Jsonator

Jsonator.java

package com.mysite.model.entities;

import java.io.Serializable;
import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import org.json.simple.JSONArray;
import org.json.simple.JSONObject;

/**
 *
 * @author Cecil.Meeks
 */
public abstract class Jsonator<T> implements Serializable {

    private Class<T> entityClass;
    private JSONObject json;
    private JSONArray jsonArray;

    public Jsonator(Class<T> entityClass) {
        this.entityClass = entityClass;
        this.json = new JSONObject();
        this.jsonArray = new JSONArray();
    }

    public void convert(List<T> paObjectList) throws IllegalArgumentException, IllegalAccessException {
        convert(paObjectList, null);
    }

    public void convert(List<T> paObjectList, String[] paExcludedColumns) throws IllegalArgumentException, IllegalAccessException {
        try {

            int count = paObjectList.size();
            
            // convert the String array to an ArrayList.  Makes it easier to find keys
            List<String> excludedList = new ArrayList<String>();
            if (paExcludedColumns != null) {
                excludedList.addAll(Arrays.asList(paExcludedColumns));
            }

            for (Object obj : paObjectList) {
                Class<?> kls = obj.getClass();

                JSONObject objJson = new JSONObject();

                Field[] fields = kls.getDeclaredFields();
                for (Field field : fields) {
                    if (excludedList.size() > 0) {
                        if (!excludedList.contains(field.getName())) {
                            field.setAccessible(true);
                            objJson.put(field.getName(), field.get(obj));
                        }
                    } else {
                        field.setAccessible(true);
                        objJson.put(field.getName(), field.get(obj));
                    }
                }

                jsonArray.add(objJson);
            }

            json.put("count", count);
            json.put("message", "Successfully found " + count + " records.");
            json.put("results", jsonArray);
            json.put("success", true);

        }
        catch (IllegalArgumentException ex) {
            appendError("There was a problem.  Please contact support.", "IllegalArgumentException");
        }
        catch (IllegalAccessException ex) {
            appendError("There was a problem.  Please contact support.", "IllegalAccessException");
        }
        catch (SecurityException ex) {
            appendError("There was a problem.  Please contact support.", "SecurityException");
        }
        catch (Exception ex) {
            appendError("There was a problem.  Please contact support.", "Exception");
        }
    }

    public String results() {
        return json.toJSONString();
    }

    private void appendError(String paMessage, String paException) {
        if (!json.containsKey("success")) {
            json.put("success", false);
        }

        if (!json.containsKey("message")) {
            json.put("message", paMessage);
        }

        if (!json.containsKey("exception")) {
            json.put("exception", paException);
        }

        if (!json.containsKey("results")) {
            json.put("results", new JSONArray());
        }
    }
}