解析Java中的缩进文本树

Question

我有一个缩进文件，需要使用java进行解析，我需要一些方法将其放在Section类中，如下所示

    root
     root1
       text1
         text1.1
         text1.2
       text2
         text2.1
         text2.2

     root2
       text1
         text1.1
         text1.2
       text2
         text2.1
         text2.2.2

我有上课的地方像缩进的东西

public class Section 
{

    private List<Section> children;
    private String text;
    private int depth;
    public Section(String t)
    {
       text =t;
    }

    public List<Section> getChildren()
    {
        if (children == null)
      {
            children = new ArrayList<Section>();
       }
        return children;
}

public void setChildren(List<Section> newChildren)
{
    if (newChildren == null) {
        children = newChildren;
    } else {
        if (children == null) {
            children = new ArrayList<Section>();
        }
        for (Section child : newChildren) {
            this.addChild(child);
        }
    }
}

public void addChild(Section child)
{
    if (children == null) {
        children = new ArrayList<Section>();
    }
    if (child != null) {
        children.add(child);
    }
}

public String getText()
{
    return text;
}

public void setText(String newText)
{
    text =newText;
}
public String getDepth()
{
    return depth;
}

 public void setDepth(int newDepth)
 {
    depth = newDepth;
 }
}

我需要一些方法来解析文件并将其放在预期的结果中，这是我们的Section对象，如下所示

Section= 

Text="Root"
Children
Child1: Text= "root1" 

        Child1: "text1"
            Child1="Text 1.1"
            Child2="Text 1.2"
        Child2: "text2"
            Child1="Text 2.1"
            Child2="Text 2.2"
            Children
Child2: Text= "root2" 
        Child1: "text1"
            Child1="Text 1.1"
            Child2="Text 1.2"
        Child2: "text2"
            Child1="Text 2.1"
            Child2="Text 2.2"


Here is some code that I have started
   int indentCount=0;
   while(String text = reader.readline()
   {
   indentCount=countLeadingSpaces(String word);
   //TODO create the section here
   }


public static int countLeadingSpaces(String word)
{
    int length=word.length();
    int count=0;

   for(int i=0;i<length;i++)
   {
       char first = word.charAt(i); 
        if(Character.isWhitespace(first))
        {
            count++;           
        }
        else
        {
            return count;
        }
   }

 return count;

}

Answer 1

我还添加了一个父指针。也许没有它也可以解析文本，但是父指针使它更容易。首先，你需要有更多的构造函数：

static final int root_depth = 4; // assuming 4 whitespaces precede the tree root

public Section(String text, int depth) {
    this.text     = text;
    this.depth    = depth;
    this.children = new ArrayList<Section>();
    this.parent   = null;
}

public Section(String text, int depth, Section parent) {
    this.text     = text;
    this.depth    = depth;
    this.children = new ArrayList<Section>();
    this.parent   = parent;
}

然后，当您开始解析文件时，逐行读取它：

Section prev = null;
for (String line; (line = bufferedReader.readLine()) != null; ) {
    if (prev == null && line begins with root_depth whitespaces) {
        Section root = new Section(text_of_line, root_depth);
        prev = root;
    }
    else {
        int t_depth = no. of whitespaces at the beginning of this line;
        if (t_depth > prev.getDepth())
            // assuming that empty sections are not allowed
            Section t_section = new Section(text_of_line, t_depth, prev);
            prev.addChild(t_section);
        }
        else if (t_depth == prev.getDepth) {
            Section t_section = new Section(text_of_line, t_depth, prev.getParent());
            prev.getParent().addChild(t_section);
        }
        else {
            while (t_depth < prev.getDepth()) {
                prev = prev.getParent();
            }
            // at this point, (t_depth == prev.getDepth()) = true
            Section t_section = new Section(text_of_line, t_depth, prev.getParent());
            prev.getParent().addChild(t_section);
        }
    }
}

我已经掩盖了伪代码的一些细节，但我认为您已经了解了如何进行此解析的总体思路。请记住实现 addChild()、getDepth()、getParent() 等方法。