public class SparseBooleanArray extends Object
implements Cloneable

SparseBooleanArrays map integers to booleans. Unlike a normal array of booleans there can be gaps in the indices. It is intended to be more memory efficient than using a HashMap to map Integers to Booleans, 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

Creates a new SparseBooleanArray containing no mappings.
SparseBooleanArray(int initialCapacity)
Creates a new SparseBooleanArray containing no mappings that will not require any additional memory allocation to store the specified number of mappings.

Public Method Summary

append(int key, boolean 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.
Removes all key-value mappings from this SparseBooleanArray.
delete(int key)
Removes the mapping from the specified key, if there was any.
get(int key)
Gets the boolean mapped from the specified key, or false if no such mapping has been made.
get(int key, boolean valueIfKeyNotFound)
Gets the boolean mapped from the specified key, or the specified value if no such mapping has been made.