MyJSONParser.java

package com.android4;

import java.lang.reflect.Array;
import java.lang.reflect.Field;
import java.lang.reflect.Modifier;

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

/**
 * Parses any class to JSON and populates any class from JSON using Android native JSON, without any third-party libraries.
 *
 * @author Ender Muab'Dib
 *
 */
public class MyJSONParser {
    private static int privacy = 2;

    /**
     * p = 0 --> Only for public fields
     * p = 1 --> Only for public + protected fields
     * p = 2 --> All fields: public + protected + private. Use only under your own responsability.
     */
    public static void setPrivacyLevel(int p) {
    if ((p >= 0) && (p <= 2)) {
        privacy = p;
    }
    }

    /**
     * privacy = 0 --> Only for public fields
     * privacy = 1 --> Only for public + protected fields
     * privacy = 2 --> All fields: public + protected + private. Use only under your own responsability.
     */
    public static int getPrivacyLevel() {
    return privacy;
    }

    /**
     * @return an object of type classname with its PUBLIC fields full with the js info
     */
    public static Object populateObjectFromJSON(Class<?> classname, JSONObject js) {
    Object obj = null;
    System.out.println("Populating " + classname.getSimpleName() + " -with- " + js.toString());
    try {
        obj = classname.newInstance();
    } catch (InstantiationException e1) {
        System.err.println(e1.getMessage());
        return null;
    } catch (IllegalAccessException e1) {
        System.err.println(e1.getMessage());
        return null;
    }

    Field[] fields;

    if (privacy == 0) {
        fields = classname.getFields();
    } else {
        fields = classname.getDeclaredFields();
    }

    for (Field f : fields) {
        // System.out.println("Declared " + f.getName());

        if ((privacy == 2) && (Modifier.isPrivate(f.getModifiers()))) {
        f.setAccessible(true);
        }

        try {
        if (js.has(f.getName())) {
            String type = f.getType().getSimpleName();
            if (type.equalsIgnoreCase("boolean")) {
            f.setBoolean(obj, js.getBoolean(f.getName()));
            } else if (type.equalsIgnoreCase("int")) {
            f.setInt(obj, js.getInt(f.getName()));
            } else if (type.equalsIgnoreCase("double")) {
            f.setDouble(obj, js.getDouble(f.getName()));
            } else if (type.equalsIgnoreCase("float")) {
            f.setFloat(obj, (float) js.getDouble(f.getName()));
            } else if (type.equalsIgnoreCase("string")) {
            f.set(obj, js.getString(f.getName()));
            } else if (f.getType().isArray()) {
            f.set(obj, Array.newInstance(f.getType().getComponentType(), js.getJSONArray(f.getName()).length()));
            insertArrayFromJSON(f.get(obj), js.getJSONArray(f.getName()));
            } else {
            f.set(obj, populateObjectFromJSON(f.getType(), js.getJSONObject(f.getName())));
            }
        }
        } catch (IllegalArgumentException e) {
        System.err.println(e.getMessage());
        } catch (IllegalAccessException e) {
        System.err.println(e.getMessage());
        } catch (JSONException e) {
        System.err.println(e.getMessage());
        }

        if ((privacy == 2) && (Modifier.isPrivate(f.getModifiers()))) {
        f.setAccessible(false);
        }
    }

    return obj;
    }

    /**
     * @param o
     *            This object will be fill up with the JSONArray js data
     */
    public static void insertArrayFromJSON(Object o, JSONArray js) throws IllegalArgumentException, NegativeArraySizeException, IllegalAccessException, JSONException {
    Class<?> c = o.getClass();

    String type = c.getComponentType().getSimpleName();

    for (int i = 0; i < js.length(); i++) {
        if (c.getComponentType().isArray()) {
        Array.set(o, i, Array.newInstance(c.getComponentType().getComponentType(), js.getJSONArray(i).length()));
        insertArrayFromJSON(Array.get(o, i), js.getJSONArray(i));
        } else if (!c.getComponentType().isPrimitive() && (!type.equalsIgnoreCase("string"))) {
        Array.set(o, i, populateObjectFromJSON(c.getComponentType(), js.getJSONObject(i)));
        } else {
        Array.set(o, i, js.get(i));
        }
    }
    }

    /**
     * @param obj Object to convert in JSON format
     * @return JSONOBject with all obj initialited AND PUBLIC fields.
     */
    public static JSONObject parseObjectToJSONClass(Object obj) {
    JSONObject js = new JSONObject();

    Class<?> c = obj.getClass();

    Field[] fields;

    if (privacy == 0) {
        fields = c.getFields();
    } else {
        fields = c.getDeclaredFields();
    }

    for (Field f : fields) {
        if ((privacy == 2) && (Modifier.isPrivate(f.getModifiers()))) {
        f.setAccessible(true);
        }

        try {
        System.out.println(f.getName() + " - " + f.getType().getSimpleName() + " - " + f.get(obj));

        String name = f.getName();
        String type = f.getType().getSimpleName();
        if (f.get(obj) != null) {
            if (type.equalsIgnoreCase("boolean")) {
            js.put(name, f.getBoolean(obj));
            } else if (type.equalsIgnoreCase("int")) {
            js.put(name, f.getInt(obj));
            } else if (type.equalsIgnoreCase("double")) {
            js.put(name, f.getDouble(obj));
            } else if (type.equalsIgnoreCase("float")) {
            js.put(name, f.getFloat(obj));
            } else if (type.equalsIgnoreCase("string")) {
            js.put(name, (String) f.get(obj));
            } else if (type.endsWith("]")) {
            js.put(name, generateJSONArray(f.get(obj)));
            } else {
            js.put(name, parseObjectToJSONClass(f.get(obj)));
            }
        }
        } catch (IllegalArgumentException e) {
        System.err.println(e.getMessage());
        } catch (IllegalAccessException e) {
        System.err.println(e.getMessage());
        } catch (JSONException e) {
        System.err.println(e.getMessage());
        }

        if ((privacy == 2) && (Modifier.isPrivate(f.getModifiers()))) {
        f.setAccessible(false);
        }
    }

    return js;
    }

    /**
     *
     * @param o  Array object to convert in JSONArray format
     * @return a JSONArray with all the o components.
     */
    public static JSONArray generateJSONArray(Object o) throws ArrayIndexOutOfBoundsException, IllegalArgumentException, JSONException {
    JSONArray ar = new JSONArray();
    for (int i = 0; i < Array.getLength(o); i++) {
        if (Array.get(o, i).getClass().isArray()) {
        ar.put(i, generateJSONArray(Array.get(o, i)));
        } else {
        ar.put(i, Array.get(o, i));
        }
    }
    return ar;
    }
}