Finder.java

Finder.java

package com.example.util;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Finder extends LinkedHashMap<String, Object> {
    public Finder(Map<String, Object> origianl) {
        super(origianl);
    }

    public Finder() {

    }

    public Finder findChild(String path) {
        Map map = find(path);
        return new Finder(map);
    }

    public <T> T find(String path, T defaultValue) {
        Object ele = (defaultValue instanceof String) ? findAsString(path) : find(path);
        ele = ele != null ? ele : defaultValue;
        return (T) ele;
    }

    public String findAsString(String path) {
        Object obj = find(path);
        return obj != null ? String.valueOf(obj) : null;
    }

    public static final Pattern ROUTE = Pattern.compile("([^\\.\\[\\]]+|\\[\\d+\\])");

    public <T> T find(String path) {
        Object ele = this;
        final Matcher matcher = ROUTE.matcher(path);
        Iterator<String> it = new Iterator<String>() {

            @Override
            public boolean hasNext() {
                return matcher.find();
            }

            @Override
            public String next() {
                return matcher.group();
            }

            @Override
            public void remove() {

            }
        };
        while (it.hasNext()) {
            String key = it.next();
            if (key.startsWith("[")) {
                ele = ((List) ele).get(Integer.parseInt(key.substring(1, key.length() - 1)));
            } else {
                ele = ((Map) ele).get(key);
            }
            if (ele == null) {
                break;
            }
        }
        return (T) ele;
    }


    public static Finder fromJSON(JSONObject object) throws JSONException {
        return new Finder(toMap(object));
    }

    protected static Map<String, Object> toMap(JSONObject object) throws JSONException {
        Map<String, Object> map = new LinkedHashMap<>();
        Iterator<String> keysItr = object.keys();
        while (keysItr.hasNext()) {
            String key = keysItr.next();
            Object value = object.get(key);

            if (value instanceof JSONArray) {
                value = toList((JSONArray) value);
            } else if (value instanceof JSONObject) {
                value = toMap((JSONObject) value);
            }
            map.put(key, value);
        }
        return map;
    }

    protected static List<Object> toList(JSONArray array) throws JSONException {
        List<Object> list = new ArrayList<>();
        for (int i = 0; i < array.length(); i++) {
            Object value = array.get(i);
            if (value instanceof JSONArray) {
                value = toList((JSONArray) value);
            } else if (value instanceof JSONObject) {
                value = toMap((JSONObject) value);
            }
            list.add(value);
        }
        return list;
    }
}