org.datanucleus.store.types.sco
Class SCOUtils

java.lang.Object
  org.datanucleus.store.types.sco.SCOUtils

public class SCOUtils
extends java.lang.Object

Collection of utilities for second class wrappers and objects.

Constructor Summary

SCOUtils()

Method Summary

static boolean	allowNullsInContainer(boolean defaultValue, AbstractMemberMetaData mmd) Utility to return whether or not to allow nulls in the container for the specified field.
static boolean	arrayIsStoredInSingleColumn(AbstractMemberMetaData fmd, MetaDataManager mmgr) Convenience method to return if an array field has the elements stored into the table of the field as a single (BLOB) column.
static boolean	attachAddNewElements(ApiAdapter api, java.util.Collection coll, java.util.Collection elements, boolean elementsWithoutId) Convenience method for use by Collection/Set/HashSet attachCopy methods to add any new elements (added whilst detached) to the collection.
static void	attachCopyForCollection(ObjectProvider ownerSM, java.lang.Object[] detachedElements, java.util.Collection attached, boolean elementsWithoutIdentity) Method to return an attached copy of the passed (detached) value.
static void	attachCopyForMap(ObjectProvider ownerSM, java.util.Set detachedEntries, java.util.Map attached, boolean keysWithoutIdentity, boolean valuesWithoutIdentity) Method to return an attached copy of the passed (detached) value.
static void	attachForCollection(ObjectProvider ownerSM, java.lang.Object[] elements, boolean elementsWithoutIdentity) Convenience method to attach (recursively) all elements for a collection field.
static void	attachForMap(ObjectProvider ownerSM, java.util.Set entries, boolean keysWithoutIdentity, boolean valuesWithoutIdentity) Convenience method to attach (recursively) all keys/values for a map field.
static boolean	attachRemoveDeletedElements(ApiAdapter api, java.util.Collection coll, java.util.Collection elements, boolean elementsWithoutId) Convenience method for use by Collection/Set/HashSet attachCopy methods to remove any no-longer-needed elements from the collection (for when elements are removed when detached).
static boolean	collectionHasElementsWithoutIdentity(AbstractMemberMetaData mmd) Convenience method to return if a collection field has elements without their own identity.
static boolean	collectionHasSerialisedElements(AbstractMemberMetaData fmd) Convenience method to return if a collection field has the elements serialised into the table of the field as a single BLOB.
static boolean	detachAsWrapped(ObjectProvider ownerSM) Convenience accessor for whether to detach SCO objects as wrapped.
static void	detachCopyForCollection(ObjectProvider ownerSM, java.lang.Object[] elements, FetchPlanState state, java.util.Collection detached) Convenience method to detach copies (recursively) of all elements for a collection field.
static void	detachCopyForMap(ObjectProvider ownerSM, java.util.Set entries, FetchPlanState state, java.util.Map detached) Convenience method to detach copies (recursively) of all elements for a map field.
static void	detachForCollection(ObjectProvider ownerSM, java.lang.Object[] elements, FetchPlanState state) Convenience method to detach (recursively) all elements for a collection field.
static void	detachForMap(ObjectProvider ownerSM, java.util.Set entries, FetchPlanState state) Convenience method to detach (recursively) all elements for a map field.
static java.util.Comparator	getComparator(AbstractMemberMetaData fmd, ClassLoaderResolver clr) Convenience method for creating a Comparator using extension metadata tags for the specified field.
static java.lang.String	getContainerInfoMessage(ObjectProvider ownerSM, java.lang.String fieldName, SCOContainer cont, boolean useCache, boolean queued, boolean allowNulls, boolean lazyLoading) Utility to generate a message representing the SCO container wrapper and its capabilities.
static java.lang.Class	getContainerInstanceType(java.lang.Class declaredType, java.lang.Boolean ordered) Method to return the type to instantiate a container as.
static java.lang.String	getSCOWrapperOptionsMessage(boolean useCache, boolean queued, boolean allowNulls, boolean lazyLoading) Convenience method to generate a message containing the options of this SCO wrapper.
static boolean	hasDependentElement(AbstractMemberMetaData mmd) Method to return if the member is a collection/array with dependent element.
static boolean	hasDependentKey(AbstractMemberMetaData mmd) Method to return if the member is a map with dependent key.
static boolean	hasDependentValue(AbstractMemberMetaData mmd) Method to return if the member is a map with dependent value.
static boolean	isListBased(java.lang.Class type) Return whether the supplied type (collection) is list based.
static boolean	mapHasKeysWithoutIdentity(AbstractMemberMetaData fmd) Convenience method to return if a map field has keys without their own identity.
static boolean	mapHasSerialisedKeysAndValues(AbstractMemberMetaData fmd) Convenience method to return if a map field has the keys/values serialised.
static boolean	mapHasValuesWithoutIdentity(AbstractMemberMetaData fmd) Convenience method to return if a map field has values without their own identity.
static SCO	newSCOInstance(ObjectProvider ownerSM, AbstractMemberMetaData fmd, java.lang.Class declaredType, java.lang.Class instantiatedType, java.lang.Object value, boolean forInsert, boolean forUpdate, boolean replaceField) Method to create a new SCO wrapper for a SCO type.
static void	populateMapDelegateWithStoreData(java.util.Map delegate, MapStore store, ObjectProvider ownerSM) Convenience method to populate the passed delegate Map with the keys/values from the associated Store.
static void	refreshFetchPlanFieldsForCollection(ObjectProvider ownerSM, java.lang.Object[] elements) Convenience method to refresh fetch plan fields for all elements for a collection field.
static void	refreshFetchPlanFieldsForMap(ObjectProvider ownerSM, java.util.Set entries) Convenience method to refresh fetch plan fields for all elements for a map field.
static java.lang.Object[]	toArray(CollectionStore backingStore, ObjectProvider sm) Returns true if this collection contains the specified element.
static java.lang.Object[]	toArray(CollectionStore backingStore, ObjectProvider sm, java.lang.Object[] a) Returns an array containing all of the elements in this collection;
static void	updateCollectionWithCollection(ApiAdapter api, java.util.Collection coll, java.util.Collection newColl) Convenience method to update a collection to contain the elements in another collection.
static boolean	updateCollectionWithCollectionElements(java.util.Collection coll, java.util.Collection elements) Convenience method for use by Collection/Set/HashSet attachCopy methods to update the passed (attached) collection using the (attached) elements passed.
static boolean	updateListWithListElements(java.util.List list, java.util.List elements) Convenience method for use by List attachCopy methods to update the passed (attached) list using the (attached) list elements passed.
static boolean	updateMapWithMapKeysValues(ApiAdapter api, java.util.Map map, java.util.Map keysValues) Convenience method for use by Map attachCopy methods to update the passed (attached) map using the (attached) map keys/values passed.
static boolean	useCachedLazyLoading(ObjectProvider ownerSM, java.lang.String fieldName) Accessor for whether the use lazy loading when caching the collection.
static boolean	useContainerCache(ObjectProvider ownerSM, java.lang.String fieldName) Utility to return whether or not to use the container cache for the collection/map for the passed StateManager SCO.
static boolean	useQueuedUpdate(boolean queued, ObjectProvider sm) Convenience method to return if we should use a queued update for the current operation.
static boolean	validateObjectForWriting(ExecutionContext ec, java.lang.Object object, FieldValues2 fieldValues) Method to check if an object to be stored in a SCO container is already persistent, or is managed by a different ObjectManager.
static void	validateObjectsForWriting(ExecutionContext ec, java.lang.Object objects) Method to check if objects to be stored in a SCO container are already persistent, or are managed by a different ObjectManager.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

SCOUtils

public SCOUtils()

Method Detail

newSCOInstance

public static SCO newSCOInstance(ObjectProvider ownerSM,
                                 AbstractMemberMetaData fmd,
                                 java.lang.Class declaredType,
                                 java.lang.Class instantiatedType,
                                 java.lang.Object value,
                                 boolean forInsert,
                                 boolean forUpdate,
                                 boolean replaceField)

Method to create a new SCO wrapper for a SCO type. The SCO wrapper will be appropriate for the passed value (which represents the instantiated type of the field) unless it is null when the wrapper will be appropriate for the declared type of the field. While the "instantiated type" and the type of "value" should be the same when value is non-null, there are situations where we need to create a List based collection yet have no value so pass in the declaredType as Collection, instantiatedType as ArrayList, and value as null.

Parameters:

ownerSM - State Manager for the owning object

fmd - The Field MetaData for the related field.

declaredType - The class of the object

instantiatedType - Instantiated type for the field if known

value - The value we are wrapping if known

forInsert - Whether the SCO needs inserting in the datastore with this value

forUpdate - Whether the SCO needs updating in the datastore with this value

replaceField - Whether to replace the field with this value

Returns:

The Second-Class Object

Throws:

NucleusUserException - if an error occurred when creating the SCO instance

getContainerInfoMessage

public static java.lang.String getContainerInfoMessage(ObjectProvider ownerSM,
                                                       java.lang.String fieldName,
                                                       SCOContainer cont,
                                                       boolean useCache,
                                                       boolean queued,
                                                       boolean allowNulls,
                                                       boolean lazyLoading)

Utility to generate a message representing the SCO container wrapper and its capabilities.

Parameters:

ownerSM - StateManager for the owner

fieldName - Field with the container

cont - The SCOContainer

useCache - Whether to use caching of values in the container

queued - Whether operations are queued in the wrapper

allowNulls - Whether to allow nulls

lazyLoading - Whether to use lazy loading in the wrapper

Returns:

The String

getSCOWrapperOptionsMessage

public static java.lang.String getSCOWrapperOptionsMessage(boolean useCache,
                                                           boolean queued,
                                                           boolean allowNulls,
                                                           boolean lazyLoading)

Convenience method to generate a message containing the options of this SCO wrapper.

Parameters:

useCache - Whether to cache the value in the wrapper (and not go to the datastore)

queued - Whether it supports queueing of updates

allowNulls - Whether it allows null entries

lazyLoading - Whether it is lazy loaded

Returns:

the message

allowNullsInContainer

public static boolean allowNullsInContainer(boolean defaultValue,
                                            AbstractMemberMetaData mmd)

Utility to return whether or not to allow nulls in the container for the specified field.

Parameters:

defaultValue - Default value for the container

mmd - MetaData for the field/property

Returns:

Whether to allow nulls

useContainerCache

public static boolean useContainerCache(ObjectProvider ownerSM,
                                        java.lang.String fieldName)

Utility to return whether or not to use the container cache for the collection/map for the passed StateManager SCO.

Parameters:

ownerSM - The StateManager for the SCO field

fieldName - Name of the field.

Returns:

Whether to use the cache.

useCachedLazyLoading

public static boolean useCachedLazyLoading(ObjectProvider ownerSM,
                                           java.lang.String fieldName)

Accessor for whether the use lazy loading when caching the collection.

Parameters:

ownerSM - StateManager of the owning object

fieldName - Name of the collection/map field

Returns:

Whether to use lazy loading when caching the collection

collectionHasElementsWithoutIdentity

public static boolean collectionHasElementsWithoutIdentity(AbstractMemberMetaData mmd)

Convenience method to return if a collection field has elements without their own identity. Checks if the elements are embedded in a join table, or in the main table, or serialised.

Parameters:

mmd - MetaData for the field

Returns:

Whether the elements have their own identity or not

mapHasKeysWithoutIdentity

public static boolean mapHasKeysWithoutIdentity(AbstractMemberMetaData fmd)

Convenience method to return if a map field has keys without their own identity. Checks if the keys are embedded in a join table, or in the main table, or serialised.

Parameters:

fmd - MetaData for the field

Returns:

Whether the keys have their own identity or not

mapHasValuesWithoutIdentity

public static boolean mapHasValuesWithoutIdentity(AbstractMemberMetaData fmd)

Convenience method to return if a map field has values without their own identity. Checks if the values are embedded in a join table, or in the main table, or serialised.

Parameters:

fmd - MetaData for the field

Returns:

Whether the values have their own identity or not

collectionHasSerialisedElements

public static boolean collectionHasSerialisedElements(AbstractMemberMetaData fmd)

Convenience method to return if a collection field has the elements serialised into the table of the field as a single BLOB. This is really for use within an RDBMS context.

Parameters:

fmd - MetaData for the field

Returns:

Whether the elements are serialised (either explicitly or implicitly)

arrayIsStoredInSingleColumn

public static boolean arrayIsStoredInSingleColumn(AbstractMemberMetaData fmd,
                                                  MetaDataManager mmgr)

Convenience method to return if an array field has the elements stored into the table of the field as a single (BLOB) column.

Parameters:

fmd - MetaData for the field

mmgr - MetaData manager

Returns:

Whether the elements are stored in a single column

mapHasSerialisedKeysAndValues

public static boolean mapHasSerialisedKeysAndValues(AbstractMemberMetaData fmd)

Convenience method to return if a map field has the keys/values serialised. This is really for use within an RDBMS context.

Parameters:

fmd - MetaData for the field

Returns:

Whether the keys and values are serialised (either explicitly or implicitly)

updateCollectionWithCollection

public static void updateCollectionWithCollection(ApiAdapter api,
                                                  java.util.Collection coll,
                                                  java.util.Collection newColl)

Convenience method to update a collection to contain the elements in another collection. Performs the updates by calling the necessary add(), remove() methods just for the elements that have changed. Allows for some elements in one collection being attached and some being detached (so having same id, but different state)

Parameters:

api - API Adapter

coll - The collection to update

newColl - The new collection whose elements we need in "coll"

attachRemoveDeletedElements

public static boolean attachRemoveDeletedElements(ApiAdapter api,
                                                  java.util.Collection coll,
                                                  java.util.Collection elements,
                                                  boolean elementsWithoutId)

Convenience method for use by Collection/Set/HashSet attachCopy methods to remove any no-longer-needed elements from the collection (for when elements are removed when detached).

Parameters:

coll - The current (attached) collection

elements - The collection of (attached) elements needed.

elementsWithoutId - Whether the elements have no identity

Returns:

If the Collection was updated

attachAddNewElements

public static boolean attachAddNewElements(ApiAdapter api,
                                           java.util.Collection coll,
                                           java.util.Collection elements,
                                           boolean elementsWithoutId)

Convenience method for use by Collection/Set/HashSet attachCopy methods to add any new elements (added whilst detached) to the collection.

Parameters:

coll - The current (attached) collection

elements - The collection of (attached) elements needed.

elementsWithoutId - Whether the elements have no identity

Returns:

If the Collection was updated

updateCollectionWithCollectionElements

public static boolean updateCollectionWithCollectionElements(java.util.Collection coll,
                                                             java.util.Collection elements)

Convenience method for use by Collection/Set/HashSet attachCopy methods to update the passed (attached) collection using the (attached) elements passed.

Parameters:

coll - The current (attached) collection

elements - The collection of (attached) elements needed.

Returns:

If the Collection was updated

updateListWithListElements

public static boolean updateListWithListElements(java.util.List list,
                                                 java.util.List elements)

Convenience method for use by List attachCopy methods to update the passed (attached) list using the (attached) list elements passed.

Parameters:

list - The current (attached) list

elements - The list of (attached) elements needed.

Returns:

If the List was updated

updateMapWithMapKeysValues

public static boolean updateMapWithMapKeysValues(ApiAdapter api,
                                                 java.util.Map map,
                                                 java.util.Map keysValues)

Convenience method for use by Map attachCopy methods to update the passed (attached) map using the (attached) map keys/values passed.

Parameters:

api - Api adapter

map - The current (attached) map

keysValues - The keys/values required

Returns:

If the map was updated

populateMapDelegateWithStoreData

public static void populateMapDelegateWithStoreData(java.util.Map delegate,
                                                    MapStore store,
                                                    ObjectProvider ownerSM)

Convenience method to populate the passed delegate Map with the keys/values from the associated Store.

The issue here is that we need to load the keys and values in as few calls as possible. The method employed here reads in the keys (if PersistenceCapable), then the values (if PersistenceCapable), and then the "entries" (ids of keys and values) so we can associate the keys to the values.

Parameters:

delegate - The delegate

store - The Store

ownerSM - State Manager of the owner of the map.

toArray

public static java.lang.Object[] toArray(CollectionStore backingStore,
                                         ObjectProvider sm)

Returns true if this collection contains the specified element. More formally, returns true if and only if this collection contains at least one element it such that (o==null ? it==null : o.equals(it)).

This implementation iterates over the elements in the collection, checking each element in turn for equality with the specified element.

Parameters:

backingStore - the Store

sm - the StateManager

Returns:

true if this collection contains the specified element.

toArray

public static java.lang.Object[] toArray(CollectionStore backingStore,
                                         ObjectProvider sm,
                                         java.lang.Object[] a)

Returns an array containing all of the elements in this collection;

Parameters:

backingStore - the Store

sm - the StateManager

a - the array into which the elements of the collection are to be stored, if it is big enough; otherwise, a new array of the same runtime type is allocated for this purpose.

Returns:

an array containing the elements of the collection.

Throws:

java.lang.NullPointerException - if the specified array is null.

java.lang.ArrayStoreException - if the runtime type of the specified array is not a supertype of the runtime type of every element in this collection.

getComparator

public static java.util.Comparator getComparator(AbstractMemberMetaData fmd,
                                                 ClassLoaderResolver clr)

Convenience method for creating a Comparator using extension metadata tags for the specified field. Uses the extension key "comparator-name".

Parameters:

fmd - The field that needs the comparator

clr - ClassLoader resolver

Returns:

The Comparator

refreshFetchPlanFieldsForCollection

public static void refreshFetchPlanFieldsForCollection(ObjectProvider ownerSM,
                                                       java.lang.Object[] elements)

Convenience method to refresh fetch plan fields for all elements for a collection field. All elements that are PersistenceCapable will be made transient.

Parameters:

ownerSM - StateManager for the owning object with the collection

elements - The elements in the collection

refreshFetchPlanFieldsForMap

public static void refreshFetchPlanFieldsForMap(ObjectProvider ownerSM,
                                                java.util.Set entries)

Convenience method to refresh fetch plan fields for all elements for a map field. All elements that are PersistenceCapable will be made transient.

Parameters:

ownerSM - StateManager for the owning object with the map

entries - The entries in the map

detachForCollection

public static void detachForCollection(ObjectProvider ownerSM,
                                       java.lang.Object[] elements,
                                       FetchPlanState state)

Convenience method to detach (recursively) all elements for a collection field. All elements that are PersistenceCapable will be detached.

Parameters:

ownerSM - StateManager for the owning object with the collection

elements - The elements in the collection

state - FetchPlan state

detachCopyForCollection

public static void detachCopyForCollection(ObjectProvider ownerSM,
                                           java.lang.Object[] elements,
                                           FetchPlanState state,
                                           java.util.Collection detached)

Convenience method to detach copies (recursively) of all elements for a collection field. All elements that are PersistenceCapable will be detached.

Parameters:

ownerSM - StateManager for the owning object with the collection

elements - The elements in the collection

state - FetchPlan state

detached - Collection to add the detached copies to

attachForCollection

public static void attachForCollection(ObjectProvider ownerSM,
                                       java.lang.Object[] elements,
                                       boolean elementsWithoutIdentity)

Convenience method to attach (recursively) all elements for a collection field. All elements that are PersistenceCapable and not yet having an attached object will be attached.

Parameters:

ownerSM - StateManager for the owning object with the collection

elements - The elements to process

elementsWithoutIdentity - Whether the elements have their own identity

attachCopyForCollection

public static void attachCopyForCollection(ObjectProvider ownerSM,
                                           java.lang.Object[] detachedElements,
                                           java.util.Collection attached,
                                           boolean elementsWithoutIdentity)

Method to return an attached copy of the passed (detached) value. The returned attached copy is a SCO wrapper. Goes through the existing elements in the store for this owner field and removes ones no longer present, and adds new elements. All elements in the (detached) value are attached.

Parameters:

ownerSM - StateManager for the owning object with the collection

detachedElements - The detached elements in the collection

attached - Collection to add the attached copies to

elementsWithoutIdentity - Whether the elements have their own identity

detachForMap

public static void detachForMap(ObjectProvider ownerSM,
                                java.util.Set entries,
                                FetchPlanState state)

Convenience method to detach (recursively) all elements for a map field. All elements that are PersistenceCapable will be detached.

Parameters:

ownerSM - StateManager for the owning object with the map

entries - The entries in the map

state - FetchPlan state

detachCopyForMap

public static void detachCopyForMap(ObjectProvider ownerSM,
                                    java.util.Set entries,
                                    FetchPlanState state,
                                    java.util.Map detached)

Convenience method to detach copies (recursively) of all elements for a map field. All elements that are PersistenceCapable will be detached.

Parameters:

ownerSM - StateManager for the owning object with the map

entries - The entries in the map

state - FetchPlan state

detached - Map to add the detached copies to

attachForMap

public static void attachForMap(ObjectProvider ownerSM,
                                java.util.Set entries,
                                boolean keysWithoutIdentity,
                                boolean valuesWithoutIdentity)

Convenience method to attach (recursively) all keys/values for a map field. All keys/values that are PersistenceCapable and don't already have an attached object will be attached.

Parameters:

ownerSM - StateManager for the owning object with the map

entries - The entries in the map to process

keysWithoutIdentity - Whether the keys have their own identity

valuesWithoutIdentity - Whether the values have their own identity

attachCopyForMap

public static void attachCopyForMap(ObjectProvider ownerSM,
                                    java.util.Set detachedEntries,
                                    java.util.Map attached,
                                    boolean keysWithoutIdentity,
                                    boolean valuesWithoutIdentity)

Method to return an attached copy of the passed (detached) value. The returned attached copy is a SCO wrapper. Goes through the existing elements in the store for this owner field and removes ones no longer present, and adds new elements. All elements in the (detached) value are attached.

Parameters:

ownerSM - StateManager for the owning object with the map

detachedEntries - The detached entries in the map

attached - Map to add the attached copies to

keysWithoutIdentity - Whether the keys have their own identity

valuesWithoutIdentity - Whether the values have their own identity

validateObjectForWriting

public static boolean validateObjectForWriting(ExecutionContext ec,
                                               java.lang.Object object,
                                               FieldValues2 fieldValues)

Method to check if an object to be stored in a SCO container is already persistent, or is managed by a different ObjectManager. If not persistent, this call will persist it. If not yet flushed to the datastore this call will flush it.

Parameters:

ec - ExecutionContext that we are using

object - The object

fieldValues - Values for any fields when persisting (if the object needs persisting)

Returns:

Whether the object was persisted during this call

validateObjectsForWriting

public static void validateObjectsForWriting(ExecutionContext ec,
                                             java.lang.Object objects)

Method to check if objects to be stored in a SCO container are already persistent, or are managed by a different ObjectManager. If not persistent, this call will persist them.

Parameters:

ec - execution context

objects - The objects (array, or Collection)

isListBased

public static boolean isListBased(java.lang.Class type)

Return whether the supplied type (collection) is list based.

Returns:

Whether it needs list ordering

getContainerInstanceType

public static java.lang.Class getContainerInstanceType(java.lang.Class declaredType,
                                                       java.lang.Boolean ordered)

Method to return the type to instantiate a container as. Returns the declared type unless it is not a concrete type, in which case returns ArrayList, HashSet, or HashMap.

Parameters:

declaredType - The declared type

ordered - Hint whether it needs ordering or not (null implies not)

Returns:

The type to instantiate as

detachAsWrapped

public static boolean detachAsWrapped(ObjectProvider ownerSM)

Convenience accessor for whether to detach SCO objects as wrapped.

Parameters:

ownerSM - StateManager

Returns:

Whether to detach SCOs in wrapped form

useQueuedUpdate

public static boolean useQueuedUpdate(boolean queued,
                                      ObjectProvider sm)

Convenience method to return if we should use a queued update for the current operation. If within a transaction, and using queueing in general, and not flushing then returns true.

Parameters:

queued - Whether supporting queued operations

sm - StateManager

Returns:

Whether to use queued for this operation

hasDependentElement

public static boolean hasDependentElement(AbstractMemberMetaData mmd)

Method to return if the member is a collection/array with dependent element.

Parameters:

mmd - member metadata

Returns:

whether it has dependent element

hasDependentKey

public static boolean hasDependentKey(AbstractMemberMetaData mmd)

Method to return if the member is a map with dependent key.

Parameters:

mmd - member metadata

Returns:

whether it has dependent key

hasDependentValue

public static boolean hasDependentValue(AbstractMemberMetaData mmd)

Method to return if the member is a map with dependent value.

Parameters:

mmd - member metadata

Returns:

whether it has dependent value