线程限制产生竞态条件的一种规避方式

[manzhizhen]

Describe what this PR does / why we need it

详细描述见： https://github.com/alibaba/Sentinel/issues/59 一种解决方案：使用信号量+ThreadLocal的方式，保证了原子性，也保证了能在接下来的Slot的处理过程中能利用到前面的结果。

该方式加强了线程限制的准确性，并保持原有的逻辑不变。

Does this pull request fix one issue?

Describe how you did it

Describe how to verify it

Special notes for reviews

[codecov-io]

Codecov Report

:exclamation: No coverage uploaded for pull request base (master@9c268bd). Click here to learn what that means. The diff coverage is n/a.

@@            Coverage Diff            @@
##             master      #76   +/-   ##
=========================================
  Coverage          ?   40.43%           
  Complexity        ?     1314           
=========================================
  Files             ?      297           
  Lines             ?     8591           
  Branches          ?     1156           
=========================================
  Hits              ?     3474           
  Misses            ?     4693           
  Partials          ?      424

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[manzhizhen]

ping @manzhizhen Conflict happens after merging a previous commit. Please rebase the branch against master and push it back again. Thanks a lot.

OK, I will deal with it later.

[manzhizhen]

ping @manzhizhen Conflict happens after merging a previous commit. Please rebase the branch against master and push it back again. Thanks a lot.

Already submitted, in integration testing

[manzhizhen]

ping @manzhizhen Conflict happens after merging a previous commit. Please rebase the branch against master and push it back again. Thanks a lot.

ok，I do it later.

[manzhizhen]

ping @manzhizhen Conflict happens after merging a previous commit. Please rebase the branch against master and push it back again. Thanks a lot.

I do it now!!

[sentinel-bot]

Ping @manzhizhen . Conflict happens after merging a previous commit. Please rebase the branch against master and push it back again. Thanks a lot.

[sentinel-bot]

Ping @manzhizhen . Conflict happens after merging a previous commit. Please rebase the branch against master and push it back again. Thanks a lot.

[sentinel-bot]

Ping @manzhizhen . Conflict happens after merging a previous commit. Please rebase the branch against master and push it back again. Thanks a lot.

[sentinel-bot]

Ping @manzhizhen . Conflict happens after merging a previous commit. Please rebase the branch against master and push it back again. Thanks a lot.

[sentinel-bot]

Ping @manzhizhen . Conflict happens after merging a previous commit. Please rebase the branch against master and push it back again. Thanks a lot.

[sentinel-bot]

Ping @manzhizhen . Conflict happens after merging a previous commit. Please rebase the branch against master and push it back again. Thanks a lot.

[manzhizhen]

ping @manzhizhen Conflict happens after merging a previous commit. Please rebase the branch against master and push it back again. Thanks a lot.

ok，I do it.

[manzhizhen]

ping @manzhizhen Conflict happens after merging a previous commit. Please rebase the branch against master and push it back again. Thanks a lot.

ok！！

[manzhizhen]

ping @manzhizhen Conflict happens after merging a previous commit. Please rebase the branch against master and push it back again. Thanks a lot.

ok

[manzhizhen]

ping @manzhizhen Conflict happens after merging a previous commit. Please rebase the branch against master and push it back again. Thanks a lot.

ok，I will do it

[codecov-commenter]

Codecov Report

Merging #76 into master will decrease coverage by 1.31%. The diff coverage is n/a.

@@             Coverage Diff              @@
##             master      #76      +/-   ##
============================================
- Coverage     41.75%   40.43%   -1.32%     
+ Complexity     1377     1314      -63     
============================================
  Files           304      297       -7     
  Lines          8766     8591     -175     
  Branches       1182     1156      -26     
============================================
- Hits           3660     3474     -186     
- Misses         4660     4693      +33     
+ Partials        446      424      -22     

Impacted Files	Coverage Δ	Complexity Δ
...apter/gateway/common/param/GatewayParamParser.java	0.00% <0.00%> (-68.26%)	0.00% <0.00%> (-17.00%)
...va/com/alibaba/csp/sentinel/init/InitExecutor.java	13.15% <0.00%> (-47.37%)	2.00% <0.00%> (-4.00%)
...src/main/java/com/alibaba/csp/sentinel/Tracer.java	0.00% <0.00%> (-31.15%)	0.00% <0.00%> (-12.00%)
...slots/statistic/StatisticSlotCallbackRegistry.java	22.22% <0.00%> (-22.23%)	3.00% <0.00%> (-2.00%)
...ba/csp/sentinel/slots/statistic/StatisticSlot.java	52.38% <0.00%> (-14.29%)	10.00% <0.00%> (-3.00%)
...java/com/alibaba/csp/sentinel/util/AssertUtil.java	13.33% <0.00%> (-13.34%)	2.00% <0.00%> (-1.00%)
...inel/slots/block/flow/param/ParamFlowRuleUtil.java	50.87% <0.00%> (-10.67%)	20.00% <0.00%> (-10.00%)
.../java/com/alibaba/csp/sentinel/util/SpiLoader.java	0.00% <0.00%> (-8.65%)	0.00% <0.00%> (-2.00%)
...ateway/common/api/GatewayApiDefinitionManager.java	27.94% <0.00%> (-5.89%)	6.00% <0.00%> (-1.00%)
...csp/sentinel/slots/block/flow/FlowRuleChecker.java	45.45% <0.00%> (-4.55%)	16.00% <0.00%> (-5.00%)
... and 20 more

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[CLAassistant]

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[LearningGp]

The PR has remained open for an extended period and has accumulated significant merge conflicts. We will therefore close it temporarily as the main development branch for Sentinel has now transitioned to the 1.8 branch. New contributions are welcome with PRs based on the 1.8 branch.