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https://issues.apache.org/jira/browse/AVRO-143?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12765659#action_12765659
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Doug Cutting commented on AVRO-143:
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> I wouldn't expect porting it to work with Avro to be too complicated, and
> I've been thinking about doing it at some point.
That'd be great if you want to give this a stab!
The good news is that the Avro version only needs to generate two methods:
- Object get(int field);
- void set(int field, Object value);
The bad news is that these each need to contain a switch statement. And, for
primitive values, the getters need to, e.g., call something like Long#valueOf
while the setters need to call something like Long#longValue to box and unbox
things.
(Yes, perhaps it would be faster not to box. But that would complicate things
substantially. We'd instead need to generate methods like 'Object
readField(Object rec, int field, Decoder d, DatumReader in, Schema actual,
Schema expected)' and 'void write(Object rec, int field, Encoder e, DatumWriter
out)' methods. For primitive types it could directly invoke the
encoder/decoder methods, without boxing. For non-primitives it would call back
to a protected DatumReader/Writer method. And we'd still need a setter method,
so that we can set default values. Etc. Or we could totally abandon
code-sharing with GenericData and directly call generated readers for each
field's type. But that would involve generating a lot more code, duplicating
lots of delicate logic. But, for now, the boxing doesn't seem to be a problem
in benchmarks.)
> use ASM to accellerate reflection
> ---------------------------------
>
> Key: AVRO-143
> URL: https://issues.apache.org/jira/browse/AVRO-143
> Project: Avro
> Issue Type: Improvement
> Components: java
> Reporter: Doug Cutting
>
> Java reflection is very slow, about 100 times slower for field access than
> normal Java code. However reflection might be a useful tool for converting
> existing codebases to use Avro.
> One could, using ASM (http://asm.ow2.org/) make existing compiled classes to
> implement the SpecificRecord interface or something similar:
> http://hadoop.apache.org/avro/docs/current/api/java/org/apache/avro/specific/SpecificRecord.html
> This would make existing classes as fast to serialize as generated classes.
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