FileTask.java

package seven;

import java.nio.file.Path;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.RecursiveTask;
import java.util.stream.Collector;
import java.util.stream.Collectors;
import java.util.stream.IntStream;

/**
 * Created by Administrator on 2016/11/26 0026.
 */
public class FileTask extends RecursiveTask<Long> {
    Path path;
    List<String> lines;
    String word;
    int start;
    int end;
    static final int THRESHOLD = 2;

    public FileTask(Path path, List<String> lines, int start, int end, String word) {
        this.path = path;
        this.lines = lines;
        this.word = word;
        this.start = start;
        this.end = end;
    }

    @Override
    protected Long compute() {
        long sum = 0;// 结果 模板代码
        boolean canCompute = (end - start) < THRESHOLD;//模板代码
        if (canCompute) {//模板代码
            //开始计算
            sum = lines.subList(start, end).stream().filter(i -> i.contains(word)).count();
        } else {//模板代码
            int taskNumber = 1;
            int step = (start + end) / taskNumber;
            ArrayList<FileTask> subTasks = new ArrayList<>();
            int pos = start;
            for (int i = 0; i < taskNumber; ++i) {
                int lastOne = pos + step;
                if (lastOne > end) {
                    lastOne = end;
                }
                if((lastOne-pos)<0){
                    System.out.println("====> ");
                }
                FileTask subTask = new FileTask(path,lines, pos, lastOne, word);
                pos += step + 1;
                subTasks.add(subTask);
                subTask.fork();
            }
            for (FileTask task : subTasks) {
                //开始计算 reduce
                sum+=task.join();
            }
        }
        return sum;
    }

    long count(List<String> line, int start, int end, String word) {
        return IntStream.range(start, end).filter(i -> line.get(i).equals(word)).count();
    }
}