1 /*
2 * Copyright 2014 The Netty Project
3 *
4 * The Netty Project licenses this file to you under the Apache License, version 2.0 (the
5 * "License"); you may not use this file except in compliance with the License. You may obtain a
6 * copy of the License at:
7 *
8 * https://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software distributed under the License
11 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
12 * or implied. See the License for the specific language governing permissions and limitations under
13 * the License.
14 */
15 package io.netty.handler.codec;
16
17 import java.util.Collections;
18 import java.util.Iterator;
19 import java.util.List;
20 import java.util.Map.Entry;
21 import java.util.Set;
22
23 import static io.netty.handler.codec.DefaultHeaders.HASH_CODE_SEED;
24
25 public class EmptyHeaders<K, V, T extends Headers<K, V, T>> implements Headers<K, V, T> {
26 @Override
27 public V get(K name) {
28 return null;
29 }
30
31 @Override
32 public V get(K name, V defaultValue) {
33 return defaultValue;
34 }
35
36 @Override
37 public V getAndRemove(K name) {
38 return null;
39 }
40
41 @Override
42 public V getAndRemove(K name, V defaultValue) {
43 return defaultValue;
44 }
45
46 @Override
47 public List<V> getAll(K name) {
48 return Collections.emptyList();
49 }
50
51 @Override
52 public List<V> getAllAndRemove(K name) {
53 return Collections.emptyList();
54 }
55
56 @Override
57 public Boolean getBoolean(K name) {
58 return null;
59 }
60
61 @Override
62 public boolean getBoolean(K name, boolean defaultValue) {
63 return defaultValue;
64 }
65
66 @Override
67 public Byte getByte(K name) {
68 return null;
69 }
70
71 @Override
72 public byte getByte(K name, byte defaultValue) {
73 return defaultValue;
74 }
75
76 @Override
77 public Character getChar(K name) {
78 return null;
79 }
80
81 @Override
82 public char getChar(K name, char defaultValue) {
83 return defaultValue;
84 }
85
86 @Override
87 public Short getShort(K name) {
88 return null;
89 }
90
91 @Override
92 public short getShort(K name, short defaultValue) {
93 return defaultValue;
94 }
95
96 @Override
97 public Integer getInt(K name) {
98 return null;
99 }
100
101 @Override
102 public int getInt(K name, int defaultValue) {
103 return defaultValue;
104 }
105
106 @Override
107 public Long getLong(K name) {
108 return null;
109 }
110
111 @Override
112 public long getLong(K name, long defaultValue) {
113 return defaultValue;
114 }
115
116 @Override
117 public Float getFloat(K name) {
118 return null;
119 }
120
121 @Override
122 public float getFloat(K name, float defaultValue) {
123 return defaultValue;
124 }
125
126 @Override
127 public Double getDouble(K name) {
128 return null;
129 }
130
131 @Override
132 public double getDouble(K name, double defaultValue) {
133 return defaultValue;
134 }
135
136 @Override
137 public Long getTimeMillis(K name) {
138 return null;
139 }
140
141 @Override
142 public long getTimeMillis(K name, long defaultValue) {
143 return defaultValue;
144 }
145
146 @Override
147 public Boolean getBooleanAndRemove(K name) {
148 return null;
149 }
150
151 @Override
152 public boolean getBooleanAndRemove(K name, boolean defaultValue) {
153 return defaultValue;
154 }
155
156 @Override
157 public Byte getByteAndRemove(K name) {
158 return null;
159 }
160
161 @Override
162 public byte getByteAndRemove(K name, byte defaultValue) {
163 return defaultValue;
164 }
165
166 @Override
167 public Character getCharAndRemove(K name) {
168 return null;
169 }
170
171 @Override
172 public char getCharAndRemove(K name, char defaultValue) {
173 return defaultValue;
174 }
175
176 @Override
177 public Short getShortAndRemove(K name) {
178 return null;
179 }
180
181 @Override
182 public short getShortAndRemove(K name, short defaultValue) {
183 return defaultValue;
184 }
185
186 @Override
187 public Integer getIntAndRemove(K name) {
188 return null;
189 }
190
191 @Override
192 public int getIntAndRemove(K name, int defaultValue) {
193 return defaultValue;
194 }
195
196 @Override
197 public Long getLongAndRemove(K name) {
198 return null;
199 }
200
201 @Override
202 public long getLongAndRemove(K name, long defaultValue) {
203 return defaultValue;
204 }
205
206 @Override
207 public Float getFloatAndRemove(K name) {
208 return null;
209 }
210
211 @Override
212 public float getFloatAndRemove(K name, float defaultValue) {
213 return defaultValue;
214 }
215
216 @Override
217 public Double getDoubleAndRemove(K name) {
218 return null;
219 }
220
221 @Override
222 public double getDoubleAndRemove(K name, double defaultValue) {
223 return defaultValue;
224 }
225
226 @Override
227 public Long getTimeMillisAndRemove(K name) {
228 return null;
229 }
230
231 @Override
232 public long getTimeMillisAndRemove(K name, long defaultValue) {
233 return defaultValue;
234 }
235
236 @Override
237 public boolean contains(K name) {
238 return false;
239 }
240
241 @Override
242 public boolean contains(K name, V value) {
243 return false;
244 }
245
246 @Override
247 public boolean containsObject(K name, Object value) {
248 return false;
249 }
250
251 @Override
252 public boolean containsBoolean(K name, boolean value) {
253 return false;
254 }
255
256 @Override
257 public boolean containsByte(K name, byte value) {
258 return false;
259 }
260
261 @Override
262 public boolean containsChar(K name, char value) {
263 return false;
264 }
265
266 @Override
267 public boolean containsShort(K name, short value) {
268 return false;
269 }
270
271 @Override
272 public boolean containsInt(K name, int value) {
273 return false;
274 }
275
276 @Override
277 public boolean containsLong(K name, long value) {
278 return false;
279 }
280
281 @Override
282 public boolean containsFloat(K name, float value) {
283 return false;
284 }
285
286 @Override
287 public boolean containsDouble(K name, double value) {
288 return false;
289 }
290
291 @Override
292 public boolean containsTimeMillis(K name, long value) {
293 return false;
294 }
295
296 @Override
297 public int size() {
298 return 0;
299 }
300
301 @Override
302 public boolean isEmpty() {
303 return true;
304 }
305
306 @Override
307 public Set<K> names() {
308 return Collections.emptySet();
309 }
310
311 @Override
312 public T add(K name, V value) {
313 throw new UnsupportedOperationException("read only");
314 }
315
316 @Override
317 public T add(K name, Iterable<? extends V> values) {
318 throw new UnsupportedOperationException("read only");
319 }
320
321 @Override
322 public T add(K name, V... values) {
323 throw new UnsupportedOperationException("read only");
324 }
325
326 @Override
327 public T addObject(K name, Object value) {
328 throw new UnsupportedOperationException("read only");
329 }
330
331 @Override
332 public T addObject(K name, Iterable<?> values) {
333 throw new UnsupportedOperationException("read only");
334 }
335
336 @Override
337 public T addObject(K name, Object... values) {
338 throw new UnsupportedOperationException("read only");
339 }
340
341 @Override
342 public T addBoolean(K name, boolean value) {
343 throw new UnsupportedOperationException("read only");
344 }
345
346 @Override
347 public T addByte(K name, byte value) {
348 throw new UnsupportedOperationException("read only");
349 }
350
351 @Override
352 public T addChar(K name, char value) {
353 throw new UnsupportedOperationException("read only");
354 }
355
356 @Override
357 public T addShort(K name, short value) {
358 throw new UnsupportedOperationException("read only");
359 }
360
361 @Override
362 public T addInt(K name, int value) {
363 throw new UnsupportedOperationException("read only");
364 }
365
366 @Override
367 public T addLong(K name, long value) {
368 throw new UnsupportedOperationException("read only");
369 }
370
371 @Override
372 public T addFloat(K name, float value) {
373 throw new UnsupportedOperationException("read only");
374 }
375
376 @Override
377 public T addDouble(K name, double value) {
378 throw new UnsupportedOperationException("read only");
379 }
380
381 @Override
382 public T addTimeMillis(K name, long value) {
383 throw new UnsupportedOperationException("read only");
384 }
385
386 @Override
387 public T add(Headers<? extends K, ? extends V, ?> headers) {
388 throw new UnsupportedOperationException("read only");
389 }
390
391 @Override
392 public T set(K name, V value) {
393 throw new UnsupportedOperationException("read only");
394 }
395
396 @Override
397 public T set(K name, Iterable<? extends V> values) {
398 throw new UnsupportedOperationException("read only");
399 }
400
401 @Override
402 public T set(K name, V... values) {
403 throw new UnsupportedOperationException("read only");
404 }
405
406 @Override
407 public T setObject(K name, Object value) {
408 throw new UnsupportedOperationException("read only");
409 }
410
411 @Override
412 public T setObject(K name, Iterable<?> values) {
413 throw new UnsupportedOperationException("read only");
414 }
415
416 @Override
417 public T setObject(K name, Object... values) {
418 throw new UnsupportedOperationException("read only");
419 }
420
421 @Override
422 public T setBoolean(K name, boolean value) {
423 throw new UnsupportedOperationException("read only");
424 }
425
426 @Override
427 public T setByte(K name, byte value) {
428 throw new UnsupportedOperationException("read only");
429 }
430
431 @Override
432 public T setChar(K name, char value) {
433 throw new UnsupportedOperationException("read only");
434 }
435
436 @Override
437 public T setShort(K name, short value) {
438 throw new UnsupportedOperationException("read only");
439 }
440
441 @Override
442 public T setInt(K name, int value) {
443 throw new UnsupportedOperationException("read only");
444 }
445
446 @Override
447 public T setLong(K name, long value) {
448 throw new UnsupportedOperationException("read only");
449 }
450
451 @Override
452 public T setFloat(K name, float value) {
453 throw new UnsupportedOperationException("read only");
454 }
455
456 @Override
457 public T setDouble(K name, double value) {
458 throw new UnsupportedOperationException("read only");
459 }
460
461 @Override
462 public T setTimeMillis(K name, long value) {
463 throw new UnsupportedOperationException("read only");
464 }
465
466 @Override
467 public T set(Headers<? extends K, ? extends V, ?> headers) {
468 throw new UnsupportedOperationException("read only");
469 }
470
471 @Override
472 public T setAll(Headers<? extends K, ? extends V, ?> headers) {
473 throw new UnsupportedOperationException("read only");
474 }
475
476 @Override
477 public boolean remove(K name) {
478 return false;
479 }
480
481 @Override
482 public T clear() {
483 return thisT();
484 }
485
486 /**
487 * Equivalent to {@link #getAll(Object)} but no intermediate list is generated.
488 * @param name the name of the header to retrieve
489 * @return an {@link Iterator} of header values corresponding to {@code name}.
490 */
491 public Iterator<V> valueIterator(@SuppressWarnings("unused") K name) {
492 List<V> empty = Collections.emptyList();
493 return empty.iterator();
494 }
495
496 @Override
497 public Iterator<Entry<K, V>> iterator() {
498 List<Entry<K, V>> empty = Collections.emptyList();
499 return empty.iterator();
500 }
501
502 @Override
503 public boolean equals(Object o) {
504 if (!(o instanceof Headers)) {
505 return false;
506 }
507
508 Headers<?, ?, ?> rhs = (Headers<?, ?, ?>) o;
509 return isEmpty() && rhs.isEmpty();
510 }
511
512 @Override
513 public int hashCode() {
514 return HASH_CODE_SEED;
515 }
516
517 @Override
518 public String toString() {
519 return new StringBuilder(getClass().getSimpleName()).append('[').append(']').toString();
520 }
521
522 @SuppressWarnings("unchecked")
523 private T thisT() {
524 return (T) this;
525 }
526 }
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