Package com.almworks.jira.structure.api.attribute.loader.delegate

Class DelegatingItemAttributeLoader<T>

Object

DelegatingAttributeLoader<T,ItemAttributeLoader<T>>

DelegatingItemAttributeLoader<T>

All Implemented Interfaces:

AttributeLoader<T>, ItemAttributeLoader<T>

public class DelegatingItemAttributeLoader<T>
extends DelegatingAttributeLoader<T,ItemAttributeLoader<T>>
implements ItemAttributeLoader<T>

Constructor Summary

Constructors

Constructor	Description
DelegatingItemAttributeLoader(ItemAttributeLoader<T> loader)

Method Summary

Modifier and Type	Method	Description
boolean	isItemTypeSupported(String itemType)	Lets the loader declare if it can handle items of a given type.
AttributeValue<T>	loadValue(ItemIdentity itemId, ItemAttributeContext context)	The loading function.
void	preload(Collection<ItemIdentity> itemIds, AttributeContext context)	Optional method to perform any bulk actions on a set of items before ItemAttributeLoader.loadValue(com.almworks.jira.structure.api.item.ItemIdentity, com.almworks.jira.structure.api.attribute.loader.ItemAttributeContext) method is called for each item in the collection.

Methods inherited from class DelegatingAttributeLoader

delegate, getAttributeDependencies, getAttributeSpec, getCachingStrategy, getContextDependencies, getGlobalTrail, toString

Methods inherited from class Object

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

Methods inherited from interface AttributeLoader

getAttributeDependencies, getAttributeSpec, getCachingStrategy, getContextDependencies, getGlobalTrail

Constructor Details

DelegatingItemAttributeLoader

public DelegatingItemAttributeLoader(@NotNull
 ItemAttributeLoader<T> loader)

Method Details

isItemTypeSupported

public boolean isItemTypeSupported(@NotNull
 String itemType)

Description copied from interface: ItemAttributeLoader

Lets the loader declare if it can handle items of a given type. If the loader returns false for some type, its ItemAttributeLoader.loadValue(com.almworks.jira.structure.api.item.ItemIdentity, com.almworks.jira.structure.api.attribute.loader.ItemAttributeContext) function will not be called for items of that type; also, non-supported items will be excluded from the collection passed to ItemAttributeLoader.preload(java.util.Collection<com.almworks.jira.structure.api.item.ItemIdentity>, com.almworks.jira.structure.api.attribute.loader.AttributeContext) method.

The returned value must be the same for the same item type throughout the lifetime of the object.

Specified by:

isItemTypeSupported in interface ItemAttributeLoader<T>

Parameters:

itemType - the type of item

Returns:

true if the loader supports this item type.

See Also:

• ItemIdentity

loadValue

@Nullable
public AttributeValue<T> loadValue(@NotNull
 ItemIdentity itemId,
 @NotNull
 ItemAttributeContext context)

Description copied from interface: ItemAttributeLoader

The loading function. The implementation is expected to take itemId or the item object (see ItemAttributeContext.getItem(java.lang.Class<I>)) and provide a value.

Attribute system's contract:

• Before this method is called, ItemAttributeLoader.isItemTypeSupported(java.lang.String) method has been called at least once for the type of the passed item, and this loader has returned true.
• Before this method is called, ItemAttributeLoader.preload(java.util.Collection<com.almworks.jira.structure.api.item.ItemIdentity>, com.almworks.jira.structure.api.attribute.loader.AttributeContext) has been called for a set of items that included itemId, and that was a part of the same loading process, sharing the same context (so all values put into the context are still there).

If the value is missing or empty, the loader should return AttributeValue.undefined(). If for some reason this loader is not applicable for the given item, it should return null.

Specified by:

loadValue in interface ItemAttributeLoader<T>

Parameters:

itemId - item to load the value for

context - loading context

Returns:

attribute value, or null to pass on loading a value for this item

preload

public void preload(@NotNull
 Collection<ItemIdentity> itemIds,
 @NotNull
 AttributeContext context)

Description copied from interface: ItemAttributeLoader

Optional method to perform any bulk actions on a set of items before ItemAttributeLoader.loadValue(com.almworks.jira.structure.api.item.ItemIdentity, com.almworks.jira.structure.api.attribute.loader.ItemAttributeContext) method is called for each item in the collection.

The results of the preloading should be stored using AttributeContext.putObject(java.lang.Object, java.lang.Object). Do not store the preloading results as loader's instance fields! All loaders should be stateless.

Note that this method may be called several times during a single loading operation, for arbitrary sets of items, including those already pre-loaded. Be careful not to overwrite one execution's result with another's.

When this method is called, the attribute system excludes any non-supported items from the list of passed items (checking ItemAttributeLoader.isItemTypeSupported(java.lang.String)).

The loader's dependencies may not be loaded at the time of the call. In fact, there's no way to access the dependency values.

Specified by:

preload in interface ItemAttributeLoader<T>

Parameters:

itemIds - a collection of item IDs about to be loaded

context - loading context