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https://issues.apache.org/jira/browse/DRILL-5116?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15789052#comment-15789052
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Paul Rogers commented on DRILL-5116:
------------------------------------
Much complexity surrounds nested classes. The byte-code fix-ups must be doing
some real magic. Nested classes in only a few places such as hash aggregates:
{code}
public abstract class HashAggTemplate implements HashAggregator {
...
public class BatchHolder {
... }
private void addBatchHolder() {
BatchHolder bh = new BatchHolder();
...
{code}
Somehow, when the byte code transforms are done, the "new" above of the
template's nested class is replaced with a "new" of the generated subclass of
the nested class. Plain old Java can't do this trick. Instead, we need to
insert a "shim" method:
{code}
private void addBatchHolder() {
BatchHolder bh = newBatchHolder();
... }
protected BatchHolder newBatchHolder() {
return new BatchHolder();
}
{code}
Then, the generated code must override the shim to create an instance of the
generated nested class:
{code}
protected HashAggTemplate.BatchHolder newBatchHolder() {
return new HashAggregatorGen29 .BatchHolder();
}
{code}
> Enable generated code debugging in each Drill operator
> ------------------------------------------------------
>
> Key: DRILL-5116
> URL: https://issues.apache.org/jira/browse/DRILL-5116
> Project: Apache Drill
> Issue Type: Improvement
> Affects Versions: 1.9.0
> Reporter: Paul Rogers
> Assignee: Paul Rogers
> Priority: Minor
>
> DRILL-5052 adds the ability to debug generated code. Some of the code
> generated by Drill's operators has minor problems when compiled directly
> using the new technique. These issues are ignore by the byte-code-merge
> technique uses in production. This ticket asks to try the DRILL-5052 feature
> in each operator, clean up any minor problems, and ensure each operator
> generates code suitable for debugging. Use the new
> {{CodeGenerator.plainOldJavaCapable()}} method to mark each generated class
> as ready for "plain-old Java" code gen.
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