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我正在编写一个 Java 程序，如果它包含 OCCURS 子句，我必须在其中扩展 COBOL 字帖。

OCCURS 关键字旁边的数字定义了 OCCURS 子句的子行重复。第一个行数定义级别。一个 OCCURS 可能有多个子元素。假设输入字帖如下所示：

01 TEST-REC.
05 VAR1 PIC X(02).
05 VAR2 OCCURS 2.
    10 VAR3 PIC X(3).
05 VAR6 PIC X(02).

那么输出应该是（忽略输入的第一行）：

05 VAR1 PIC X(02).
10 VAR3 PIC X(3).
10 VAR3 PIC X(3).
05 VAR6 PIC X(02).

我已经编写了以下代码来处理这个问题，它工作正常。

public class Test{

    private static String copyBookExpansaion = "";
    private static BufferedReader br1 = null;

    public static void parseLine() throws IOException{
      String line;
      while((line = br1.readLine()) != null){
          if(line.indexOf(" OCCURS ") == -1){
              copyBookExpansaion = copyBookExpansaion + line.trim() + "\n";
          }
          else{
              String s[] = line.trim().replaceAll(" +"," ").split(" ");
              int size = Integer.parseInt(s[3].replaceAll("[^0-9]", ""));
              line  = br1.readLine();
              for(int i = 0; i < size;i++){
                    copyBookExpansaion = copyBookExpansaion + line.trim() + "\n";
              }
          }
      }
      return;
  }

  /**
   * @param args
   * @throws IOException 
   */
  public static void main(String[] args) throws IOException {
      // TODO Auto-generated method stub

      FileInputStream copyBook= new FileInputStream("C:\\Users\\DadMadhR\\Desktop\\temp\\copybook\\test_Copybook.cpy");
      br1 = new BufferedReader(new InputStreamReader(copyBook));
      br1.readLine();
      parseLine();
      System.out.println(copyBookExpansaion);

  }

}

我无法处理嵌套的 OCCURS 子句。假设我的输入如下所示：

01 TEST-REC.
05 VAR1 PIC X(02).
05 VAR2 OCCURS 2.
    10 VAR3 PIC X(3).
    10 VAR4 OCCURS 2.
        15 VAR5 PIC X(2).
05 VAR6 PIC X(02).

那么输出应该如下所示：

05 VAR1 PIC X(02).
10 VAR3 PIC X(3).
15 VAR5 PIC X(2).
15 VAR5 PIC X(2).
10 VAR3 PIC X(3).
15 VAR5 PIC X(2).
15 VAR5 PIC X(2).
05 VAR6 PIC X(02).

嵌套 OCCURS 的数量没有限制。我没有得到处理嵌套 OCCURS 的方法。

任何人都可以提出一种处理这种情况的方法吗？

4

1 回答 1

1

尝试这个

步骤 1. 制作树状结构。每条线都有一个父级。父级 (01, 05, ...) 小于行级。所以结构是

01 TEST-REC.
 |
 +--05 VAR1 PIC X(02).
 |
 +--05 VAR2 OCCURS 2.
 |   |
 |   +--10 VAR3 PIC X(3).
 |   |
 |   +--10 VAR4 OCCURS 2.
 |       |
 |       +--15 VAR5 PIC X(2).
 |
 +--05 VAR6 PIC X(02).

步骤 2. 将结构写入流。(a) 如果该行包含PIC则写自行。(b) 递归地写出每个孩子。（如果该行包含OCCURS N则重复 N 次。）

public class Test {

    static class Node {

        final int level;
        final String line;
        final List<Node> children = new ArrayList<>();

        Node(int level, String line) {
            this.level = level;
            this.line = line;
        }

        void write(PrintStream out) {
            int n = 1;
            if (line.contains("OCCURS"))
                n = Integer.parseInt(line.replaceAll("^.* |[^\\d]*$", ""));
            if (line.contains("PIC"))
                out.println(line);
            for (int i = 0; i < n; ++i)
                for (Node child : children)
                    child.write(out);
        }

    }

    static Node parse(String inputFile) throws IOException {
        try (BufferedReader reader = new BufferedReader(
                new InputStreamReader(new FileInputStream(inputFile)))) {
            List<Node> lines = new ArrayList<>();
            String line;
            int no = 0;
            while ((line = reader.readLine()) != null) {
                ++no;
                line = line.trim();
                int level = Integer.parseInt(line.replaceFirst("\\s.*", ""));
                Node child = new Node(level, line);
                if (lines.size() > 0) {
                    boolean found = false;
                    for (int i = lines.size() - 1; i >= 0; --i) {
                        Node parent = lines.get(i);
                        if (parent.level < level) {
                            parent.children.add(child);
                            found = true;
                            break;
                        }
                    }
                    if (!found)
                        throw new RuntimeException(
                            "parent not found for line " + no + " : " + line);
                }
                lines.add(child);
            }
            return lines.get(0);
        }
    }

    public static void main(String[] args) throws IOException {
        // Step 1
        Node top = parse("C:\\Users\\DadMadhR\\Desktop\\temp\\copybook\\test_Copybook.cpy");
        // Step 2
        top.write(System.out);
    }

}
于 2016-01-25T10:25:25.050 回答