+doc #16549 StreamTCP docs

akka-docs-dev/rst/scala/code/docs/stream/cookbook/RecipeParseLines.scala

@@ -1,6 +1,7 @@
 package docs.stream.cookbook
 
-import akka.stream.scaladsl.{ Sink, Source }
+import akka.stream.scaladsl.Sink
+import akka.stream.scaladsl.Source
 import akka.util.ByteString
 
 import scala.annotation.tailrec
@@ -18,63 +19,11 @@ class RecipeParseLines extends RecipeSpec {
         ByteString("!\r"),
         ByteString("\nHello Akka!\r\nHello Streams!"),
         ByteString("\r\n\r\n")))
-      import akka.stream.stage._
 
-      //#parse-lines
-      def parseLines(separator: String, maximumLineBytes: Int) =
-        new StatefulStage[ByteString, String] {
-          private val separatorBytes = ByteString(separator)
-          private val firstSeparatorByte = separatorBytes.head
-          private var buffer = ByteString.empty
-          private var nextPossibleMatch = 0
-
-          def initial = new State {
-            override def onPush(chunk: ByteString, ctx: Context[String]): Directive = {
-              buffer ++= chunk
-              if (buffer.size > maximumLineBytes)
-                ctx.fail(new IllegalStateException(s"Read ${buffer.size} bytes " +
-                  s"which is more than $maximumLineBytes without seeing a line terminator"))
-              else emit(doParse(Vector.empty).iterator, ctx)
-            }
-
-            @tailrec
-            private def doParse(parsedLinesSoFar: Vector[String]): Vector[String] = {
-              val possibleMatchPos = buffer.indexOf(firstSeparatorByte, from = nextPossibleMatch)
-              if (possibleMatchPos == -1) {
-                // No matching character, we need to accumulate more bytes into the buffer
-                nextPossibleMatch = buffer.size
-                parsedLinesSoFar
-              } else {
-                if (possibleMatchPos + separatorBytes.size > buffer.size) {
-                  // We have found a possible match (we found the first character of the terminator
-                  // sequence) but we don't have yet enough bytes. We remember the position to
-                  // retry from next time.
-                  nextPossibleMatch = possibleMatchPos
-                  parsedLinesSoFar
-                } else {
-                  if (buffer.slice(possibleMatchPos, possibleMatchPos + separatorBytes.size)
-                    == separatorBytes) {
-                    // Found a match
-                    val parsedLine = buffer.slice(0, possibleMatchPos).utf8String
-                    buffer = buffer.drop(possibleMatchPos + separatorBytes.size)
-                    nextPossibleMatch -= possibleMatchPos + separatorBytes.size
-                    doParse(parsedLinesSoFar :+ parsedLine)
-                  } else {
-                    nextPossibleMatch += 1
-                    doParse(parsedLinesSoFar)
-                  }
-                }
-              }
-
-            }
-          }
-
-        }
+      import RecipeParseLines._
 
       val linesStream = rawData.transform(() => parseLines("\r\n", 100))
 
-      //#parse-lines
-
       Await.result(linesStream.grouped(10).runWith(Sink.head), 3.seconds) should be(List(
         "Hello World\r!",
         "Hello Akka!",
@@ -85,3 +34,60 @@ class RecipeParseLines extends RecipeSpec {
   }
 
 }
+
+object RecipeParseLines {
+
+  import akka.stream.stage._
+
+  //#parse-lines
+  def parseLines(separator: String, maximumLineBytes: Int) =
+    new StatefulStage[ByteString, String] {
+      private val separatorBytes = ByteString(separator)
+      private val firstSeparatorByte = separatorBytes.head
+      private var buffer = ByteString.empty
+      private var nextPossibleMatch = 0
+
+      def initial = new State {
+        override def onPush(chunk: ByteString, ctx: Context[String]): Directive = {
+          buffer ++= chunk
+          if (buffer.size > maximumLineBytes)
+            ctx.fail(new IllegalStateException(s"Read ${buffer.size} bytes " +
+              s"which is more than $maximumLineBytes without seeing a line terminator"))
+          else emit(doParse(Vector.empty).iterator, ctx)
+        }
+
+        @tailrec
+        private def doParse(parsedLinesSoFar: Vector[String]): Vector[String] = {
+          val possibleMatchPos = buffer.indexOf(firstSeparatorByte, from = nextPossibleMatch)
+          if (possibleMatchPos == -1) {
+            // No matching character, we need to accumulate more bytes into the buffer
+            nextPossibleMatch = buffer.size
+            parsedLinesSoFar
+          } else {
+            if (possibleMatchPos + separatorBytes.size > buffer.size) {
+              // We have found a possible match (we found the first character of the terminator
+              // sequence) but we don't have yet enough bytes. We remember the position to
+              // retry from next time.
+              nextPossibleMatch = possibleMatchPos
+              parsedLinesSoFar
+            } else {
+              if (buffer.slice(possibleMatchPos, possibleMatchPos + separatorBytes.size)
+                == separatorBytes) {
+                // Found a match
+                val parsedLine = buffer.slice(0, possibleMatchPos).utf8String
+                buffer = buffer.drop(possibleMatchPos + separatorBytes.size)
+                nextPossibleMatch -= possibleMatchPos + separatorBytes.size
+                doParse(parsedLinesSoFar :+ parsedLine)
+              } else {
+                nextPossibleMatch += 1
+                doParse(parsedLinesSoFar)
+              }
+            }
+          }
+
+        }
+      }
+    }
+  //#parse-lines
+
+}