com.gilt.gfc.util.VersionUtil.scala Maven / Gradle / Ivy
package com.gilt.gfc.util
import java.io.InputStream
import java.net.URL
import java.util.jar.Manifest
import scala.util.control.NonFatal
/**
* Used to get hold of the version of a particular item in the manifest.
*/
trait VersionUtil {
/**
* This trawls through all the jar files, so just call this once per JVM.
*
* @param title value of Implementation-Title key to filter from all the manifests on the classpath
* @return version of a given library or app based on the gilt MANIFEST.MF Implementation-Version standard
*/
def loadVersion(title: String): Option[String] = {
import scala.collection.JavaConverters._
this.getClass.getClassLoader.getResources("META-INF/MANIFEST.MF").asScala.map(readManifest).toSeq.
flatten.find(_.getMainAttributes.getValue("Implementation-Title") == title).
flatMap(m => Option(m.getMainAttributes.getValue("Implementation-Version")))
}
def readManifest(url: URL): Option[Manifest] = {
safeReadUrl(url)(new Manifest(_))
}
def safeReadUrl[T](url: URL)(f: InputStream => T): Option[T] = {
try {
val input = url.openStream()
try {
Some(f(input))
} finally {
try { input.close() } catch { case NonFatal(_) => /* ignore */ }
}
} catch {
case e: Exception => None
}
}
}
object VersionUtil extends VersionUtil