/**
* 使用本章的日志生成器特质,给前一个练习中的方案增加日志功能，要求体现缓冲的效果
*/
import java.io.{InputStream, FileInputStream}
trait Logger {
def log(msg: String)
}
trait NoneLogger extends Logger {
def log(msg: String) = {}
}
trait PrintLogger extends Logger {
def log(msg: String) = println(msg)
}
trait Buffering {
this: InputStream with Logger =>
val BUF_SIZE: Int = 5
private val buf = new Array[Byte](BUF_SIZE)
private var bufsize: Int = 0
private var pos: Int = 0
override def read(): Int = {
if (pos >= bufsize) {
bufsize = this.read(buf, 0, BUF_SIZE)
log("buffered %d bytes: %s".format(bufsize, buf.mkString(", ")))
if (bufsize > 0) -1
pos = 0
}
pos += 1
buf(pos-1)
}
}
val f = new FileInputStream("exercise08.txt") with Buffering with PrintLogger
for(i <- 1 to 10) println(f.read())
