AbstractMap

AbstractMap

protected AbstractMap()

Sole constructor. (For invocation by subclass constructors, typically implicit.)

clear

open fun clear(): Unit

Removes all of the mappings from this map (optional operation). The map will be empty after this call returns.

containsKey

open fun containsKey(key: K?): Boolean

Returns true if this map contains a mapping for the specified key. More formally, returns true if and only if this map contains a mapping for a key k such that Objects.equals(key, k). (There can be at most one such mapping.)

containsValue

open fun containsValue(value: V?): Boolean

Returns true if this map maps one or more keys to the specified value. More formally, returns true if and only if this map contains at least one mapping to a value v such that Objects.equals(value, v). This operation will probably require time linear in the map size for most implementations of the Map interface.

equals

open fun equals(other: Any?): Boolean

Compares the specified object with this map for equality. Returns true if the given object is also a map and the two maps represent the same mappings. More formally, two maps m1 and m2 represent the same mappings if m1.entrySet().equals(m2.entrySet()). This ensures that the equals method works properly across different implementations of the Map interface.

get

open fun get(key: K?): V?

Returns the value to which the specified key is mapped, or null if this map contains no mapping for the key.

More formally, if this map contains a mapping from a key k to a value v such that Objects.equals(key, k), then this method returns v; otherwise it returns null. (There can be at most one such mapping.)

If this map permits null values, then a return value of null does not necessarily indicate that the map contains no mapping for the key; it's also possible that the map explicitly maps the key to null. The containsKey operation may be used to distinguish these two cases.

hashCode

open fun hashCode(): Int

Returns the hash code value for this map. The hash code of a map is defined to be the sum of the hash codes of each entry in the map's entrySet() view. This ensures that m1.equals(m2) implies that m1.hashCode()==m2.hashCode() for any two maps m1 and m2, as required by the general contract of Object.hashCode.

isEmpty

open fun isEmpty(): Boolean

Returns true if this map contains no key-value mappings.

put

open fun put(
    key: K, 
    value: V
): V?

Associates the specified value with the specified key in this map (optional operation). If the map previously contained a mapping for the key, the old value is replaced by the specified value. (A map m is said to contain a mapping for a key k if and only if m.containsKey(k) would return true.)

putAll

open fun putAll(from: Map<out K, V>): Unit

Copies all of the mappings from the specified map to this map (optional operation). The effect of this call is equivalent to that of calling put(k, v) on this map once for each mapping from key k to value v in the specified map. The behavior of this operation is undefined if the specified map is modified while the operation is in progress. If the specified map has a defined encounter order, processing of its mappings generally occurs in that order.

remove

open fun remove(key: K?): V?

Removes the mapping for a key from this map if it is present (optional operation). More formally, if this map contains a mapping from key k to value v such that Objects.equals(key, k), that mapping is removed. (The map can contain at most one such mapping.)

Returns the value to which this map previously associated the key, or null if the map contained no mapping for the key.

If this map permits null values, then a return value of null does not necessarily indicate that the map contained no mapping for the key; it's also possible that the map explicitly mapped the key to null.

The map will not contain a mapping for the specified key once the call returns.

toString

open fun toString(): String

Returns a string representation of this map. The string representation consists of a list of key-value mappings in the order returned by the map's entrySet view's iterator, enclosed in braces ("{}"). Adjacent mappings are separated by the characters ", " (comma and space). Each key-value mapping is rendered as the key followed by an equals sign ("=") followed by the associated value. Keys and values are converted to strings as by String.valueOf(Object).

clone

protected open fun clone(): Any

Returns a shallow copy of this AbstractMap instance: the keys and values themselves are not cloned.

entries

abstract val entries: MutableSet<MutableEntry<K, V>>

keys

open val keys: MutableSet<K>

Returns a Set view of the keys contained in this map. The set is backed by the map, so changes to the map are reflected in the set, and vice-versa. If the map is modified while an iteration over the set is in progress (except through the iterator's own remove operation), the results of the iteration are undefined. The set supports element removal, which removes the corresponding mapping from the map, via the Iterator.remove, Set.remove, removeAll, retainAll, and clear operations. It does not support the add or addAll operations.

size

open val size: Int

Returns the number of key-value mappings in this map. If the map contains more than Integer.MAX_VALUE elements, returns Integer.MAX_VALUE.

values

open val values: MutableCollection<V>

Returns a Collection view of the values contained in this map. The collection is backed by the map, so changes to the map are reflected in the collection, and vice-versa. If the map is modified while an iteration over the collection is in progress (except through the iterator's own remove operation), the results of the iteration are undefined. The collection supports element removal, which removes the corresponding mapping from the map, via the Iterator.remove, Collection.remove, removeAll, retainAll and clear operations. It does not support the add or addAll operations.