Apache Commons Collections 4.4 · org.apache.commons.collections4.splitmap.TransformedSplitMap

Decorates another 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 java.util.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 org.apache.commons.collections4.map.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 java.util.Map but is intended to be worked with either directly or by Put and Get generalizations.

Field Summary

Modifier and Type	Field and Description
private final Transformer<? super J, ? extends K>	keyTransformer The transformer to use for the key
private static final long	serialVersionUID Serialization version
private final Transformer<? super U, ? extends V>	valueTransformer The transformer to use for the value

Inherited from org.apache.commons.collections4.splitmap.AbstractIterableGetMapDecorator:: map

Constructor Summary

Access	Constructor and Description
protected	TransformedSplitMap(final Map<K, V> the map to decorate, must not be null map, final Transformer<? super J, ? extends K> the transformer to use for key conversion, must not be null keyTransformer, final Transformer<? super U, ? extends V> the transformer to use for value conversion, must not be null valueTransformer) Constructor that wraps (not copies).

Method Summary

Modifier and Type	Method and Description
protected V	Returns: the transformed value checkSetValue(final U the value to transform value) Override to transform the value when using `setValue`.
public void	clear() Implements org.apache.commons.collections4.Put.clear.
public V	put(final J key with which the specified value is to be associated key, final U value to be associated with the specified key value) Implements org.apache.commons.collections4.Put.put. Note that the return type is Object, rather than V as in the Map interface.
public void	putAll(final Map<? extends J, ? extends U> mappings to be stored in this map mapToCopy) Implements org.apache.commons.collections4.Put.putAll.
private void	readObject(final ObjectInputStream the input stream in) Read the map in using a custom routine.
public static < the input key type J, the output key type K, the input value type U, the output value type V> TransformedSplitMap<J, K, U, V>	Returns: a new transformed map transformingMap(final Map<K, V> the map to decorate, must not be null map, final Transformer<? super J, ? extends K> the transformer to use for key conversion, must not be null keyTransformer, final Transformer<? super U, ? extends V> the transformer to use for value conversion, must not be null valueTransformer) Factory method to create a transforming map.
protected K	Returns: the transformed object transformKey(final J the object to transform object) Transforms a key.
protected Map<K, V>	Returns: the transformed object transformMap(final Map<? extends J, ? extends U> the map to transform map) Transforms a map.
protected V	Returns: the transformed object transformValue(final U the object to transform object) Transforms a value.
private void	writeObject(final ObjectOutputStream the output stream out) Write the map out using a custom routine.

Inherited from org.apache.commons.collections4.splitmap.AbstractIterableGetMapDecorator:: containsKey containsValue decorated entrySet equals get hashCode isEmpty keySet mapIterator remove size toString values

Field Detail

keyTransformer	back to summary
private final Transformer<? super J, ? extends K> keyTransformer The transformer to use for the key

serialVersionUID	back to summary
private static final long serialVersionUID Serialization version

valueTransformer	back to summary
private final Transformer<? super U, ? extends V> valueTransformer The transformer to use for the value

Constructor Detail

TransformedSplitMap	back to summary
protected TransformedSplitMap(final Map<K, V> map, final Transformer<? super J, ? extends K> keyTransformer, final Transformer<? super U, ? 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:Map<K, V> the map to decorate, must not be null keyTransformer:Transformer<? super J, ? extends K> the transformer to use for key conversion, must not be null valueTransformer:Transformer<? super U, ? extends V> the transformer to use for value conversion, must not be null Exceptions NullPointerException: if map or either of the transformers is null

TransformedSplitMap

back to summary

protected TransformedSplitMap(final Map<K, V> map, final Transformer<? super J, ? extends K> keyTransformer, final Transformer<? super U, ? 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:Map<K, V>: the map to decorate, must not be null
keyTransformer:Transformer<? super J, ? extends K>: the transformer to use for key conversion, must not be null
valueTransformer:Transformer<? super U, ? extends V>: the transformer to use for value conversion, must not be null

Exceptions

NullPointerException:: if map or either of the transformers is null

Method Detail

checkSetValue back to summary

checkSetValue	back to summary
protected V checkSetValue(final U value) Override to transform the value when using `setValue`. Parameters value:U the value to transform Returns:V the transformed value

protected V checkSetValue(final U value)

Override to transform the value when using setValue.

Parameters

value:U: the value to transform

Returns:V

the transformed value

clear	back to summary
public void clear() Implements org.apache.commons.collections4.Put.clear. Annotations @Override

clear

back to summary

public void clear()

Implements org.apache.commons.collections4.Put.clear.

Annotations

@Override

put back to summary

put	back to summary
public V put(final J key, final U value) Implements org.apache.commons.collections4.Put.put. Doc from org.apache.commons.collections4.Put.put. Note that the return type is Object, rather than V as in the Map interface. See the class Javadoc for further info. Parameters key:J key with which the specified value is to be associated value:U value to be associated with the specified key Returns:V the previous value associated with `key`, 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.) Annotations @Override

public V put(final J key, final U value)

Implements org.apache.commons.collections4.Put.put.

Doc from org.apache.commons.collections4.Put.put.

Note that the return type is Object, rather than V as in the Map interface. See the class Javadoc for further info.

Parameters

key:J: key with which the specified value is to be associated
value:U: value to be associated with the specified key

Returns:V

the previous value associated with key, 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.)

Annotations

@Override

putAll	back to summary
public void putAll(final Map<? extends J, ? extends U> mapToCopy) Implements org.apache.commons.collections4.Put.putAll. Parameters mapToCopy:Map<? extends J, ? extends U> Doc from org.apache.commons.collections4.Put.putAll. mappings to be stored in this map Annotations @Override

putAll

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public void putAll(final Map<? extends J, ? extends U> mapToCopy)

Implements org.apache.commons.collections4.Put.putAll.

Parameters

mapToCopy:Map<? extends J, ? extends U>

Doc from org.apache.commons.collections4.Put.putAll.

mappings to be stored in this map

Annotations

@Override

readObject	back to summary
private void readObject(final ObjectInputStream in) throws IOException, ClassNotFoundException Read the map in using a custom routine. Parameters in:ObjectInputStream the input stream Annotations @SuppressWarnings:unchecked Exceptions IOException: if an error occurs while reading from the stream ClassNotFoundException: if an object read from the stream can not be loaded Since 3.1

readObject

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private void readObject(final ObjectInputStream in) throws IOException, ClassNotFoundException

Read the map in using a custom routine.

Parameters

in:ObjectInputStream: the input stream

Annotations

@SuppressWarnings:unchecked

Exceptions

IOException:: if an error occurs while reading from the stream
ClassNotFoundException:: if an object read from the stream can not be loaded

Since

3.1

transformingMap	back to summary
public static <J, K, U, V> TransformedSplitMap<J, K, U, V> transformingMap(final Map<K, V> map, final Transformer<? super J, ? extends K> keyTransformer, final Transformer<? super U, ? 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. Parameters <J> the input key type <K> the output key type <U> the input value type <V> the output value type map:Map<K, V> the map to decorate, must not be null keyTransformer:Transformer<? super J, ? extends K> the transformer to use for key conversion, must not be null valueTransformer:Transformer<? super U, ? extends V> the transformer to use for value conversion, must not be null Returns:TransformedSplitMap<J, K, U, V> a new transformed map Exceptions NullPointerException: if map or either of the transformers is null

transformingMap

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public static <J, K, U, V> TransformedSplitMap<J, K, U, V> transformingMap(final Map<K, V> map, final Transformer<? super J, ? extends K> keyTransformer, final Transformer<? super U, ? 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.

Parameters

<J>: the input key type
<K>: the output key type
<U>: the input value type
<V>: the output value type
map:Map<K, V>: the map to decorate, must not be null
keyTransformer:Transformer<? super J, ? extends K>: the transformer to use for key conversion, must not be null
valueTransformer:Transformer<? super U, ? extends V>: the transformer to use for value conversion, must not be null

Returns:TransformedSplitMap<J, K, U, V>

a new transformed map

Exceptions

NullPointerException:: if map or either of the transformers is null

transformKey	back to summary
protected K transformKey(final J object) Transforms a key. The transformer itself may throw an exception if necessary. Parameters object:J the object to transform Returns:K the transformed object

transformKey

back to summary

protected K transformKey(final J object)

Transforms a key.

The transformer itself may throw an exception if necessary.

Parameters

object:J: the object to transform

Returns:K

the transformed object

transformMap	back to summary
protected Map<K, V> transformMap(final Map<? extends J, ? extends U> map) Transforms a map. The transformer itself may throw an exception if necessary. Parameters map:Map<? extends J, ? extends U> the map to transform Returns:Map<K, V> the transformed object Annotations @SuppressWarnings:unchecked

transformMap

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protected Map<K, V> transformMap(final Map<? extends J, ? extends U> map)

Transforms a map.

The transformer itself may throw an exception if necessary.

Parameters

map:Map<? extends J, ? extends U>: the map to transform

Returns:Map<K, V>

the transformed object

Annotations

@SuppressWarnings:unchecked

transformValue	back to summary
protected V transformValue(final U object) Transforms a value. The transformer itself may throw an exception if necessary. Parameters object:U the object to transform Returns:V the transformed object

transformValue

back to summary

protected V transformValue(final U object)

Transforms a value.

The transformer itself may throw an exception if necessary.

Parameters

object:U: the object to transform

Returns:V

the transformed object

writeObject	back to summary
private void writeObject(final ObjectOutputStream out) throws IOException Write the map out using a custom routine. Parameters out:ObjectOutputStream the output stream Exceptions IOException: if an error occurs while writing to the stream

writeObject

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private void writeObject(final ObjectOutputStream out) throws IOException

Write the map out using a custom routine.

Parameters

out:ObjectOutputStream: the output stream

Exceptions

IOException:: if an error occurs while writing to the stream

public Class TransformedSplitMap<J, K, U, V>

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail