Update comment in MyBatisBatchItemWriter.java

[evans810]

Modify comment in Line 67. As in code line 150, if assertUpdates is true, only results.size()==1 can pass the validation

#390

[kazuki43zoo]

@evans810 Thanks for your contributing!

I've confirmed your suggestion and current implementation. As a result, I thought the current comment was correct because assertUpdates property is flag that whether assert results.get(0).getUpdateCounts()[i] != 0(L.159) rather that results.size() == 1.
results.size() != 1 never occur if used the MyBatisBatchItemWriter correctly.

spring/src/main/java/org/mybatis/spring/batch/MyBatisBatchItemWriter.java

Lines 155 to 163 in b04ba37

	int[] updateCounts = results.get(0).getUpdateCounts();
	for (int i = 0; i < updateCounts.length; i++) {
	int value = updateCounts[i];
	if (value == 0) {
	throw new EmptyResultDataAccessException(
	"Item " + i + " of " + updateCounts.length + " did not update any rows: [" + items.get(i) + "]", 1);
	}
	}

If you agree my opinion, I will close this PR. WDYT?

Thanks.

[evans810]

@kazuki43zoo Thank you for your reply.

As the code, in the code block of below if statements(line 149 ~ line 166) ,

if (assertUpdate) {...}

two conditions will be checked:
1.

if (results.size() != 1) {
          throw new InvalidDataAccessResourceUsageException("Batch execution returned invalid results. "
              + "Expected 1 but number of BatchResult objects returned was " + results.size());
        }

if (value == 0) {
            throw new EmptyResultDataAccessException(
                "Item " + i + " of " + updateCounts.length + " did not update any rows: [" + items.get:i + "]", 1);
          }

In our practice, results.size() == 1 has appeared and we were confused by the comment of assertUpdates. That's why we thought the comment should be more clear or change the code to reflect the logic more clearly.

I have updated PR. Could you help to review?

Thanks.

[kazuki43zoo]

@evans810 thx!