MultimapBuilder (Guava: Google Core Libraries for Java 20.0 API)

java.lang.Object
- com.google.common.collect.MultimapBuilder<K0,V0>

Type Parameters:

K0 - An upper bound on the key type of the generated multimap.

V0 - An upper bound on the value type of the generated multimap.

Direct Known Subclasses:

MultimapBuilder.ListMultimapBuilder, MultimapBuilder.SetMultimapBuilder
```
@Beta
 @GwtCompatible
public abstract class MultimapBuilder<K0,V0>
extends Object
```
A builder for a multimap implementation that allows customization of the backing map and value collection implementations used in a particular multimap.
This can be used to easily configure multimap data structure implementations not provided explicitly in com.google.common.collect, for example:
```
   
   ListMultimap<String, Integer> treeListMultimap =
       MultimapBuilder.treeKeys().arrayListValues().build();
   SetMultimap<Integer, MyEnum> hashEnumMultimap =
       MultimapBuilder.hashKeys().enumSetValues(MyEnum.class).build();
```
MultimapBuilder instances are immutable. Invoking a configuration method has no effect on the receiving instance; you must store and use the new builder instance it returns instead.
The generated multimaps are serializable if the key and value types are serializable, unless stated otherwise in one of the configuration methods.
Since:

16.0

Author:

Louis Wasserman

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`static class`	`MultimapBuilder.ListMultimapBuilder<K0,V0>` A specialization of `MultimapBuilder` that generates `ListMultimap` instances.
`static class`	`MultimapBuilder.MultimapBuilderWithKeys<K0>` An intermediate stage in a `MultimapBuilder` in which the key-value collection map implementation has been specified, but the value collection implementation has not.
`static class`	`MultimapBuilder.SetMultimapBuilder<K0,V0>` A specialization of `MultimapBuilder` that generates `SetMultimap` instances.
`static class`	`MultimapBuilder.SortedSetMultimapBuilder<K0,V0>` A specialization of `MultimapBuilder` that generates `SortedSetMultimap` instances.

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method and Description
`abstract <K extends K0,V extends V0> Multimap<K,V>`	`build()` Returns a new, empty `Multimap` with the specified implementation.
`<K extends K0,V extends V0> Multimap<K,V>`	`build(Multimap<? extends K,? extends V> multimap)` Returns a `Multimap` with the specified implementation, initialized with the entries of `multimap`.
`static <K0 extends Enum<K0>> MultimapBuilder.MultimapBuilderWithKeys<K0>`	`enumKeys(Class<K0> keyClass)` Uses an `EnumMap` to map keys to value collections.
`static MultimapBuilder.MultimapBuilderWithKeys<Object>`	`hashKeys()` Uses a `HashMap` to map keys to value collections.
`static MultimapBuilder.MultimapBuilderWithKeys<Object>`	`hashKeys(int expectedKeys)` Uses a `HashMap` to map keys to value collections, initialized to expect the specified number of keys.
`static MultimapBuilder.MultimapBuilderWithKeys<Object>`	`linkedHashKeys()` Uses a `LinkedHashMap` to map keys to value collections.
`static MultimapBuilder.MultimapBuilderWithKeys<Object>`	`linkedHashKeys(int expectedKeys)` Uses a `LinkedHashMap` to map keys to value collections, initialized to expect the specified number of keys.
`static MultimapBuilder.MultimapBuilderWithKeys<Comparable>`	`treeKeys()` Uses a naturally-ordered `TreeMap` to map keys to value collections.
`static <K0> MultimapBuilder.MultimapBuilderWithKeys<K0>`	`treeKeys(Comparator<K0> comparator)` Uses a `TreeMap` sorted by the specified comparator to map keys to value collections.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Method Detail
  - hashKeys
```
public static MultimapBuilder.MultimapBuilderWithKeys<Object> hashKeys()
```
    Uses a HashMap to map keys to value collections.
  - hashKeys
```
public static MultimapBuilder.MultimapBuilderWithKeys<Object> hashKeys(int expectedKeys)
```
    Uses a HashMap to map keys to value collections, initialized to expect the specified number of keys.
    
    Throws:
    
    IllegalArgumentException - if expectedKeys < 0
  - linkedHashKeys
```
public static MultimapBuilder.MultimapBuilderWithKeys<Object> linkedHashKeys()
```
    Uses a LinkedHashMap to map keys to value collections.
    The collections returned by Multimap.keySet(), Multimap.keys(), and Multimap.asMap() will iterate through the keys in the order that they were first added to the multimap, save that if all values associated with a key are removed and then the key is added back into the multimap, that key will come last in the key iteration order.
  - linkedHashKeys
```
public static MultimapBuilder.MultimapBuilderWithKeys<Object> linkedHashKeys(int expectedKeys)
```
    Uses a LinkedHashMap to map keys to value collections, initialized to expect the specified number of keys.
    The collections returned by Multimap.keySet(), Multimap.keys(), and Multimap.asMap() will iterate through the keys in the order that they were first added to the multimap, save that if all values associated with a key are removed and then the key is added back into the multimap, that key will come last in the key iteration order.
  - treeKeys
```
public static MultimapBuilder.MultimapBuilderWithKeys<Comparable> treeKeys()
```
    Uses a naturally-ordered TreeMap to map keys to value collections.
    The collections returned by Multimap.keySet(), Multimap.keys(), and Multimap.asMap() will iterate through the keys in sorted order.
    For all multimaps generated by the resulting builder, the Multimap.keySet() can be safely cast to a SortedSet, and the Multimap.asMap() can safely be cast to a SortedMap.
  - treeKeys
```
public static <K0> MultimapBuilder.MultimapBuilderWithKeys<K0> treeKeys(Comparator<K0> comparator)
```
    Uses a TreeMap sorted by the specified comparator to map keys to value collections.
    The collections returned by Multimap.keySet(), Multimap.keys(), and Multimap.asMap() will iterate through the keys in sorted order.
    For all multimaps generated by the resulting builder, the Multimap.keySet() can be safely cast to a SortedSet, and the Multimap.asMap() can safely be cast to a SortedMap.
    Multimaps generated by the resulting builder will not be serializable if comparator is not serializable.
  - enumKeys
```
public static <K0 extends Enum<K0>> MultimapBuilder.MultimapBuilderWithKeys<K0> enumKeys(Class<K0> keyClass)
```
    Uses an EnumMap to map keys to value collections.
  - build
```
public abstract <K extends K0,V extends V0> Multimap<K,V> build()
```
    Returns a new, empty Multimap with the specified implementation.
  - build
```
public <K extends K0,V extends V0> Multimap<K,V> build(Multimap<? extends K,? extends V> multimap)
```
    Returns a Multimap with the specified implementation, initialized with the entries of multimap.

Class MultimapBuilder<K0,V0>

Nested Class Summary

Method Summary

Methods inherited from class java.lang.Object

Method Detail

hashKeys

hashKeys

linkedHashKeys

linkedHashKeys

treeKeys

treeKeys

enumKeys

build

build