RxIo
The AsyncFiles class allows Java
applications to easily read/write files asynchronously and without blocking.
This is an equivalent to the standard JDK
Files
class but using non-blocking IO.
In section Usage we present some examples using the
AsyncFiles
class side by side with the corresponding blocking version of
Files.
Installation
First, in order to include it to your project, simply add this dependency:
| Maven | Gradle |
|---|---|
<dependency>
<groupId>com.github.javasync</groupId>
<artifactId>RxIo</artifactId>
<version>1.2.1</version>
</dependency> |
implementation 'com.github.javasync:RxIo:1.2.1' |
Usage
String path = "input.txt";
AsyncFiles
.asyncQuery(path) // printing all lines from input.txt
.subscribe((line, err) -> out.println(line)) // lack check err
.join(); // block if you want to wait for completion |
Path path = Paths.get("input.txt");
Files
.lines(path) // printing all lines from input.txt
.forEach(out::println) |
Path path = Paths.get("output.txt")
List<String> data = asList("super", "brave", "isel", "gain");
AsyncFiles
.write(path, data) // writing lines to output.txt
.join(); // block if you want to wait for completion |
/**
* Writing lines to output.txt
*/
Path path = Paths.get("output.txt")
List<String> data = asList("super", "brave", "isel", "gain");
Files.write(path, data); |
Path in = Paths.get("input.txt");
Path out = Paths.get("output.txt");
AsyncFiles
.readAllBytes(in)
.thenCompose(bytes -> AsyncFiles.writeBytes(out, bytes))
.join(); // block if you want to wait for completion |
/**
* Copying from one file to another.
*/
Path in = Paths.get("input.txt");
Path out = Paths.get("output.txt");
byte[] bytes = Files.readAllBytes(in);
Files.write(out, bytes); |
The AsyncFiles::asyncQuery()
returns an AsyncQuery that allows asynchronous subscription and chaining intermediate operations
such as filter, map and others.
In the following example we show how to print all words of a gutenberg.org file content without repetitions:
AsyncFiles
.asyncQuery(file)
.filter(line -> !line.isEmpty()) // Skip empty lines
.skip(14) // Skip gutenberg header
.takeWhile(line -> !line.contains("*** END OF ")) // Skip gutenberg footnote
.flatMapMerge(line -> AsyncQuery.of(line.split("\\W+")))
.distinct()
.subscribe((word, err) -> {
if(err != null) err.printStackTrace();
else out.println(word);
})
.join(); // block if you want to wait for completionAlternatively, the AsyncFiles::lines()
returns a reactive Publisher
which is compatible with Reactor or RxJava streams.
Thus we can use their utility methods to easily operate on the result of AsyncFiles::lines().
For example, with the utility methods of Reactor
Flux
we can rewrite the previous sample as:
Flux
.from(AsyncFiles.lines(file))
.filter(line -> !line.isEmpty()) // Skip empty lines
.skip(14) // Skip gutenberg header
.takeWhile(line -> !line.contains("*** END OF ")) // Skip gutenberg footnote
.flatMap(line -> Flux.fromArray(line.split("\\W+")))
.distinct()
.doOnNext(out::println)
.doOnError(Throwable::printStackTrace)
.blockLast(); // block if you want to wait for completion