- using DataInputStream
- using Scanner
- using Reader
- using Files.readLines
and they all suck.
I think they all connected, for example with added lambdas they also added streams, so collections library now allows to do the same thing using old iterators or new streams APIs, and somehow those APIs are not compatible, it is not easy to produce stream from iterator.
which I never seen anyone uses and it makes everything more complicated
they probably should've have some ParallelStream interface
core ecosystem, e.g. apache commons will add several more ways.
Java’s standard library is one of the best stdlibs out there.
programmers in 95% cases want something like following to read lines from text file:
for s in open('file.txt'): print(s)
Java has 5 different io APIs and no one provides such construct, you need to stack various verbose abstractions to just read text file.
How it is the best? Ergonomics and brain load is very bad.
string[] lines = ReadFile("path", "filename");
- it will produce OOM if file is very large
- iterating array is usually verbose in many of languages (at least in Java)
- not sure why you would want to have path and filename as separate params
In Java, it would be more ergonomical if they add something like following:
Iterable<String> Files.readAllLines(String fileName);
Also, I really don’t understand your last example - that’s literally available in java returning a List of lines. If you add a .stream().collect(joining(“\n”)), you get the whole string in one go.
I think in python it will lazely iterate through the file, and not load everything at once
> Java’s List is much more ergonomic that arrays.
right, but commenter above proposed array..
> that’s literally available in java returning a List of lines.
current API has two issues:
- OOM if file is large
- it takes Path instance which you need to construct and not "String file" parameter, thus hit on ergonomics
- it will produce OOM if file is very large
- not sure why you would want to have path and filename as separate params
Iterable<String> Files.readAllLines(String fileName);
I think in python it will lazely iterate through the file,
this is possible solution, still it doesn't allow to iterate lines one by one and handle large files
> Throws path not found. Throws file not found.
I think it is some very niche use cases when you need to distinguish between these cases. From another hand there are many places in the code which operate absolute file paths already, and you force them to split path, which is cumbersome. At least two alternative APIs probably are justified to have.
> Fastest was suck each one into memory and call split.
I really don't think pre-splitting is any kind of performance bottleneck, it is likely 1% of performance compared to all IO stack and subsequent string/objects memory management.