Class UnmodifiableMap<K,V>
- java.lang.Object
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- org.apache.commons.collections4.map.AbstractIterableMap<K,V>
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- org.apache.commons.collections4.map.AbstractMapDecorator<K,V>
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- org.apache.commons.collections4.map.UnmodifiableMap<K,V>
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- Type Parameters:
K
- the type of the keys in this mapV
- the type of the values in this map
- All Implemented Interfaces:
java.io.Serializable
,java.util.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, java.io.Serializable
Decorates anotherMap
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:
- Serialized Form
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Field Summary
Fields Modifier and Type Field Description private static long
serialVersionUID
Serialization version-
Fields inherited from class org.apache.commons.collections4.map.AbstractMapDecorator
map
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Constructor Summary
Constructors Modifier Constructor Description private
UnmodifiableMap(java.util.Map<? extends K,? extends V> map)
Constructor that wraps (not copies).
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description void
clear()
java.util.Set<java.util.Map.Entry<K,V>>
entrySet()
java.util.Set<K>
keySet()
MapIterator<K,V>
mapIterator()
Obtains aMapIterator
over the map.V
put(K key, V value)
Note that the return type is Object, rather than V as in the Map interface.void
putAll(java.util.Map<? extends K,? extends V> mapToCopy)
private void
readObject(java.io.ObjectInputStream in)
Read the map in using a custom routine.V
remove(java.lang.Object key)
static <K,V>
java.util.Map<K,V>unmodifiableMap(java.util.Map<? extends K,? extends V> map)
Factory method to create an unmodifiable map.java.util.Collection<V>
values()
private void
writeObject(java.io.ObjectOutputStream out)
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
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Field Detail
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serialVersionUID
private static final long serialVersionUID
Serialization version- See Also:
- Constant Field Values
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Method Detail
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unmodifiableMap
public static <K,V> java.util.Map<K,V> unmodifiableMap(java.util.Map<? extends K,? extends V> map)
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:
java.lang.NullPointerException
- if map is null- Since:
- 4.0
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writeObject
private void writeObject(java.io.ObjectOutputStream out) throws java.io.IOException
Write the map out using a custom routine.- Parameters:
out
- the output stream- Throws:
java.io.IOException
- if an error occurs while writing to the stream- Since:
- 3.1
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readObject
private void readObject(java.io.ObjectInputStream in) throws java.io.IOException, java.lang.ClassNotFoundException
Read the map in using a custom routine.- Parameters:
in
- the input stream- Throws:
java.io.IOException
- if an error occurs while reading from the streamjava.lang.ClassNotFoundException
- if an object read from the stream can not be loaded- Since:
- 3.1
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clear
public void clear()
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put
public V put(K key, V value)
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 interfacejava.util.Map<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:
Map.put(Object, Object)
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remove
public V remove(java.lang.Object key)
- Specified by:
remove
in interfaceGet<K,V>
- Specified by:
remove
in interfacejava.util.Map<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:
Map.remove(Object)
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mapIterator
public MapIterator<K,V> 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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keySet
public java.util.Set<K> keySet()
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