0rtis/jsak

Java Swiss Army Knife

JSAK - Java Swiss Army Knife

The Java Swiss Army Knife is a utility package that provide various tools for Java development

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Examples

FormatUtils

Utility class for string formatting:

• Format bytes length
• Format duration
• Format exception

Pointer

Pointer of object (useful to access outer field from anonymous class)

final Pointer<Integer> p = Pointer.of(42);
new Thread(){
    @Override
    public void run()
    {
        while(true) {
            synchonized(p) {
                System.out.println(p.getValue());
            }			
        }
    }
}.start();

while(true)
    synchonized(p) {
        p.setValue(p.getValue() + 1);
    }

see ConcurrentPointer for built-in thread safe equivalent

UZ

Unsigned integer

UZ.ONE.add(7).subtract(3).multiply(2)

Bytes

Array of bytes as object (can be instanciated immutable)

byte [] buffer = ...
Bytes bytes = Bytes.copy(buffer); //immutable

BytesProvider & BytesConsumer

Interfaces for agnostic I/O operation

InputStream inputstream = ...
BytesProvider provider = BytesProvider.of(inputstream);

OutputStream outputstream = ...
BytesConsumer consumer = BytesConsumer.of(outputstream);

IOUtils

Utility class for I/O operations:

• Read internal resources
• Copy N bytes from Path/RandomAccessFile to any BytesConsumer
• Copy at most N bytes or until the end of the stream (whichever come first) from Path/RandomAccessFile to any BytesConsumer
• Copy until the end of the stream from any BytesProvider to any BytesConsumer

FileContentMonitor

Monitor change in one or more files

FileContentMonitor fileMonitor = new FileContentMonitor(Paths.get("path to my file"), Duration.ofMinutes(5));
new Thread(fileMonitor).start();
fileMonitor.addListener(new FileContentListener()
{
    @Override
    public void onFileContentChange(final Path path, final Bytes content)
    {
        System.out.println("File " + path + " has changed");
    }
});

LogService

Helper for the default Java log API

final LogService logService = new LogService().start();
logService.addListener(FilteredLogListener.CONSOLE_ALL);
final Logger logger = logService.getLogger("my logger");
logger.info("Hello world")

LogService can be configured from a JSON file through LogConfigFileMonitor

new LogConfigFileMonitor(logService, Paths.get("log_config.json"), null, Duration.ofSeconds(10), logService.getLogger("log-config")).start();

Web server

A simple & lightweight web server (based of SUN implementation)

final HTTPServer httpServer = new HTTPServer(new InetSocketAddress("0.0.0.0", 8888), Executors.newFixedThreadPool(2), 2);
HTTPEndpoint endpoint = new HTTPEndpoint()
{
    @Override
    public boolean isMatch(final String requestMethod, final Map<String, List<String>> requestHeaders, final String path)
    {
        return true;
    }

    @Override
    public Response respond(final String requestMethod, final Map<String, List<String>> requestHeaders, final String path,
            final String query, final InputStream requestBody)
    {
        return new Response(null, 200, "hello world".getBytes(StandardCharsets.UTF_8), false);
    }
};
httpServer.addContext("/myPath", new HTTPRequestHttpHandler("/myPath", httpServerConfig, List.of(endpoint), Compression.Algorithm.Raw, new NoLimitHTTPLimiter(), 4096, logger));

CachedIterator

Get the current value of an Iterator more than once

final List<Integer> list = new ArrayList<>();
for (int i = 0; i < 256; i++)
    list.add(i);

final Iterator<Integer> iterator = list.iterator();
final CachedIterator<Integer> cachedIterator = CachedIterator.of(list);

int index = 0;
while (iterator.hasNext())
{
    final Integer value = iterator.next();
    Assert.assertEquals(value, cachedIterator.next());
    Assert.assertEquals(index++, cachedIterator.getIndex());
    Assert.assertEquals(value, cachedIterator.getCurrent());
}