130 lines
3.3 KiB
Java
130 lines
3.3 KiB
Java
package threadPool;
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import java.io.*;
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import java.util.*;
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import java.util.concurrent.*;
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/**
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* @version 1.02 2015-06-21
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* @author Cay Horstmann
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*/
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public class ThreadPoolTest
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{
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public static void main(String[] args) throws Exception
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{
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try (Scanner in = new Scanner(System.in))
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{
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System.out.print("Enter base directory (e.g. /usr/local/jdk5.0/src): ");
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String directory = in.nextLine();
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System.out.print("Enter keyword (e.g. volatile): ");
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String keyword = in.nextLine();
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ExecutorService pool = Executors.newCachedThreadPool();
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MatchCounter counter = new MatchCounter(new File(directory), keyword, pool);
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Future<Integer> result = pool.submit(counter);
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try
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{
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System.out.println(result.get() + " matching files.");
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}
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catch (ExecutionException e)
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{
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e.printStackTrace();
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}
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catch (InterruptedException e)
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{
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}
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pool.shutdown();
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int largestPoolSize = ((ThreadPoolExecutor) pool).getLargestPoolSize();
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System.out.println("largest pool size=" + largestPoolSize);
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}
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}
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}
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/**
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* This task counts the files in a directory and its subdirectories that contain a given keyword.
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*/
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class MatchCounter implements Callable<Integer>
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{
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private File directory;
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private String keyword;
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private ExecutorService pool;
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private int count;
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/**
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* Constructs a MatchCounter.
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* @param directory the directory in which to start the search
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* @param keyword the keyword to look for
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* @param pool the thread pool for submitting subtasks
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*/
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public MatchCounter(File directory, String keyword, ExecutorService pool)
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{
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this.directory = directory;
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this.keyword = keyword;
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this.pool = pool;
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}
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public Integer call()
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{
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count = 0;
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try
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{
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File[] files = directory.listFiles();
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List<Future<Integer>> results = new ArrayList<>();
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for (File file : files)
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if (file.isDirectory())
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{
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MatchCounter counter = new MatchCounter(file, keyword, pool);
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Future<Integer> result = pool.submit(counter);
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results.add(result);
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}
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else
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{
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if (search(file)) count++;
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}
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for (Future<Integer> result : results)
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try
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{
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count += result.get();
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}
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catch (ExecutionException e)
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{
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e.printStackTrace();
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}
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}
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catch (InterruptedException e)
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{
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}
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return count;
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}
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/**
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* Searches a file for a given keyword.
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* @param file the file to search
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* @return true if the keyword is contained in the file
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*/
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public boolean search(File file)
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{
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try
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{
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try (Scanner in = new Scanner(file, "UTF-8"))
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{
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boolean found = false;
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while (!found && in.hasNextLine())
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{
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String line = in.nextLine();
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if (line.contains(keyword)) found = true;
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}
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return found;
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}
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}
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catch (IOException e)
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{
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return false;
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}
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}
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} |