Class InheritedValueLoader<T>

All Implemented Interfaces:
AttributeLoader<T>, MultiRowAttributeLoader<T>, PropagateAttributeLoader<T>, RowAttributeLoader<T>

public class InheritedValueLoader<T> extends AbstractPropagateLoader<T>
  • Constructor Details

    • InheritedValueLoader

      public InheritedValueLoader(AttributeSpec<T> spec, @NotNull AttributeSpec<T> valueSpec, boolean forceParentValue)
  • Method Details

    • getAttributeDependencies

      public Set<AttributeSpec<?>> getAttributeDependencies()
      Description copied from interface: AttributeLoader

      Returns attributes that need to be loaded prior to calling this loader's loading function.

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

      Returns:
      the set of attribute dependencies, or null if there are none
      See Also:
    • loadChildren

      @Nullable public BiFunction<StructureRow,PropagateAttributeContext,AttributeValue<T>> loadChildren(@NotNull AttributeValue<T> parentValue, @NotNull PropagateAttributeContext.Parent parentContext)
      Description copied from interface: PropagateAttributeLoader

      Provider of a loading function for the children of the given parent row. When there's a need to load a propagate value for row R, then first this method is called for the parent of R. Then the function that is received will be called to calculate the value for R and any other siblings that are also requested in this loading process.

      The implementation can make preparatory calculations and then return a function that will produce results for specific rows. The value of the dependencies for the children rows are available only when that function is called.

      You should not include costly calculations for all the children rows in the implementation of this method, because loadChildren() may called even when only one child row needs to be calculated.

      The implementation must be a stable function - see PropagateAttributeLoader. Note that loadChildren() and the functions it produced may be called intermittently without any particular order. In other words, the function produced by loadChildren() should be working even after another loadChildren() is called.

      If for some reason this loader is not applicable for the given row, it should return null. Note, however, that if multiple propagate loaders work on the same attribute, it could be tricky and lead to unexpected results.

      Parameters:
      parentValue - the value of this attribute for the parent row, or AttributeValue.undefined() if there's no parent
      parentContext - loading context
      Returns:
      a function that will produce a value for every child row of this parent, given the child row and the loading context, or null if the values for the children rows of this parent cannot be loaded with this loader