Java tutorial
/* * Copyright (C) 2013 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package android.util; import libcore.util.EmptyArray; import android.annotation.UnsupportedAppUsage; import android.os.Build; import java.util.Collection; import java.util.ConcurrentModificationException; import java.util.Map; import java.util.Set; /** * ArrayMap is a generic key->value mapping data structure that is * designed to be more memory efficient than a traditional {@link java.util.HashMap}. * It keeps its mappings in an array data structure -- an integer array of hash * codes for each item, and an Object array of the key/value pairs. This allows it to * avoid having to create an extra object for every entry put in to the map, and it * also tries to control the growth of the size of these arrays more aggressively * (since growing them only requires copying the entries in the array, not rebuilding * a hash map). * * <p>Note that this implementation is not intended to be appropriate for data structures * that may contain large numbers of items. It is generally slower than a traditional * HashMap, since lookups require a binary search and adds and removes require inserting * and deleting entries in the array. For containers holding up to hundreds of items, * the performance difference is not significant, less than 50%.</p> * * <p>Because this container is intended to better balance memory use, unlike most other * standard Java containers it will shrink its array as items are removed from it. Currently * you have no control over this shrinking -- if you set a capacity and then remove an * item, it may reduce the capacity to better match the current size. In the future an * explicit call to set the capacity should turn off this aggressive shrinking behavior.</p> */ public final class ArrayMap<K, V> implements Map<K, V> { private static final boolean DEBUG = false; private static final String TAG = "ArrayMap"; /** * Attempt to spot concurrent modifications to this data structure. * * It's best-effort, but any time we can throw something more diagnostic than an * ArrayIndexOutOfBoundsException deep in the ArrayMap internals it's going to * save a lot of development time. * * Good times to look for CME include after any allocArrays() call and at the end of * functions that change mSize (put/remove/clear). */ private static final boolean CONCURRENT_MODIFICATION_EXCEPTIONS = true; /** * The minimum amount by which the capacity of a ArrayMap will increase. * This is tuned to be relatively space-efficient. */ private static final int BASE_SIZE = 4; /** * Maximum number of entries to have in array caches. */ @UnsupportedAppUsage private static final int CACHE_SIZE = 10; /** * Special hash array value that indicates the container is immutable. */ @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P, trackingBug = 115609023) static final int[] EMPTY_IMMUTABLE_INTS = new int[0]; /** * @hide Special immutable empty ArrayMap. */ @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P, trackingBug = 115609023) public static final ArrayMap EMPTY = new ArrayMap<>(-1); /** * Caches of small array objects to avoid spamming garbage. The cache * Object[] variable is a pointer to a linked list of array objects. * The first entry in the array is a pointer to the next array in the * list; the second entry is a pointer to the int[] hash code array for it. */ @UnsupportedAppUsage static Object[] mBaseCache; @UnsupportedAppUsage static int mBaseCacheSize; @UnsupportedAppUsage static Object[] mTwiceBaseCache; @UnsupportedAppUsage static int mTwiceBaseCacheSize; final boolean mIdentityHashCode; @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P, trackingBug = 115609023) int[] mHashes; @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P, trackingBug = 115609023) Object[] mArray; @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P, trackingBug = 115609023) int mSize; MapCollections<K, V> mCollections; private static int binarySearchHashes(int[] hashes, int N, int hash) { try { return ContainerHelpers.binarySearch(hashes, N, hash); } catch (ArrayIndexOutOfBoundsException e) { if (CONCURRENT_MODIFICATION_EXCEPTIONS) { throw new ConcurrentModificationException(); } else { throw e; // the cache is poisoned at this point, there's not much we can do } } } @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P, trackingBug = 115609023) int indexOf(Object key, int hash) { final int N = mSize; // Important fast case: if nothing is in here, nothing to look for. if (N == 0) { return ~0; } int index = binarySearchHashes(mHashes, N, hash); // If the hash code wasn't found, then we have no entry for this key. if (index < 0) { return index; } // If the key at the returned index matches, that's what we want. if (key.equals(mArray[index << 1])) { return index; } // Search for a matching key after the index. int end; for (end = index + 1; end < N && mHashes[end] == hash; end++) { if (key.equals(mArray[end << 1])) return end; } // Search for a matching key before the index. for (int i = index - 1; i >= 0 && mHashes[i] == hash; i--) { if (key.equals(mArray[i << 1])) return i; } // Key not found -- return negative value indicating where a // new entry for this key should go. We use the end of the // hash chain to reduce the number of array entries that will // need to be copied when inserting. return ~end; } @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P, trackingBug = 115609023) int indexOfNull() { final int N = mSize; // Important fast case: if nothing is in here, nothing to look for. if (N == 0) { return ~0; } int index = binarySearchHashes(mHashes, N, 0); // If the hash code wasn't found, then we have no entry for this key. if (index < 0) { return index; } // If the key at the returned index matches, that's what we want. if (null == mArray[index << 1]) { return index; } // Search for a matching key after the index. int end; for (end = index + 1; end < N && mHashes[end] == 0; end++) { if (null == mArray[end << 1]) return end; } // Search for a matching key before the index. for (int i = index - 1; i >= 0 && mHashes[i] == 0; i--) { if (null == mArray[i << 1]) return i; } // Key not found -- return negative value indicating where a // new entry for this key should go. We use the end of the // hash chain to reduce the number of array entries that will // need to be copied when inserting. return ~end; } @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P, trackingBug = 115609023) private void allocArrays(final int size) { if (mHashes == EMPTY_IMMUTABLE_INTS) { throw new UnsupportedOperationException("ArrayMap is immutable"); } if (size == (BASE_SIZE * 2)) { synchronized (ArrayMap.class) { if (mTwiceBaseCache != null) { final Object[] array = mTwiceBaseCache; mArray = array; mTwiceBaseCache = (Object[]) array[0]; mHashes = (int[]) array[1]; array[0] = array[1] = null; mTwiceBaseCacheSize--; if (DEBUG) Log.d(TAG, "Retrieving 2x cache " + mHashes + " now have " + mTwiceBaseCacheSize + " entries"); return; } } } else if (size == BASE_SIZE) { synchronized (ArrayMap.class) { if (mBaseCache != null) { final Object[] array = mBaseCache; mArray = array; mBaseCache = (Object[]) array[0]; mHashes = (int[]) array[1]; array[0] = array[1] = null; mBaseCacheSize--; if (DEBUG) Log.d(TAG, "Retrieving 1x cache " + mHashes + " now have " + mBaseCacheSize + " entries"); return; } } } mHashes = new int[size]; mArray = new Object[size << 1]; } @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P, trackingBug = 115609023) private static void freeArrays(final int[] hashes, final Object[] array, final int size) { if (hashes.length == (BASE_SIZE * 2)) { synchronized (ArrayMap.class) { if (mTwiceBaseCacheSize < CACHE_SIZE) { array[0] = mTwiceBaseCache; array[1] = hashes; for (int i = (size << 1) - 1; i >= 2; i--) { array[i] = null; } mTwiceBaseCache = array; mTwiceBaseCacheSize++; if (DEBUG) Log.d(TAG, "Storing 2x cache " + array + " now have " + mTwiceBaseCacheSize + " entries"); } } } else if (hashes.length == BASE_SIZE) { synchronized (ArrayMap.class) { if (mBaseCacheSize < CACHE_SIZE) { array[0] = mBaseCache; array[1] = hashes; for (int i = (size << 1) - 1; i >= 2; i--) { array[i] = null; } mBaseCache = array; mBaseCacheSize++; if (DEBUG) Log.d(TAG, "Storing 1x cache " + array + " now have " + mBaseCacheSize + " entries"); } } } } /** * Create a new empty ArrayMap. The default capacity of an array map is 0, and * will grow once items are added to it. */ public ArrayMap() { this(0, false); } /** * Create a new ArrayMap with a given initial capacity. */ public ArrayMap(int capacity) { this(capacity, false); } /** {@hide} */ public ArrayMap(int capacity, boolean identityHashCode) { mIdentityHashCode = identityHashCode; // If this is immutable, use the sentinal EMPTY_IMMUTABLE_INTS // instance instead of the usual EmptyArray.INT. The reference // is checked later to see if the array is allowed to grow. if (capacity < 0) { mHashes = EMPTY_IMMUTABLE_INTS; mArray = EmptyArray.OBJECT; } else if (capacity == 0) { mHashes = EmptyArray.INT; mArray = EmptyArray.OBJECT; } else { allocArrays(capacity); } mSize = 0; } /** * Create a new ArrayMap with the mappings from the given ArrayMap. */ public ArrayMap(ArrayMap<K, V> map) { this(); if (map != null) { putAll(map); } } /** * Make the array map empty. All storage is released. */ @Override public void clear() { if (mSize > 0) { final int[] ohashes = mHashes; final Object[] oarray = mArray; final int osize = mSize; mHashes = EmptyArray.INT; mArray = EmptyArray.OBJECT; mSize = 0; freeArrays(ohashes, oarray, osize); } if (CONCURRENT_MODIFICATION_EXCEPTIONS && mSize > 0) { throw new ConcurrentModificationException(); } } /** * @hide * Like {@link #clear}, but doesn't reduce the capacity of the ArrayMap. */ public void erase() { if (mSize > 0) { final int N = mSize << 1; final Object[] array = mArray; for (int i = 0; i < N; i++) { array[i] = null; } mSize = 0; } } /** * Ensure the array map can hold at least <var>minimumCapacity</var> * items. */ public void ensureCapacity(int minimumCapacity) { final int osize = mSize; if (mHashes.length < minimumCapacity) { final int[] ohashes = mHashes; final Object[] oarray = mArray; allocArrays(minimumCapacity); if (mSize > 0) { System.arraycopy(ohashes, 0, mHashes, 0, osize); System.arraycopy(oarray, 0, mArray, 0, osize << 1); } freeArrays(ohashes, oarray, osize); } if (CONCURRENT_MODIFICATION_EXCEPTIONS && mSize != osize) { throw new ConcurrentModificationException(); } } /** * Check whether a key exists in the array. * * @param key The key to search for. * @return Returns true if the key exists, else false. */ @Override public boolean containsKey(Object key) { return indexOfKey(key) >= 0; } /** * Returns the index of a key in the set. * * @param key The key to search for. * @return Returns the index of the key if it exists, else a negative integer. */ public int indexOfKey(Object key) { return key == null ? indexOfNull() : indexOf(key, mIdentityHashCode ? System.identityHashCode(key) : key.hashCode()); } @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P, trackingBug = 115609023) int indexOfValue(Object value) { final int N = mSize * 2; final Object[] array = mArray; if (value == null) { for (int i = 1; i < N; i += 2) { if (array[i] == null) { return i >> 1; } } } else { for (int i = 1; i < N; i += 2) { if (value.equals(array[i])) { return i >> 1; } } } return -1; } /** * Check whether a value exists in the array. This requires a linear search * through the entire array. * * @param value The value to search for. * @return Returns true if the value exists, else false. */ @Override public boolean containsValue(Object value) { return indexOfValue(value) >= 0; } /** * Retrieve a value from the array. * @param key The key of the value to retrieve. * @return Returns the value associated with the given key, * or null if there is no such key. */ @Override public V get(Object key) { final int index = indexOfKey(key); return index >= 0 ? (V) mArray[(index << 1) + 1] : null; } /** * Return the key at the given index in the array. * @param index The desired index, must be between 0 and {@link #size()}-1. * @return Returns the key stored at the given index. */ public K keyAt(int index) { return (K) mArray[index << 1]; } /** * Return the value at the given index in the array. * @param index The desired index, must be between 0 and {@link #size()}-1. * @return Returns the value stored at the given index. */ public V valueAt(int index) { return (V) mArray[(index << 1) + 1]; } /** * Set the value at a given index in the array. * @param index The desired index, must be between 0 and {@link #size()}-1. * @param value The new value to store at this index. * @return Returns the previous value at the given index. */ public V setValueAt(int index, V value) { index = (index << 1) + 1; V old = (V) mArray[index]; mArray[index] = value; return old; } /** * Return true if the array map contains no items. */ @Override public boolean isEmpty() { return mSize <= 0; } /** * Add a new value to the array map. * @param key The key under which to store the value. If * this key already exists in the array, its value will be replaced. * @param value The value to store for the given key. * @return Returns the old value that was stored for the given key, or null if there * was no such key. */ @Override public V put(K key, V value) { final int osize = mSize; final int hash; int index; if (key == null) { hash = 0; index = indexOfNull(); } else { hash = mIdentityHashCode ? System.identityHashCode(key) : key.hashCode(); index = indexOf(key, hash); } if (index >= 0) { index = (index << 1) + 1; final V old = (V) mArray[index]; mArray[index] = value; return old; } index = ~index; if (osize >= mHashes.length) { final int n = osize >= (BASE_SIZE * 2) ? (osize + (osize >> 1)) : (osize >= BASE_SIZE ? (BASE_SIZE * 2) : BASE_SIZE); if (DEBUG) Log.d(TAG, "put: grow from " + mHashes.length + " to " + n); final int[] ohashes = mHashes; final Object[] oarray = mArray; allocArrays(n); if (CONCURRENT_MODIFICATION_EXCEPTIONS && osize != mSize) { throw new ConcurrentModificationException(); } if (mHashes.length > 0) { if (DEBUG) Log.d(TAG, "put: copy 0-" + osize + " to 0"); System.arraycopy(ohashes, 0, mHashes, 0, ohashes.length); System.arraycopy(oarray, 0, mArray, 0, oarray.length); } freeArrays(ohashes, oarray, osize); } if (index < osize) { if (DEBUG) Log.d(TAG, "put: move " + index + "-" + (osize - index) + " to " + (index + 1)); System.arraycopy(mHashes, index, mHashes, index + 1, osize - index); System.arraycopy(mArray, index << 1, mArray, (index + 1) << 1, (mSize - index) << 1); } if (CONCURRENT_MODIFICATION_EXCEPTIONS) { if (osize != mSize || index >= mHashes.length) { throw new ConcurrentModificationException(); } } mHashes[index] = hash; mArray[index << 1] = key; mArray[(index << 1) + 1] = value; mSize++; return null; } /** * Special fast path for appending items to the end of the array without validation. * The array must already be large enough to contain the item. * @hide */ @UnsupportedAppUsage public void append(K key, V value) { int index = mSize; final int hash = key == null ? 0 : (mIdentityHashCode ? System.identityHashCode(key) : key.hashCode()); if (index >= mHashes.length) { throw new IllegalStateException("Array is full"); } if (index > 0 && mHashes[index - 1] > hash) { RuntimeException e = new RuntimeException("here"); e.fillInStackTrace(); Log.w(TAG, "New hash " + hash + " is before end of array hash " + mHashes[index - 1] + " at index " + index + " key " + key, e); put(key, value); return; } mSize = index + 1; mHashes[index] = hash; index <<= 1; mArray[index] = key; mArray[index + 1] = value; } /** * The use of the {@link #append} function can result in invalid array maps, in particular * an array map where the same key appears multiple times. This function verifies that * the array map is valid, throwing IllegalArgumentException if a problem is found. The * main use for this method is validating an array map after unpacking from an IPC, to * protect against malicious callers. * @hide */ public void validate() { final int N = mSize; if (N <= 1) { // There can't be dups. return; } int basehash = mHashes[0]; int basei = 0; for (int i = 1; i < N; i++) { int hash = mHashes[i]; if (hash != basehash) { basehash = hash; basei = i; continue; } // We are in a run of entries with the same hash code. Go backwards through // the array to see if any keys are the same. final Object cur = mArray[i << 1]; for (int j = i - 1; j >= basei; j--) { final Object prev = mArray[j << 1]; if (cur == prev) { throw new IllegalArgumentException("Duplicate key in ArrayMap: " + cur); } if (cur != null && prev != null && cur.equals(prev)) { throw new IllegalArgumentException("Duplicate key in ArrayMap: " + cur); } } } } /** * Perform a {@link #put(Object, Object)} of all key/value pairs in <var>array</var> * @param array The array whose contents are to be retrieved. */ public void putAll(ArrayMap<? extends K, ? extends V> array) { final int N = array.mSize; ensureCapacity(mSize + N); if (mSize == 0) { if (N > 0) { System.arraycopy(array.mHashes, 0, mHashes, 0, N); System.arraycopy(array.mArray, 0, mArray, 0, N << 1); mSize = N; } } else { for (int i = 0; i < N; i++) { put(array.keyAt(i), array.valueAt(i)); } } } /** * Remove an existing key from the array map. * @param key The key of the mapping to remove. * @return Returns the value that was stored under the key, or null if there * was no such key. */ @Override public V remove(Object key) { final int index = indexOfKey(key); if (index >= 0) { return removeAt(index); } return null; } /** * Remove the key/value mapping at the given index. * @param index The desired index, must be between 0 and {@link #size()}-1. * @return Returns the value that was stored at this index. */ public V removeAt(int index) { final Object old = mArray[(index << 1) + 1]; final int osize = mSize; final int nsize; if (osize <= 1) { // Now empty. if (DEBUG) Log.d(TAG, "remove: shrink from " + mHashes.length + " to 0"); final int[] ohashes = mHashes; final Object[] oarray = mArray; mHashes = EmptyArray.INT; mArray = EmptyArray.OBJECT; freeArrays(ohashes, oarray, osize); nsize = 0; } else { nsize = osize - 1; if (mHashes.length > (BASE_SIZE * 2) && mSize < mHashes.length / 3) { // Shrunk enough to reduce size of arrays. We don't allow it to // shrink smaller than (BASE_SIZE*2) to avoid flapping between // that and BASE_SIZE. final int n = osize > (BASE_SIZE * 2) ? (osize + (osize >> 1)) : (BASE_SIZE * 2); if (DEBUG) Log.d(TAG, "remove: shrink from " + mHashes.length + " to " + n); final int[] ohashes = mHashes; final Object[] oarray = mArray; allocArrays(n); if (CONCURRENT_MODIFICATION_EXCEPTIONS && osize != mSize) { throw new ConcurrentModificationException(); } if (index > 0) { if (DEBUG) Log.d(TAG, "remove: copy from 0-" + index + " to 0"); System.arraycopy(ohashes, 0, mHashes, 0, index); System.arraycopy(oarray, 0, mArray, 0, index << 1); } if (index < nsize) { if (DEBUG) Log.d(TAG, "remove: copy from " + (index + 1) + "-" + nsize + " to " + index); System.arraycopy(ohashes, index + 1, mHashes, index, nsize - index); System.arraycopy(oarray, (index + 1) << 1, mArray, index << 1, (nsize - index) << 1); } } else { if (index < nsize) { if (DEBUG) Log.d(TAG, "remove: move " + (index + 1) + "-" + nsize + " to " + index); System.arraycopy(mHashes, index + 1, mHashes, index, nsize - index); System.arraycopy(mArray, (index + 1) << 1, mArray, index << 1, (nsize - index) << 1); } mArray[nsize << 1] = null; mArray[(nsize << 1) + 1] = null; } } if (CONCURRENT_MODIFICATION_EXCEPTIONS && osize != mSize) { throw new ConcurrentModificationException(); } mSize = nsize; return (V) old; } /** * Return the number of items in this array map. */ @Override public int size() { return mSize; } /** * {@inheritDoc} * * <p>This implementation returns false if the object is not a map, or * if the maps have different sizes. Otherwise, for each key in this map, * values of both maps are compared. If the values for any key are not * equal, the method returns false, otherwise it returns true. */ @Override public boolean equals(Object object) { if (this == object) { return true; } if (object instanceof Map) { Map<?, ?> map = (Map<?, ?>) object; if (size() != map.size()) { return false; } try { for (int i = 0; i < mSize; i++) { K key = keyAt(i); V mine = valueAt(i); Object theirs = map.get(key); if (mine == null) { if (theirs != null || !map.containsKey(key)) { return false; } } else if (!mine.equals(theirs)) { return false; } } } catch (NullPointerException ignored) { return false; } catch (ClassCastException ignored) { return false; } return true; } return false; } /** * {@inheritDoc} */ @Override public int hashCode() { final int[] hashes = mHashes; final Object[] array = mArray; int result = 0; for (int i = 0, v = 1, s = mSize; i < s; i++, v += 2) { Object value = array[v]; result += hashes[i] ^ (value == null ? 0 : value.hashCode()); } return result; } /** * {@inheritDoc} * * <p>This implementation composes a string by iterating over its mappings. If * this map contains itself as a key or a value, the string "(this Map)" * will appear in its place. */ @Override public String toString() { if (isEmpty()) { return "{}"; } StringBuilder buffer = new StringBuilder(mSize * 28); buffer.append('{'); for (int i = 0; i < mSize; i++) { if (i > 0) { buffer.append(", "); } Object key = keyAt(i); if (key != this) { buffer.append(key); } else { buffer.append("(this Map)"); } buffer.append('='); Object value = valueAt(i); if (value != this) { buffer.append(value); } else { buffer.append("(this Map)"); } } buffer.append('}'); return buffer.toString(); } // ------------------------------------------------------------------------ // Interop with traditional Java containers. Not as efficient as using // specialized collection APIs. // ------------------------------------------------------------------------ private MapCollections<K, V> getCollection() { if (mCollections == null) { mCollections = new MapCollections<K, V>() { @Override protected int colGetSize() { return mSize; } @Override protected Object colGetEntry(int index, int offset) { return mArray[(index << 1) + offset]; } @Override protected int colIndexOfKey(Object key) { return indexOfKey(key); } @Override protected int colIndexOfValue(Object value) { return indexOfValue(value); } @Override protected Map<K, V> colGetMap() { return ArrayMap.this; } @Override protected void colPut(K key, V value) { put(key, value); } @Override protected V colSetValue(int index, V value) { return setValueAt(index, value); } @Override protected void colRemoveAt(int index) { removeAt(index); } @Override protected void colClear() { clear(); } }; } return mCollections; } /** * Determine if the array map contains all of the keys in the given collection. * @param collection The collection whose contents are to be checked against. * @return Returns true if this array map contains a key for every entry * in <var>collection</var>, else returns false. */ public boolean containsAll(Collection<?> collection) { return MapCollections.containsAllHelper(this, collection); } /** * Perform a {@link #put(Object, Object)} of all key/value pairs in <var>map</var> * @param map The map whose contents are to be retrieved. */ @Override public void putAll(Map<? extends K, ? extends V> map) { ensureCapacity(mSize + map.size()); for (Map.Entry<? extends K, ? extends V> entry : map.entrySet()) { put(entry.getKey(), entry.getValue()); } } /** * Remove all keys in the array map that exist in the given collection. * @param collection The collection whose contents are to be used to remove keys. * @return Returns true if any keys were removed from the array map, else false. */ public boolean removeAll(Collection<?> collection) { return MapCollections.removeAllHelper(this, collection); } /** * Remove all keys in the array map that do <b>not</b> exist in the given collection. * @param collection The collection whose contents are to be used to determine which * keys to keep. * @return Returns true if any keys were removed from the array map, else false. */ public boolean retainAll(Collection<?> collection) { return MapCollections.retainAllHelper(this, collection); } /** * Return a {@link java.util.Set} for iterating over and interacting with all mappings * in the array map. * * <p><b>Note:</b> this is a very inefficient way to access the array contents, it * requires generating a number of temporary objects and allocates additional state * information associated with the container that will remain for the life of the container.</p> * * <p><b>Note:</b></p> the semantics of this * Set are subtly different than that of a {@link java.util.HashMap}: most important, * the {@link java.util.Map.Entry Map.Entry} object returned by its iterator is a single * object that exists for the entire iterator, so you can <b>not</b> hold on to it * after calling {@link java.util.Iterator#next() Iterator.next}.</p> */ @Override public Set<Map.Entry<K, V>> entrySet() { return getCollection().getEntrySet(); } /** * Return a {@link java.util.Set} for iterating over and interacting with all keys * in the array map. * * <p><b>Note:</b> this is a fairly inefficient way to access the array contents, it * requires generating a number of temporary objects and allocates additional state * information associated with the container that will remain for the life of the container.</p> */ @Override public Set<K> keySet() { return getCollection().getKeySet(); } /** * Return a {@link java.util.Collection} for iterating over and interacting with all values * in the array map. * * <p><b>Note:</b> this is a fairly inefficient way to access the array contents, it * requires generating a number of temporary objects and allocates additional state * information associated with the container that will remain for the life of the container.</p> */ @Override public Collection<V> values() { return getCollection().getValues(); } }