Most visited

Recently visited

Results for

Summary: Ctors | Methods | Inherited Methods | [Expand All]

ArrayMap

public class ArrayMap
extends SimpleArrayMap<K, V> implements Map<K, V>

java.lang.Object
↳	android.support.v4.util.SimpleArrayMap<K, V>
	↳	android.support.v4.util.ArrayMap<K, V>

Known Direct Subclasses

ObservableArrayMap<K, V>

ArrayMap is a generic key->value mapping data structure that is designed to be more memory efficient than a traditional HashMap, this implementation is a version of the platform's ArrayMap that can be used on older versions of the platform. It keeps its mappings in an array data structure -- an integer array of hash codes for each item, and an Object array of the key/value pairs. This allows it to avoid having to create an extra object for every entry put in to the map, and it also tries to control the growth of the size of these arrays more aggressively (since growing them only requires copying the entries in the array, not rebuilding a hash map).

If you don't need the standard Java container APIs provided here (iterators etc), consider using SimpleArrayMap instead.

Note that this 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%.

Because this container is intended to better balance memory use, unlike most other standard Java containers it will shrink its array as items are removed from it. Currently you have no control over this shrinking -- if you set a capacity and then remove an item, it may reduce the capacity to better match the current size. In the future an explicit call to set the capacity should turn off this aggressive shrinking behavior.

Summary

Public constructors
`ArrayMap()`
`ArrayMap(int capacity)` Create a new ArrayMap with a given initial capacity.
`ArrayMap(SimpleArrayMap map)` Create a new ArrayMap with the mappings from the given ArrayMap.

Public methods
`boolean`	`containsAll(Collection<?> collection)` Determine if the array map contains all of the keys in the given collection.
`Set<Entry<K, V>>`	`entrySet()` Return a `Set` for iterating over and interacting with all mappings in the array map.
`Set<K>`	`keySet()` Return a `Set` for iterating over and interacting with all keys in the array map.
`void`	`putAll(Map<? extends K, ? extends V> map)` Perform a `put(Object, Object)` of all key/value pairs in `map`
`boolean`	`removeAll(Collection<?> collection)` Remove all keys in the array map that exist in the given collection.
`boolean`	`retainAll(Collection<?> collection)` Remove all keys in the array map that do not exist in the given collection.
`Collection<V>`	`values()` Return a `Collection` for iterating over and interacting with all values in the array map.

Inherited methods

From class


  
    android.support.v4.util.SimpleArrayMap

`void`	`clear()` Make the array map empty.
`boolean`	`containsKey(Object key)` Check whether a key exists in the array.
`boolean`	`containsValue(Object value)` Check whether a value exists in the array.
`void`	`ensureCapacity(int minimumCapacity)` Ensure the array map can hold at least `minimumCapacity` items.
`boolean`	`equals(Object object)` Indicates whether some other object is "equal to" this one. This implementation returns false if the object is not a Map or SimpleArrayMap, or if the maps have different sizes.
`V`	`get(Object key)` Retrieve a value from the array.
`int`	`hashCode()` Returns a hash code value for the object.
`int`	`indexOfKey(Object key)` Returns the index of a key in the set.
`boolean`	`isEmpty()` Return true if the array map contains no items.
`K`	`keyAt(int index)` Return the key at the given index in the array.
`V`	`put(K key, V value)` Add a new value to the array map.
`void`	`putAll(SimpleArrayMap<? extends K, ? extends V> array)` Perform a `put(Object, Object)` of all key/value pairs in `array`
`V`	`remove(Object key)` Remove an existing key from the array map.
`V`	`removeAt(int index)` Remove the key/value mapping at the given index.
`V`	`setValueAt(int index, V value)` Set the value at a given index in the array.
`int`	`size()` Return the number of items in this array map.
`String`	`toString()` Returns a string representation of the object. This implementation composes a string by iterating over its mappings.
`V`	`valueAt(int index)` Return the value at the given index in the array.

From class


  
    java.lang.Object

`Object`	`clone()` Creates and returns a copy of this object.
`boolean`	`equals(Object obj)` Indicates whether some other object is "equal to" this one.
`void`	`finalize()` Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.
`final Class<?>`	`getClass()` Returns the runtime class of this `Object`.
`int`	`hashCode()` Returns a hash code value for the object.
`final void`	`notify()` Wakes up a single thread that is waiting on this object's monitor.
`final void`	`notifyAll()` Wakes up all threads that are waiting on this object's monitor.
`String`	`toString()` Returns a string representation of the object.
`final void`	`wait(long millis, int nanos)` Causes the current thread to wait until another thread invokes the `notify()` method or the `notifyAll()` method for this object, or some other thread interrupts the current thread, or a certain amount of real time has elapsed.
`final void`	`wait(long millis)` Causes the current thread to wait until either another thread invokes the `notify()` method or the `notifyAll()` method for this object, or a specified amount of time has elapsed.
`final void`	`wait()` Causes the current thread to wait until another thread invokes the `notify()` method or the `notifyAll()` method for this object.

From interface


  
    java.util.Map

`abstract void`	`clear()` Removes all of the mappings from this map (optional operation).
`default V`	`compute(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction)` Attempts to compute a mapping for the specified key and its current mapped value (or `null` if there is no current mapping).
`default V`	`computeIfAbsent(K key, Function<? super K, ? extends V> mappingFunction)` If the specified key is not already associated with a value (or is mapped to `null`), attempts to compute its value using the given mapping function and enters it into this map unless `null`.
`default V`	`computeIfPresent(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction)` If the value for the specified key is present and non-null, attempts to compute a new mapping given the key and its current mapped value.
`abstract boolean`	`containsKey(Object key)` Returns `true` if this map contains a mapping for the specified key.
`abstract boolean`	`containsValue(Object value)` Returns `true` if this map maps one or more keys to the specified value.
`abstract Set<Entry<K, V>>`	`entrySet()` Returns a `Set` view of the mappings contained in this map.
`abstract boolean`	`equals(Object o)` Compares the specified object with this map for equality.
`default void`	`forEach(BiConsumer<? super K, ? super V> action)` Performs the given action for each entry in this map until all entries have been processed or the action throws an exception.
`abstract V`	`get(Object key)` Returns the value to which the specified key is mapped, or `null` if this map contains no mapping for the key.
`default V`	`getOrDefault(Object key, V defaultValue)` Returns the value to which the specified key is mapped, or `defaultValue` if this map contains no mapping for the key.
`abstract int`	`hashCode()` Returns the hash code value for this map.
`abstract boolean`	`isEmpty()` Returns `true` if this map contains no key-value mappings.
`abstract Set<K>`	`keySet()` Returns a `Set` view of the keys contained in this map.
`default V`	`merge(K key, V value, BiFunction<? super V, ? super V, ? extends V> remappingFunction)` If the specified key is not already associated with a value or is associated with null, associates it with the given non-null value.
`abstract V`	`put(K key, V value)` Associates the specified value with the specified key in this map (optional operation).
`abstract void`	`putAll(Map<? extends K, ? extends V> m)` Copies all of the mappings from the specified map to this map (optional operation).
`default V`	`putIfAbsent(K key, V value)` If the specified key is not already associated with a value (or is mapped to `null`) associates it with the given value and returns `null`, else returns the current value.
`default boolean`	`remove(Object key, Object value)` Removes the entry for the specified key only if it is currently mapped to the specified value.
`abstract V`	`remove(Object key)` Removes the mapping for a key from this map if it is present (optional operation).
`default boolean`	`replace(K key, V oldValue, V newValue)` Replaces the entry for the specified key only if currently mapped to the specified value.
`default V`	`replace(K key, V value)` Replaces the entry for the specified key only if it is currently mapped to some value.
`default void`	`replaceAll(BiFunction<? super K, ? super V, ? extends V> function)` Replaces each entry's value with the result of invoking the given function on that entry until all entries have been processed or the function throws an exception.
`abstract int`	`size()` Returns the number of key-value mappings in this map.
`abstract Collection<V>`	`values()` Returns a `Collection` view of the values contained in this map.

Public constructors

ArrayMap

ArrayMap ()

ArrayMap

ArrayMap (int capacity)

Create a new ArrayMap with a given initial capacity.

Parameters
`capacity`	`int`

ArrayMap

ArrayMap (SimpleArrayMap map)

Create a new ArrayMap with the mappings from the given ArrayMap.

Parameters
`map`	`SimpleArrayMap`

Public methods

containsAll

boolean containsAll (Collection<?> collection)

Determine if the array map contains all of the keys in the given collection.

Parameters
`collection`	`Collection`: The collection whose contents are to be checked against.

Returns
`boolean`	Returns true if this array map contains a key for every entry in `collection`, else returns false.

entrySet

Set<Entry<K, V>> entrySet ()

Return a Set for iterating over and interacting with all mappings in the array map.

Note: this is a very inefficient way to access the array contents, it requires generating a number of temporary objects.

Note:

the semantics of this Set are subtly different than that of a HashMap: most important, the Map.Entry object returned by its iterator is a single object that exists for the entire iterator, so you can not hold on to it after calling Iterator.next.

Returns
`Set<Entry<K, V>>`	a set view of the mappings contained in this map

keySet

Set<K> keySet ()

Return a Set for iterating over and interacting with all keys in the array map.

Note: this is a fairly inefficient way to access the array contents, it requires generating a number of temporary objects.

Returns
`Set<K>`	a set view of the keys contained in this map

putAll

void putAll (Map<? extends K, ? extends V> map)

Perform a put(Object, Object) of all key/value pairs in map

Parameters
`map`	`Map`: The map whose contents are to be retrieved.

removeAll

boolean removeAll (Collection<?> collection)

Remove all keys in the array map that exist in the given collection.

Parameters
`collection`	`Collection`: The collection whose contents are to be used to remove keys.

Returns
`boolean`	Returns true if any keys were removed from the array map, else false.

retainAll

boolean retainAll (Collection<?> collection)

Remove all keys in the array map that do not exist in the given collection.

Parameters
`collection`	`Collection`: The collection whose contents are to be used to determine which keys to keep.

Returns
`boolean`	Returns true if any keys were removed from the array map, else false.

values

Collection<V> values ()

Return a Collection for iterating over and interacting with all values in the array map.

Note: this is a fairly inefficient way to access the array contents, it requires generating a number of temporary objects.

Returns
`Collection<V>`	a collection view of the values contained in this map

Interfaces

Classes

Most visited

Recently visited

Results for

ArrayMap

Summary

Public constructors

Public methods

Inherited methods

Public constructors

ArrayMap

ArrayMap

ArrayMap

Public methods

containsAll

entrySet

keySet

putAll

removeAll

retainAll

values