From b458d7067d77530afa33ce2fdd311ab861bde49b Mon Sep 17 00:00:00 2001
From: Karsten Jeppesen <karsten@jeppesens.com>
Date: Wed, 14 Apr 2021 18:42:18 +0200
Subject: [PATCH] NioLineCount: Working

---
 NioLineCount/src/NioLineCount.java | 63 +++++++++++++++++++-----------
 1 file changed, 41 insertions(+), 22 deletions(-)

diff --git a/NioLineCount/src/NioLineCount.java b/NioLineCount/src/NioLineCount.java
index 267dde3..16cd84a 100644
--- a/NioLineCount/src/NioLineCount.java
+++ b/NioLineCount/src/NioLineCount.java
@@ -8,6 +8,7 @@ import java.nio.file.OpenOption;
 import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.nio.file.StandardOpenOption;
+import java.util.concurrent.Semaphore;
 
 /**
  * 
@@ -20,36 +21,54 @@ import java.nio.file.StandardOpenOption;
 public class NioLineCount {
 	
 	static int theCount = 0;
+	// A 0 means that you will be waited until signalled
+	static Semaphore partialReadGate = new Semaphore(1);
+	static boolean doContinue = true;
+	static long readPosition = 0;
 
 	private static int lineCount(String thePath, boolean doDance){
 		if ( ! doDance ) return -1;
 		ByteBuffer buffer = ByteBuffer.allocate(1024);
-		long myPosition = 0;
 		Path myPath = Paths.get( thePath );
 		try {
 			AsynchronousFileChannel fileChannel = AsynchronousFileChannel.open(myPath, StandardOpenOption.READ);
-			fileChannel.read(buffer, myPosition, buffer, new CompletionHandler<Integer,ByteBuffer>() {
-				@Override
-				public void completed(Integer result, ByteBuffer attachment) {
-					System.out.println("Result = " + result + " Limit = " + attachment.limit());
-					attachment.flip();
-					//System.out.println(Charset.defaultCharset().decode(buffer));
-					byte[] data = new byte[attachment.limit()];
-					attachment.get( data );
-					System.out.println(new String(data));
-					System.out.println(">> " + data.toString());
-					for (int i = 0; i < data.length; i++ ) {
-						if ( data[i] == '\n' )
-							theCount++;
-						//System.out.println("data: " + data[i]);
+			while ( doContinue ) {
+				try {
+					// In the end we will be waiting here
+					partialReadGate.acquire();
+					if ( ! doContinue ) return theCount;
+				} catch (InterruptedException e) {
+					// TODO Auto-generated catch block
+					e.printStackTrace();
+				}
+				fileChannel.read(buffer, readPosition, buffer, new CompletionHandler<Integer,ByteBuffer>() {
+					@Override
+					public void completed(Integer result, ByteBuffer attachment) {
+						// System.out.println("Result = " + result + " Limit = " + attachment.limit());
+						if ( result != -1 ) {
+						attachment.flip();
+						byte[] data = new byte[attachment.limit()];
+						attachment.get( data );
+						//System.out.println(new String(data));
+						for (int i = 0; i < data.length; i++ ) {
+							if ( data[i] == '\n' )
+								theCount++;
+							//System.out.println("data: " + data[i]);
+						}
+						// System.out.println("position: " + readPosition + " Count: " + theCount);
+						readPosition += data.length;
+						attachment.clear();
+						} else {
+							doContinue = false;
+						}
+						partialReadGate.release();
 					}
-					attachment.clear();
-				}
-			
-				@Override
-				public void failed(Throwable exc, ByteBuffer attachment) {
-				}
-			});
+				
+					@Override
+					public void failed(Throwable exc, ByteBuffer attachment) {
+					}
+				});
+			}
 		} catch (IOException e) {
 			// TODO Auto-generated catch block
 			e.printStackTrace();