Class Map<K,V>
java.lang.Object
java.util.AbstractMap<K,V>
org.datanucleus.store.types.wrappers.Map<K,V>
org.datanucleus.store.types.wrappers.backed.Map<K,V>
- All Implemented Interfaces:
Serializable
,Cloneable
,Map<K,
,V> SCO<Map<K,
,V>> SCOContainer<Map<K,
,V>> SCOMap<Map<K,
,V>, K, V> BackedSCO
A mutable second-class Map object.
Uses a "delegate" as a local store for the Map. Uses a "backing store" (SetStore) to represent the datastore.
The "delegate" is updated with the "backing store" information at necessary intervals.
Modes of Operation
The user can operate the map in 2 modes. The cached mode will use an internal cache of the elements (in the "delegate") reading them at the first opportunity and then using the cache thereafter. The non-cached mode will just go direct to the "backing store" each call.Mutators
When the backing store is present any updates are passed direct to the datastore as well as to the "delegate". If the "backing store" isn't present the changes are made to the "delegate" only.Accessors
When any accessor method is invoked, it typically checks whether the map has been loaded from its backing store and does this as necessary. Some methods (size(), containsKey()) just check if everything is loaded and use the delegate if possible, otherwise going direct to the datastore.- See Also:
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Nested Class Summary
Nested classes/interfaces inherited from class java.util.AbstractMap
AbstractMap.SimpleEntry<K,
V>, AbstractMap.SimpleImmutableEntry<K, V> -
Field Summary
FieldsModifier and TypeFieldDescriptionprotected boolean
protected boolean
protected boolean
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Constructor Summary
ConstructorsConstructorDescriptionMap
(DNStateManager sm, AbstractMemberMetaData mmd) Constructor, using StateManager of the "owner" and the field name. -
Method Summary
Modifier and TypeMethodDescriptionvoid
clear()
Method to clear the Map.clone()
Creates and returns a copy of this object.boolean
containsKey
(Object key) Utility to check if a key is contained in the Map.boolean
containsValue
(Object value) Utility to check if a value is contained in the Map.entrySet()
Accessor for the set of entries in the Map.boolean
Method to check the equality of this map, and another.void
forEach
(BiConsumer<? super K, ? super V> action) Accessor for the value stored against a key.getValue()
Accessor for the unwrapped value that we are wrapping.int
hashCode()
Method to generate a hashcode for this Map.void
Method to initialise the SCO for use.void
initialise
(Map m) Method to initialise the SCO from an existing value.void
initialise
(Map newValue, Object oldValue) Method to initialise the SCO for use, where replacing an old value with a new value such as when calling a setter field passing in a new value.boolean
isEmpty()
Method to return if the Map is empty.boolean
isLoaded()
Method to return if the SCO has its contents loaded.keySet()
Accessor for the set of keys in the Map.void
load()
Method to effect the load of the data in the SCO.protected void
Method to load all elements from the "backing store" where appropriate.Method to add a value to the Map.void
Method to add a Map of values to this map.Method to remove a value from the Map.int
size()
Method to return the size of the Map.toString()
Method to return a string form of this Map.void
Method to unset the owner and field information.void
updateEmbeddedKey
(K key, int fieldNumber, Object newValue, boolean makeDirty) Method to update an embedded key in this map.void
updateEmbeddedValue
(V value, int fieldNumber, Object newValue, boolean makeDirty) Method to update an embedded value in this map.values()
Accessor for the set of values in the Map.protected Object
The writeReplace method is called when ObjectOutputStream is preparing to write the object to the stream.Methods inherited from class org.datanucleus.store.types.wrappers.Map
attachCopy, detachCopy, getFieldName, getOwner, makeDirty, setValue
Methods inherited from class java.lang.Object
finalize, getClass, notify, notifyAll, wait, wait, wait
Methods inherited from interface java.util.Map
compute, computeIfAbsent, computeIfPresent, getOrDefault, merge, putIfAbsent, remove, replace, replace, replaceAll
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Field Details
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allowNulls
protected transient boolean allowNulls -
backingStore
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useCache
protected transient boolean useCache -
isCacheLoaded
protected transient boolean isCacheLoaded
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Constructor Details
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Map
Constructor, using StateManager of the "owner" and the field name.- Parameters:
sm
- The owner StateManagermmd
- Metadata for the member
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Method Details
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initialise
Description copied from interface:SCO
Method to initialise the SCO for use, where replacing an old value with a new value such as when calling a setter field passing in a new value. Note that oldValue is marked as Object since for cases where the member type is Collection the newValue could be, for example, ArrayList, and the oldValue of type Collection (representing null).- Specified by:
initialise
in interfaceSCO<K>
- Overrides:
initialise
in classMap<K,
V> - Parameters:
newValue
- New value (to wrap)oldValue
- Old value (to use in deciding what needs deleting etc)
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initialise
Method to initialise the SCO from an existing value.- Specified by:
initialise
in interfaceSCO<K>
- Overrides:
initialise
in classMap<K,
V> - Parameters:
m
- The object to set from
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initialise
public void initialise()Method to initialise the SCO for use.- Specified by:
initialise
in interfaceSCO<K>
- Overrides:
initialise
in classMap<K,
V>
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getValue
Accessor for the unwrapped value that we are wrapping. -
load
public void load()Method to effect the load of the data in the SCO. Used when the SCO supports lazy-loading to tell it to load all now. -
isLoaded
public boolean isLoaded()Method to return if the SCO has its contents loaded. If the SCO doesn't support lazy loading will just return true. -
loadFromStore
protected void loadFromStore()Method to load all elements from the "backing store" where appropriate. -
getBackingStore
- Specified by:
getBackingStore
in interfaceBackedSCO
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updateEmbeddedKey
Method to update an embedded key in this map. -
updateEmbeddedValue
Method to update an embedded value in this map. -
unsetOwner
public void unsetOwner()Method to unset the owner and field information.- Specified by:
unsetOwner
in interfaceSCO<K>
- Overrides:
unsetOwner
in classMap<K,
V>
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clone
Creates and returns a copy of this object.Mutable second-class Objects are required to provide a public clone method in order to allow for copying persistable objects. In contrast to Object.clone(), this method must not throw a CloneNotSupportedException.
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containsKey
Utility to check if a key is contained in the Map.- Specified by:
containsKey
in interfaceMap<K,
V> - Overrides:
containsKey
in classMap<K,
V> - Parameters:
key
- The key to check- Returns:
- Whether it is contained
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containsValue
Utility to check if a value is contained in the Map.- Specified by:
containsValue
in interfaceMap<K,
V> - Overrides:
containsValue
in classMap<K,
V> - Parameters:
value
- The value to check- Returns:
- Whether it is contained
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entrySet
Accessor for the set of entries in the Map. -
equals
Method to check the equality of this map, and another. -
forEach
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get
Accessor for the value stored against a key. -
hashCode
public int hashCode()Method to generate a hashcode for this Map. -
isEmpty
public boolean isEmpty()Method to return if the Map is empty. -
keySet
Accessor for the set of keys in the Map. -
size
public int size()Method to return the size of the Map. -
values
Accessor for the set of values in the Map. -
toString
Method to return a string form of this Map.- Overrides:
toString
in classAbstractMap<K,
V> - Returns:
- String form of this Map.
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clear
public void clear()Method to clear the Map. -
put
Method to add a value to the Map. -
putAll
Method to add a Map of values to this map. -
remove
Method to remove a value from the Map. -
writeReplace
The writeReplace method is called when ObjectOutputStream is preparing to write the object to the stream. The ObjectOutputStream checks whether the class defines the writeReplace method. If the method is defined, the writeReplace method is called to allow the object to designate its replacement in the stream. The object returned should be either of the same type as the object passed in or an object that when read and resolved will result in an object of a type that is compatible with all references to the object.- Overrides:
writeReplace
in classMap<K,
V> - Returns:
- the replaced object
- Throws:
ObjectStreamException
- if an error occurs
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