Class SingletonMap<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,Cloneable,Map<K,,V> BoundedMap<K,,V> Get<K,,V> IterableGet<K,,V> IterableMap<K,,V> KeyValue<K,,V> OrderedMap<K,,V> Put<K,V>
Map implementation that holds a single item and is fixed size.
The single key/value pair is specified at creation.
The map is fixed size so any action that would change the size is disallowed.
However, the put or setValue methods can change
the value associated with the key.
If trying to remove or clear the map, an UnsupportedOperationException is thrown. If trying to put a new mapping into the map, an IllegalArgumentException is thrown. The put method will only succeed if the key specified is the same as the singleton key.
The key and value can be obtained by:
- normal Map methods and views
- the
MapIterator, seemapIterator() - the
KeyValueinterface (just cast - no object creation)
- Since:
- 3.1
- See Also:
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Nested Class Summary
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Constructor Summary
ConstructorsConstructorDescriptionConstructor that creates a map ofnulltonull.SingletonMap(Map.Entry<? extends K, ? extends V> mapEntry) Constructor specifying the key and value as aMapEntry.SingletonMap(Map<? extends K, ? extends V> map) Constructor copying elements from another map.SingletonMap(K key, V value) Constructor specifying the key and value.SingletonMap(KeyValue<K, V> keyValue) Constructor specifying the key and value as aKeyValue. -
Method Summary
Modifier and TypeMethodDescriptionvoidclear()Unsupported operation.clone()Clones the map without cloning the key or value.booleancontainsKey(Object key) Checks whether the map contains the specified key.booleancontainsValue(Object value) Checks whether the map contains the specified value.entrySet()Gets the entrySet view of the map.booleanCompares this map with another.firstKey()Gets the first (and only) key in the map.Gets the value mapped to the key specified.getKey()Gets the key.getValue()Gets the value.inthashCode()Gets the standard Map hashCode.booleanisEmpty()Checks whether the map is currently empty, which it never is.protected booleanisEqualKey(Object key) Compares the specified key to the stored key.protected booleanisEqualValue(Object value) Compares the specified value to the stored value.booleanisFull()Is the map currently full, always true.keySet()Gets the unmodifiable keySet view of the map.lastKey()Gets the last (and only) key in the map.Obtains anOrderedMapIteratorover the map.intmaxSize()Gets the maximum size of the map, always 1.Gets the next key after the key specified, always null.previousKey(K key) Gets the previous key before the key specified, always null.Puts a key-value mapping into this map where the key must match the existing key.voidPuts the values from the specified map into this map.Unsupported operation.Sets the value.intsize()Gets the size of the map, always 1.toString()Gets the map as a String.values()Gets the unmodifiable values view of the map.Methods inherited from class java.lang.Object
finalize, getClass, notify, notifyAll, wait, wait, waitMethods inherited from interface java.util.Map
compute, computeIfAbsent, computeIfPresent, forEach, getOrDefault, merge, putIfAbsent, remove, replace, replace, replaceAll
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Constructor Details
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SingletonMap
public SingletonMap()Constructor that creates a map ofnulltonull. -
SingletonMap
Constructor specifying the key and value.- Parameters:
key- the key to usevalue- the value to use
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SingletonMap
Constructor specifying the key and value as aKeyValue.- Parameters:
keyValue- the key value pair to use
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SingletonMap
Constructor specifying the key and value as aMapEntry.- Parameters:
mapEntry- the mapEntry to use
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SingletonMap
Constructor copying elements from another map.- Parameters:
map- the map to copy, must be size 1- Throws:
NullPointerException- if the map is nullIllegalArgumentException- if the size is not 1
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Method Details
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clear
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clone
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containsKey
Checks whether the map contains the specified key.- Specified by:
containsKeyin interfaceGet<K,V> - Specified by:
containsKeyin interfaceMap<K,V> - Parameters:
key- the key to search for- Returns:
- true if the map contains the key
- See Also:
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containsValue
Checks whether the map contains the specified value.- Specified by:
containsValuein interfaceGet<K,V> - Specified by:
containsValuein interfaceMap<K,V> - Parameters:
value- the value to search for- Returns:
- true if the map contains the key
- See Also:
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entrySet
Gets the entrySet view of the map. Changes made viasetValueaffect this map. To simply iterate through the entries, usemapIterator(). -
equals
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firstKey
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get
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getKey
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getValue
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hashCode
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isEmpty
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isEqualKey
Compares the specified key to the stored key.- Parameters:
key- the key to compare- Returns:
- true if equal
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isEqualValue
Compares the specified value to the stored value.- Parameters:
value- the value to compare- Returns:
- true if equal
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isFull
Is the map currently full, always true.- Specified by:
isFullin interfaceBoundedMap<K,V> - Returns:
- true always
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keySet
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lastKey
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mapIterator
Obtains anOrderedMapIteratorover the map.An ordered map iterator is an efficient way of iterating over maps in both directions.
- Specified by:
mapIteratorin interfaceIterableGet<K,V> - Specified by:
mapIteratorin interfaceOrderedMap<K,V> - Returns:
- a map iterator
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maxSize
Gets the maximum size of the map, always 1.- Specified by:
maxSizein interfaceBoundedMap<K,V> - Returns:
- 1 always
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nextKey
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previousKey
Gets the previous key before the key specified, always null.- Specified by:
previousKeyin interfaceOrderedMap<K,V> - Parameters:
key- the next key- Returns:
- null always
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put
Puts a key-value mapping into this map where the key must match the existing key.An IllegalArgumentException is thrown if the key does not match as the map is fixed size.
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putAll
Puts the values from the specified map into this map.The map must be of size 0 or size 1. If it is size 1, the key must match the key of this map otherwise an IllegalArgumentException is thrown.
- Specified by:
putAllin interfaceMap<K,V> - Specified by:
putAllin interfacePut<K,V> - Parameters:
map- the map to add, must be size 0 or 1, and the key must match- Throws:
NullPointerException- if the map is nullIllegalArgumentException- if the key does not match- See Also:
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remove
Unsupported operation. -
setValue
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size
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toString
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values
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