Java tutorial
// // Copyright (c) 2014 VK.com // // Permission is hereby granted, free of charge, to any person obtaining a copy of // this software and associated documentation files (the "Software"), to deal in // the Software without restriction, including without limitation the rights to // use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of // the Software, and to permit persons to whom the Software is furnished to do so, // subject to the following conditions: // // The above copyright notice and this permission notice shall be included in all // copies or substantial portions of the Software. // // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS // FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR // COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER // IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN // CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. // package com.vk.sdk.api.model; import android.os.Parcelable; import org.json.JSONArray; import org.json.JSONException; import org.json.JSONObject; import java.lang.reflect.*; /** * Collection of helpers to parse server responses. */ class ParseUtils { private ParseUtils() { } /** * Parse boolean from server response. * * @param from server response like this format: {@code response: 1} * @throws JSONException if server response is not valid */ public static boolean parseBoolean(String from) throws JSONException { return new JSONObject(from).optInt("response", 0) == 1; } /** * Parse boolean from JSONObject with given name. * * @param from server response like this format: {@code field: 1} * @param name name of field to read */ public static boolean parseBoolean(JSONObject from, String name) { return from != null && from.optInt(name, 0) == 1; } /** * Parse int from JSONObject with given name. * * @param from server response like this format: {@code field: 34} * @param name name of field to read */ public static int parseInt(JSONObject from, String name) { if (from == null) return 0; return from.optInt(name, 0); } /** * Parse int from server response. * * @param from server response like this format: {@code response: 34} * @throws JSONException if server response is not valid */ public static int parseInt(String from) throws JSONException { if (from == null) return 0; return new JSONObject(from).optInt("response"); } /** * Parse long from JSONObject with given name. * * @param from server response like this format: {@code field: 34} * @param name name of field to read */ public static long parseLong(JSONObject from, String name) { if (from == null) return 0; return from.optLong(name, 0); } /** * Parse int array from JSONObject with given name. * * @param from int JSON array like this one {@code {11, 34, 42}} */ public static int[] parseIntArray(JSONArray from) { int[] result = new int[from.length()]; for (int i = 0; i < result.length; i++) { result[i] = from.optInt(i); } return result; } /** * Returns root JSONObject from server response * * @param source standart VK server response * @throws JSONException if source is not valid */ public static JSONObject rootJSONObject(String source) throws JSONException { return new JSONObject(source).getJSONObject("response"); } /** * Returns root JSONArray from server response * * @param source standart VK server response * @throws JSONException if source is not valid */ public static JSONArray rootJSONArray(String source) throws JSONException { return new JSONObject(source).getJSONArray("response"); } /** * Parses object with follow rules: * * 1. All fields should had a public access. * 2. The name of the filed should be fully equal to name of JSONObject key. * 3. Supports parse of all Java primitives, all {@link String}, * arrays of primitive types, {@link String}s and {@link com.vk.sdk.api.model.VKApiModel}s, * list implementation line {@link com.vk.sdk.api.model.VKList}, {@link com.vk.sdk.api.model.VKAttachments.VKAttachment} or {@link com.vk.sdk.api.model.VKPhotoSizes}, * {@link com.vk.sdk.api.model.VKApiModel}s. * * 4. Boolean fields defines by vk_int == 1 expression. * @param object object to initialize * @param source data to read values * @return initialized according with given data object * @throws JSONException if source object structure is invalid */ @SuppressWarnings({ "rawtypes", "unchecked" }) public static <T> T parseViaReflection(T object, JSONObject source) throws JSONException { if (source.has("response")) { source = source.optJSONObject("response"); } if (source == null) { return object; } for (Field field : object.getClass().getFields()) { field.setAccessible(true); String fieldName = field.getName(); Class<?> fieldType = field.getType(); Object value = source.opt(fieldName); if (value == null) { continue; } try { if (fieldType.isPrimitive() && value instanceof Number) { Number number = (Number) value; if (fieldType.equals(int.class)) { field.setInt(object, number.intValue()); } else if (fieldType.equals(long.class)) { field.setLong(object, number.longValue()); } else if (fieldType.equals(float.class)) { field.setFloat(object, number.floatValue()); } else if (fieldType.equals(double.class)) { field.setDouble(object, number.doubleValue()); } else if (fieldType.equals(boolean.class)) { field.setBoolean(object, number.intValue() == 1); } else if (fieldType.equals(short.class)) { field.setShort(object, number.shortValue()); } else if (fieldType.equals(byte.class)) { field.setByte(object, number.byteValue()); } } else { Object result = field.get(object); if (value.getClass().equals(fieldType)) { result = value; } else if (fieldType.isArray() && value instanceof JSONArray) { result = parseArrayViaReflection((JSONArray) value, fieldType); } else if (VKPhotoSizes.class.isAssignableFrom(fieldType) && value instanceof JSONArray) { Constructor<?> constructor = fieldType.getConstructor(JSONArray.class); result = constructor.newInstance((JSONArray) value); } else if (VKAttachments.class.isAssignableFrom(fieldType) && value instanceof JSONArray) { Constructor<?> constructor = fieldType.getConstructor(JSONArray.class); result = constructor.newInstance((JSONArray) value); } else if (VKList.class.equals(fieldType)) { ParameterizedType genericTypes = (ParameterizedType) field.getGenericType(); Class<?> genericType = (Class<?>) genericTypes.getActualTypeArguments()[0]; if (VKApiModel.class.isAssignableFrom(genericType) && Parcelable.class.isAssignableFrom(genericType) && Identifiable.class.isAssignableFrom(genericType)) { if (value instanceof JSONArray) { result = new VKList((JSONArray) value, genericType); } else if (value instanceof JSONObject) { result = new VKList((JSONObject) value, genericType); } } } else if (VKApiModel.class.isAssignableFrom(fieldType) && value instanceof JSONObject) { result = ((VKApiModel) fieldType.newInstance()).parse((JSONObject) value); } field.set(object, result); } } catch (InstantiationException e) { throw new JSONException(e.getMessage()); } catch (IllegalAccessException e) { throw new JSONException(e.getMessage()); } catch (NoSuchMethodException e) { throw new JSONException(e.getMessage()); } catch (InvocationTargetException e) { throw new JSONException(e.getMessage()); } catch (NoSuchMethodError e) { // ?????????? ???????: // ?? ?? ????????, ?? ? ????????? ???????? getFields() ???????? ??? ???. // ?????? ? ??????? ???????????, ????????? ?? ? ????????, ?????? Android ? ???????? ????????? ??????????. throw new JSONException(e.getMessage()); } } return object; } /** * Parses array from given JSONArray. * Supports parsing of primitive types and {@link com.vk.sdk.api.model.VKApiModel} instances. * @param array JSONArray to parse * @param arrayClass type of array field in class. * @return object to set to array field in class * @throws JSONException if given array have incompatible type with given field. */ private static Object parseArrayViaReflection(JSONArray array, Class arrayClass) throws JSONException { Object result = Array.newInstance(arrayClass.getComponentType(), array.length()); Class<?> subType = arrayClass.getComponentType(); for (int i = 0; i < array.length(); i++) { try { Object item = array.opt(i); if (VKApiModel.class.isAssignableFrom(subType) && item instanceof JSONObject) { VKApiModel model = (VKApiModel) subType.newInstance(); item = model.parse((JSONObject) item); } Array.set(result, i, item); } catch (InstantiationException e) { throw new JSONException(e.getMessage()); } catch (IllegalAccessException e) { throw new JSONException(e.getMessage()); } catch (IllegalArgumentException e) { throw new JSONException(e.getMessage()); } } return result; } }