refactor(core): improve backend code by flow idea suggests

[jadepeng]

No description provided.

[codecov]

Codecov Report

Merging #2000 (516579d) into master (b1b1209) will increase coverage by 3.97%.
The diff coverage is 76.00%.

@@             Coverage Diff              @@
##             master    #2000      +/-   ##
============================================
+ Coverage     62.41%   66.38%   +3.97%     
  Complexity      976      976              
============================================
  Files           482      482              
  Lines         41450    41449       -1     
  Branches       5896     5890       -6     
============================================
+ Hits          25870    27516    +1646     
+ Misses        13034    11232    -1802     
- Partials       2546     2701     +155     

Impacted Files	Coverage Δ
.../com/baidu/hugegraph/backend/BackendException.java	53.84% <ø> (ø)
...ugegraph/backend/cache/CachedGraphTransaction.java	85.71% <ø> (+5.29%)	⬆️
...va/com/baidu/hugegraph/backend/id/IdGenerator.java	77.20% <ø> (+2.94%)	⬆️
...idu/hugegraph/backend/id/SnowflakeIdGenerator.java	69.49% <ø> (+0.63%)	⬆️
...a/com/baidu/hugegraph/backend/query/Condition.java	79.09% <ø> (+0.69%)	⬆️
...hugegraph/backend/query/ConditionQueryFlatten.java	75.73% <ø> (-0.11%)	⬇️
...egraph/backend/serializer/BinaryEntryIterator.java	87.03% <ø> (+25.92%)	⬆️
...ugegraph/backend/serializer/SerializerFactory.java	85.18% <ø> (ø)
...ugegraph/backend/serializer/TableBackendEntry.java	88.88% <ø> (ø)
...aidu/hugegraph/backend/serializer/BytesBuffer.java	89.16% <50.00%> (ø)
... and 69 more

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[imbajin]

should warn if it influence the performance. some suggestions are not perf friendly

[jadepeng]

这里就两个string，用StringBuilder代价更大

[imbajin]

也是, 而且高版本 JDK 编译器似乎已经会自动判断开销转换了. (当然我不确定是从 JDK 几开始的)

[javeme]

@jadepeng you can use git rebase and git push -f to update the code

[imbajin]

@jadepeng you can use git rebase and git push -f to update the code

The github UI will alert update with the master automatically (I have clicked it)

It is safer and doesn't need to review the code again (avoid unnecessary manual rebase operations)

TODO: I'll enable the required in CI after all package renamed