Github user ryaneleary commented on the pull request:
https://github.com/apache/accumulo/pull/7#issuecomment-43555087
Sure. Here's an example of what I've done (by modifying the
WholeRowIterator). Assume a table that contains 'documents' and various
document information. Assume a table format like this (format: ```<row <cf :
cq>> = value```):
```
<docid1 <META : timestamp>> (long) 12345
<docid1 <META : meta_field_1>> (String) metaFieldValue1
<docid1 <META : meta_field_2>> (String) metaFieldValue2
<docid2 <META : timestamp>> (long) 23456
```
For other reasons in the system, I have a protocol buffer definition that
can be used for shipping this data around. It's definition looks like this:
```
message DocumentMessage {
optional int64 timestamp = 1;
optional string meta_field_1 = 2;
optional string meta_field_2 = 3;
}
```
I can define an iterator that is passed a generated protocol buffer class
that can iterate over the whole row and automatically build the protocol buffer
object. getTopValue() now returns a protocol buffer message that the
application knows how to parse.
This is nice for bulk loading and saves the client from having to build the
message it would have had to build anyway. When iterating over the results
returned by the scanner, an entire document at a time is returned instead of
individual columns.
I can provide a more concrete example/implementation of such a class if
you'd like.
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