corejava第10版

corejava第10版/v1ch14/blockingQueue/BlockingQueueTest.java

@@ -0,0 +1,101 @@
+package blockingQueue;
+
+import java.io.*;
+import java.util.*;
+import java.util.concurrent.*;
+
+/**
+ * @version 1.02 2015-06-21
+ * @author Cay Horstmann
+ */
+public class BlockingQueueTest
+{
+   private static final int FILE_QUEUE_SIZE = 10;
+   private static final int SEARCH_THREADS = 100;
+   private static final File DUMMY = new File("");
+   private static BlockingQueue<File> queue = new ArrayBlockingQueue<>(FILE_QUEUE_SIZE);
+
+   public static void main(String[] args)
+   {
+      try (Scanner in = new Scanner(System.in)) 
+      {
+         System.out.print("Enter base directory (e.g. /opt/jdk1.8.0/src): ");
+         String directory = in.nextLine();
+         System.out.print("Enter keyword (e.g. volatile): ");
+         String keyword = in.nextLine();
+          
+         Runnable enumerator = () -> {
+            try
+            {
+               enumerate(new File(directory));
+               queue.put(DUMMY);
+            }
+            catch (InterruptedException e)
+            {
+            }            
+         };
+         
+         new Thread(enumerator).start();
+         for (int i = 1; i <= SEARCH_THREADS; i++) {
+            Runnable searcher = () -> {
+               try
+               {
+                  boolean done = false;
+                  while (!done)
+                  {
+                     File file = queue.take();
+                     if (file == DUMMY)
+                     {
+                        queue.put(file);
+                        done = true;
+                     }
+                     else search(file, keyword);
+                  }
+               }
+               catch (IOException e)
+               {
+                  e.printStackTrace();
+               }
+               catch (InterruptedException e)
+               {
+               }               
+            };
+            new Thread(searcher).start();
+         }
+      }
+   }
+   
+   /**
+    * Recursively enumerates all files in a given directory and its subdirectories.
+    * @param directory the directory in which to start
+    */
+   public static void enumerate(File directory) throws InterruptedException
+   {
+      File[] files = directory.listFiles();
+      for (File file : files)
+      {
+         if (file.isDirectory()) enumerate(file);
+         else queue.put(file);
+      }
+   }
+   
+   /**
+    * Searches a file for a given keyword and prints all matching lines.
+    * @param file the file to search
+    * @param keyword the keyword to search for
+    */
+   public static void search(File file, String keyword) throws IOException
+   {
+      try (Scanner in = new Scanner(file, "UTF-8"))
+      {
+         int lineNumber = 0;
+         while (in.hasNextLine())
+         {
+            lineNumber++;
+            String line = in.nextLine();
+            if (line.contains(keyword)) 
+               System.out.printf("%s:%d:%s%n", file.getPath(), lineNumber, line);
+         }
+      }
+   }
+}