Dianne Hackborn | 21ab6f4 | 2013-06-10 15:59:15 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2013 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | package android.util; |
| 18 | |
Adam Lesinski | 776abc2 | 2014-03-07 11:30:59 -0500 | [diff] [blame] | 19 | import libcore.util.EmptyArray; |
| 20 | |
Dianne Hackborn | 21ab6f4 | 2013-06-10 15:59:15 -0700 | [diff] [blame] | 21 | import java.lang.reflect.Array; |
| 22 | import java.util.Collection; |
| 23 | import java.util.Iterator; |
| 24 | import java.util.Map; |
| 25 | import java.util.Set; |
| 26 | |
| 27 | /** |
| 28 | * ArraySet is a generic set data structure that is designed to be more memory efficient than a |
| 29 | * traditional {@link java.util.HashSet}. The design is very similar to |
| 30 | * {@link ArrayMap}, with all of the caveats described there. This implementation is |
| 31 | * separate from ArrayMap, however, so the Object array contains only one item for each |
| 32 | * entry in the set (instead of a pair for a mapping). |
| 33 | * |
| 34 | * <p>Note that this implementation is not intended to be appropriate for data structures |
| 35 | * that may contain large numbers of items. It is generally slower than a traditional |
| 36 | * HashSet, since lookups require a binary search and adds and removes require inserting |
| 37 | * and deleting entries in the array. For containers holding up to hundreds of items, |
Dianne Hackborn | b993f41 | 2013-07-12 17:46:45 -0700 | [diff] [blame] | 38 | * the performance difference is not significant, less than 50%.</p> |
Dianne Hackborn | 21ab6f4 | 2013-06-10 15:59:15 -0700 | [diff] [blame] | 39 | * |
Dianne Hackborn | 21ab6f4 | 2013-06-10 15:59:15 -0700 | [diff] [blame] | 40 | * <p>Because this container is intended to better balance memory use, unlike most other |
| 41 | * standard Java containers it will shrink its array as items are removed from it. Currently |
| 42 | * you have no control over this shrinking -- if you set a capacity and then remove an |
| 43 | * item, it may reduce the capacity to better match the current size. In the future an |
Dianne Hackborn | b993f41 | 2013-07-12 17:46:45 -0700 | [diff] [blame] | 44 | * explicit call to set the capacity should turn off this aggressive shrinking behavior.</p> |
Dianne Hackborn | 21ab6f4 | 2013-06-10 15:59:15 -0700 | [diff] [blame] | 45 | */ |
| 46 | public final class ArraySet<E> implements Collection<E>, Set<E> { |
| 47 | private static final boolean DEBUG = false; |
| 48 | private static final String TAG = "ArraySet"; |
| 49 | |
| 50 | /** |
| 51 | * The minimum amount by which the capacity of a ArraySet will increase. |
| 52 | * This is tuned to be relatively space-efficient. |
| 53 | */ |
| 54 | private static final int BASE_SIZE = 4; |
| 55 | |
| 56 | /** |
| 57 | * Maximum number of entries to have in array caches. |
| 58 | */ |
| 59 | private static final int CACHE_SIZE = 10; |
| 60 | |
| 61 | /** |
| 62 | * Caches of small array objects to avoid spamming garbage. The cache |
| 63 | * Object[] variable is a pointer to a linked list of array objects. |
| 64 | * The first entry in the array is a pointer to the next array in the |
| 65 | * list; the second entry is a pointer to the int[] hash code array for it. |
| 66 | */ |
| 67 | static Object[] mBaseCache; |
| 68 | static int mBaseCacheSize; |
| 69 | static Object[] mTwiceBaseCache; |
| 70 | static int mTwiceBaseCacheSize; |
| 71 | |
| 72 | int[] mHashes; |
| 73 | Object[] mArray; |
| 74 | int mSize; |
| 75 | MapCollections<E, E> mCollections; |
| 76 | |
| 77 | private int indexOf(Object key, int hash) { |
| 78 | final int N = mSize; |
| 79 | |
| 80 | // Important fast case: if nothing is in here, nothing to look for. |
| 81 | if (N == 0) { |
| 82 | return ~0; |
| 83 | } |
| 84 | |
Dianne Hackborn | 3e82ba1 | 2013-07-16 13:23:55 -0700 | [diff] [blame] | 85 | int index = ContainerHelpers.binarySearch(mHashes, N, hash); |
Dianne Hackborn | 21ab6f4 | 2013-06-10 15:59:15 -0700 | [diff] [blame] | 86 | |
| 87 | // If the hash code wasn't found, then we have no entry for this key. |
| 88 | if (index < 0) { |
| 89 | return index; |
| 90 | } |
| 91 | |
| 92 | // If the key at the returned index matches, that's what we want. |
Dianne Hackborn | 62d708f | 2013-07-25 16:42:59 -0700 | [diff] [blame] | 93 | if (key.equals(mArray[index])) { |
Dianne Hackborn | 21ab6f4 | 2013-06-10 15:59:15 -0700 | [diff] [blame] | 94 | return index; |
| 95 | } |
| 96 | |
| 97 | // Search for a matching key after the index. |
| 98 | int end; |
| 99 | for (end = index + 1; end < N && mHashes[end] == hash; end++) { |
Dianne Hackborn | 62d708f | 2013-07-25 16:42:59 -0700 | [diff] [blame] | 100 | if (key.equals(mArray[end])) return end; |
Dianne Hackborn | 21ab6f4 | 2013-06-10 15:59:15 -0700 | [diff] [blame] | 101 | } |
| 102 | |
| 103 | // Search for a matching key before the index. |
| 104 | for (int i = index - 1; i >= 0 && mHashes[i] == hash; i--) { |
Dianne Hackborn | 62d708f | 2013-07-25 16:42:59 -0700 | [diff] [blame] | 105 | if (key.equals(mArray[i])) return i; |
| 106 | } |
| 107 | |
| 108 | // Key not found -- return negative value indicating where a |
| 109 | // new entry for this key should go. We use the end of the |
| 110 | // hash chain to reduce the number of array entries that will |
| 111 | // need to be copied when inserting. |
| 112 | return ~end; |
| 113 | } |
| 114 | |
| 115 | private int indexOfNull() { |
| 116 | final int N = mSize; |
| 117 | |
| 118 | // Important fast case: if nothing is in here, nothing to look for. |
| 119 | if (N == 0) { |
| 120 | return ~0; |
| 121 | } |
| 122 | |
| 123 | int index = ContainerHelpers.binarySearch(mHashes, N, 0); |
| 124 | |
| 125 | // If the hash code wasn't found, then we have no entry for this key. |
| 126 | if (index < 0) { |
| 127 | return index; |
| 128 | } |
| 129 | |
| 130 | // If the key at the returned index matches, that's what we want. |
| 131 | if (null == mArray[index]) { |
| 132 | return index; |
| 133 | } |
| 134 | |
| 135 | // Search for a matching key after the index. |
| 136 | int end; |
| 137 | for (end = index + 1; end < N && mHashes[end] == 0; end++) { |
| 138 | if (null == mArray[end]) return end; |
| 139 | } |
| 140 | |
| 141 | // Search for a matching key before the index. |
| 142 | for (int i = index - 1; i >= 0 && mHashes[i] == 0; i--) { |
| 143 | if (null == mArray[i]) return i; |
Dianne Hackborn | 21ab6f4 | 2013-06-10 15:59:15 -0700 | [diff] [blame] | 144 | } |
| 145 | |
| 146 | // Key not found -- return negative value indicating where a |
| 147 | // new entry for this key should go. We use the end of the |
| 148 | // hash chain to reduce the number of array entries that will |
| 149 | // need to be copied when inserting. |
| 150 | return ~end; |
| 151 | } |
| 152 | |
| 153 | private void allocArrays(final int size) { |
| 154 | if (size == (BASE_SIZE*2)) { |
| 155 | synchronized (ArraySet.class) { |
| 156 | if (mTwiceBaseCache != null) { |
| 157 | final Object[] array = mTwiceBaseCache; |
| 158 | mArray = array; |
| 159 | mTwiceBaseCache = (Object[])array[0]; |
| 160 | mHashes = (int[])array[1]; |
| 161 | array[0] = array[1] = null; |
| 162 | mTwiceBaseCacheSize--; |
| 163 | if (DEBUG) Log.d(TAG, "Retrieving 2x cache " + mHashes |
| 164 | + " now have " + mTwiceBaseCacheSize + " entries"); |
| 165 | return; |
| 166 | } |
| 167 | } |
| 168 | } else if (size == BASE_SIZE) { |
| 169 | synchronized (ArraySet.class) { |
| 170 | if (mBaseCache != null) { |
| 171 | final Object[] array = mBaseCache; |
| 172 | mArray = array; |
| 173 | mBaseCache = (Object[])array[0]; |
| 174 | mHashes = (int[])array[1]; |
| 175 | array[0] = array[1] = null; |
| 176 | mBaseCacheSize--; |
| 177 | if (DEBUG) Log.d(TAG, "Retrieving 1x cache " + mHashes |
| 178 | + " now have " + mBaseCacheSize + " entries"); |
| 179 | return; |
| 180 | } |
| 181 | } |
| 182 | } |
| 183 | |
| 184 | mHashes = new int[size]; |
| 185 | mArray = new Object[size]; |
| 186 | } |
| 187 | |
| 188 | private static void freeArrays(final int[] hashes, final Object[] array, final int size) { |
| 189 | if (hashes.length == (BASE_SIZE*2)) { |
| 190 | synchronized (ArraySet.class) { |
| 191 | if (mTwiceBaseCacheSize < CACHE_SIZE) { |
| 192 | array[0] = mTwiceBaseCache; |
| 193 | array[1] = hashes; |
| 194 | for (int i=size-1; i>=2; i--) { |
| 195 | array[i] = null; |
| 196 | } |
| 197 | mTwiceBaseCache = array; |
| 198 | mTwiceBaseCacheSize++; |
| 199 | if (DEBUG) Log.d(TAG, "Storing 2x cache " + array |
| 200 | + " now have " + mTwiceBaseCacheSize + " entries"); |
| 201 | } |
| 202 | } |
| 203 | } else if (hashes.length == BASE_SIZE) { |
| 204 | synchronized (ArraySet.class) { |
| 205 | if (mBaseCacheSize < CACHE_SIZE) { |
| 206 | array[0] = mBaseCache; |
| 207 | array[1] = hashes; |
| 208 | for (int i=size-1; i>=2; i--) { |
| 209 | array[i] = null; |
| 210 | } |
| 211 | mBaseCache = array; |
| 212 | mBaseCacheSize++; |
| 213 | if (DEBUG) Log.d(TAG, "Storing 1x cache " + array |
| 214 | + " now have " + mBaseCacheSize + " entries"); |
| 215 | } |
| 216 | } |
| 217 | } |
| 218 | } |
| 219 | |
| 220 | /** |
| 221 | * Create a new empty ArraySet. The default capacity of an array map is 0, and |
| 222 | * will grow once items are added to it. |
| 223 | */ |
| 224 | public ArraySet() { |
Adam Lesinski | 776abc2 | 2014-03-07 11:30:59 -0500 | [diff] [blame] | 225 | mHashes = EmptyArray.INT; |
| 226 | mArray = EmptyArray.OBJECT; |
Dianne Hackborn | 21ab6f4 | 2013-06-10 15:59:15 -0700 | [diff] [blame] | 227 | mSize = 0; |
| 228 | } |
| 229 | |
| 230 | /** |
| 231 | * Create a new ArraySet with a given initial capacity. |
| 232 | */ |
| 233 | public ArraySet(int capacity) { |
| 234 | if (capacity == 0) { |
Adam Lesinski | 776abc2 | 2014-03-07 11:30:59 -0500 | [diff] [blame] | 235 | mHashes = EmptyArray.INT; |
| 236 | mArray = EmptyArray.OBJECT; |
Dianne Hackborn | 21ab6f4 | 2013-06-10 15:59:15 -0700 | [diff] [blame] | 237 | } else { |
| 238 | allocArrays(capacity); |
| 239 | } |
| 240 | mSize = 0; |
| 241 | } |
| 242 | |
| 243 | /** |
| 244 | * Create a new ArraySet with the mappings from the given ArraySet. |
| 245 | */ |
Jeff Sharkey | 9f837a9 | 2014-10-24 12:07:24 -0700 | [diff] [blame] | 246 | public ArraySet(ArraySet<E> set) { |
Dianne Hackborn | 21ab6f4 | 2013-06-10 15:59:15 -0700 | [diff] [blame] | 247 | this(); |
| 248 | if (set != null) { |
| 249 | addAll(set); |
| 250 | } |
| 251 | } |
| 252 | |
Jeff Sharkey | 9f837a9 | 2014-10-24 12:07:24 -0700 | [diff] [blame] | 253 | /** {@hide} */ |
| 254 | public ArraySet(Collection<E> set) { |
| 255 | this(); |
| 256 | if (set != null) { |
| 257 | addAll(set); |
| 258 | } |
| 259 | } |
Dianne Hackborn | 21ab6f4 | 2013-06-10 15:59:15 -0700 | [diff] [blame] | 260 | |
| 261 | /** |
| 262 | * Make the array map empty. All storage is released. |
| 263 | */ |
| 264 | @Override |
| 265 | public void clear() { |
| 266 | if (mSize != 0) { |
| 267 | freeArrays(mHashes, mArray, mSize); |
Adam Lesinski | 776abc2 | 2014-03-07 11:30:59 -0500 | [diff] [blame] | 268 | mHashes = EmptyArray.INT; |
| 269 | mArray = EmptyArray.OBJECT; |
Dianne Hackborn | 21ab6f4 | 2013-06-10 15:59:15 -0700 | [diff] [blame] | 270 | mSize = 0; |
| 271 | } |
| 272 | } |
| 273 | |
| 274 | /** |
| 275 | * Ensure the array map can hold at least <var>minimumCapacity</var> |
| 276 | * items. |
| 277 | */ |
| 278 | public void ensureCapacity(int minimumCapacity) { |
| 279 | if (mHashes.length < minimumCapacity) { |
| 280 | final int[] ohashes = mHashes; |
| 281 | final Object[] oarray = mArray; |
| 282 | allocArrays(minimumCapacity); |
| 283 | if (mSize > 0) { |
| 284 | System.arraycopy(ohashes, 0, mHashes, 0, mSize); |
| 285 | System.arraycopy(oarray, 0, mArray, 0, mSize); |
| 286 | } |
| 287 | freeArrays(ohashes, oarray, mSize); |
| 288 | } |
| 289 | } |
| 290 | |
| 291 | /** |
| 292 | * Check whether a value exists in the set. |
| 293 | * |
| 294 | * @param key The value to search for. |
| 295 | * @return Returns true if the value exists, else false. |
| 296 | */ |
| 297 | @Override |
| 298 | public boolean contains(Object key) { |
Adam Lesinski | 4e9c07c | 2014-08-26 11:53:32 -0700 | [diff] [blame] | 299 | return indexOf(key) >= 0; |
| 300 | } |
| 301 | |
| 302 | /** |
| 303 | * Returns the index of a value in the set. |
| 304 | * |
| 305 | * @param key The value to search for. |
| 306 | * @return Returns the index of the value if it exists, else a negative integer. |
| 307 | */ |
| 308 | public int indexOf(Object key) { |
| 309 | return key == null ? indexOfNull() : indexOf(key, key.hashCode()); |
Dianne Hackborn | 21ab6f4 | 2013-06-10 15:59:15 -0700 | [diff] [blame] | 310 | } |
| 311 | |
| 312 | /** |
| 313 | * Return the value at the given index in the array. |
| 314 | * @param index The desired index, must be between 0 and {@link #size()}-1. |
| 315 | * @return Returns the value stored at the given index. |
| 316 | */ |
| 317 | public E valueAt(int index) { |
| 318 | return (E)mArray[index]; |
| 319 | } |
| 320 | |
| 321 | /** |
| 322 | * Return true if the array map contains no items. |
| 323 | */ |
| 324 | @Override |
| 325 | public boolean isEmpty() { |
| 326 | return mSize <= 0; |
| 327 | } |
| 328 | |
| 329 | /** |
| 330 | * Adds the specified object to this set. The set is not modified if it |
| 331 | * already contains the object. |
| 332 | * |
| 333 | * @param value the object to add. |
| 334 | * @return {@code true} if this set is modified, {@code false} otherwise. |
| 335 | * @throws ClassCastException |
| 336 | * when the class of the object is inappropriate for this set. |
| 337 | */ |
| 338 | @Override |
| 339 | public boolean add(E value) { |
Dianne Hackborn | 62d708f | 2013-07-25 16:42:59 -0700 | [diff] [blame] | 340 | final int hash; |
| 341 | int index; |
| 342 | if (value == null) { |
| 343 | hash = 0; |
| 344 | index = indexOfNull(); |
| 345 | } else { |
| 346 | hash = value.hashCode(); |
| 347 | index = indexOf(value, hash); |
| 348 | } |
Dianne Hackborn | 21ab6f4 | 2013-06-10 15:59:15 -0700 | [diff] [blame] | 349 | if (index >= 0) { |
| 350 | return false; |
| 351 | } |
| 352 | |
| 353 | index = ~index; |
| 354 | if (mSize >= mHashes.length) { |
| 355 | final int n = mSize >= (BASE_SIZE*2) ? (mSize+(mSize>>1)) |
| 356 | : (mSize >= BASE_SIZE ? (BASE_SIZE*2) : BASE_SIZE); |
| 357 | |
| 358 | if (DEBUG) Log.d(TAG, "add: grow from " + mHashes.length + " to " + n); |
| 359 | |
| 360 | final int[] ohashes = mHashes; |
| 361 | final Object[] oarray = mArray; |
| 362 | allocArrays(n); |
| 363 | |
| 364 | if (mHashes.length > 0) { |
| 365 | if (DEBUG) Log.d(TAG, "add: copy 0-" + mSize + " to 0"); |
| 366 | System.arraycopy(ohashes, 0, mHashes, 0, ohashes.length); |
| 367 | System.arraycopy(oarray, 0, mArray, 0, oarray.length); |
| 368 | } |
| 369 | |
| 370 | freeArrays(ohashes, oarray, mSize); |
| 371 | } |
| 372 | |
| 373 | if (index < mSize) { |
| 374 | if (DEBUG) Log.d(TAG, "add: move " + index + "-" + (mSize-index) |
| 375 | + " to " + (index+1)); |
| 376 | System.arraycopy(mHashes, index, mHashes, index + 1, mSize - index); |
| 377 | System.arraycopy(mArray, index, mArray, index + 1, mSize - index); |
| 378 | } |
| 379 | |
| 380 | mHashes[index] = hash; |
| 381 | mArray[index] = value; |
| 382 | mSize++; |
| 383 | return true; |
| 384 | } |
| 385 | |
| 386 | /** |
| 387 | * Perform a {@link #add(Object)} of all values in <var>array</var> |
| 388 | * @param array The array whose contents are to be retrieved. |
| 389 | */ |
Dianne Hackborn | 497175b | 2014-07-01 12:56:08 -0700 | [diff] [blame] | 390 | public void addAll(ArraySet<? extends E> array) { |
Dianne Hackborn | 21ab6f4 | 2013-06-10 15:59:15 -0700 | [diff] [blame] | 391 | final int N = array.mSize; |
| 392 | ensureCapacity(mSize + N); |
| 393 | if (mSize == 0) { |
| 394 | if (N > 0) { |
| 395 | System.arraycopy(array.mHashes, 0, mHashes, 0, N); |
| 396 | System.arraycopy(array.mArray, 0, mArray, 0, N); |
| 397 | mSize = N; |
| 398 | } |
| 399 | } else { |
| 400 | for (int i=0; i<N; i++) { |
| 401 | add(array.valueAt(i)); |
| 402 | } |
| 403 | } |
| 404 | } |
| 405 | |
| 406 | /** |
| 407 | * Removes the specified object from this set. |
| 408 | * |
| 409 | * @param object the object to remove. |
| 410 | * @return {@code true} if this set was modified, {@code false} otherwise. |
| 411 | */ |
| 412 | @Override |
| 413 | public boolean remove(Object object) { |
Adam Lesinski | 4e9c07c | 2014-08-26 11:53:32 -0700 | [diff] [blame] | 414 | final int index = indexOf(object); |
Dianne Hackborn | 21ab6f4 | 2013-06-10 15:59:15 -0700 | [diff] [blame] | 415 | if (index >= 0) { |
| 416 | removeAt(index); |
| 417 | return true; |
| 418 | } |
| 419 | return false; |
| 420 | } |
| 421 | |
| 422 | /** |
| 423 | * Remove the key/value mapping at the given index. |
| 424 | * @param index The desired index, must be between 0 and {@link #size()}-1. |
| 425 | * @return Returns the value that was stored at this index. |
| 426 | */ |
| 427 | public E removeAt(int index) { |
Dianne Hackborn | 62d708f | 2013-07-25 16:42:59 -0700 | [diff] [blame] | 428 | final Object old = mArray[index]; |
Dianne Hackborn | 21ab6f4 | 2013-06-10 15:59:15 -0700 | [diff] [blame] | 429 | if (mSize <= 1) { |
| 430 | // Now empty. |
| 431 | if (DEBUG) Log.d(TAG, "remove: shrink from " + mHashes.length + " to 0"); |
| 432 | freeArrays(mHashes, mArray, mSize); |
Adam Lesinski | 776abc2 | 2014-03-07 11:30:59 -0500 | [diff] [blame] | 433 | mHashes = EmptyArray.INT; |
| 434 | mArray = EmptyArray.OBJECT; |
Dianne Hackborn | 21ab6f4 | 2013-06-10 15:59:15 -0700 | [diff] [blame] | 435 | mSize = 0; |
| 436 | } else { |
| 437 | if (mHashes.length > (BASE_SIZE*2) && mSize < mHashes.length/3) { |
| 438 | // Shrunk enough to reduce size of arrays. We don't allow it to |
| 439 | // shrink smaller than (BASE_SIZE*2) to avoid flapping between |
| 440 | // that and BASE_SIZE. |
| 441 | final int n = mSize > (BASE_SIZE*2) ? (mSize + (mSize>>1)) : (BASE_SIZE*2); |
| 442 | |
| 443 | if (DEBUG) Log.d(TAG, "remove: shrink from " + mHashes.length + " to " + n); |
| 444 | |
| 445 | final int[] ohashes = mHashes; |
| 446 | final Object[] oarray = mArray; |
| 447 | allocArrays(n); |
| 448 | |
| 449 | mSize--; |
| 450 | if (index > 0) { |
| 451 | if (DEBUG) Log.d(TAG, "remove: copy from 0-" + index + " to 0"); |
| 452 | System.arraycopy(ohashes, 0, mHashes, 0, index); |
| 453 | System.arraycopy(oarray, 0, mArray, 0, index); |
| 454 | } |
| 455 | if (index < mSize) { |
| 456 | if (DEBUG) Log.d(TAG, "remove: copy from " + (index+1) + "-" + mSize |
| 457 | + " to " + index); |
| 458 | System.arraycopy(ohashes, index + 1, mHashes, index, mSize - index); |
| 459 | System.arraycopy(oarray, index + 1, mArray, index, mSize - index); |
| 460 | } |
| 461 | } else { |
| 462 | mSize--; |
| 463 | if (index < mSize) { |
| 464 | if (DEBUG) Log.d(TAG, "remove: move " + (index+1) + "-" + mSize |
| 465 | + " to " + index); |
| 466 | System.arraycopy(mHashes, index + 1, mHashes, index, mSize - index); |
| 467 | System.arraycopy(mArray, index + 1, mArray, index, mSize - index); |
| 468 | } |
| 469 | mArray[mSize] = null; |
| 470 | } |
| 471 | } |
Dianne Hackborn | 62d708f | 2013-07-25 16:42:59 -0700 | [diff] [blame] | 472 | return (E)old; |
Dianne Hackborn | 21ab6f4 | 2013-06-10 15:59:15 -0700 | [diff] [blame] | 473 | } |
| 474 | |
| 475 | /** |
Andreas Gampe | f9345e9 | 2015-03-04 17:14:10 -0800 | [diff] [blame] | 476 | * Perform a {@link #remove(Object)} of all values in <var>array</var> |
| 477 | * @param array The array whose contents are to be removed. |
| 478 | */ |
| 479 | public boolean removeAll(ArraySet<? extends E> array) { |
| 480 | // TODO: If array is sufficiently large, a marking approach might be beneficial. In a first |
| 481 | // pass, use the property that the sets are sorted by hash to make this linear passes |
| 482 | // (except for hash collisions, which means worst case still n*m), then do one |
| 483 | // collection pass into a new array. This avoids binary searches and excessive memcpy. |
| 484 | final int N = array.mSize; |
| 485 | |
| 486 | // Note: ArraySet does not make thread-safety guarantees. So instead of OR-ing together all |
| 487 | // the single results, compare size before and after. |
| 488 | final int originalSize = mSize; |
| 489 | for (int i = 0; i < N; i++) { |
| 490 | remove(array.valueAt(i)); |
| 491 | } |
| 492 | return originalSize != mSize; |
| 493 | } |
| 494 | |
| 495 | /** |
Dianne Hackborn | 21ab6f4 | 2013-06-10 15:59:15 -0700 | [diff] [blame] | 496 | * Return the number of items in this array map. |
| 497 | */ |
| 498 | @Override |
| 499 | public int size() { |
| 500 | return mSize; |
| 501 | } |
| 502 | |
| 503 | @Override |
| 504 | public Object[] toArray() { |
| 505 | Object[] result = new Object[mSize]; |
| 506 | System.arraycopy(mArray, 0, result, 0, mSize); |
| 507 | return result; |
| 508 | } |
| 509 | |
| 510 | @Override |
| 511 | public <T> T[] toArray(T[] array) { |
| 512 | if (array.length < mSize) { |
| 513 | @SuppressWarnings("unchecked") T[] newArray |
| 514 | = (T[]) Array.newInstance(array.getClass().getComponentType(), mSize); |
| 515 | array = newArray; |
| 516 | } |
| 517 | System.arraycopy(mArray, 0, array, 0, mSize); |
| 518 | if (array.length > mSize) { |
| 519 | array[mSize] = null; |
| 520 | } |
| 521 | return array; |
| 522 | } |
| 523 | |
| 524 | /** |
| 525 | * {@inheritDoc} |
| 526 | * |
| 527 | * <p>This implementation returns false if the object is not a set, or |
| 528 | * if the sets have different sizes. Otherwise, for each value in this |
| 529 | * set, it checks to make sure the value also exists in the other set. |
| 530 | * If any value doesn't exist, the method returns false; otherwise, it |
| 531 | * returns true. |
| 532 | */ |
| 533 | @Override |
| 534 | public boolean equals(Object object) { |
| 535 | if (this == object) { |
| 536 | return true; |
| 537 | } |
| 538 | if (object instanceof Set) { |
| 539 | Set<?> set = (Set<?>) object; |
| 540 | if (size() != set.size()) { |
| 541 | return false; |
| 542 | } |
| 543 | |
| 544 | try { |
| 545 | for (int i=0; i<mSize; i++) { |
| 546 | E mine = valueAt(i); |
| 547 | if (!set.contains(mine)) { |
| 548 | return false; |
| 549 | } |
| 550 | } |
| 551 | } catch (NullPointerException ignored) { |
| 552 | return false; |
| 553 | } catch (ClassCastException ignored) { |
| 554 | return false; |
| 555 | } |
| 556 | return true; |
| 557 | } |
| 558 | return false; |
| 559 | } |
| 560 | |
| 561 | /** |
| 562 | * {@inheritDoc} |
| 563 | */ |
| 564 | @Override |
| 565 | public int hashCode() { |
| 566 | final int[] hashes = mHashes; |
| 567 | int result = 0; |
| 568 | for (int i = 0, s = mSize; i < s; i++) { |
| 569 | result += hashes[i]; |
| 570 | } |
| 571 | return result; |
| 572 | } |
| 573 | |
Dianne Hackborn | a17c0f5 | 2013-06-20 18:59:11 -0700 | [diff] [blame] | 574 | /** |
| 575 | * {@inheritDoc} |
| 576 | * |
| 577 | * <p>This implementation composes a string by iterating over its values. If |
| 578 | * this set contains itself as a value, the string "(this Set)" |
| 579 | * will appear in its place. |
| 580 | */ |
| 581 | @Override |
| 582 | public String toString() { |
| 583 | if (isEmpty()) { |
| 584 | return "{}"; |
| 585 | } |
| 586 | |
| 587 | StringBuilder buffer = new StringBuilder(mSize * 14); |
| 588 | buffer.append('{'); |
| 589 | for (int i=0; i<mSize; i++) { |
| 590 | if (i > 0) { |
| 591 | buffer.append(", "); |
| 592 | } |
| 593 | Object value = valueAt(i); |
| 594 | if (value != this) { |
| 595 | buffer.append(value); |
| 596 | } else { |
| 597 | buffer.append("(this Set)"); |
| 598 | } |
| 599 | } |
| 600 | buffer.append('}'); |
| 601 | return buffer.toString(); |
| 602 | } |
| 603 | |
Dianne Hackborn | 21ab6f4 | 2013-06-10 15:59:15 -0700 | [diff] [blame] | 604 | // ------------------------------------------------------------------------ |
| 605 | // Interop with traditional Java containers. Not as efficient as using |
| 606 | // specialized collection APIs. |
| 607 | // ------------------------------------------------------------------------ |
| 608 | |
| 609 | private MapCollections<E, E> getCollection() { |
| 610 | if (mCollections == null) { |
| 611 | mCollections = new MapCollections<E, E>() { |
| 612 | @Override |
| 613 | protected int colGetSize() { |
| 614 | return mSize; |
| 615 | } |
| 616 | |
| 617 | @Override |
| 618 | protected Object colGetEntry(int index, int offset) { |
| 619 | return mArray[index]; |
| 620 | } |
| 621 | |
| 622 | @Override |
| 623 | protected int colIndexOfKey(Object key) { |
Adam Lesinski | 4e9c07c | 2014-08-26 11:53:32 -0700 | [diff] [blame] | 624 | return indexOf(key); |
Dianne Hackborn | 21ab6f4 | 2013-06-10 15:59:15 -0700 | [diff] [blame] | 625 | } |
| 626 | |
| 627 | @Override |
| 628 | protected int colIndexOfValue(Object value) { |
Adam Lesinski | 4e9c07c | 2014-08-26 11:53:32 -0700 | [diff] [blame] | 629 | return indexOf(value); |
Dianne Hackborn | 21ab6f4 | 2013-06-10 15:59:15 -0700 | [diff] [blame] | 630 | } |
| 631 | |
| 632 | @Override |
| 633 | protected Map<E, E> colGetMap() { |
| 634 | throw new UnsupportedOperationException("not a map"); |
| 635 | } |
| 636 | |
| 637 | @Override |
| 638 | protected void colPut(E key, E value) { |
| 639 | add(key); |
| 640 | } |
| 641 | |
| 642 | @Override |
| 643 | protected E colSetValue(int index, E value) { |
| 644 | throw new UnsupportedOperationException("not a map"); |
| 645 | } |
| 646 | |
| 647 | @Override |
| 648 | protected void colRemoveAt(int index) { |
| 649 | removeAt(index); |
| 650 | } |
| 651 | |
| 652 | @Override |
| 653 | protected void colClear() { |
| 654 | clear(); |
| 655 | } |
| 656 | }; |
| 657 | } |
| 658 | return mCollections; |
| 659 | } |
| 660 | |
Dianne Hackborn | f16747d | 2015-06-10 17:49:43 -0700 | [diff] [blame] | 661 | /** |
| 662 | * Return an {@link java.util.Iterator} over all values in the set. |
| 663 | * |
| 664 | * <p><b>Note:</b> this is a fairly inefficient way to access the array contents, it |
| 665 | * requires generating a number of temporary objects and allocates additional state |
| 666 | * information associated with the container that will remain for the life of the container.</p> |
| 667 | */ |
Dianne Hackborn | 21ab6f4 | 2013-06-10 15:59:15 -0700 | [diff] [blame] | 668 | @Override |
| 669 | public Iterator<E> iterator() { |
| 670 | return getCollection().getKeySet().iterator(); |
| 671 | } |
| 672 | |
Dianne Hackborn | f16747d | 2015-06-10 17:49:43 -0700 | [diff] [blame] | 673 | /** |
| 674 | * Determine if the array set contains all of the values in the given collection. |
| 675 | * @param collection The collection whose contents are to be checked against. |
| 676 | * @return Returns true if this array set contains a value for every entry |
| 677 | * in <var>collection</var>, else returns false. |
| 678 | */ |
Dianne Hackborn | 21ab6f4 | 2013-06-10 15:59:15 -0700 | [diff] [blame] | 679 | @Override |
| 680 | public boolean containsAll(Collection<?> collection) { |
| 681 | Iterator<?> it = collection.iterator(); |
| 682 | while (it.hasNext()) { |
| 683 | if (!contains(it.next())) { |
| 684 | return false; |
| 685 | } |
| 686 | } |
| 687 | return true; |
| 688 | } |
| 689 | |
Dianne Hackborn | f16747d | 2015-06-10 17:49:43 -0700 | [diff] [blame] | 690 | /** |
| 691 | * Perform an {@link #add(Object)} of all values in <var>collection</var> |
| 692 | * @param collection The collection whose contents are to be retrieved. |
| 693 | */ |
Dianne Hackborn | 21ab6f4 | 2013-06-10 15:59:15 -0700 | [diff] [blame] | 694 | @Override |
| 695 | public boolean addAll(Collection<? extends E> collection) { |
| 696 | ensureCapacity(mSize + collection.size()); |
| 697 | boolean added = false; |
| 698 | for (E value : collection) { |
| 699 | added |= add(value); |
| 700 | } |
| 701 | return added; |
| 702 | } |
| 703 | |
Dianne Hackborn | f16747d | 2015-06-10 17:49:43 -0700 | [diff] [blame] | 704 | /** |
| 705 | * Remove all values in the array set that exist in the given collection. |
| 706 | * @param collection The collection whose contents are to be used to remove values. |
| 707 | * @return Returns true if any values were removed from the array set, else false. |
| 708 | */ |
Dianne Hackborn | 21ab6f4 | 2013-06-10 15:59:15 -0700 | [diff] [blame] | 709 | @Override |
| 710 | public boolean removeAll(Collection<?> collection) { |
| 711 | boolean removed = false; |
| 712 | for (Object value : collection) { |
| 713 | removed |= remove(value); |
| 714 | } |
| 715 | return removed; |
| 716 | } |
| 717 | |
Dianne Hackborn | f16747d | 2015-06-10 17:49:43 -0700 | [diff] [blame] | 718 | /** |
| 719 | * Remove all values in the array set that do <b>not</b> exist in the given collection. |
| 720 | * @param collection The collection whose contents are to be used to determine which |
| 721 | * values to keep. |
| 722 | * @return Returns true if any values were removed from the array set, else false. |
| 723 | */ |
Dianne Hackborn | 21ab6f4 | 2013-06-10 15:59:15 -0700 | [diff] [blame] | 724 | @Override |
| 725 | public boolean retainAll(Collection<?> collection) { |
| 726 | boolean removed = false; |
| 727 | for (int i=mSize-1; i>=0; i--) { |
| 728 | if (!collection.contains(mArray[i])) { |
| 729 | removeAt(i); |
| 730 | removed = true; |
| 731 | } |
| 732 | } |
| 733 | return removed; |
| 734 | } |
| 735 | } |