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JSONWriter | 66 | 104 | 58 |
1 | package org.json; | |
2 | ||
3 | import java.io.IOException; | |
4 | import java.math.BigDecimal; | |
5 | import java.util.Collection; | |
6 | import java.util.Map; | |
7 | ||
8 | /* | |
9 | Copyright (c) 2006 JSON.org | |
10 | ||
11 | Permission is hereby granted, free of charge, to any person obtaining a copy | |
12 | of this software and associated documentation files (the "Software"), to deal | |
13 | in the Software without restriction, including without limitation the rights | |
14 | to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
15 | copies of the Software, and to permit persons to whom the Software is | |
16 | furnished to do so, subject to the following conditions: | |
17 | ||
18 | The above copyright notice and this permission notice shall be included in all | |
19 | copies or substantial portions of the Software. | |
20 | ||
21 | The Software shall be used for Good, not Evil. | |
22 | ||
23 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
24 | IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
25 | FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
26 | AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
27 | LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
28 | OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE | |
29 | SOFTWARE. | |
30 | */ | |
31 | ||
32 | /** | |
33 | * JSONWriter provides a quick and convenient way of producing JSON text. The | |
34 | * texts produced strictly conform to JSON syntax rules. No whitespace is added, | |
35 | * so the results are ready for transmission or storage. Each instance of | |
36 | * JSONWriter can produce one JSON text. | |
37 | * <p> | |
38 | * A JSONWriter instance provides a <code>value</code> method for appending | |
39 | * values to the text, and a <code>key</code> method for adding keys before | |
40 | * values in objects. There are <code>array</code> and <code>endArray</code> | |
41 | * methods that make and bound array values, and <code>object</code> and | |
42 | * <code>endObject</code> methods which make and bound object values. All of | |
43 | * these methods return the JSONWriter instance, permitting a cascade style. For | |
44 | * example, | |
45 | * | |
46 | * <pre> | |
47 | * new JSONWriter(myWriter).object().key("JSON").value("Hello, World!") | |
48 | * .endObject(); | |
49 | * </pre> | |
50 | * | |
51 | * which writes | |
52 | * | |
53 | * <pre> | |
54 | * {"JSON":"Hello, World!"} | |
55 | * </pre> | |
56 | * <p> | |
57 | * The first method called must be <code>array</code> or <code>object</code>. | |
58 | * There are no methods for adding commas or colons. JSONWriter adds them for | |
59 | * you. Objects and arrays can be nested up to 200 levels deep. | |
60 | * <p> | |
61 | * This can sometimes be easier than using a JSONObject to build a string. | |
62 | * | |
63 | * @author JSON.org | |
64 | * @version 2016-08-08 | |
65 | */ | |
66 | public class JSONWriter | |
67 | { | |
68 | private static final int maxdepth = 200; | |
69 | ||
70 | /** | |
71 | * The comma flag determines if a comma should be output before the next | |
72 | * value. | |
73 | */ | |
74 | private boolean comma; | |
75 | ||
76 | /** | |
77 | * The current mode. Values: 'a' (array), 'd' (done), 'i' (initial), 'k' | |
78 | * (key), 'o' (object). | |
79 | */ | |
80 | protected char mode; | |
81 | ||
82 | /** | |
83 | * The object/array stack. | |
84 | */ | |
85 | private final JSONObject stack[]; | |
86 | ||
87 | /** | |
88 | * The stack top index. A value of 0 indicates that the stack is empty. | |
89 | */ | |
90 | private int top; | |
91 | ||
92 | /** | |
93 | * The writer that will receive the output. | |
94 | */ | |
95 | protected Appendable writer; | |
96 | ||
97 | /** | |
98 | * Make a fresh JSONWriter. It can be used to build one JSON text. | |
99 | */ | |
100 | 0 | public JSONWriter(Appendable w) |
101 | { | |
102 | 0 | this.comma = false; |
103 | 0 | this.mode = 'i'; |
104 | 0 | this.stack = new JSONObject[maxdepth]; |
105 | 0 | this.top = 0; |
106 | 0 | this.writer = w; |
107 | } | |
108 | ||
109 | /** | |
110 | * Append a value. | |
111 | * | |
112 | * @param string | |
113 | * A string value. | |
114 | * @return this | |
115 | * @throws JSONException | |
116 | * If the value is out of sequence. | |
117 | */ | |
118 | 0 | private JSONWriter append(String string) throws JSONException |
119 | { | |
120 | 0 | if (string == null) |
121 | { | |
122 | 0 | throw new JSONException("Null pointer"); |
123 | } | |
124 | 0 | if (this.mode == 'o' || this.mode == 'a') |
125 | { | |
126 | 0 | try |
127 | { | |
128 | 0 | if (this.comma && this.mode == 'a') |
129 | { | |
130 | 0 | this.writer.append(','); |
131 | } | |
132 | 0 | this.writer.append(string); |
133 | } catch (IOException e) | |
134 | { | |
135 | // Android as of API 25 does not support this exception constructor | |
136 | // however we won't worry about it. If an exception is happening here | |
137 | // it will just throw a "Method not found" exception instead. | |
138 | 0 | throw new JSONException(e); |
139 | } | |
140 | 0 | if (this.mode == 'o') |
141 | { | |
142 | 0 | this.mode = 'k'; |
143 | } | |
144 | 0 | this.comma = true; |
145 | 0 | return this; |
146 | } | |
147 | 0 | throw new JSONException("Value out of sequence."); |
148 | } | |
149 | ||
150 | /** | |
151 | * Begin appending a new array. All values until the balancing | |
152 | * <code>endArray</code> will be appended to this array. The | |
153 | * <code>endArray</code> method must be called to mark the array's end. | |
154 | * | |
155 | * @return this | |
156 | * @throws JSONException | |
157 | * If the nesting is too deep, or if the object is started in the | |
158 | * wrong place (for example as a key or after the end of the | |
159 | * outermost array or object). | |
160 | */ | |
161 | 0 | public JSONWriter array() throws JSONException |
162 | { | |
163 | 0 | if (this.mode == 'i' || this.mode == 'o' || this.mode == 'a') |
164 | { | |
165 | 0 | this.push(null); |
166 | 0 | this.append("["); |
167 | 0 | this.comma = false; |
168 | 0 | return this; |
169 | } | |
170 | 0 | throw new JSONException("Misplaced array."); |
171 | } | |
172 | ||
173 | /** | |
174 | * End something. | |
175 | * | |
176 | * @param m | |
177 | * Mode | |
178 | * @param c | |
179 | * Closing character | |
180 | * @return this | |
181 | * @throws JSONException | |
182 | * If unbalanced. | |
183 | */ | |
184 | 0 | private JSONWriter end(char m, char c) throws JSONException |
185 | { | |
186 | 0 | if (this.mode != m) |
187 | { | |
188 | 0 | throw new JSONException( |
189 | 0 | m == 'a' ? "Misplaced endArray." : "Misplaced endObject."); |
190 | } | |
191 | 0 | this.pop(m); |
192 | 0 | try |
193 | { | |
194 | 0 | this.writer.append(c); |
195 | } catch (IOException e) | |
196 | { | |
197 | // Android as of API 25 does not support this exception constructor | |
198 | // however we won't worry about it. If an exception is happening here | |
199 | // it will just throw a "Method not found" exception instead. | |
200 | 0 | throw new JSONException(e); |
201 | } | |
202 | 0 | this.comma = true; |
203 | 0 | return this; |
204 | } | |
205 | ||
206 | /** | |
207 | * End an array. This method most be called to balance calls to | |
208 | * <code>array</code>. | |
209 | * | |
210 | * @return this | |
211 | * @throws JSONException | |
212 | * If incorrectly nested. | |
213 | */ | |
214 | 0 | public JSONWriter endArray() throws JSONException |
215 | { | |
216 | 0 | return this.end('a', ']'); |
217 | } | |
218 | ||
219 | /** | |
220 | * End an object. This method most be called to balance calls to | |
221 | * <code>object</code>. | |
222 | * | |
223 | * @return this | |
224 | * @throws JSONException | |
225 | * If incorrectly nested. | |
226 | */ | |
227 | 0 | public JSONWriter endObject() throws JSONException |
228 | { | |
229 | 0 | return this.end('k', '}'); |
230 | } | |
231 | ||
232 | /** | |
233 | * Append a key. The key will be associated with the next value. In an object, | |
234 | * every value must be preceded by a key. | |
235 | * | |
236 | * @param string | |
237 | * A key string. | |
238 | * @return this | |
239 | * @throws JSONException | |
240 | * If the key is out of place. For example, keys do not belong in | |
241 | * arrays or if the key is null. | |
242 | */ | |
243 | 0 | public JSONWriter key(String string) throws JSONException |
244 | { | |
245 | 0 | if (string == null) |
246 | { | |
247 | 0 | throw new JSONException("Null key."); |
248 | } | |
249 | 0 | if (this.mode == 'k') |
250 | { | |
251 | 0 | try |
252 | { | |
253 | 0 | JSONObject topObject = this.stack[this.top - 1]; |
254 | // don't use the built in putOnce method to maintain Android support | |
255 | 0 | if (topObject.has(string)) |
256 | { | |
257 | 0 | throw new JSONException("Duplicate key \"" + string + "\""); |
258 | } | |
259 | 0 | topObject.put(string, true); |
260 | 0 | if (this.comma) |
261 | { | |
262 | 0 | this.writer.append(','); |
263 | } | |
264 | 0 | this.writer.append(JSONObject.quote(string)); |
265 | 0 | this.writer.append(':'); |
266 | 0 | this.comma = false; |
267 | 0 | this.mode = 'o'; |
268 | 0 | return this; |
269 | } catch (IOException e) | |
270 | { | |
271 | // Android as of API 25 does not support this exception constructor | |
272 | // however we won't worry about it. If an exception is happening here | |
273 | // it will just throw a "Method not found" exception instead. | |
274 | 0 | throw new JSONException(e); |
275 | } | |
276 | } | |
277 | 0 | throw new JSONException("Misplaced key."); |
278 | } | |
279 | ||
280 | /** | |
281 | * Begin appending a new object. All keys and values until the balancing | |
282 | * <code>endObject</code> will be appended to this object. The | |
283 | * <code>endObject</code> method must be called to mark the object's end. | |
284 | * | |
285 | * @return this | |
286 | * @throws JSONException | |
287 | * If the nesting is too deep, or if the object is started in the | |
288 | * wrong place (for example as a key or after the end of the | |
289 | * outermost array or object). | |
290 | */ | |
291 | 0 | public JSONWriter object() throws JSONException |
292 | { | |
293 | 0 | if (this.mode == 'i') |
294 | { | |
295 | 0 | this.mode = 'o'; |
296 | } | |
297 | 0 | if (this.mode == 'o' || this.mode == 'a') |
298 | { | |
299 | 0 | this.append("{"); |
300 | 0 | this.push(new JSONObject()); |
301 | 0 | this.comma = false; |
302 | 0 | return this; |
303 | } | |
304 | 0 | throw new JSONException("Misplaced object."); |
305 | ||
306 | } | |
307 | ||
308 | /** | |
309 | * Pop an array or object scope. | |
310 | * | |
311 | * @param c | |
312 | * The scope to close. | |
313 | * @throws JSONException | |
314 | * If nesting is wrong. | |
315 | */ | |
316 | 0 | private void pop(char c) throws JSONException |
317 | { | |
318 | 0 | if (this.top <= 0) |
319 | { | |
320 | 0 | throw new JSONException("Nesting error."); |
321 | } | |
322 | 0 | char m = this.stack[this.top - 1] == null ? 'a' : 'k'; |
323 | 0 | if (m != c) |
324 | { | |
325 | 0 | throw new JSONException("Nesting error."); |
326 | } | |
327 | 0 | this.top -= 1; |
328 | 0 | this.mode = this.top == 0 ? 'd' |
329 | 0 | : this.stack[this.top - 1] == null ? 'a' : 'k'; |
330 | } | |
331 | ||
332 | /** | |
333 | * Push an array or object scope. | |
334 | * | |
335 | * @param jo | |
336 | * The scope to open. | |
337 | * @throws JSONException | |
338 | * If nesting is too deep. | |
339 | */ | |
340 | 0 | private void push(JSONObject jo) throws JSONException |
341 | { | |
342 | 0 | if (this.top >= maxdepth) |
343 | { | |
344 | 0 | throw new JSONException("Nesting too deep."); |
345 | } | |
346 | 0 | this.stack[this.top] = jo; |
347 | 0 | this.mode = jo == null ? 'a' : 'k'; |
348 | 0 | this.top += 1; |
349 | } | |
350 | ||
351 | /** | |
352 | * Make a JSON text of an Object value. If the object has an | |
353 | * value.toJSONString() method, then that method will be used to produce the | |
354 | * JSON text. The method is required to produce a strictly conforming text. If | |
355 | * the object does not contain a toJSONString method (which is the most common | |
356 | * case), then a text will be produced by other means. If the value is an | |
357 | * array or Collection, then a JSONArray will be made from it and its | |
358 | * toJSONString method will be called. If the value is a MAP, then a | |
359 | * JSONObject will be made from it and its toJSONString method will be called. | |
360 | * Otherwise, the value's toString method will be called, and the result will | |
361 | * be quoted. | |
362 | * | |
363 | * <p> | |
364 | * Warning: This method assumes that the data structure is acyclical. | |
365 | * | |
366 | * @param value | |
367 | * The value to be serialized. | |
368 | * @return a printable, displayable, transmittable representation of the | |
369 | * object, beginning with <code>{</code> <small>(left | |
370 | * brace)</small> and ending with <code>}</code> <small>(right | |
371 | * brace)</small>. | |
372 | * @throws JSONException | |
373 | * If the value is or contains an invalid number. | |
374 | */ | |
375 | 0 | public static String valueToString(Object value) throws JSONException |
376 | { | |
377 | 0 | if (value == null || value.equals(null)) |
378 | { | |
379 | 0 | return "null"; |
380 | } | |
381 | 0 | if (value instanceof JSONString) |
382 | { | |
383 | 0 | Object object; |
384 | 0 | try |
385 | { | |
386 | 0 | object = ((JSONString) value).toJSONString(); |
387 | } catch (Exception e) | |
388 | { | |
389 | 0 | throw new JSONException(e); |
390 | } | |
391 | 0 | if (object instanceof String) |
392 | { | |
393 | 0 | return (String) object; |
394 | } | |
395 | 0 | throw new JSONException("Bad value from toJSONString: " + object); |
396 | } | |
397 | 0 | if (value instanceof Number) |
398 | { | |
399 | // not all Numbers may match actual JSON Numbers. i.e. Fractions or | |
400 | // Complex | |
401 | 0 | final String numberAsString = JSONObject |
402 | .numberToString((Number) value); | |
403 | 0 | try |
404 | { | |
405 | // Use the BigDecimal constructor for it's parser to validate the | |
406 | // format. | |
407 | 0 | @SuppressWarnings("unused") |
408 | BigDecimal unused = new BigDecimal(numberAsString); | |
409 | // Close enough to a JSON number that we will return it unquoted | |
410 | 0 | return numberAsString; |
411 | } catch (NumberFormatException ex) | |
412 | { | |
413 | // The Number value is not a valid JSON number. | |
414 | // Instead we will quote it as a string | |
415 | 0 | return JSONObject.quote(numberAsString); |
416 | } | |
417 | } | |
418 | 0 | if (value instanceof Boolean || value instanceof JSONObject |
419 | || value instanceof JSONArray) | |
420 | { | |
421 | 0 | return value.toString(); |
422 | } | |
423 | 0 | if (value instanceof Map) |
424 | { | |
425 | 0 | Map<?, ?> map = (Map<?, ?>) value; |
426 | 0 | return new JSONObject(map).toString(); |
427 | } | |
428 | 0 | if (value instanceof Collection) |
429 | { | |
430 | 0 | Collection<?> coll = (Collection<?>) value; |
431 | 0 | return new JSONArray(coll).toString(); |
432 | } | |
433 | 0 | if (value.getClass().isArray()) |
434 | { | |
435 | 0 | return new JSONArray(value).toString(); |
436 | } | |
437 | 0 | if (value instanceof Enum<?>) |
438 | { | |
439 | 0 | return JSONObject.quote(((Enum<?>) value).name()); |
440 | } | |
441 | 0 | return JSONObject.quote(value.toString()); |
442 | } | |
443 | ||
444 | /** | |
445 | * Append either the value <code>true</code> or the value <code>false</code>. | |
446 | * | |
447 | * @param b | |
448 | * A boolean. | |
449 | * @return this | |
450 | * @throws JSONException | |
451 | */ | |
452 | 0 | public JSONWriter value(boolean b) throws JSONException |
453 | { | |
454 | 0 | return this.append(b ? "true" : "false"); |
455 | } | |
456 | ||
457 | /** | |
458 | * Append a double value. | |
459 | * | |
460 | * @param d | |
461 | * A double. | |
462 | * @return this | |
463 | * @throws JSONException | |
464 | * If the number is not finite. | |
465 | */ | |
466 | 0 | public JSONWriter value(double d) throws JSONException |
467 | { | |
468 | 0 | return this.value(Double.valueOf(d)); |
469 | } | |
470 | ||
471 | /** | |
472 | * Append a long value. | |
473 | * | |
474 | * @param l | |
475 | * A long. | |
476 | * @return this | |
477 | * @throws JSONException | |
478 | */ | |
479 | 0 | public JSONWriter value(long l) throws JSONException |
480 | { | |
481 | 0 | return this.append(Long.toString(l)); |
482 | } | |
483 | ||
484 | /** | |
485 | * Append an object value. | |
486 | * | |
487 | * @param object | |
488 | * The object to append. It can be null, or a Boolean, Number, | |
489 | * String, JSONObject, or JSONArray, or an object that implements | |
490 | * JSONString. | |
491 | * @return this | |
492 | * @throws JSONException | |
493 | * If the value is out of sequence. | |
494 | */ | |
495 | 0 | public JSONWriter value(Object object) throws JSONException |
496 | { | |
497 | 0 | return this.append(valueToString(object)); |
498 | } | |
499 | } |