com.eharmony.aloha.io.GZippedReadable.scala Maven / Gradle / Ivy

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package com.eharmony.aloha.io

import java.io.InputStream
import java.util.zip.GZIPInputStream
import com.eharmony.aloha.io.multiple.MultipleFileReadable
import com.eharmony.aloha.util.Logging

/**
 * When mixed in with a [[com.eharmony.aloha.io.NonFileReadable]][A], this will provide a method ''gz'' that
 * will read [[http://www.gzip.org/ gzipped]] versions of files.  This works by creating a private object that
 * implements [[com.eharmony.aloha.io.FileReadableByInputStream]] with a ''fromInputStream'' method that
 * wraps the incoming InputStream in a
 * [[http://docs.oracle.com/javase/6/docs/api/java/util/zip/GZIPInputStream.html java.util.zip.GZIPInputStream]] and
 * then forwards the wrapped InputStream to the ''fromInputStream'' of the object into which GZippedReadable was mixed.
 *
 * This gives all the different ways to unpack gzipped data from a File, URL, FileObject, etc.  For instance:
 *
 * {{{
 * class X[Seq[String]] extends ReadableByString[Seq[String]] with GZippedReadable[Seq[String]] {
 *   def fromString(s: String) = s.split("\t", -1)
 *   def doSomething() {
 *     val zippedResourcePath = "..."
 *
 *     // Get the Seq[String] from resource and do stuff to it...
 *     gz.fromResource(zippedResourcePath).filter(_.size > 1).size
 *   }
 * }
 * }}}
 *
 * @tparam A
 */
trait GZippedReadable[A] { self: NonFileReadable[A] =>
  private[this] object gzip
    extends FileReadableByInputStream[A]
    with MultipleFileReadable[A]
    with LocationLoggingReadable[A]
    with Logging {

    def fromInputStream(is: InputStream) = self.fromInputStream(new GZIPInputStream(is))
  }

  def gz: FileReadableByInputStream[A] with MultipleFileReadable[A] = gzip
}