Class ArrayMap<K,V>
- Type Parameters:
K
- the type of keys maintained by this mapV
- the type of mapped values
Supports null keys and values. Conceptually, the keys and values are stored in a simpler array
in order to minimize memory use and provide for fast access to a key/value at a certain index
(for example getKey(int)
). However, traditional mapping operations like get(Object)
and put(Object, Object)
are slower because they need to look up all
key/value pairs in the worst case.
Implementation is not thread-safe. For a thread-safe choice instead use an implementation of
ConcurrentMap
.
- Since:
- 1.0
-
Nested Class Summary
Nested ClassesModifier and TypeClassDescription(package private) final class
(package private) final class
(package private) final class
Nested classes/interfaces inherited from class java.util.AbstractMap
AbstractMap.SimpleEntry<K,
V>, AbstractMap.SimpleImmutableEntry<K, V> -
Field Summary
Fields -
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionfinal void
Adds the key/value mapping at the end of the list.void
clear()
clone()
final boolean
containsKey
(Object key) Returns whether there is a mapping for the given key.final boolean
containsValue
(Object value) static <K,
V> ArrayMap <K, V> create()
Returns a new instance of an array map with initial capacity of zero.static <K,
V> ArrayMap <K, V> create
(int initialCapacity) Returns a new instance of an array map of the given initial capacity.final void
ensureCapacity
(int minCapacity) Ensures that the capacity of the internal arrays is at least a given capacity.entrySet()
final V
Returns the value set for the given key ornull
if there is no such mapping or if the mapping value isnull
.private int
getDataIndexOfKey
(Object key) Returns the data index of the given key or-2
if there is no such key.final int
getIndexOfKey
(K key) Returns the index of the given key or-1
if there is no such key.final K
getKey
(int index) Returns the key at the given index ornull
if out of bounds.final V
getValue
(int index) Returns the value at the given index ornull
if out of bounds.static <K,
V> ArrayMap <K, V> Returns a new instance of an array map of the given key value pairs in alternating order.final V
Sets the value for the given key, overriding any existing value.final V
remove
(int index) Removes the key/value mapping at the given index, or ignored if the index is out of bounds.final V
Removes the key-value pair of the given key, or ignore if the key cannot be found.private V
removeFromDataIndexOfKey
(int dataIndexOfKey) Removes the key/value mapping at the given data index of key, or ignored if the index is out of bounds.final V
Sets the key/value mapping at the given index, overriding any existing key/value mapping.final V
Sets the value at the given index, overriding any existing value mapping.private void
private void
setDataCapacity
(int newDataCapacity) final int
size()
Returns the number of key-value pairs set.final void
trim()
Trims the internal array storage to minimize memory usage.private V
valueAtDataIndex
(int dataIndex) Methods inherited from class java.util.AbstractMap
equals, hashCode, isEmpty, keySet, putAll, toString, values
Methods inherited from class java.lang.Object
finalize, getClass, notify, notifyAll, wait, wait, wait
Methods inherited from interface java.util.Map
compute, computeIfAbsent, computeIfPresent, forEach, getOrDefault, merge, putIfAbsent, remove, replace, replace, replaceAll
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Field Details
-
size
int size -
data
-
-
Constructor Details
-
ArrayMap
public ArrayMap()
-
-
Method Details
-
create
Returns a new instance of an array map with initial capacity of zero. Equivalent to calling the default constructor, except without the need to specify the type parameters. For example:ArrayMap<String, String> map = ArrayMap.create();
. -
create
Returns a new instance of an array map of the given initial capacity. For example:ArrayMap<String, String> map = ArrayMap.create(8);
. -
of
Returns a new instance of an array map of the given key value pairs in alternating order. For example:ArrayMap<String, String> map = ArrayMap.of("key1", "value1", "key2", "value2", ...);
.WARNING: there is no compile-time checking of the
keyValuePairs
parameter to ensure that the keys or values have the correct type, so if the wrong type is passed in, any problems will occur at runtime. Also, there is no checking that the keys are unique, which the caller must ensure is true. -
size
public final int size()Returns the number of key-value pairs set. -
getKey
Returns the key at the given index ornull
if out of bounds. -
getValue
Returns the value at the given index ornull
if out of bounds. -
set
Sets the key/value mapping at the given index, overriding any existing key/value mapping.There is no checking done to ensure that the key does not already exist. Therefore, this method is dangerous to call unless the caller can be certain the key does not already exist in the map.
- Returns:
- previous value or
null
for none - Throws:
IndexOutOfBoundsException
- if index is negative
-
set
Sets the value at the given index, overriding any existing value mapping.- Returns:
- previous value or
null
for none - Throws:
IndexOutOfBoundsException
- if index is negative or>=
size
-
add
Adds the key/value mapping at the end of the list. Behaves identically toset(size(), key, value)
.- Throws:
IndexOutOfBoundsException
- if index is negative
-
remove
Removes the key/value mapping at the given index, or ignored if the index is out of bounds.- Returns:
- previous value or
null
for none
-
containsKey
Returns whether there is a mapping for the given key.- Specified by:
containsKey
in interfaceMap<K,
V> - Overrides:
containsKey
in classAbstractMap<K,
V>
-
getIndexOfKey
Returns the index of the given key or-1
if there is no such key. -
get
Returns the value set for the given key ornull
if there is no such mapping or if the mapping value isnull
. -
put
Sets the value for the given key, overriding any existing value. -
remove
Removes the key-value pair of the given key, or ignore if the key cannot be found. -
trim
public final void trim()Trims the internal array storage to minimize memory usage. -
ensureCapacity
public final void ensureCapacity(int minCapacity) Ensures that the capacity of the internal arrays is at least a given capacity. -
setDataCapacity
private void setDataCapacity(int newDataCapacity) -
setData
-
valueAtDataIndex
-
getDataIndexOfKey
Returns the data index of the given key or-2
if there is no such key. -
removeFromDataIndexOfKey
Removes the key/value mapping at the given data index of key, or ignored if the index is out of bounds. -
clear
public void clear() -
containsValue
- Specified by:
containsValue
in interfaceMap<K,
V> - Overrides:
containsValue
in classAbstractMap<K,
V>
-
entrySet
-
clone
- Overrides:
clone
in classAbstractMap<K,
V>
-