Class TransformedMap<K,V>
- Type Parameters:
K- the type of the keys in this mapV- the type of the values in this map
- All Implemented Interfaces:
Serializable,Map<K,,V> Get<K,,V> IterableGet<K,,V> IterableMap<K,,V> Put<K,V>
- Direct Known Subclasses:
TransformedSortedMap
Map to transform objects that are added.
The Map put methods and Map.Entry setValue method are affected by this class. Thus objects must be removed or searched for using their transformed form. For example, if the transformation converts Strings to Integers, you must use the Integer form to remove objects.
Note that TransformedMap is not synchronized and is not thread-safe.
If you wish to use this map from multiple threads concurrently, you must use
appropriate synchronization. The simplest approach is to wrap this map
using Collections.synchronizedMap(Map). This class may throw
exceptions when accessed by concurrent threads without synchronization.
This class is Serializable from Commons Collections 3.1.
- Since:
- 3.0
- See Also:
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Nested Class Summary
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Field Summary
FieldsModifier and TypeFieldDescriptionprotected final Transformer<? super K, ? extends K> The transformer to use for the keyprotected final Transformer<? super V, ? extends V> The transformer to use for the value -
Constructor Summary
ConstructorsModifierConstructorDescriptionprotectedTransformedMap(Map<K, V> map, Transformer<? super K, ? extends K> keyTransformer, Transformer<? super V, ? extends V> valueTransformer) Constructor that wraps (not copies). -
Method Summary
Modifier and TypeMethodDescriptionprotected VcheckSetValue(V value) Override to transform the value when usingsetValue.entrySet()Gets a set view of the mappings contained in this map.protected booleanOverride to only return true when there is a value transformer.Associates the specified value with the specified key in this map.voidCopies all of the mappings from the specified map to this map.static <K,V> TransformedMap <K, V> transformedMap(Map<K, V> map, Transformer<? super K, ? extends K> keyTransformer, Transformer<? super V, ? extends V> valueTransformer) Factory method to create a transforming map that will transform existing contents of the specified map.static <K,V> TransformedMap <K, V> transformingMap(Map<K, V> map, Transformer<? super K, ? extends K> keyTransformer, Transformer<? super V, ? extends V> valueTransformer) Factory method to create a transforming map.protected KtransformKey(K object) Transforms a key.transformMap(Map<? extends K, ? extends V> map) Transforms a map.protected VtransformValue(V object) Transforms a value.Methods inherited from class org.apache.commons.collections4.map.AbstractMapDecorator
clear, containsKey, containsValue, decorated, equals, get, hashCode, isEmpty, keySet, remove, size, toString, valuesMethods inherited from class org.apache.commons.collections4.map.AbstractIterableMap
mapIteratorMethods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, waitMethods inherited from interface java.util.Map
compute, computeIfAbsent, computeIfPresent, forEach, getOrDefault, merge, putIfAbsent, remove, replace, replace, replaceAll
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Field Details
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keyTransformer
The transformer to use for the key -
valueTransformer
The transformer to use for the value
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Constructor Details
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TransformedMap
protected TransformedMap(Map<K, V> map, Transformer<? super K, ? extends K> keyTransformer, Transformer<? super V, ? extends V> valueTransformer) Constructor that wraps (not copies).If there are any elements already in the collection being decorated, they are NOT transformed.
- Parameters:
map- the map to decorate, must not be nullkeyTransformer- the transformer to use for key conversion, null means no conversionvalueTransformer- the transformer to use for value conversion, null means no conversion- Throws:
NullPointerException- if map is null
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Method Details
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transformedMap
public static <K,V> TransformedMap<K,V> transformedMap(Map<K, V> map, Transformer<? super K, ? extends K> keyTransformer, Transformer<? super V, ? extends V> valueTransformer) Factory method to create a transforming map that will transform existing contents of the specified map.If there are any elements already in the map being decorated, they will be transformed by this method. Contrast this with
transformingMap(Map, Transformer, Transformer).- Type Parameters:
K- the key typeV- the value type- Parameters:
map- the map to decorate, must not be nullkeyTransformer- the transformer to use for key conversion, null means no transformationvalueTransformer- the transformer to use for value conversion, null means no transformation- Returns:
- a new transformed map
- Throws:
NullPointerException- if map is null- Since:
- 4.0
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transformingMap
public static <K,V> TransformedMap<K,V> transformingMap(Map<K, V> map, Transformer<? super K, ? extends K> keyTransformer, Transformer<? super V, ? extends V> valueTransformer) Factory method to create a transforming map.If there are any elements already in the map being decorated, they are NOT transformed. Contrast this with
transformedMap(Map, Transformer, Transformer).- Type Parameters:
K- the key typeV- the value type- Parameters:
map- the map to decorate, must not be nullkeyTransformer- the transformer to use for key conversion, null means no transformationvalueTransformer- the transformer to use for value conversion, null means no transformation- Returns:
- a new transformed map
- Throws:
NullPointerException- if map is null- Since:
- 4.0
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checkSetValue
Override to transform the value when usingsetValue.- Parameters:
value- the value to transform- Returns:
- the transformed value
- Since:
- 3.1
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isSetValueChecking
Override to only return true when there is a value transformer.- Returns:
- true if a value transformer is in use
- Since:
- 3.1
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put
Description copied from interface:PutAssociates the specified value with the specified key in this map.Note that the return type is Object, rather than V as in the Map interface. See the class Javadoc for further info.
- Specified by:
putin interfaceMap<K,V> - Specified by:
putin interfacePut<K,V> - Overrides:
putin classAbstractMapDecorator<K,V> - Parameters:
key- key with which the specified value is to be associatedvalue- value to be associated with the specified key- Returns:
- the previous value associated with
key, ornullif there was no mapping forkey. (Anullreturn can also indicate that the map previously associatednullwithkey, if the implementation supportsnullvalues.) - See Also:
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putAll
Description copied from interface:PutCopies all of the mappings from the specified map to this map. -
transformKey
Transforms a key.The transformer itself may throw an exception if necessary.
- Parameters:
object- the object to transform- Returns:
- the transformed object
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transformMap
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transformValue
Transforms a value.The transformer itself may throw an exception if necessary.
- Parameters:
object- the object to transform- Returns:
- the transformed object
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entrySet
Description copied from interface:GetGets a set view of the mappings contained in this map.
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