@GwtCompatible(serializable=true, emulated=true) public abstract class ImmutableMap<K,V> extends Object implements Map<K,V>, Serializable
Map
with reliable user-specified iteration
order. Does not permit null keys or values.
Unlike Collections.unmodifiableMap(java.util.Map<? extends K, ? extends V>)
, which is a view of a
separate map which can still change, an instance of ImmutableMap
contains its own data and will never change. ImmutableMap
is
convenient for public static final
maps ("constant maps") and also
lets you easily make a "defensive copy" of a map provided to your class by a
caller.
Performance notes: unlike HashMap
, ImmutableMap
is
not optimized for element types that have slow Object.equals(java.lang.Object)
or
Object.hashCode()
implementations. You can get better performance by
having your element type cache its own hash codes, and by making use of the
cached values to short-circuit a slow equals
algorithm.
See the Guava User Guide article on immutable collections.
Modifier and Type | Class and Description |
---|---|
static class |
ImmutableMap.Builder<K,V>
A builder for creating immutable map instances, especially
public
static final maps ("constant maps"). |
Modifier and Type | Method and Description |
---|---|
ImmutableSetMultimap<K,V> |
asMultimap()
Returns a multimap view of the map.
|
static <K,V> ImmutableMap.Builder<K,V> |
builder()
Returns a new builder.
|
void |
clear()
Deprecated.
Unsupported operation.
|
boolean |
containsKey(Object key) |
boolean |
containsValue(Object value) |
static <K,V> ImmutableMap<K,V> |
copyOf(Map<? extends K,? extends V> map)
Returns an immutable map containing the same entries as
map . |
ImmutableSet<Map.Entry<K,V>> |
entrySet()
Returns an immutable set of the mappings in this map.
|
boolean |
equals(Object object) |
abstract V |
get(Object key) |
int |
hashCode() |
boolean |
isEmpty() |
ImmutableSet<K> |
keySet()
Returns an immutable set of the keys in this map.
|
static <K,V> ImmutableMap<K,V> |
of()
Returns the empty map.
|
static <K,V> ImmutableMap<K,V> |
of(K k1,
V v1)
Returns an immutable map containing a single entry.
|
static <K,V> ImmutableMap<K,V> |
of(K k1,
V v1,
K k2,
V v2)
Returns an immutable map containing the given entries, in order.
|
static <K,V> ImmutableMap<K,V> |
of(K k1,
V v1,
K k2,
V v2,
K k3,
V v3)
Returns an immutable map containing the given entries, in order.
|
static <K,V> ImmutableMap<K,V> |
of(K k1,
V v1,
K k2,
V v2,
K k3,
V v3,
K k4,
V v4)
Returns an immutable map containing the given entries, in order.
|
static <K,V> ImmutableMap<K,V> |
of(K k1,
V v1,
K k2,
V v2,
K k3,
V v3,
K k4,
V v4,
K k5,
V v5)
Returns an immutable map containing the given entries, in order.
|
V |
put(K k,
V v)
Deprecated.
Unsupported operation.
|
void |
putAll(Map<? extends K,? extends V> map)
Deprecated.
Unsupported operation.
|
V |
remove(Object o)
Deprecated.
Unsupported operation.
|
String |
toString() |
ImmutableCollection<V> |
values()
Returns an immutable collection of the values in this map.
|
public static <K,V> ImmutableMap<K,V> of()
Collections.emptyMap()
, and is preferable mainly for consistency
and maintainability of your code.public static <K,V> ImmutableMap<K,V> of(K k1, V v1)
Collections.singletonMap(K, V)
but will not accept
a null key or value. It is preferable mainly for consistency and
maintainability of your code.public static <K,V> ImmutableMap<K,V> of(K k1, V v1, K k2, V v2)
IllegalArgumentException
- if duplicate keys are providedpublic static <K,V> ImmutableMap<K,V> of(K k1, V v1, K k2, V v2, K k3, V v3)
IllegalArgumentException
- if duplicate keys are providedpublic static <K,V> ImmutableMap<K,V> of(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4)
IllegalArgumentException
- if duplicate keys are providedpublic static <K,V> ImmutableMap<K,V> of(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4, K k5, V v5)
IllegalArgumentException
- if duplicate keys are providedpublic static <K,V> ImmutableMap.Builder<K,V> builder()
ImmutableMap.Builder
constructor.public static <K,V> ImmutableMap<K,V> copyOf(Map<? extends K,? extends V> map)
map
. If
map
somehow contains entries with duplicate keys (for example, if
it is a SortedMap
whose comparator is not consistent with
equals), the results of this method are undefined.
Despite the method name, this method attempts to avoid actually copying the data when it is safe to do so. The exact circumstances under which a copy will or will not be performed are undocumented and subject to change.
NullPointerException
- if any key or value in map
is null@Deprecated public final V put(K k, V v)
put
in interface Map<K,V>
UnsupportedOperationException
- always@Deprecated public final V remove(Object o)
remove
in interface Map<K,V>
UnsupportedOperationException
- always@Deprecated public final void putAll(Map<? extends K,? extends V> map)
putAll
in interface Map<K,V>
UnsupportedOperationException
- always@Deprecated public final void clear()
clear
in interface Map<K,V>
UnsupportedOperationException
- alwayspublic boolean containsKey(@Nullable Object key)
containsKey
in interface Map<K,V>
public boolean containsValue(@Nullable Object value)
containsValue
in interface Map<K,V>
public ImmutableSet<Map.Entry<K,V>> entrySet()
public ImmutableSet<K> keySet()
public ImmutableCollection<V> values()
@Beta public ImmutableSetMultimap<K,V> asMultimap()
public int hashCode()
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