Class UnmodifiableMap<K,V>
java.lang.Object
org.apache.commons.collections4.map.AbstractIterableMap<K,V>
org.apache.commons.collections4.map.AbstractMapDecorator<K,V>
org.apache.commons.collections4.map.UnmodifiableMap<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> Unmodifiable
public final class UnmodifiableMap<K,V>
extends AbstractMapDecorator<K,V>
implements Unmodifiable, Serializable
Decorates another
Map
to ensure it can't be altered.
This class is Serializable from Commons Collections 3.1.
Attempts to modify it will result in an UnsupportedOperationException.
- Since:
- 3.0
- See Also:
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Nested Class Summary
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Field Summary
FieldsModifier and TypeFieldDescriptionprivate static final long
Serialization versionFields inherited from class org.apache.commons.collections4.map.AbstractMapDecorator
map
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Constructor Summary
ConstructorsModifierConstructorDescriptionprivate
UnmodifiableMap
(Map<? extends K, ? extends V> map) Constructor that wraps (not copies). -
Method Summary
Modifier and TypeMethodDescriptionvoid
clear()
entrySet()
keySet()
Obtains aMapIterator
over the map.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> Map <K, V> unmodifiableMap
(Map<? extends K, ? extends V> map) Factory method to create an unmodifiable map.values()
private void
Write the map out using a custom routine.Methods inherited from class org.apache.commons.collections4.map.AbstractMapDecorator
containsKey, containsValue, decorated, equals, get, hashCode, isEmpty, size, toString
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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Constructor Details
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UnmodifiableMap
Constructor that wraps (not copies).- Parameters:
map
- the map to decorate, must not be null- Throws:
NullPointerException
- if map is null
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Method Details
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unmodifiableMap
Factory method to create an unmodifiable map.- Type Parameters:
K
- the key typeV
- the value type- Parameters:
map
- the map to decorate, must not be null- Returns:
- a new unmodifiable 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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clear
public void clear() -
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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remove
- Specified by:
remove
in interfaceGet<K,
V> - Specified by:
remove
in interfaceMap<K,
V> - Overrides:
remove
in classAbstractMapDecorator<K,
V> - Parameters:
key
- key whose mapping is to be removed from the map- Returns:
- the previous value associated with
key
, ornull
if there was no mapping forkey
. - See Also:
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mapIterator
Description copied from class:AbstractIterableMap
Obtains aMapIterator
over the map.A map iterator is an efficient way of iterating over maps. There is no need to access the entry set or use Map Entry objects.
IterableMap<String,Integer> map = new HashedMap<String,Integer>(); MapIterator<String,Integer> it = map.mapIterator(); while (it.hasNext()) { String key = it.next(); Integer value = it.getValue(); it.setValue(value + 1); }
- Specified by:
mapIterator
in interfaceIterableGet<K,
V> - Overrides:
mapIterator
in classAbstractIterableMap<K,
V> - Returns:
- a map iterator
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entrySet
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keySet
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values
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