com.almworks.jira.structure.api.attribute.loader.builder

Class BaseSingleRowAttributeLoader<T>

Object

BaseAttributeLoader<T>

BaseSingleRowAttributeLoader<T>

All Implemented Interfaces:

AttributeLoader<T>, RowAttributeLoader<T>, SingleRowAttributeLoader<T>

public class BaseSingleRowAttributeLoader<T>
extends BaseAttributeLoader<T>
implements SingleRowAttributeLoader<T>

Constructor Summary

Constructors

Constructor and Description
BaseSingleRowAttributeLoader(AttributeSpec<T> attributeSpec, Set<AttributeSpec<?>> dependencies, Set<AttributeContextDependency> contextDependencies, AttributeCachingStrategy cachingStrategy, TrailItemSet globalTrail, BiFunction<StructureRow,SingleRowAttributeContext,AttributeValue<T>> loadingFunction, RowPreloadFunction preloadFunction, boolean wholeForestDependent)

Method Summary

Modifier and Type	Method and Description
boolean	isWholeForestDependent() Allows the loader to declare dependency on the whole forest.
AttributeValue<T>	loadValue(StructureRow row, SingleRowAttributeContext context) The loading function.
void	preload(LongSet rowIds, ItemForest forest, AttributeContext context) Optional method to perform any bulk actions on a set of rows before the loading function is called for each row.

Methods inherited from class BaseAttributeLoader

getAttributeDependencies, getAttributeSpec, getCachingStrategy, getContextDependencies, getGlobalTrail

Methods inherited from class Object

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

Methods inherited from interface AttributeLoader

getAttributeDependencies, getAttributeSpec, getCachingStrategy, getContextDependencies, getGlobalTrail

Constructor Detail

BaseSingleRowAttributeLoader

public BaseSingleRowAttributeLoader(@NotNull
                                    AttributeSpec<T> attributeSpec,
                                    @Nullable
                                    Set<AttributeSpec<?>> dependencies,
                                    @Nullable
                                    Set<AttributeContextDependency> contextDependencies,
                                    @Nullable
                                    AttributeCachingStrategy cachingStrategy,
                                    @Nullable
                                    TrailItemSet globalTrail,
                                    @NotNull
                                    BiFunction<StructureRow,SingleRowAttributeContext,AttributeValue<T>> loadingFunction,
                                    @Nullable
                                    RowPreloadFunction preloadFunction,
                                    boolean wholeForestDependent)

Method Detail

loadValue

@Nullable
public AttributeValue<T> loadValue(@NotNull
                                             StructureRow row,
                                             @NotNull
                                             SingleRowAttributeContext context)

Description copied from interface: SingleRowAttributeLoader

The loading function. The implementation is expected to take row and provide a value.

Before this method is called, RowAttributeLoader.preload(com.almworks.integers.LongSet, com.almworks.jira.structure.api.forest.item.ItemForest, com.almworks.jira.structure.api.attribute.loader.AttributeContext) has been called for a set of rows that included this row, and that was a part of the same loading process, sharing the same context (so all values put into the context are still there).

The exception to this rule is the super-root row, which is not included in the preload call. See SuperRootRow for more information about the super-root.

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 row, it should return null.

Specified by:

loadValue in interface SingleRowAttributeLoader<T>

Parameters:

row - the row 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
                    LongSet rowIds,
                    @NotNull
                    ItemForest forest,
                    @NotNull
                    AttributeContext context)

Description copied from interface: RowAttributeLoader

Optional method to perform any bulk actions on a set of rows before the loading function is called for each row.

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 rows, including those that were already pre-loaded. Be careful not to overwrite one execution's result with another's.

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.

Note that rowIds will never contain the super-root row id (-1), even if the value for it is about to be loaded. See SuperRootRow for details about the super-root.

Specified by:

preload in interface RowAttributeLoader<T>

Parameters:

rowIds - set of row IDs for which attribute values are needed

forest - forest for which attribute values are being loaded

context - loading context

isWholeForestDependent

public boolean isWholeForestDependent()

Description copied from interface: RowAttributeLoader

Allows the loader to declare dependency on the whole forest. In that case, the value loaded might depend on the forest and dependencies for the current row. (No dependencies on other values.)

The effect of such declaration is that the values of this attribute, as well as any other values depending on them, will be invalidated as soon as there's any forest or item changes.

You should almost never override this method. Introducing a whole-forest attribute takes toll on application performance.

Specified by:

isWholeForestDependent in interface RowAttributeLoader<T>

Returns:

true if the attribute is whole forest-dependent