com.zink.scala.fly.stub.CompressingFieldCodec.scala Maven / Gradle / Ivy

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package com.zink.scala.fly.stub

import com.zink.scala.fly.{FieldCodec, FlyPrime, FlyAccessException}
import java.io.{ByteArrayInputStream, ByteArrayOutputStream, ObjectInputStream, ObjectOutputStream}
import java.util.zip.{Deflater, Inflater}

class CompressingFieldCodec extends FieldCodec {

    // buffer for coding java objects into byte arrays
    private val bos = new ByteArrayOutputStream(FlyPrime.DEFAULT_BUFFER_SIZE)

    override def writeField(field:AnyRef):Array[Byte] = {
      bos.reset()
      val oos = new ObjectOutputStream(bos)
      oos.writeObject(field)
      oos.flush()
      compress(bos.toByteArray)
    }

    override def readField(fieldBytes:Array[Byte]):Option[AnyRef] = {
        val bis = new ByteArrayInputStream(decompress(fieldBytes))
        val ois = new ObjectInputStream(bis)
        Option(ois.readObject)
    }

    private def compress(toCompress:Array[Byte]):Array[Byte] = {
        try {
        	val baos = new ByteArrayOutputStream(FlyPrime.DEFAULT_BUFFER_SIZE)
            val compressor = new Deflater()   // move to fields
            compressor.setLevel(Deflater.BEST_COMPRESSION) // move to ctor
            compressor.setInput(toCompress)
            compressor.finish()

            val buffer = new Array[Byte](FlyPrime.DEFAULT_BUFFER_SIZE)
            while (!compressor.finished()) {
                compressor.deflate(buffer)
                baos.write(buffer)
            }
            baos.close()
            baos.toByteArray
        } catch {
          case _ => throw new FlyAccessException("Compression failed in field codec")
        }
    }

    private def decompress(toDecompress:Array[Byte]):Array[Byte] = {
        try {
        	val decompressor = new Inflater()
        	decompressor.setInput(toDecompress)
        	val bos = new ByteArrayOutputStream(toDecompress.length)
            val buf = new Array[Byte](FlyPrime.DEFAULT_BUFFER_SIZE)
            while (!decompressor.finished()) {
                val count = decompressor.inflate(buf)
                bos.write(buf, 0, count)
                bos.close()
            }
        	bos.toByteArray
        } catch {
          case _ => throw new FlyAccessException("Decompression failed in field codec")
        }
    }
}