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From "Benedikt Ritter (JIRA)" <>
Subject [jira] [Closed] (CSV-42) Lots of possible changes
Date Thu, 14 Aug 2014 20:08:24 GMT


Benedikt Ritter closed CSV-42.

> Lots of possible changes
> ------------------------
>                 Key: CSV-42
>                 URL:
>             Project: Commons CSV
>          Issue Type: Improvement
>    Affects Versions: 1.0
>            Reporter: Bob Smith
>            Priority: Minor
>             Fix For: 1.0
>         Attachments:
> I made a lot of changes to pretty much all of the classes in the csv package.  I thought
it would be better to put all of the the changes here in one issue, but feel free to only
take the parts you like (if any).  Hopefully if nothing else the test cases will be useful
to you.
> I'll try to list most of the changes here, but I'm sure I'm forgetting some. This should
include all of the big changes at least. I focused mostly on the parser, but I also made a
few changes to the printer classes (although I don't think I added any new test cases there).
> h3. General Changes
> - Changed all class names with "CSV" in them to use "Csv". This is how it appears in
the commons-lang "escapeCsv" methods and I think it's easier to read the class name when acronyms
are not in all upper case. (x) {color:red}3 letter acronyms are usually kept in uppercase
(for example URLConnection or SAXParser in the JDK, but there are some exceptions){color}
> - Formatted the code. I used Eclipse with a version of the Java formatting style that
uses spaces instead of tabs and with a few other small changes to try to make it more similar
to the style of this code. The formatting was inconsistent before (sometimes 2 space indent,
sometimes 4) which made it really hard to work on. (/) {color:green}DONE{color}
> - Removed all deprecated methods/constructors (/) {color:green}DONE{color}
> - Made all public classes final. If there is ever a need to create subclasses of them
then this could be changed, but I think it would be better to at least start them as final
(since once they are released as non-final it's hard to go back). (/) {color:green}DONE{color}
> - A few bug fixes (and test cases for them)
> h3. CsvParser
> - There were a few bugs for special cases, so I made as small of changes as I could to
the parser code to fix these.
> - Added a lot of test cases. I created a test case for all bugs that I found, so even
if you don't use my changes to this class you should be able to use the test cases to find
all of the same bugs.
> - Added a close method. (x) {color:red} The try-with-resources statement in Java 7 makes
resources management much easier, there is no need to add a close() method to the parser.{color}
> - Renamed the nextValue method to getValue (so it is more consistent with the getAll
and getLine method names). I think I would prefer to use a different method name prefix for
all three of these (like "readAll") since I wouldn't normally expect a "get" method to have
side effects, but I didn't want to just change the names of the most used methods. (x) {color:red}This
method has been removed, the parser now works line by line.{color}
> - Changed the getLineNumber method to return the correct line number when there are multi-line
values. (x) {color:red}The suggested code counts the number of records instead of the number
of lines. For debugging it's better to return the actual line number.{color}
> - Moved all of the lexer methods into an inner CsvLexer class that is completely independent
of the CsvParser class. The methods were already separated out, so it wasn't a very big change.
I also moved the lexer test cases into a new CsvLexerTest class. (/) {color:green}DONE{color}
> - Got rid of the interpreting unicode escape options. This doesn't really have anything
to do with parsing a CSV file so I think it should be left up to the user of the class to
implement this if needed. As an example, I made a CsvParserUnicodeEscapeTest class that uses
the code from the lexer in a Reader subclass. One nice thing is that with this implementation,
the interpreted values can be used as the delimiter, encapsulator, etc. (/) {color:green}DONE
- The unicode unescaping is now handled by a class implementing (to be contributed
to Commons IO).{color}
> - Got rid of the "escape" option for the same reason as the unicode escape option. I
replaced it with an encapsulator escape option that is only used as an escape operator on
the encapsulator character.
> h3. ExtendedBufferedReader
> - Greatly simplified this class. I removed all the methods that weren't being used (including
keeping track of the line number) and changed the lookahead option to use the BufferedReader
mark and reset methods. (/) {color:green}DONE - ExtendedBufferedReader is still counting the
lines, but the mark/reset lookahead improved the performance by 30%.{color}
> h3. CsvStrategy
> - I split this class into three classes: an abstract base class (CsvStrategy), a parser-specific
version (CsvParseStrategy) and a printer-specific version (CsvPrintStrategy). I didn't like
that the strategy was used for both parsing and printing even though some of the values only
applied to parsing (and there could be values that apply only to printing as well). (x) {color:red}There
aren't enough properties in CSVFormat to split the class{color}
> - Made this class immutable (as described in SANDBOX-279) (/) {color:green}DONE{color}
> - Changed the whitespace options to not ignore whitespace by default. This is what the
document at recommends for the CSV format, so I
think it should be like that by default. I added an "IGNORE_WHITESPACE_STRATEGY" field that
works the same as the old defaults. (/) {color:green}DONE{color}
> - Removed the interpretUnicodeEscape option and replaced the escape field with an encapsulatorEscape
field (as described in the CsvParser change details). (/) {color:green}DONE - Unicode unescaping
has been removed from the format parameters as part of CSV-67{color}
> - Added an ignoreEncapsulationTrailingCharacters field. This is used to either ignore
or append characters that are after an encapsulated value. Previously an IOException was being
thrown here, which I don't think is ever a good idea.
> - Added some restrictions to prevent the values from being things that would break the
parser. This includes using a line break for anything or having equal two values (other than
the encapsulator and encapsulator escape). (/) {color:green}DONE{color}
> h3. CsvPrinter
> - I changed this to use a modified version of the commons-lang escapeCsv method (I hope
it is ok to copy a small amount of code from one commons project to another?). The escaping
is a little different (and simpler) that the old version, but I think the commons-lang version
seems to be the best way to do it. (x) {color:red}Good point on the code reuse, but escapeCsv
doesn't handle properly a format using escaped characters instead of quoted values, such as
the default MySQL format.{color}
> - I added an option to the constructor to allow disabling auto-flushing of the output
stream (similar to what is in the PrintStream class). I also reduced the number of times the
output is flushed when using the print method that take array input. (x) {color:red}CSVPrinter
now outputs to an Appendable instead of a Writer, which means you can use a PrintStream and
control exactly the behavior of the flushing.{color}
> h3. CharBuffer
> - I didn't really make any changes other than to make it a non-public class. (/) {color:green}DONE{color}

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