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 keyprivate static final long
Serialization versionprotected final Transformer
<? super V, ? extends V> The transformer to use for the valueFields inherited from class org.apache.commons.collections4.map.AbstractMapDecorator
map
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Constructor Summary
ConstructorsModifierConstructorDescriptionprotected
TransformedMap
(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 V
checkSetValue
(V value) Override to transform the value when usingsetValue
.protected boolean
Override to only return true when there is a value transformer.Note that the return type is Object, rather than V as in the Map interface.void
private void
Read the map in using a custom routine.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 K
transformKey
(K object) Transforms a key.transformMap
(Map<? extends K, ? extends V> map) Transforms a map.protected V
transformValue
(V object) Transforms a value.private void
Write the map out using a custom routine.Methods inherited from class org.apache.commons.collections4.map.AbstractInputCheckedMapDecorator
entrySet
Methods inherited from class org.apache.commons.collections4.map.AbstractMapDecorator
clear, containsKey, containsValue, decorated, equals, get, hashCode, isEmpty, keySet, remove, size, toString, values
Methods inherited from class org.apache.commons.collections4.map.AbstractIterableMap
mapIterator
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
Methods 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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serialVersionUID
private static final long serialVersionUIDSerialization version- See Also:
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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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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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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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writeObject
Write the map out using a custom routine.- Parameters:
out
- the output stream- Throws:
IOException
- if an error occurs while writing to the stream- Since:
- 3.1
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readObject
Read the map in using a custom routine.- Parameters:
in
- the input stream- Throws:
IOException
- if an error occurs while reading from the streamClassNotFoundException
- if an object read from the stream can not be loaded- Since:
- 3.1
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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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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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transformMap
Transforms a map.The transformer itself may throw an exception if necessary.
- Parameters:
map
- the map to transform- Returns:
- the transformed object
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checkSetValue
Override to transform the value when usingsetValue
.- Specified by:
checkSetValue
in classAbstractInputCheckedMapDecorator<K,
V> - Parameters:
value
- the value to transform- Returns:
- the transformed value
- Since:
- 3.1
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isSetValueChecking
protected boolean isSetValueChecking()Override to only return true when there is a value transformer.- Overrides:
isSetValueChecking
in classAbstractInputCheckedMapDecorator<K,
V> - Returns:
- true if a value transformer is in use
- Since:
- 3.1
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put
Description copied from interface:Put
Note that the return type is Object, rather than V as in the Map interface. See the class Javadoc for further info.- Specified by:
put
in interfaceMap<K,
V> - Specified by:
put
in interfacePut<K,
V> - Overrides:
put
in 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
, ornull
if there was no mapping forkey
. (Anull
return can also indicate that the map previously associatednull
withkey
, if the implementation supportsnull
values.) - See Also:
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putAll
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