A library that contains a few scala utility classes.
A fork and new home of the now unmaintained Gilt Foundation Classes (com.gilt.gfc), now called the GFC Collective, maintained by some of the original authors.
The latest version is 1.0.0, released on 21/Jan/2020 and cross-built against Scala 2.12.x and 2.13.x.
If you're using SBT, add the following line to your build file:
libraryDependencies += "org.gfccollective" %% "gfc-util" % "1.0.0"For Maven and other build tools, you can visit search.maven.org. (This search will also list other available libraries from the GFC Collective.)
Allows a retry of a potentially failing function with or without an exponentially growing wait period:
// some potentially failing function
def inputNumber: Int = ???
// Retry the function up to 10 times or until it succeeds
val number: Int = Retry.retry(10)(inputNumber)// some potentially failing function
def readFile: Seq[String] = ???
// Retry the function up to 10 times until it succeeds, with an exponential backoff,
// starting at 10 ms and doubling each iteration until it reaches 1 second, i.e.
// 10ms, 20ms, 40ms, 80ms, 160ms, 320ms, 640ms, 1s, 1s, 1s
val contents: Seq[String] = Retry.retryWithExponentialDelay(maxRetryTimes = 10,
maxRetryTimeout = 5.minutes.fromNow,
initialDelay = 10.millis,
maxDelay = 1.second,
exponentFactor = 2)
(readFile)Allows a retry of a function I => O via a function I => Either[I, O]:
val arr: Array[Boolean] = Array.fill(5)(false)
// Up to 10 times, set a random array index to 'true' and
// return "success" when all array elements are 'true', or throw 'TooManyRetries'
Retry.retryFold(maxRetryTimes = 10)(arr){ a: Array[Boolean] =>
if (a.forall(identity)) {
Right("success")
} else {
a(scala.util.Random.nextInt(a.length)) = true
Left(a)
}
}// Set a random array index to 'true' and return "success" when all array elements are 'true'.
// Retry this up to 10 times until it succeeds, with an exponential backoff,
// starting at 10 ms and doubling each iteration until it reaches 1 second, i.e.
// 10ms, 20ms, 40ms, 80ms, 160ms, 320ms, 640ms, 1s, 1s, 1s, or throw 'TooManyRetries'
def func(a: Array[Boolean]): Either[Array[Boolean], String] = {
if (a.forall(identity)) {
Right("success")
} else {
a(scala.util.Random.nextInt(a.length)) = true
Left(a)
}
}
val result: String = Retry.retryFoldWithExponentialDelay(maxRetryTimes = 10,
maxRetryTimeout = 5.minutes.fromNow,
initialDelay = 10.millis,
maxDelay = 1.second,
exponentFactor = 2)
(arr)
(func)RateLimiter can be used to rate-limit calls to a work function, e.g. a function that writes to a db. ThreadSafeRateLimiter is a thread safe version of RateLimiter, that synchronizes calls to the limit function.
val rateLimiter = new ThreadSafeRateLimiter(100) // Limit to 100 calls/second
def writeObject(obj: DBObject) = rateLimiter.limit {
db.insert(obj)
}A cache for objects that need their lifecycle to be managed and can't be just throw-away, e.g. for when ConcurrentHashMap.putIfAbsent(new Something()) may result in a Something instance that need to be closed if another thread's putIfAbsent was successful.
val inputStreamCache = new SingletonCache[File]
val file = new File("foo")
val is: InputStream = inputStreamCache(file) {
new FileInputStream(file)
}Utility to unwind nested Throwable stacks
val e1 = new Exception()
val e2 = new Exception(e1)
val e3 = new Exception(e3)
val t: Throwable = Throwables.rootCause(e3)
t should be theSameInstanceAs e1Licensed under the Apache License, Version 2.0: http://www.apache.org/licenses/LICENSE-2.0
