DataAccessUtils result accessors with Optional return value #27735
Conversation
spring-projects-issues
added
the
status: waiting-for-triage
|
Using the * form of import should be avoided - java.util.*. |
rstoyanchev
added
in: data
rstoyanchev
changed the title
rstoyanchev
removed
the
status: waiting-for-triage
| if (results == null) { | ||
| return null; | ||
| } | ||
| List<T> resultList = results.toList(); |
There was a problem hiding this comment.
Wouldn't it be better to do a
.limit(2).toList()
and then avoid opening the second stream and instead do
resultList.get(0)
There was a problem hiding this comment.
Hi @marschall,
thanks for reviewing, sounds good, i refactored this. Does it make more sense now?
throw new IncorrectResultSizeDataAccessException(1, resultList.size());
as we limited the resultList size with .limit, this would not report the original passed Stream results size though but instead a maximum of 2... is that an issue?
There was a problem hiding this comment.
Yes, looks better to me.
| return null; | ||
| } | ||
| Iterable<T> iterable = () -> results; | ||
| List<T> resultList = StreamSupport.stream(iterable.spliterator(), false).toList(); |
There was a problem hiding this comment.
Why a stream instead of just
results.next()
Thanks for the tip, i adjusted that. |
| if (results == null) { | ||
| return null; | ||
| } | ||
| List<T> resultList = results.limit(2).toList(); |
There was a problem hiding this comment.
There is a trade off here and in #optionalResult whether we should call #close on the stream:
On one hand Java convention is the code who creates a "resource" is responsible for disposing it, in this case the caller of this method would be responsible to call #close on the streams where required.
On the other hand failing to call #close on some streams, like the ones returned by JdbcOperations#queryForStream, can lead to resource leaks. Having the caller put streams in a try-with-resources block is both cumbersome and error prone.
There was a problem hiding this comment.
Makes sense. The passed stream is now closed in both methods. Also e.g. hibernate's Query.stream() documentation suggests the stream should be closed afterwards, so not so far fetched 👍
spring-tx/src/main/java/org/springframework/dao/support/DataAccessUtils.java
Outdated
Show resolved
Hide resolved
spring-tx/src/main/java/org/springframework/dao/support/DataAccessUtils.java
Outdated
Show resolved
Hide resolved
spring-tx/src/main/java/org/springframework/dao/support/DataAccessUtils.java
Outdated
Show resolved
Hide resolved
…cessUtils.java re-use newly added singleResult methods Co-authored-by: Vigneswaran <[email protected]>
…cessUtils.java re-use newly added singleResult methods Co-authored-by: Vigneswaran <[email protected]>
…cessUtils.java re-use newly added singleResult methods Co-authored-by: Vigneswaran <[email protected]>
spring-tx/src/main/java/org/springframework/dao/support/DataAccessUtils.java
Outdated
Show resolved
Hide resolved
spring-tx/src/main/java/org/springframework/dao/support/DataAccessUtils.java
Outdated
Show resolved
Hide resolved
…cessUtils.java use "public IncorrectResultSizeDataAccessException(int expectedSize)" in stream and iterator method Co-authored-by: Kwangyong Kim <[email protected]>
…cessUtils.java use "public IncorrectResultSizeDataAccessException(int expectedSize)" in stream and iterator method Co-authored-by: Vigneswaran <[email protected]>
Closes #27728
(#27728)
Hi everyone, this is my first PR in any project here on github with the goal of improving my understanding of java. Hope i understood the enhancement request correctly.