implements Cloneable
SparseLongArrays map integers to longs. Unlike a normal array of longs, there can be gaps in the indices. It is intended to be more memory efficient than using a HashMap to map Integers to Longs, both because it avoids auto-boxing keys and values 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%.
It is possible to iterate over the items in this container using
keyAt(int)
and valueAt(int)
. Iterating over the keys using
keyAt(int)
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(int)
.
Public Constructor Summary
SparseLongArray()
Creates a new SparseLongArray containing no mappings.
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SparseLongArray(int initialCapacity)
Creates a new SparseLongArray containing no mappings that will not
require any additional memory allocation to store the specified
number of mappings.
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Public Method Summary
void |
append(int key, long 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.
|
void |
clear()
Removes all key-value mappings from this SparseIntArray.
|
SparseLongArray |
clone()
|
void |
delete(int key)
Removes the mapping from the specified key, if there was any.
|
long |
get(int key)
Gets the long mapped from the specified key, or
0
if no such mapping has been made. |
long |
get(int key, long valueIfKeyNotFound)
Gets the long mapped from the specified key, or the specified value
if no such mapping has been made.
|
int |
indexOfKey(int key)
Returns the index for which
keyAt(int) would return the
specified key, or a negative number if the specified
key is not mapped. |
int |
indexOfValue(long value)
Returns an index for which
valueAt(int) would return the
specified key, or a negative number if no keys map to the
specified value. |
int |
keyAt(int index)
Given an index in the range
0...size()-1 , returns
the key from the index th key-value mapping that this
SparseLongArray stores. |
void |
put(int key, long value)
Adds a mapping from the specified key to the specified value,
replacing the previous mapping from the specified key if there
was one.
|
void |
removeAt(int index)
Removes the mapping at the given index.
|
int |
size()
Returns the number of key-value mappings that this SparseIntArray
currently stores.
|
String |
toString()
This implementation composes a string by iterating over its mappings. |
long |
valueAt(int index)
Given an index in the range
0...size()-1 , returns
the value from the index th key-value mapping that this
SparseLongArray stores. |
Inherited Method Summary
Public Constructors
public SparseLongArray ()
Creates a new SparseLongArray containing no mappings.
public SparseLongArray (int initialCapacity)
Creates a new SparseLongArray 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.
Parameters
initialCapacity |
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Public Methods
public void append (int key, long 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.
Parameters
key | |
---|---|
value |
public void clear ()
Removes all key-value mappings from this SparseIntArray.
public void delete (int key)
Removes the mapping from the specified key, if there was any.
Parameters
key |
---|
public long get (int key)
Gets the long mapped from the specified key, or 0
if no such mapping has been made.
Parameters
key |
---|
public long get (int key, long valueIfKeyNotFound)
Gets the long mapped from the specified key, or the specified value if no such mapping has been made.
Parameters
key | |
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valueIfKeyNotFound |
public int indexOfKey (int key)
Returns the index for which keyAt(int)
would return the
specified key, or a negative number if the specified
key is not mapped.
Parameters
key |
---|
public int indexOfValue (long value)
Returns an index for which valueAt(int)
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.
Parameters
value |
---|
public int keyAt (int index)
Given an index in the range 0...size()-1
, returns
the key from the index
th key-value mapping that this
SparseLongArray 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.
Parameters
index |
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public void put (int key, long value)
Adds a mapping from the specified key to the specified value, replacing the previous mapping from the specified key if there was one.
Parameters
key | |
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value |
public void removeAt (int index)
Removes the mapping at the given index.
Parameters
index |
---|
public int size ()
Returns the number of key-value mappings that this SparseIntArray currently stores.
public String toString ()
This implementation composes a string by iterating over its mappings.
public long valueAt (int index)
Given an index in the range 0...size()-1
, returns
the value from the index
th key-value mapping that this
SparseLongArray 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.
Parameters
index |
---|