitespaceAfter: ',' is not followed by whitespace. [ERROR] src/main/java/org/apache/commons/collections4/PairedIterable.java:[85,41] (whitespace) WhitespaceAfter: ',' is not followed by whitespace. [ERROR] src/main/java/org/apache/commons/collections4/PairedIterable.java:[97,31] (whitespace) WhitespaceAfter: ',' is not followed by whitespace. [ERROR] src/test/java/org/apache/commons/collections4/PairedIterableTest.java:[64,9] (whitespace) WhitespaceAfter: 'for' is not followed by whitespace. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[33,3] (indentation) Indentation: 'ctor def modifier' has incorrect indentation level 2, expected level should be 4. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[34,5] (indentation) Indentation: 'ctor def' child has incorrect indentation level 4, expected level should be 8. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[35,3] (indentation) Indentation: 'ctor def rcurly' has incorrect indentation level 2, expected level should be 4. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[39,3] (indentation) Indentation: 'member def modifier' has incorrect indentation level 2, expected level should be 4. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[40,3] (indentation) Indentation: 'member def modifier' has incorrect indentation level 2, expected level should be 4. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[41,3] (indentation) Indentation: 'member def modifier' has incorrect indentation level 2, expected level should be 4. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[42,3] (indentation) Indentation: 'member def modifier' has incorrect indentation level 2, expected level should be 4. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[45,3] (indentation) Indentation: 'member def modifier' has incorrect indentation level 2, expected level should be 4. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[46,3] (indentation) Indentation: 'member def modifier' has incorrect indentation level 2, expected level should be 4. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[48,3] (indentation) Indentation: 'method def modifier' has incorrect indentation level 2, expected level should be 4. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[50,5] (indentation) Indentation: 'method def' child has incorrect indentation level 4, expected level should be 8. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[52,5] (indentation) Indentation: 'method def' child has incorrect indentation level 4, expected level should be 8. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[53,5] (indentation) Indentation: 'method def' child has incorrect indentation level 4, expected level should be 8. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[54,5] (indentation) Indentation: 'method def' child has incorrect indentation level 4, expected level should be 8. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[55,5] (indentation) Indentation: 'method def' child has incorrect indentation level 4, expected level should be 8. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[57,5] (indentation) Indentation: 'method def' child has incorrect indentation level 4, expected level should be 8. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[59,5] (indentation) Indentation: 'for' has incorrect indentation level 4, expected level should be 8. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[60,7] (indentation) Indentation: 'for' child has incorrect indentation level 6, expected level should be 12. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[61,7] (indentation) Indentation: 'for' child has incorrect indentation level 6, expected level should be 12. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[62,5] (indentation) Indentation: 'for rcurly' has incorrect indentation level 4, expected level should be 8. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[64,5] (indentation) Indentation: 'for' has incorrect indentation level 4, expected level should be 8. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[65,7] (indentation) Indentation: 'for' child has incorrect indentation level 6, expected level should be 12. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[66,7] (indentation) Indentation: 'for' child has incorrect indentation level 6, expected level should be 12. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[67,5] (indentation) Indentation: 'for rcurly' has incorrect indentation level 4, expected level should be 8. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[68,3] (indentation) Indentation: 'method def rcurly' has incorrect indentation level 2, expected level should be 4. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[70,3] (indentation) Indentation: 'method def modifier' has incorrect indentation level 2, expected level should be 4. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[72,5] (indentation) Indentation: 'method def' child has incorrect indentation level 4, expected level should be 8. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[73,3] (indentation) Indentation: 'method def rcurly' has incorrect indentation level 2, expected level should be 4. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[77,3] (indentation) Indentation: 'method def modifier' has incorrect indentation level 2, expected level should be 4. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[79,5] (indentation) Indentation: 'method def' child has incorrect indentation level 4, expected level should be 8. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[80,3] (indentation) Indentation: 'method def rcurly' has incorrect indentation level 2, expected level should be 4. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[82,3] (indentation) Indentation: 'method def modifier' has incorrect indentation level 2, expected level should be 4. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[84,5] (indentation) Indentation: 'method def' child has incorrect indentation level 4, expected level should be 8. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[85,3] (indentation) Indentation: 'method def rcurly' has incorrect indentation level 2, expected level should be 4. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[87,3] (indentation) Indentation: 'method def modifier' has incorrect indentation level 2, expected level should be 4. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[88,5] (indentation) Indentation: 'method def' child has incorrect indentation level 4, expected level should be 8. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[92,5] (indentation) Indentation: 'for' has incorrect indentation level 4, expected level should be 8. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[93,7] (indentation) Indentation: 'for' child has incorrect indentation level 6, expected level should be 12. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[94,7] (indentation) Indentation: 'for' child has incorrect indentation level 6, expected level should be 12. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[96,7] (indentation) Indentation: 'for' child has incorrect indentation level 6, expected level should be 12. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[96,44] (whitespace) NoWhitespaceBefore: ',' is preceded with whitespace. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[97,7] (indentation) Indentation: 'for' child has incorrect indentation level 6, expected level should be 12. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[97,41] (whitespace) NoWhitespaceBefore: ',' is preceded with whitespace. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[98,5] (indentation) Indentation: 'for rcurly' has incorrect indentation level 4, expected level should be 8. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[100,5] (indentation) Indentation: 'method def' child has incorrect indentation level 4, expected level should be 8. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[101,3] (indentation) Indentation: 'method def rcurly' has incorrect indentation level 2, expected level should be 4. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[103,3] (indentation) Indentation: 'method def modifier' has incorrect indentation level 2, expected level should be 4. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[104,5] (indentation) Indentation: 'method def' child has incorrect indentation level 4, expected level should be 8. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[108,5] (indentation) Indentation: 'for' has incorrect indentation level 4, expected level should be 8. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[109,7] (indentation) Indentation: 'for' child has incorrect indentation level 6, expected level should be 12. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[110,7] (indentation) Indentation: 'for' child has incorrect indentation level 6, expected level should be 12. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[112,7] (indentation) Indentation: 'for' child has incorrect indentation level 6, expected level should be 12. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[112,44] (whitespace) NoWhitespaceBefore: ',' is preceded with whitespace. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[113,7] (indentation) Indentation: 'for' child has incorrect indentation level 6, expected level should be 12. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[113,41] (whitespace) NoWhitespaceBefore: ',' is preceded with whitespace. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[114,5] (indentation) Indentation: 'for rcurly' has incorrect indentation level 4, expected level should be 8. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[116,5] (indentation) Indentation: 'method def' child has incorrect indentation level 4, expected level should be 8. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[117,3] (indentation) Indentation: 'method def rcurly' has incorrect indentation level 2, expected level should be 4. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[119,3] (indentation) Indentation: 'method def modifier' has incorrect indentation level 2, expected level should be 4. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[120,5] (indentation) Indentation: 'method def' child has incorrect indentation level 4, expected level should be 8. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[123,5] (indentation) Indentation: 'method def' child has incorrect indentation level 4, expected level should be 8. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[124,3] (indentation) Indentation: 'method def rcurly' has incorrect indentation level 2, expected level should be 4. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[126,3] (indentation) Indentation: 'method def modifier' has incorrect indentation level 2, expected level should be 4. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[127,5] (indentation) Indentation: 'method def' child has incorrect indentation level 4, expected level should be 8. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[130,5] (indentation) Indentation: 'method def' child has incorrect indentation level 4, expected level should be 8. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[131,3] (indentation) Indentation: 'method def rcurly' has incorrect indentation level 2, expected level should be 4. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[134,3] (indentation) Indentation: 'method def modifier' has incorrect indentation level 2, expected level should be 4. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[135,5] (indentation) Indentation: 'method def' child has incorrect indentation level 4, expected level should be 8. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[139,5] (indentation) Indentation: 'for' has incorrect indentation level 4, expected level should be 8. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[140,7] (indentation) Indentation: 'for' child has incorrect indentation level 6, expected level should be 12. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[141,7] (indentation) Indentation: 'for' child has incorrect indentation level 6, expected level should be 12. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[143,7] (indentation) Indentation: 'for' child has incorrect indentation level 6, expected level should be 12. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[146,5] (indentation) Indentation: 'for rcurly' has incorrect indentation level 4, expected level should be 8. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[148,5] (indentation) Indentation: 'method def' child has incorrect indentation level 4, expected level should be 8. [ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[149,3] (indentation) Indentation: 'method def rcurly' has incorrect indentation level 2, expected level should be 4.

[kinow]

@anantdamle

The CI flagged failing tests are not stemming from any code that I have touched, How to resolve?

Click on the link of the failed Travis CI builds. Then choose one of the JDK versions (e.g. 8). There you should find the logs of the job that failed. For instance:

[ERROR] src/test/java/org/apache/commons/collections4/iterators/PairedIteratorTest.java:[149,3] (indentation) Indentation: 'method def rcurly' has incorrect indentation level 2, expected level should be 4.

[anantdamle]

thanks @XenoAmess and @kinow Fixed checkstyles issues (also checked locally using mvn checkstyle:check)

The sytle checks & corrections can be simplified using spotless plugin. Should I create a separate PR to implement spotless plugin for auto style correction?

[coveralls]

Coverage decreased (-0.008%) to 90.134% when pulling 1ed50ce573ad05d3228cc59336fac76779eef326 on anantdamle:collections_795 into 0f54cb20903e75d43da9383464093a827e19b2e9 on apache:master.

[anantdamle]

Added tests to improve coverage

[anantdamle]

What are the next steps?

[anantdamle]

@garydgregory there is one big difference with ZippingIterator, ZippingIterator<T> allows iterating over iterators of same generic type, whereas the proposed solution (PairedIterator<L, R>) allows using two different types and hence needs a Pair equivalent class. Its also clearly demonstrated in the unit tests, by using Lists of two different types .

[anantdamle]

@garydgregory gentle bump up.

[anantdamle]

Gentle bump: any comments or changes today I should be doing?

[anantdamle]

Gentle Bump: Any review comments or improvements

[garydgregory]

No bumping needed. We are all volunteers. We are all busy. Please be patient.

[anantdamle]

sorry to nag! Any updates?

[garydgregory]

@anantdamle We are volunteers here, we do what we can when we can ;-)

[garydgregory]

I'll try to take a look this week...

[anantdamle]

Any updates on this one?