## com.google.common.collect
Class ImmutableMap<K,V>

    java.lang.Object
      com.google.common.collect.ImmutableMap<K,V>

All Implemented Interfaces:
  Serializable, Map<K,V>

Direct Known Subclasses:
  ImmutableBiMap, ImmutableSortedMap

    @GwtCompatible(serializable=true,
                   emulated=true)
    public abstract class ImmutableMap<K,V>

extends Object
implements Map<K,V>, Serializable

An immutable, hash-based `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.

Since:
  2.0 (imported from Google Collections Library)
Author:
  Jesse Wilson, Kevin Bourrillion
See Also:
  Serialized Form

Nested Class Summary
`static class` `ImmutableMap.Builder<K,V>` A builder for creating immutable map instances, especially `public static final` maps ("constant maps").

Nested classes/interfaces inherited from interface java.util.Map
`Map.Entry<K,V>`

Method Summary

`static

`<K,V> ImmutableMap.Builder<K,V>`

`

`builder()`
Returns a new builder.

`void` `clear()` Guaranteed to throw an exception and leave the map unmodified.
`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)` Guaranteed to throw an exception and leave the map unmodified.
`void` `putAll(Map<? extends K,? extends V> map)` Guaranteed to throw an exception and leave the map unmodified.
`V` `remove(Object o)` Guaranteed to throw an exception and leave the map unmodified.
`String` `toString()`
`ImmutableCollection<V>` `values()` Returns an immutable collection of the values in this map.

Methods inherited from class java.lang.Object
`clone, finalize, getClass, notify, notifyAll, wait, wait, wait`

Methods inherited from interface java.util.Map
`size`

Method Detail

### of

    public static <K,V> ImmutableMap<K,V> of()

  Returns the empty map. This map behaves and performs comparably to `Collections.emptyMap()`, and is preferable mainly for consistency and maintainability of your code.

### of

    public static <K,V> ImmutableMap<K,V> of(K k1,
                                             V v1)

  Returns an immutable map containing a single entry. This map behaves and performs comparably to `Collections.singletonMap(K, V)` but will not accept a null key or value. It is preferable mainly for consistency and maintainability of your code.

### of

    public 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.

  Throws:
    `IllegalArgumentException` - if duplicate keys are provided

### of

    public 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.

  Throws:
    `IllegalArgumentException` - if duplicate keys are provided

### of

    public 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.

  Throws:
    `IllegalArgumentException` - if duplicate keys are provided

### of

    public 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.

  Throws:
    `IllegalArgumentException` - if duplicate keys are provided

### builder

    public static <K,V> ImmutableMap.Builder<K,V> builder()

  Returns a new builder. The generated builder is equivalent to the builder created by the `ImmutableMap.Builder` constructor.

### copyOf

    public static <K,V> ImmutableMap<K,V> copyOf(Map<? extends K,? extends V> map)

  Returns an immutable map containing the same entries as `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.

  Throws:
    `NullPointerException` - if any key or value in `map` is null

### put

    public final V put(K k,
                       V v)

  Guaranteed to throw an exception and leave the map unmodified.

  Specified by:
    `put` in interface `Map<K,V>`
  Throws:
    `UnsupportedOperationException` - always

### remove

    public final V remove(Object o)

  Guaranteed to throw an exception and leave the map unmodified.

  Specified by:
    `remove` in interface `Map<K,V>`
  Throws:
    `UnsupportedOperationException` - always

### putAll

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

  Guaranteed to throw an exception and leave the map unmodified.

  Specified by:
    `putAll` in interface `Map<K,V>`
  Throws:
    `UnsupportedOperationException` - always

### clear

    public final void clear()

  Guaranteed to throw an exception and leave the map unmodified.

  Specified by:
    `clear` in interface `Map<K,V>`
  Throws:
    `UnsupportedOperationException` - always

### isEmpty

    public boolean isEmpty()

  Specified by:
    `isEmpty` in interface `Map<K,V>`

### containsKey

    public boolean containsKey(@Nullable
                               Object key)

  Specified by:
    `containsKey` in interface `Map<K,V>`

### containsValue

    public boolean containsValue(@Nullable
                                 Object value)

  Specified by:
    `containsValue` in interface `Map<K,V>`

### get

    public abstract V get(@Nullable
                          Object key)

  Specified by:
    `get` in interface `Map<K,V>`

### entrySet

    public ImmutableSet<Map.Entry<K,V>> entrySet()

  Returns an immutable set of the mappings in this map. The entries are in the same order as the parameters used to build this map.

  Specified by:
    `entrySet` in interface `Map<K,V>`

### keySet

    public ImmutableSet<K> keySet()

  Returns an immutable set of the keys in this map. These keys are in the same order as the parameters used to build this map.

  Specified by:
    `keySet` in interface `Map<K,V>`

### values

    public ImmutableCollection<V> values()

  Returns an immutable collection of the values in this map. The values are in the same order as the parameters used to build this map.

  Specified by:
    `values` in interface `Map<K,V>`

### equals

    public boolean equals(@Nullable
                          Object object)

  Specified by:
    `equals` in interface `Map<K,V>`
  Overrides:
    `equals` in class `Object`

### hashCode

    public int hashCode()

  Specified by:
    `hashCode` in interface `Map<K,V>`
  Overrides:
    `hashCode` in class `Object`

### toString

    public String toString()

  Overrides:
    `toString` in class `Object`

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