Data commit

Task/Synchronous-concurrency/Java/synchronous-concurrency.java

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+import java.io.BufferedReader;
+import java.io.FileReader;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.LinkedBlockingQueue;
+
+class SynchronousConcurrency
+{
+  public static void main(String[] args) throws Exception
+  {
+    final AtomicLong lineCount = new AtomicLong(0);
+    final BlockingQueue<String> queue = new LinkedBlockingQueue<String>();
+    final String EOF = new String();
+
+    final Thread writerThread = new Thread(new Runnable() {
+        public void run()
+        {
+          long linesWrote = 0;
+          while (true)
+          {
+            try
+            {
+              String line = queue.take();
+              // Reference equality
+              if (line == EOF)
+                break;
+              System.out.println(line);
+              linesWrote++;
+            }
+            catch (InterruptedException ie)
+            {  }
+          }
+          lineCount.set(linesWrote);
+        }
+      }
+    );
+    writerThread.start();
+
+    // No need to start a third thread for the reader, just use this thread
+    BufferedReader br = new BufferedReader(new FileReader("input.txt"));
+    String line;
+    while ((line = br.readLine()) != null)
+      queue.put(line);
+    br.close();
+    queue.put(EOF);
+    writerThread.join();
+    // AtomicLong is not needed here due to memory barrier created by thread join, but still need a mutable long since lineCount must be final to access it from an anonymous class
+    System.out.println("Line count: " + lineCount.get());
+    return;
+  }
+}