LinkedHashMultimap (Guava: Google Core Libraries for Java 15.0 API)

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

All Implemented Interfaces:

Multimap<K,V>, SetMultimap<K,V>, Serializable
```
@GwtCompatible(serializable=true,
               emulated=true)
public final class LinkedHashMultimap<K,V>
extends Object
```
Implementation of Multimap that does not allow duplicate key-value entries and that returns collections whose iterators follow the ordering in which the data was added to the multimap.
The collections returned by keySet, keys, and asMap iterate through the keys in the order they were first added to the multimap. Similarly, get, removeAll, and replaceValues return collections that iterate through the values in the order they were added. The collections generated by entries and values iterate across the key-value mappings in the order they were added to the multimap.
The iteration ordering of the collections generated by keySet, keys, and asMap has a few subtleties. As long as the set of keys remains unchanged, adding or removing mappings does not affect the key iteration order. However, if you remove all values associated with a key and then add the key back to the multimap, that key will come last in the key iteration order.
The multimap does not store duplicate key-value pairs. Adding a new key-value pair equal to an existing key-value pair has no effect.
Keys and values may be null. All optional multimap methods are supported, and all returned views are modifiable.
This class is not threadsafe when any concurrent operations update the multimap. Concurrent read operations will work correctly. To allow concurrent update operations, wrap your multimap with a call to Multimaps.synchronizedSetMultimap(com.google.common.collect.SetMultimap<K, V>).
See the Guava User Guide article on Multimap.

Since:

2.0 (imported from Google Collections Library)

Author:

Jared Levy, Louis Wasserman

See Also:
Serialized Form

Method Summary

Methods
Modifier and Type	Method and Description
`Map<K,Collection<V>>`	`asMap()` Returns a map view that associates each key with the corresponding values in the multimap.
`void`	`clear()` Removes all key-value pairs from the multimap.
`boolean`	`containsEntry(Object key, Object value)` Returns `true` if the multimap contains the specified key-value pair.
`boolean`	`containsKey(Object key)` Returns `true` if the multimap contains any values for the specified key.
`boolean`	`containsValue(Object value)` Returns `true` if the multimap contains the specified value for any key.
`static <K,V> LinkedHashMultimap<K,V>`	`create()` Creates a new, empty `LinkedHashMultimap` with the default initial capacities.
`static <K,V> LinkedHashMultimap<K,V>`	`create(int expectedKeys, int expectedValuesPerKey)` Constructs an empty `LinkedHashMultimap` with enough capacity to hold the specified numbers of keys and values without rehashing.
`static <K,V> LinkedHashMultimap<K,V>`	`create(Multimap<? extends K,? extends V> multimap)` Constructs a `LinkedHashMultimap` with the same mappings as the specified multimap.
`Set<Map.Entry<K,V>>`	`entries()` Returns a set of all key-value pairs.
`boolean`	`equals(Object object)` Compares the specified object to this multimap for equality.
`Set<V>`	`get(K key)` Returns a collection view containing the values associated with `key` in this multimap, if any.
`int`	`hashCode()` Returns the hash code for this multimap.
`boolean`	`isEmpty()` Returns `true` if the multimap contains no key-value pairs.
`Multiset<K>`	`keys()` Returns a collection, which may contain duplicates, of all keys.
`Set<K>`	`keySet()` Returns the set of all keys, each appearing once in the returned set.
`boolean`	`put(K key, V value)` Stores a key-value pair in the multimap.
`boolean`	`putAll(K key, Iterable<? extends V> values)` Stores key-value pairs in this multimap with one key and multiple values.
`boolean`	`putAll(Multimap<? extends K,? extends V> multimap)` Copies all of another multimap's key-value pairs into this multimap.
`boolean`	`remove(Object key, Object value)` Removes a single key-value pair from the multimap.
`Set<V>`	`removeAll(Object key)` Removes all values associated with a given key.
`Set<V>`	`replaceValues(K key, Iterable<? extends V> values)` Stores a collection of values with the same key, replacing any existing values for that key.
`int`	`size()` Returns the number of key-value pairs in the multimap.
`String`	`toString()` Returns a string representation of the multimap, generated by calling `toString` on the map returned by `Multimap.asMap()`.
`Collection<V>`	`values()` Returns a collection of all values in the multimap.

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

Methods inherited from interface com.google.common.collect.Multimap
containsEntry, containsKey, containsValue, hashCode, isEmpty, keys, keySet, putAll, putAll, remove, size

- Method Detail
  - create
```
public static <K,V> LinkedHashMultimap<K,V> create()
```
    Creates a new, empty LinkedHashMultimap with the default initial capacities.
  - create
```
public static <K,V> LinkedHashMultimap<K,V> create(int expectedKeys,
                                   int expectedValuesPerKey)
```
    Constructs an empty LinkedHashMultimap with enough capacity to hold the specified numbers of keys and values without rehashing.
    
    Parameters:
    expectedKeys - the expected number of distinct keys
    expectedValuesPerKey - the expected average number of values per key
    
    Throws:
    
    IllegalArgumentException - if expectedKeys or expectedValuesPerKey is negative
  - create
```
public static <K,V> LinkedHashMultimap<K,V> create(Multimap<? extends K,? extends V> multimap)
```
    Constructs a LinkedHashMultimap with the same mappings as the specified multimap. If a key-value mapping appears multiple times in the input multimap, it only appears once in the constructed multimap. The new multimap has the same Multimap.entries() iteration order as the input multimap, except for excluding duplicate mappings.
    
    Parameters:
    multimap - the multimap whose contents are copied to this multimap
  - replaceValues
```
public Set<V> replaceValues(@Nullable
                   K key,
                   Iterable<? extends V> values)
```
    Stores a collection of values with the same key, replacing any existing values for that key.
    If values is empty, this is equivalent to removeAll(key).
    The returned collection is immutable.
    Because a SetMultimap has unique values for a given key, this method returns a Set, instead of the Collection specified in the Multimap interface.
    Any duplicates in values will be stored in the multimap once.
    If values is not empty and the multimap already contains a mapping for key, the keySet() ordering is unchanged. However, the provided values always come last in the entries() and values() iteration orderings.
    
    Specified by:
    
    replaceValues in interface Multimap<K,V>
    
    Specified by:
    
    replaceValues in interface SetMultimap<K,V>
    
    Parameters:
    key - key to store in the multimap
    values - values to store in the multimap
    
    Returns:
    the collection of replaced values, or an empty collection if no values were previously associated with the key. The collection may be modifiable, but updating it will have no effect on the multimap.
  - entries
```
public Set<Map.Entry<K,V>> entries()
```
    Returns a set of all key-value pairs. Changes to the returned set will update the underlying multimap, and vice versa. The entries set does not support the add or addAll operations.
    The iterator generated by the returned set traverses the entries in the order they were added to the multimap.
    Each entry is an immutable snapshot of a key-value mapping in the multimap, taken at the time the entry is returned by a method call to the collection or its iterator.
    
    Specified by:
    
    entries in interface Multimap<K,V>
    
    Specified by:
    
    entries in interface SetMultimap<K,V>
    
    Returns:
    collection of map entries consisting of key-value pairs
  - values
```
public Collection<V> values()
```
    Returns a collection of all values in the multimap. Changes to the returned collection will update the underlying multimap, and vice versa.
    The iterator generated by the returned collection traverses the values in the order they were added to the multimap.
    
    Specified by:
    
    values in interface Multimap<K,V>
    
    Returns:
    collection of values, which may include the same value multiple times if it occurs in multiple mappings
  - clear
```
public void clear()
```
    Description copied from interface: Multimap
    
    Removes all key-value pairs from the multimap.
    
    Specified by:
    
    clear in interface Multimap<K,V>
  - get
```
public Set<V> get(@Nullable
         K key)
```
    Returns a collection view containing the values associated with key in this multimap, if any. Note that even when (containsKey(key) is false, get(key) still returns an empty collection, not null.
    Changes to the returned collection will update the underlying multimap, and vice versa.
    The returned collection is not serializable.
    Because a SetMultimap has unique values for a given key, this method returns a Set, instead of the Collection specified in the Multimap interface.
    
    Specified by:
    
    get in interface Multimap<K,V>
    
    Specified by:
    
    get in interface SetMultimap<K,V>
    
    Parameters:
    key - key to search for in multimap
    
    Returns:
    a view collection containing the zero or more values that the key maps to
  - removeAll
```
public Set<V> removeAll(@Nullable
               Object key)
```
    Removes all values associated with a given key.
    Once this method returns, key will not be mapped to any values, so it will not appear in Multimap.keySet(), Multimap.asMap(), or any other views.
    The returned collection is immutable.
    Because a SetMultimap has unique values for a given key, this method returns a Set, instead of the Collection specified in the Multimap interface.
    
    Specified by:
    
    removeAll in interface Multimap<K,V>
    
    Specified by:
    
    removeAll in interface SetMultimap<K,V>
    
    Parameters:
    key - key of entries to remove from the multimap
    
    Returns:
    the collection of removed values, or an empty collection if no values were associated with the provided key. The collection may be modifiable, but updating it will have no effect on the multimap.
  - asMap
```
public Map<K,Collection<V>> asMap()
```
    Returns a map view that associates each key with the corresponding values in the multimap. Changes to the returned map, such as element removal, will update the underlying multimap. The map does not support setValue() on its entries, put, or putAll.
    When passed a key that is present in the map, asMap().get(Object) has the same behavior as Multimap.get(K), returning a live collection. When passed a key that is not present, however, asMap().get(Object) returns null instead of an empty collection.
    Though the method signature doesn't say so explicitly, the returned map has Set values.
    
    Specified by:
    
    asMap in interface Multimap<K,V>
    
    Specified by:
    
    asMap in interface SetMultimap<K,V>
    
    Returns:
    a map view from a key to its collection of values
  - put
```
public boolean put(@Nullable
          K key,
          @Nullable
          V value)
```
    Stores a key-value pair in the multimap.
    
    Specified by:
    
    put in interface Multimap<K,V>
    
    Parameters:
    key - key to store in the multimap
    value - value to store in the multimap
    
    Returns:
    true if the method increased the size of the multimap, or false if the multimap already contained the key-value pair
  - equals
```
public boolean equals(@Nullable
             Object object)
```
    Compares the specified object to this multimap for equality.
    Two SetMultimap instances are equal if, for each key, they contain the same values. Equality does not depend on the ordering of keys or values.
    
    Specified by:
    
    equals in interface Multimap<K,V>
    
    Specified by:
    
    equals in interface SetMultimap<K,V>
    
    Parameters:
    object - the reference object with which to compare.
    
    Returns:
    true if this object is the same as the obj argument; false otherwise.
    See Also:
    Object.hashCode(), HashMap
  - size
```
public int size()
```
    Description copied from interface: Multimap
    
    Returns the number of key-value pairs in the multimap.
    
    Specified by:
    
    size in interface Multimap<K,V>
  - containsKey
```
public boolean containsKey(@Nullable
                  Object key)
```
    Description copied from interface: Multimap
    
    Returns true if the multimap contains any values for the specified key.
    
    Specified by:
    
    containsKey in interface Multimap<K,V>
    
    Parameters:
    key - key to search for in multimap
  - isEmpty
```
public boolean isEmpty()
```
    Description copied from interface: Multimap
    
    Returns true if the multimap contains no key-value pairs.
    
    Specified by:
    
    isEmpty in interface Multimap<K,V>
  - containsValue
```
public boolean containsValue(@Nullable
                    Object value)
```
    Description copied from interface: Multimap
    
    Returns true if the multimap contains the specified value for any key.
    
    Specified by:
    
    containsValue in interface Multimap<K,V>
    
    Parameters:
    value - value to search for in multimap
  - containsEntry
```
public boolean containsEntry(@Nullable
                    Object key,
                    @Nullable
                    Object value)
```
    Description copied from interface: Multimap
    
    Returns true if the multimap contains the specified key-value pair.
    
    Specified by:
    
    containsEntry in interface Multimap<K,V>
    
    Parameters:
    key - key to search for in multimap
    value - value to search for in multimap
  - remove
```
public boolean remove(@Nullable
             Object key,
             @Nullable
             Object value)
```
    Description copied from interface: Multimap
    
    Removes a single key-value pair from the multimap.
    
    Specified by:
    
    remove in interface Multimap<K,V>
    
    Parameters:
    key - key of entry to remove from the multimap
    value - value of entry to remove the multimap
    
    Returns:
    true if the multimap changed
  - putAll
```
public boolean putAll(@Nullable
             K key,
             Iterable<? extends V> values)
```
    Description copied from interface: Multimap
    Stores key-value pairs in this multimap with one key and multiple values.
    This is equivalent to
```
   for (V value : values) {
     put(key, value);
   } 
```
    In particular, this is a no-op if values is empty.
    Specified by:
    
    putAll in interface Multimap<K,V>
    
    Parameters:
    key - key to store in the multimap
    values - values to store in the multimap
    
    Returns:
    true if the multimap changed
  - putAll
```
public boolean putAll(Multimap<? extends K,? extends V> multimap)
```
    Description copied from interface: Multimap
    
    Copies all of another multimap's key-value pairs into this multimap. The order in which the mappings are added is determined by multimap.entries().
    
    Specified by:
    
    putAll in interface Multimap<K,V>
    
    Parameters:
    multimap - mappings to store in this multimap
    
    Returns:
    true if the multimap changed
  - keySet
```
public Set<K> keySet()
```
    Description copied from interface: Multimap
    
    Returns the set of all keys, each appearing once in the returned set. Changes to the returned set will update the underlying multimap, and vice versa.
    Note that the key set contains a key if and only if this multimap maps that key to at least one value.
    
    Specified by:
    
    keySet in interface Multimap<K,V>
    
    Returns:
    the collection of distinct keys
  - keys
```
public Multiset<K> keys()
```
    Description copied from interface: Multimap
    
    Returns a collection, which may contain duplicates, of all keys. The number of times of key appears in the returned multiset equals the number of mappings the key has in the multimap. Changes to the returned multiset will update the underlying multimap, and vice versa.
    
    Specified by:
    
    keys in interface Multimap<K,V>
    
    Returns:
    a multiset with keys corresponding to the distinct keys of the multimap and frequencies corresponding to the number of values that each key maps to
  - hashCode
```
public int hashCode()
```
    Returns the hash code for this multimap.
    The hash code of a multimap is defined as the hash code of the map view, as returned by Multimap.asMap().
    
    Specified by:
    
    hashCode in interface Multimap<K,V>
    
    Overrides:
    
    hashCode in class Object
    
    Returns:
    a hash code value for this object.
    See Also:
    Map.hashCode()
  - toString
```
public String toString()
```
    Returns a string representation of the multimap, generated by calling toString on the map returned by Multimap.asMap().
    
    Overrides:
    
    toString in class Object
    
    Returns:
    a string representation of the multimap

Class LinkedHashMultimap<K,V>

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface com.google.common.collect.Multimap

Method Detail

create

create

create

replaceValues

entries

values

clear

get

removeAll

asMap

put

equals

size

containsKey

isEmpty

containsValue

containsEntry

remove

putAll

putAll

keySet

keys

hashCode

toString