DelimitedTextProtocol.scala

package org.elves

import java.nio.charset.Charset
import java.nio.{CharBuffer, ByteBuffer}
import scala.annotation.tailrec

class DelimitedTextProtocol(inputDelimiter: String, outputDelimiter: String, charset: Charset) extends Protocol {
  def encode(session: Session, o: Any): ByteBuffer = ByteBuffer wrap (o.toString + outputDelimiter).getBytes(charset)

  def decode(session: Session, buf: ByteBuffer): List[Any] = {
    def writeDown(remaining: String) {
      session.bufferOption match {
        case Some(buffer) => charset.newEncoder.encode(CharBuffer wrap remaining, buffer, true)
        case None => session.buffer = charset encode remaining
      }
    }

    @tailrec
    def rec(elems: List[Any], input: String): List[Any] = {
      val index = input.indexOf(inputDelimiter)
      if (index < 0) {
        if (!input.isEmpty) writeDown(input)
        return elems :: Nil
      }
      rec(elems :+ input.substring(0, index), input.substring(index + inputDelimiter.length))
    }
    
    val data: String = ???
    
    rec(List.empty, data)
  }
}

object DelimitedTextProtocol {
  def create(inputDelimiter: String, outputDelimiter: String, charset: Charset)
    = new DelimitedTextProtocol(inputDelimiter, outputDelimiter, charset)

  def apply(inputDelimiter: String, outputDelimiter: String)(implicit charset: Charset)
    = create(inputDelimiter, outputDelimiter, charset)
}