J
- the type of the keys to put in this mapK
- the type of the keys to get in this mapU
- the type of the values to put in this mapV
- the type of the values to get in this mappublic class TransformedSplitMap<J,K,U,V> extends AbstractIterableGetMapDecorator<K,V> implements Put<J,U>, java.io.Serializable
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.
The "put" and "get" type constraints of this class are mutually independent;
contrast with TransformedMap
which,
by virtue of its implementing Map
<K, V>, must be constructed in such
a way that its read and write parameters are generalized to a common (super-)type.
In practice this would often mean >Object, Object>
, defeating
much of the usefulness of having parameterized types.
On the downside, this class is not drop-in compatible with Map
but is intended to be worked with either directly or by Put
and
Get
generalizations.
Modifier and Type | Field and Description |
---|---|
private Transformer<? super J,? extends K> |
keyTransformer
The transformer to use for the key
|
private static long |
serialVersionUID
Serialization version
|
private Transformer<? super U,? extends V> |
valueTransformer
The transformer to use for the value
|
map
Modifier | Constructor and Description |
---|---|
protected |
TransformedSplitMap(java.util.Map<K,V> map,
Transformer<? super J,? extends K> keyTransformer,
Transformer<? super U,? extends V> valueTransformer)
Constructor that wraps (not copies).
|
Modifier and Type | Method and Description |
---|---|
protected V |
checkSetValue(U value)
Override to transform the value when using
setValue . |
void |
clear() |
V |
put(J key,
U value)
Note that the return type is Object, rather than V as in the Map interface.
|
void |
putAll(java.util.Map<? extends J,? extends U> mapToCopy) |
private void |
readObject(java.io.ObjectInputStream in)
Read the map in using a custom routine.
|
static <J,K,U,V> TransformedSplitMap<J,K,U,V> |
transformingMap(java.util.Map<K,V> map,
Transformer<? super J,? extends K> keyTransformer,
Transformer<? super U,? extends V> valueTransformer)
Factory method to create a transforming map.
|
protected K |
transformKey(J object)
Transforms a key.
|
protected java.util.Map<K,V> |
transformMap(java.util.Map<? extends J,? extends U> map)
Transforms a map.
|
protected V |
transformValue(U object)
Transforms a value.
|
private void |
writeObject(java.io.ObjectOutputStream out)
Write the map out using a custom routine.
|
containsKey, containsValue, decorated, entrySet, equals, get, hashCode, isEmpty, keySet, mapIterator, remove, size, toString, values
private static final long serialVersionUID
private final Transformer<? super J,? extends K> keyTransformer
private final Transformer<? super U,? extends V> valueTransformer
protected TransformedSplitMap(java.util.Map<K,V> map, Transformer<? super J,? extends K> keyTransformer, Transformer<? super U,? extends V> valueTransformer)
If there are any elements already in the collection being decorated, they are NOT transformed.
map
- the map to decorate, must not be nullkeyTransformer
- the transformer to use for key conversion, must not be nullvalueTransformer
- the transformer to use for value conversion, must not be nulljava.lang.NullPointerException
- if map or either of the transformers is nullpublic static <J,K,U,V> TransformedSplitMap<J,K,U,V> transformingMap(java.util.Map<K,V> map, Transformer<? super J,? extends K> keyTransformer, Transformer<? super U,? extends V> valueTransformer)
If there are any elements already in the map being decorated, they are NOT transformed.
J
- the input key typeK
- the output key typeU
- the input value typeV
- the output value typemap
- the map to decorate, must not be nullkeyTransformer
- the transformer to use for key conversion, must not be nullvalueTransformer
- the transformer to use for value conversion, must not be nulljava.lang.NullPointerException
- if map or either of the transformers is nullprivate void writeObject(java.io.ObjectOutputStream out) throws java.io.IOException
out
- the output streamjava.io.IOException
- if an error occurs while writing to the streamprivate void readObject(java.io.ObjectInputStream in) throws java.io.IOException, java.lang.ClassNotFoundException
in
- the input streamjava.io.IOException
- if an error occurs while reading from the streamjava.lang.ClassNotFoundException
- if an object read from the stream can not be loadedprotected K transformKey(J object)
The transformer itself may throw an exception if necessary.
object
- the object to transformprotected V transformValue(U object)
The transformer itself may throw an exception if necessary.
object
- the object to transformprotected java.util.Map<K,V> transformMap(java.util.Map<? extends J,? extends U> map)
The transformer itself may throw an exception if necessary.
map
- the map to transformprotected V checkSetValue(U value)
setValue
.value
- the value to transformpublic V put(J key, U value)
Put
put
in interface Put<J,U>
key
- key with which the specified value is to be associatedvalue
- value to be associated with the specified keykey
, or
null
if there was no mapping for key
.
(A null
return can also indicate that the map
previously associated null
with key
,
if the implementation supports null
values.)Map.put(Object, Object)