Holger Stratmann created CSV-131:
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Summary: save positions of records to enable random access
Key: CSV-131
URL: https://issues.apache.org/jira/browse/CSV-131
Project: Commons CSV
Issue Type: Improvement
Components: Parser
Affects Versions: 1.1
Reporter: Holger Stratmann
Priority: Minor
It would be good to have the position of the {{CSVRecord}} save its position in
the source stream.
Reason: Knowing the position of the records would enable random access to
retrieve records from the source (after reading it once to build an index) if
the file is too large to be read into memory (or if we don't want to read the
full file to access a record in the middle).
Additional info: I have created a "random access csv reader" and a "csv viewer"
(Swing) for arbitrarily large CSV files. It requires one additional scan of the
file to build an index (multi-byte charsets supported). The index can be saved
to a file so it only needs to be built once. Because the lexer uses a
BufferedReader, we need "internal information" to know where each record starts.
The change to "core" is minor: one field in {{CSVRecord}}s and some associated
methods to store the position.
Patch will be attached.
Code for random access (both UI and non-UI) will be proposed (and possibly
submitted) as a separate issue. It could also be an independent add-on but
requires this one little change to Commons CSV.
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