public class LongSparseArray<E> extends Object implements Cloneable
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 the map size or entry values are retrieved.
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).
| 构造器和说明 |
|---|
LongSparseArray()
Creates a new LongSparseArray containing no mappings.
|
LongSparseArray(int initialCapacity)
Creates a new LongSparseArray containing no mappings that will not
require any additional memory allocation to store the specified
number of mappings.
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| 限定符和类型 | 方法和说明 |
|---|---|
void |
append(long key,
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.
|
void |
clear()
Removes all key-value mappings from this LongSparseArray.
|
LongSparseArray<E> |
clone() |
void |
delete(long key)
Removes the mapping from the specified key, if there was any.
|
E |
get(long key)
Gets the Object mapped from the specified key, or
null
if no such mapping has been made. |
E |
get(long key,
E valueIfKeyNotFound)
Gets the Object mapped from the specified key, or the specified Object
if no such mapping has been made.
|
int |
indexOfKey(long 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(E 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 |
indexOfValueByValue(E 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. |
long |
keyAt(int index)
Given an index in the range
0...size()-1, returns
the key from the indexth key-value mapping that this
LongSparseArray stores. |
void |
put(long key,
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.
|
void |
remove(long key)
Alias for
delete(long). |
void |
removeAt(int index)
Removes the mapping at the specified index.
|
void |
setValueAt(int index,
E value)
Given an index in the range
0...size()-1, sets a new
value for the indexth key-value mapping that this
LongSparseArray stores. |
int |
size()
Returns the number of key-value mappings that this LongSparseArray
currently stores.
|
String |
toString()
This implementation composes a string by iterating over its mappings.
|
E |
valueAt(int index)
Given an index in the range
0...size()-1, returns
the value from the indexth key-value mapping that this
LongSparseArray stores. |
public LongSparseArray()
public LongSparseArray(int initialCapacity)
public LongSparseArray<E> clone()
public E get(long key)
null
if no such mapping has been made.public E get(long key, E valueIfKeyNotFound)
public void delete(long key)
public void remove(long key)
delete(long).public void removeAt(int index)
public void put(long key,
E value)
public int size()
public long keyAt(int index)
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.
public E valueAt(int index)
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.
public void setValueAt(int index,
E value)
0...size()-1, sets a new
value for the indexth key-value mapping that this
LongSparseArray stores.public int indexOfKey(long key)
keyAt(int) would return the
specified key, or a negative number if the specified
key is not mapped.public int indexOfValue(E value)
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.public int indexOfValueByValue(E value)
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.
Note also that this method uses equals unlike indexOfValue.
public void clear()
public void append(long key,
E value)
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