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FooSparseArray

public interface FooSparseArray<E extends Object>


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 methods

abstract void
append(long key, @NonNull E value)

Puts a key/value pair into the array, optimizing for the case where the key is greater than all existing keys in the array.

abstract void

Removes all key-value mappings from this FooSparseArray.

abstract boolean
containsKey(long key)

Returns true if the specified key is mapped.

abstract boolean

Returns true if the specified value is mapped from any key.

abstract void
delete(long key)

This method is deprecated. Alias for `remove(key)`.

abstract E
get(long key)

Gets the value mapped from the specified key, or null if no such mapping has been made.

abstract @NonNull E
get(long key, @NonNull E defaultValue)

Gets the value mapped from the specified key, or defaultValue if no such mapping has been made.

abstract boolean
abstract @NonNull long[]
abstract int
abstract @NonNull Object[]
abstract int
indexOfKey(long key)

Returns the index for which keyAt would return the specified key, or a negative number if the specified key is not mapped.

abstract int

Returns an index for which valueAt would return the specified key, or a negative number if no keys map to the specified value.

abstract boolean

Return true if size is 0.

abstract long
keyAt(int index)

Given an index in the range 0...size()-1, returns the key from the indexth key-value mapping that this FooSparseArray stores.

abstract void
put(long key, @NonNull E value)

Adds a mapping from the specified key to the specified value, replacing the previous mapping from the specified key if there was one.

abstract void

Copies all of the mappings from other to this map.

abstract E
putIfAbsent(long key, @NonNull E value)

Add a new value to the array map only if the key does not already have a value or it is mapped to null.

abstract void
remove(long key)

Removes the mapping from the specified key, if there was any.

abstract boolean
remove(long key, @NonNull E value)

Remove an existing key from the array map only if it is currently mapped to value.

abstract void
removeAt(int index)

Removes the mapping at the specified index.

abstract E
replace(long key, @NonNull E value)

Replace the mapping for key only if it is already mapped to a value.

abstract boolean
replace(long key, @NonNull E oldValue, @NonNull E newValue)

Replace the mapping for key only if it is already mapped to a value.

abstract void
setGarbage(boolean garbage)
abstract void
setKeys(@NonNull long[] keys)
abstract void
setSize(int size)
abstract void
setValueAt(int index, @NonNull E value)

Given an index in the range 0...size()-1, sets a new value for the indexth key-value mapping that this FooSparseArray stores.

abstract void
setValues(@NonNull Object[] values)
abstract int

Returns the number of key-value mappings that this FooSparseArray currently stores.

abstract @NonNull String

Returns a string representation of the object.

abstract @NonNull E
valueAt(int index)

Given an index in the range 0...size()-1, returns the value from the indexth key-value mapping that this FooSparseArray stores.

Extension functions

default final boolean
<T extends Object> FooSparseArrayKt.contains(
    @NonNull FooSparseArray<@NonNull T> receiver,
    long key
)

Returns true if the collection contains key.

default final void
<T extends Object> FooSparseArrayKt.forEach(
    @NonNull FooSparseArray<@NonNull T> receiver,
    @NonNull Function2<@NonNull Long, @NonNull value, Unit> action
)

Performs the given action for each key/value entry.

default final @NonNull T
<T extends Object> FooSparseArrayKt.getOrDefault(
    @NonNull FooSparseArray<@NonNull T> receiver,
    long key,
    @NonNull T defaultValue
)

Return the value corresponding to key, or defaultValue when not present.

default final @NonNull T
<T extends Object> FooSparseArrayKt.getOrElse(
    @NonNull FooSparseArray<@NonNull T> receiver,
    long key,
    @NonNull Function0<@NonNull T> defaultValue
)

Return the value corresponding to key, or from defaultValue when not present.

default final int

Returns the number of key/value pairs in the collection.

default final boolean
<T extends Object> FooSparseArrayKt.isNotEmpty(
    @NonNull FooSparseArray<@NonNull T> receiver
)

Return true when the collection contains elements.

default final @NonNull LongIterator
<T extends Object> FooSparseArrayKt.keyIterator(
    @NonNull FooSparseArray<@NonNull T> receiver
)

Return an iterator over the collection's keys.

default final void
<T extends Object> FooSparseArrayKt.set(
    @NonNull FooSparseArray<@NonNull T> receiver,
    long key,
    @NonNull T value
)

Allows the use of the index operator for storing values in the collection.

default final @NonNull Iterator<@NonNull T>
<T extends Object> FooSparseArrayKt.valueIterator(
    @NonNull FooSparseArray<@NonNull T> receiver
)

Return an iterator over the collection's values.

Public methods

append

abstract void append(long key, @NonNull E value)

Puts a key/value pair into the array, optimizing for the case where the key is greater than all existing keys in the array.

clear

abstract void clear()

Removes all key-value mappings from this FooSparseArray.

containsKey

abstract boolean containsKey(long key)

Returns true if the specified key is mapped.

containsValue

abstract boolean containsValue(@NonNull E value)

Returns true if the specified value is mapped from any key.

delete

abstract void delete(long key)

Removes the mapping from the specified key, if there was any.

get

abstract E get(long key)

Gets the value mapped from the specified key, or null if no such mapping has been made.

get

abstract @NonNullget(long key, @NonNull E defaultValue)

Gets the value mapped from the specified key, or defaultValue if no such mapping has been made.

getGarbage

abstract boolean getGarbage()

getKeys

abstract @NonNull long[] getKeys()

getSize

abstract int getSize()

getValues

abstract @NonNull Object[] getValues()

indexOfKey

abstract int indexOfKey(long key)

Returns the index for which keyAt would return the specified key, or a negative number if the specified key is not mapped.

indexOfValue

abstract int indexOfValue(@NonNull E value)

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.

isEmpty

abstract boolean isEmpty()

Return true if size is 0.

Returns
boolean

true if size is 0.

keyAt

abstract long keyAt(int index)

Given an index in the range 0...size()-1, returns the key from the indexth key-value mapping that this FooSparseArray 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.

Throws
kotlin.IllegalArgumentException

if index is not in the range 0...size()-1

put

abstract void put(long key, @NonNull E value)

Adds a mapping from the specified key to the specified value, replacing the previous mapping from the specified key if there was one.

putAll

abstract void putAll(@NonNull FooSparseArray<@NonNull E> other)

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

abstract E putIfAbsent(long key, @NonNull E value)

Add a new value to the array map only if the key does not already have a value or it is mapped to null.

Parameters
long key

The key under which to store the value.

@NonNull E value

The value to store for the given key.

Returns
E

Returns the value that was stored for the given key, or null if there was no such key.

remove

abstract void remove(long key)

Removes the mapping from the specified key, if there was any.

remove

abstract boolean remove(long key, @NonNull E value)

Remove an existing key from the array map only if it is currently mapped to value.

Parameters
long key

The key of the mapping to remove.

@NonNull E value

The value expected to be mapped to the key.

Returns
boolean

Returns true if the mapping was removed.

removeAt

abstract void removeAt(int index)

Removes the mapping at the specified index.

replace

abstract E replace(long key, @NonNull E value)

Replace the mapping for key only if it is already mapped to a value.

Parameters
long key

The key of the mapping to replace.

@NonNull E value

The value to store for the given key.

Returns
E

Returns the previous mapped value or null.

replace

abstract boolean replace(long key, @NonNull E oldValue, @NonNull E newValue)

Replace the mapping for key only if it is already mapped to a value.

Parameters
long key

The key of the mapping to replace.

@NonNull E oldValue

The value expected to be mapped to the key.

@NonNull E newValue

The value to store for the given key.

Returns
boolean

Returns true if the value was replaced.

setGarbage

abstract void setGarbage(boolean garbage)

setKeys

abstract void setKeys(@NonNull long[] keys)

setSize

abstract void setSize(int size)

setValueAt

abstract void setValueAt(int index, @NonNull E value)

Given an index in the range 0...size()-1, sets a new value for the indexth key-value mapping that this FooSparseArray stores.

Throws
kotlin.IllegalArgumentException

if index is not in the range 0...size()-1

setValues

abstract void setValues(@NonNull Object[] values)

size

abstract int size()

Returns the number of key-value mappings that this FooSparseArray currently stores.

toString

abstract @NonNull String toString()

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

abstract @NonNullvalueAt(int index)

Given an index in the range 0...size()-1, returns the value from the indexth key-value mapping that this FooSparseArray 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
kotlin.IllegalArgumentException

if index is not in the range 0...size()-1

Extension functions

FooSparseArrayKt.contains

default final boolean <T extends Object> FooSparseArrayKt.contains(
    @NonNull FooSparseArray<@NonNull T> receiver,
    long key
)

Returns true if the collection contains key.

FooSparseArrayKt.forEach

default final void <T extends Object> FooSparseArrayKt.forEach(
    @NonNull FooSparseArray<@NonNull T> receiver,
    @NonNull Function2<@NonNull Long, @NonNull value, Unit> action
)

Performs the given action for each key/value entry.

FooSparseArrayKt.getOrDefault

default final @NonNull T <T extends Object> FooSparseArrayKt.getOrDefault(
    @NonNull FooSparseArray<@NonNull T> receiver,
    long key,
    @NonNull T defaultValue
)

Return the value corresponding to key, or defaultValue when not present.

FooSparseArrayKt.getOrElse

default final @NonNull T <T extends Object> FooSparseArrayKt.getOrElse(
    @NonNull FooSparseArray<@NonNull T> receiver,
    long key,
    @NonNull Function0<@NonNull T> defaultValue
)

Return the value corresponding to key, or from defaultValue when not present.

FooSparseArrayKt.getSize

default final int FooSparseArrayKt.getSize(@NonNull FooSparseArray<@NonNull T> receiver)

Returns the number of key/value pairs in the collection.

FooSparseArrayKt.isNotEmpty

default final boolean <T extends Object> FooSparseArrayKt.isNotEmpty(
    @NonNull FooSparseArray<@NonNull T> receiver
)

Return true when the collection contains elements.

FooSparseArrayKt.keyIterator

default final @NonNull LongIterator <T extends Object> FooSparseArrayKt.keyIterator(
    @NonNull FooSparseArray<@NonNull T> receiver
)

Return an iterator over the collection's keys.

FooSparseArrayKt.set

default final void <T extends Object> FooSparseArrayKt.set(
    @NonNull FooSparseArray<@NonNull T> receiver,
    long key,
    @NonNull T value
)

Allows the use of the index operator for storing values in the collection.

FooSparseArrayKt.valueIterator

default final @NonNull Iterator<@NonNull T> <T extends Object> FooSparseArrayKt.valueIterator(
    @NonNull FooSparseArray<@NonNull T> receiver
)

Return an iterator over the collection's values.