Package org.apache.commons.collections4
Interface SetValuedMap<K,V>
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- Type Parameters:
K
- the type of the keys in this mapV
- the type of the values in this map
- All Superinterfaces:
MultiValuedMap<K,V>
- All Known Implementing Classes:
AbstractSetValuedMap
,HashSetValuedHashMap
public interface SetValuedMap<K,V> extends MultiValuedMap<K,V>
Defines a map that holds a set of values against each key.A
SetValuedMap
is a Map with slightly different semantics:- Putting a value into the map will add the value to a
Set
at that key. - Getting a value will return a
Set
, holding all the values put to that key.
- Since:
- 4.1
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Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description java.util.Set<V>
get(K key)
Gets the set of values associated with the specified key.java.util.Set<V>
remove(java.lang.Object key)
Removes all values associated with the specified key.-
Methods inherited from interface org.apache.commons.collections4.MultiValuedMap
asMap, clear, containsKey, containsMapping, containsValue, entries, isEmpty, keys, keySet, mapIterator, put, putAll, putAll, putAll, removeMapping, size, values
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Method Detail
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get
java.util.Set<V> get(K key)
Gets the set of values associated with the specified key.Implementations typically return an empty
Set
if no values have been mapped to the key.- Specified by:
get
in interfaceMultiValuedMap<K,V>
- Parameters:
key
- the key to retrieve- Returns:
- the
Set
of values, implementations should return an emptySet
for no mapping - Throws:
java.lang.NullPointerException
- if the key is null and null keys are invalid
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remove
java.util.Set<V> remove(java.lang.Object key)
Removes all values associated with the specified key.The returned set may be modifiable, but updates will not be propagated to this set-valued map. In case no mapping was stored for the specified key, an empty, unmodifiable set will be returned.
- Specified by:
remove
in interfaceMultiValuedMap<K,V>
- Parameters:
key
- the key to remove values from- Returns:
- the
Set
of values removed, implementations should return null for no mapping found, but may return an empty collection - Throws:
java.lang.UnsupportedOperationException
- if the map is unmodifiablejava.lang.NullPointerException
- if the key is null and null keys are invalid
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