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/*
* This is part of Geomajas, a GIS framework, http://www.geomajas.org/.
*
* Copyright 2008-2015 Geosparc nv, http://www.geosparc.com/, Belgium.
*
* The program is available in open source according to the GNU Affero
* General Public License. All contributions in this program are covered
* by the Geomajas Contributors License Agreement. For full licensing
* details, see LICENSE.txt in the project root.
*/
package org.geomajas.gwt2.client.service;
import java.util.Date;
import org.geomajas.geometry.Coordinate;
import org.geomajas.geometry.Geometry;
import org.geomajas.gwt2.client.map.attribute.GeometryType;
import com.google.gwt.core.client.JavaScriptObject;
import com.google.gwt.core.client.JsonUtils;
import com.google.gwt.i18n.client.DateTimeFormat;
import com.google.gwt.i18n.client.DateTimeFormat.PredefinedFormat;
import com.google.gwt.json.client.JSONArray;
import com.google.gwt.json.client.JSONBoolean;
import com.google.gwt.json.client.JSONException;
import com.google.gwt.json.client.JSONNull;
import com.google.gwt.json.client.JSONNumber;
import com.google.gwt.json.client.JSONObject;
import com.google.gwt.json.client.JSONString;
import com.google.gwt.json.client.JSONValue;
/**
* Utility class for JSON related functionality.
*
* @author Pieter De Graef
* @author Jan De Moerloose
*/
public final class JsonService {
// Specific date formatter for communication with back-end rest.
// TODO provide a way to override this default.
private static final DateTimeFormat DEFAULT_DATEFORMAT = DateTimeFormat.getFormat(PredefinedFormat.ISO_8601);
private JsonService() {
// No public constructors for final classes.
}
/**
* Format the given date to a string. The idea is that this string can be used in a JSON object.
*
* @param date The date to format.
* @return The formatted date-string.
*/
public static String format(Date date) {
return DEFAULT_DATEFORMAT.format(date);
}
/**
* Takes in a trusted JSON String and evals it.
*
* @param jsonString JSON string that you trust.
* @return JavaScriptObject that you can cast to an Overlay Type
*/
public static JavaScriptObject eval(String jsonString) {
return JsonUtils.safeEval(jsonString);
}
/**
* Parse the given JSON string into a {@link JSONObject}.
*
* @param jsonString The trusted JSON string to parse.
* @return The JSON object that results from the parsed string.
* @throws JSONException Thrown in case something went wrong during parsing.
*/
public static JSONValue parse(String jsonString) throws JSONException {
if (jsonString == null || "".equals(jsonString)) {
return JSONNull.getInstance();
}
if (jsonString.charAt(0) == '[') {
return new JSONArray(eval(jsonString));
}
return new JSONObject(eval(jsonString));
}
/**
* Get a child JSON object from a parent JSON object.
*
* @param jsonObject The parent JSON object.
* @param key The name of the child object.
* @return Returns the child JSON object if it could be found, or null if the value was null.
* @throws JSONException In case something went wrong while searching for the child.
*/
public static JSONObject getChild(JSONObject jsonObject, String key) throws JSONException {
checkArguments(jsonObject, key);
JSONValue value = jsonObject.get(key);
if (value != null) {
if (value.isObject() != null) {
return value.isObject();
} else if (value.isNull() != null) {
return null;
}
throw new JSONException("Child is not a JSONObject, but a: " + value.getClass());
}
return null;
}
/**
* Get a child JSON array from a parent JSON object.
*
* @param jsonObject The parent JSON object.
* @param key The name of the child object.
* @return Returns the child JSON array if it could be found, or null if the value was null.
* @throws JSONException In case something went wrong while searching for the child.
*/
public static JSONArray getChildArray(JSONObject jsonObject, String key) throws JSONException {
checkArguments(jsonObject, key);
JSONValue value = jsonObject.get(key);
if (value != null) {
if (value.isArray() != null) {
return value.isArray();
} else if (value.isNull() != null) {
return null;
}
throw new JSONException("Child is not a JSONArray, but a: " + value.getClass());
}
return null;
}
/**
* Get a string value from a {@link JSONObject}.
*
* @param jsonObject The object to get the key value from.
* @param key The name of the key to search the value for.
* @return Returns the value for the key in the object or null.
* @throws JSONException Thrown in case the key could not be found in the JSON object.
*/
public static String getStringValue(JSONObject jsonObject, String key) throws JSONException {
checkArguments(jsonObject, key);
JSONValue value = jsonObject.get(key);
if (value != null) {
if (value.isString() != null) {
return ((JSONString) value).stringValue();
} else {
String valueString = value.toString();
if (!"null".equals(valueString)) {
if (valueString.charAt(0) == '"') {
return valueString.substring(1, valueString.length() - 1);
}
return valueString;
}
}
}
return null;
}
/**
* Get a character value from a {@link JSONObject}.
*
* @param jsonObject The object to get the key value from.
* @param key The name of the key to search the value for.
* @return Returns the value for the key in the object or null.
* @throws JSONException Thrown in case the key could not be found in the JSON object.
*/
public static Character getCharValue(JSONObject jsonObject, String key) throws JSONException {
String stringValue = getStringValue(jsonObject, key);
if (stringValue != null) {
return stringValue.charAt(0);
}
return null;
}
/**
* Get a date value from a {@link JSONObject}.
*
* @param jsonObject The object to get the key value from.
* @param key The name of the key to search the value for.
* @return Returns the value for the key in the object or null.
* @throws JSONException Thrown in case the key could not be found in the JSON object, or if the date could not be
* parsed correctly.
*/
public static Date getDateValue(JSONObject jsonObject, String key) throws JSONException {
checkArguments(jsonObject, key);
JSONValue value = jsonObject.get(key);
if (value != null && value.isString() != null) {
String dateString = getStringValue(jsonObject, key);
if (dateString.charAt(0) == '"') {
dateString = dateString.substring(1);
}
if (dateString.endsWith("\"")) {
dateString = dateString.substring(0, dateString.length() - 1);
}
try {
return DEFAULT_DATEFORMAT.parse(dateString);
} catch (Exception e) {
try {
long millis = Long.parseLong(dateString);
return new Date(millis);
} catch (Exception e2) {
throw new JSONException("Could not parse the date for key '" + key + "'", e);
}
}
}
return null;
}
/**
* Get a geometry value from a {@link JSONObject}.
*
* @param jsonObject The object to get the key value from.
* @param key The name of the key to search the value for.
* @return Returns the value for the key in the object or null.
* @throws JSONException Thrown in case the key could not be found in the JSON object, or if the date could not be
* parsed correctly.
*/
public static Geometry getGeometryValue(JSONObject jsonObject, String key) throws JSONException {
checkArguments(jsonObject, key);
JSONValue value = jsonObject.get(key);
if (value != null && value.isObject() != null) {
JSONObject obj = value.isObject();
String type = JsonService.getStringValue(obj, "type");
Geometry geometry = new Geometry(type, 0, 5);
JSONArray array = JsonService.getChildArray(obj, "coordinates");
switch (GeometryType.fromValue(type)) {
case POINT:
parseSimple(GeometryType.POINT, geometry, array);
break;
case LINESTRING:
parseSimple(GeometryType.LINEARRING, geometry, array);
break;
case MULTILINESTRING:
parseCollection(GeometryType.LINESTRING, geometry, array);
break;
case MULTIPOINT:
parseCollection(GeometryType.POINT, geometry, array);
break;
case MULTIPOLYGON:
parseCollection(GeometryType.POLYGON, geometry, array);
break;
case POLYGON:
parseCollection(GeometryType.LINEARRING, geometry, array);
break;
default:
break;
}
return geometry;
}
return null;
}
/**
* Get a integer value from a {@link JSONObject}.
*
* @param jsonObject The object to get the key value from.
* @param key The name of the key to search the value for.
* @return Returns the value for the key in the object .
* @throws JSONException Thrown in case the key could not be found in the JSON object.
*/
public static Integer getIntValue(JSONObject jsonObject, String key) throws JSONException {
checkArguments(jsonObject, key);
JSONValue value = jsonObject.get(key);
if (value != null && value.isNumber() != null) {
double number = ((JSONNumber) value).doubleValue();
return new Integer((int) number);
}
return null;
}
/**
* Get a double value from a {@link JSONObject}.
*
* @param jsonObject The object to get the key value from.
* @param key The name of the key to search the value for.
* @return Returns the value for the key in the object .
* @throws JSONException Thrown in case the key could not be found in the JSON object.
*/
public static Double getDoubleValue(JSONObject jsonObject, String key) throws JSONException {
checkArguments(jsonObject, key);
JSONValue value = jsonObject.get(key);
if (value != null && value.isNumber() != null) {
double number = ((JSONNumber) value).doubleValue();
return number;
}
return null;
}
/**
* Get a long value from a {@link JSONObject}.
*
* @param jsonObject The object to get the key value from.
* @param key The name of the key to search the value for.
* @return Returns the value for the key in the object .
* @throws JSONException Thrown in case the key could not be found in the JSON object.
*/
public static Long getLongValue(JSONObject jsonObject, String key) throws JSONException {
checkArguments(jsonObject, key);
JSONValue value = jsonObject.get(key);
if (value != null && value.isNumber() != null) {
double number = ((JSONNumber) value).doubleValue();
return new Long((long) number);
}
return null;
}
/**
* Get a short value from a {@link JSONObject}.
*
* @param jsonObject The object to get the key value from.
* @param key The name of the key to search the value for.
* @return Returns the value for the key in the object .
* @throws JSONException Thrown in case the key could not be found in the JSON object.
*/
public static Short getShortValue(JSONObject jsonObject, String key) throws JSONException {
checkArguments(jsonObject, key);
JSONValue value = jsonObject.get(key);
if (value != null && value.isNumber() != null) {
double number = ((JSONNumber) value).doubleValue();
return new Short((short) number);
}
return null;
}
/**
* Add a certain object value to the given JSON object.
*
* @param jsonObject The JSON object to add the value to.
* @param key The key to be used when adding the value.
* @param value The value to attach to the key in the JSON object.
* @throws JSONException In case something went wrong while adding.
*/
public static void addToJson(JSONObject jsonObject, String key, Object value) throws JSONException {
if (jsonObject == null) {
throw new JSONException("Can't add key '" + key + "' to a null object.");
}
if (key == null) {
throw new JSONException("Can't add null key.");
}
JSONValue jsonValue = null;
if (value != null) {
if (value instanceof Date) {
jsonValue = new JSONString(JsonService.format((Date) value));
} else if (value instanceof JSONValue) {
jsonValue = (JSONValue) value;
} else {
jsonValue = new JSONString(value.toString());
}
}
jsonObject.put(key, jsonValue);
}
/**
* checks if a certain object value is null.
*
* @param jsonObject The object to get the key value from.
* @param key The name of the key to search the value for.
* @throws JSONException In case something went wrong while parsing.
*/
public static boolean isNullObject(JSONObject jsonObject, String key) throws JSONException {
checkArguments(jsonObject, key);
JSONValue value = jsonObject.get(key);
boolean isNull = false;
if (value == null || value.isNull() != null) {
isNull = true;
}
return isNull;
}
/**
* Get a boolean value from a {@link JSONObject}.
*
* @param jsonObject The object to get the key value from.
* @param key The name of the key to search the value for.
* @return Returns the value for the key in the object .
* @throws JSONException Thrown in case the key could not be found in the JSON object.
*/
public static Boolean getBooleanValue(JSONObject jsonObject, String key) throws JSONException {
checkArguments(jsonObject, key);
JSONValue value = jsonObject.get(key);
Boolean result = null;
if (value != null && value.isBoolean() != null) {
return ((JSONBoolean) value).booleanValue();
}
return result;
}
// ------------------------------------------------------------------------
// Private methods:
// ------------------------------------------------------------------------
private static void checkArguments(JSONObject jsonObject, String key) throws JSONException {
if (key == null) {
throw new IllegalArgumentException("Can't go searching for a null key.");
}
if (jsonObject == null) {
throw new JSONException("Can't search for key '" + key + "' in a null object.");
}
if (!jsonObject.containsKey(key)) {
throw new JSONException("Key '" + key + "' could not be found.");
}
// Please, proceed...
}
private static void parseCollection(GeometryType type, Geometry geometry, JSONArray array) {
Geometry[] geometries = new Geometry[array.size()];
geometry.setGeometries(geometries);
for (int i = 0; i < array.size(); i++) {
switch (type) {
case POINT:
geometries[i] = new Geometry(Geometry.POINT, 0, 5);
parseSimple(GeometryType.POINT, geometries[i], array.get(i).isArray());
break;
case LINEARRING:
geometries[i] = new Geometry(Geometry.LINEAR_RING, 0, 5);
parseSimple(GeometryType.LINEARRING, geometries[i], array.get(i).isArray());
break;
case LINESTRING:
geometries[i] = new Geometry(Geometry.LINE_STRING, 0, 5);
parseSimple(GeometryType.LINESTRING, geometries[i], array.get(i).isArray());
break;
case POLYGON:
geometries[i] = new Geometry(Geometry.POLYGON, 0, 5);
parseCollection(GeometryType.LINEARRING, geometries[i], array.get(i).isArray());
break;
default:
break;
}
}
}
private static void parseSimple(GeometryType type, Geometry geometry, JSONArray array) {
Coordinate[] coords;
switch (type) {
case POINT:
coords = new Coordinate[1];
coords[0] = new Coordinate();
coords[0].setX(array.get(0).isNumber().doubleValue());
coords[0].setY(array.get(1).isNumber().doubleValue());
geometry.setCoordinates(coords);
break;
case LINEARRING:
case LINESTRING:
coords = new Coordinate[array.size()];
for (int i = 0; i < coords.length; i++) {
coords[i] = new Coordinate();
coords[i].setX(array.get(i).isArray().get(0).isNumber().doubleValue());
coords[i].setY(array.get(i).isArray().get(1).isNumber().doubleValue());
}
geometry.setCoordinates(coords);
break;
default:
break;
}
}
}
