LongSparseArray
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open class LongSparseArray<E : Any?>
SparseArray mapping longs to Objects. Unlike a normal array of Objects, there can be gaps in the indices. It is intended to be more memory efficient than using a HashMap to map Longs to Objects, both because it avoids auto-boxing keys and its data structure doesn't rely on an extra entry object for each mapping.
Note that this container keeps its mappings in an array data structure, using a binary search to find keys. The 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%.
To help with performance, the container includes an optimization when removing keys: instead of compacting its array immediately, it leaves the removed entry marked as deleted. The entry can then be re-used for the same key, or compacted later in a single garbage collection step of all removed entries. This garbage collection will need to be performed at any time the array needs to be grown or the map size or entry values are retrieved.
It is possible to iterate over the items in this container using keyAt and valueAt. Iterating over the keys using keyAt with ascending values of the index will return the keys in ascending order, or the values corresponding to the keys in ascending order in the case of valueAt.
Summary
Public constructors |
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<E : Any?> LongSparseArray(initialCapacity: Int)Creates a new |
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Public functions |
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open Unit |
Puts a key/value pair into the array, optimizing for the case where the key is greater than all existing keys in the array. |
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open Unit |
clear()Removes all key-value mappings from this |
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open LongSparseArray<E> |
clone() |
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open Boolean |
containsKey(key: Long)Returns |
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open Boolean |
containsValue(value: E)Returns |
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open Unit |
This function is deprecated. Alias for `remove(key)`. |
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open operator E? |
Gets the value mapped from the specified |
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open E |
Gets the value mapped from the specified |
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open Int |
indexOfKey(key: Long)Returns the index for which |
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open Int |
indexOfValue(value: E)Returns an index for which |
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open Boolean |
isEmpty()Return |
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open Long |
Given an index in the range |
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open Unit |
Adds a mapping from the specified key to the specified value, replacing the previous mapping from the specified key if there was one. |
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open Unit |
putAll(other: LongSparseArray<E>)Copies all of the mappings from |
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open E? |
putIfAbsent(key: Long, value: E)Add a new value to the array map only if the key does not already have a value or it is mapped to |
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open Unit |
Removes the mapping from the specified |
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open Boolean |
Remove an existing key from the array map only if it is currently mapped to |
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open Unit |
Removes the mapping at the specified |
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open E? |
Replace the mapping for |
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open Boolean |
Replace the mapping for |
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open Unit |
setValueAt(index: Int, value: E)Given an index in the range |
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open Int |
size()Returns the number of key-value mappings that this |
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open String |
toString()Returns a string representation of the object. |
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open E |
Given an index in the range |
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Extension functions |
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inline operator Boolean |
<T : Any?> LongSparseArray<T>.contains(key: Long)Returns true if the collection contains |
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inline Unit |
<T : Any?> LongSparseArray<T>.forEach(action: (key: Long, value) -> Unit)Performs the given |
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inline T |
<T : Any?> LongSparseArray<T>.getOrDefault(key: Long, defaultValue: T)Return the value corresponding to |
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inline T |
<T : Any?> LongSparseArray<T>.getOrElse(key: Long, defaultValue: () -> T)Return the value corresponding to |
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inline Boolean |
<T : Any?> LongSparseArray<T>.isNotEmpty()Return true when the collection contains elements. |
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LongIterator |
<T : Any?> LongSparseArray<T>.keyIterator()Return an iterator over the collection's keys. |
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operator LongSparseArray<T> |
<T : Any?> LongSparseArray<T>.plus(other: LongSparseArray<T>)Creates a new collection by adding or replacing entries from |
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inline operator Unit |
<T : Any?> LongSparseArray<T>.set(key: Long, value: T)Allows the use of the index operator for storing values in the collection. |
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Iterator<T> |
<T : Any?> LongSparseArray<T>.valueIterator()Return an iterator over the collection's values. |
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Extension properties |
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Int |
Returns the number of key/value pairs in the collection. |
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Public constructors
LongSparseArray
<E : Any?> LongSparseArray(initialCapacity: Int = 10)
Creates a new LongSparseArray containing no mappings that will not require any additional memory allocation to store the specified number of mappings. If you supply an initial capacity of 0, the sparse array will be initialized with a light-weight representation not requiring any additional array allocations.
Public functions
append
open fun append(key: Long, value: E): Unit
Puts a key/value pair into the array, optimizing for the case where the key is greater than all existing keys in the array.
containsValue
open fun containsValue(value: E): Boolean
Returns true if the specified value is mapped from any key.
delete
open fundelete(key: Long): Unit
Removes the mapping from the specified key, if there was any.
get
open operator fun get(key: Long): E?
Gets the value mapped from the specified key, or null if no such mapping has been made.
get
open fun get(key: Long, defaultValue: E): E
Gets the value mapped from the specified key, or defaultValue if no such mapping has been made.
indexOfKey
open fun indexOfKey(key: Long): Int
Returns the index for which keyAt would return the specified key, or a negative number if the specified key is not mapped.
indexOfValue
open fun indexOfValue(value: E): Int
Returns an index for which valueAt would return the specified key, or a negative number if no keys map to the specified value.
Beware that this is a linear search, unlike lookups by key, and that multiple keys can map to the same value and this will find only one of them.
keyAt
open fun keyAt(index: Int): Long
Given an index in the range 0...size()-1, returns the key from the indexth key-value mapping that this LongSparseArray stores.
The keys corresponding to indices in ascending order are guaranteed to be in ascending order, e.g., keyAt(0) will return the smallest key and keyAt(size()-1) will return the largest key.
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kotlin.IllegalArgumentException |
if |
put
open fun put(key: Long, value: E): Unit
Adds a mapping from the specified key to the specified value, replacing the previous mapping from the specified key if there was one.
putAll
open fun putAll(other: LongSparseArray<E>): Unit
Copies all of the mappings from other to this map. The effect of this call is equivalent to that of calling put on this map once for each mapping from key to value in other.
putIfAbsent
open fun putIfAbsent(key: Long, value: E): E?
Add a new value to the array map only if the key does not already have a value or it is mapped to null.
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key: Long |
The key under which to store the value. |
value: E |
The value to store for the given key. |
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E? |
Returns the value that was stored for the given key, or |
remove
open fun remove(key: Long): Unit
Removes the mapping from the specified key, if there was any.
remove
open fun remove(key: Long, value: E): Boolean
Remove an existing key from the array map only if it is currently mapped to value.
| Parameters | |
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key: Long |
The key of the mapping to remove. |
value: E |
The value expected to be mapped to the key. |
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Boolean |
Returns |
replace
open fun replace(key: Long, value: E): E?
Replace the mapping for key only if it is already mapped to a value.
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key: Long |
The key of the mapping to replace. |
value: E |
The value to store for the given key. |
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E? |
Returns the previous mapped value or |
replace
open fun replace(key: Long, oldValue: E, newValue: E): Boolean
Replace the mapping for key only if it is already mapped to a value.
| Parameters | |
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key: Long |
The key of the mapping to replace. |
oldValue: E |
The value expected to be mapped to the key. |
newValue: E |
The value to store for the given key. |
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Boolean |
Returns |
setValueAt
open fun setValueAt(index: Int, value: E): Unit
Given an index in the range 0...size()-1, sets a new value for the indexth key-value mapping that this LongSparseArray stores.
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kotlin.IllegalArgumentException |
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size
open fun size(): Int
Returns the number of key-value mappings that this LongSparseArray currently stores.
toString
open fun toString(): String
Returns a string representation of the object.
This implementation composes a string by iterating over its mappings. If this map contains itself as a value, the string "(this Map)" will appear in its place.
valueAt
open fun valueAt(index: Int): E
Given an index in the range 0...size()-1, returns the value from the indexth key-value mapping that this LongSparseArray stores.
The values corresponding to indices in ascending order are guaranteed to be associated with keys in ascending order, e.g., valueAt(0) will return the value associated with the smallest key and valueAt(size()-1) will return the value associated with the largest key.
| Throws | |
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kotlin.IllegalArgumentException |
if |
Extension functions
contains
inline operator fun <T : Any?> LongSparseArray<T>.contains(key: Long): Boolean
Returns true if the collection contains key.
forEach
inline fun <T : Any?> LongSparseArray<T>.forEach(action: (key: Long, value) -> Unit): Unit
Performs the given action for each key/value entry.
getOrDefault
inline fun <T : Any?> LongSparseArray<T>.getOrDefault(key: Long, defaultValue: T): T
Return the value corresponding to key, or defaultValue when not present.
getOrElse
inline fun <T : Any?> LongSparseArray<T>.getOrElse(key: Long, defaultValue: () -> T): T
Return the value corresponding to key, or from defaultValue when not present.
isNotEmpty
inline fun <T : Any?> LongSparseArray<T>.isNotEmpty(): Boolean
Return true when the collection contains elements.
keyIterator
fun <T : Any?> LongSparseArray<T>.keyIterator(): LongIterator
Return an iterator over the collection's keys.
plus
operator fun <T : Any?> LongSparseArray<T>.plus(other: LongSparseArray<T>): LongSparseArray<T>
Creates a new collection by adding or replacing entries from other.
set
inline operator fun <T : Any?> LongSparseArray<T>.set(key: Long, value: T): Unit
Allows the use of the index operator for storing values in the collection.
valueIterator
fun <T : Any?> LongSparseArray<T>.valueIterator(): Iterator<T>
Return an iterator over the collection's values.