Package jetbrains.mps.generator.runtime

Class FragmentResult

java.lang.Object

jetbrains.mps.generator.runtime.FragmentResult

public abstract class FragmentResult
extends Object

Represents an outcome of template fragment. We use this to hide difference between TF that produce single node and collection of nodes. Besides, we keep TF parent's containment link needed for weave scenario (during weave, there's supplied parent node, and knowledge about specific aggregations comes from TF's parent node, while during regular apply, all TFs in template are assumed (there's checking rule to ensure that) to be under same parent AND aggregation. As there's no distinction between templates for WEAVE and CALL, effectively WEAVE can not inject TF nodes into different aggregation links, though it pretends it does. (well, one can ignore errors in templates and get TF with different aggregation links).

XXX Though I like the idea of templates being functional and side-effect free supplier of new nodes, I find possibility to have single template with fragments for different aggregation roles appealing. Besides, I'd like uniformity for WEAVE and CALL templates, and though different aggregations for weave don't work now (due to checking rule), there's code already that supports scenario of different aggregation roles and it's a pity to throw it away. HOWEVER, shall not forget about 'in-line' templates where no aggregation link is available. Therefore, I plan to use this FragmentResult to experiment with alternatives for TemplateDeclaration#apply. First, FragmentResult would help to streamline implementation of apply and weave, I'd like to keep differences between the two minimal. After all, there's Perhaps, in the future, a composite object with FragmentResult may replace #apply() return value (now Collection<SNode>) and there'd be no need for explicit TemplateDeclarationWeavingAware2.weave(WeaveContext, NodeWeaveFacility), return value of apply would give a chance for outer code to control whether to apply or to weave TF outcome nodes.

XXX If there's ever a handy way to generate sequence of optional calls a.first().second().third(), might be reasonable to return this from methods to get nice nodeFragment(tnode1).label("").reportTo() lines without intermediate local variables. Check TemplateDeclarationWeavingAware2 for extra stuff.

Since:

2018.2

Field Summary

Fields

Modifier and Type	Field	Description
protected SContainmentLink	myAggregation

Method Summary

Modifier and Type	Method	Description
abstract void	addTo(SNode parent)	Insert node/collection of nodes into supplied parent into fragment's aggregation link.
SContainmentLink	getAggregation()
abstract void	label(TemplateContext templateContext, String label)	Tells to register node/collection of nodes this TF had produced with a given mapping label XXX is there need in indirection TEE provides or I can do it directly through e.g.
abstract void	reportTo(Collection<SNode> collection)	Report node/collection of nodes this TF has produced to supplied collection
abstract FragmentResult	weaveWith(NodeWeaveFacility weaveFacility)	Code similar to addTo(SNode) intended for weave scenario, where anchor query has to be respected.

Methods inherited from class java.lang.Object

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

Field Detail

myAggregation

protected final SContainmentLink myAggregation

Method Detail

getAggregation

public final SContainmentLink getAggregation()

Returns:

containment relationship of template fragment, never null

label

public abstract void label(TemplateContext templateContext,
                           String label)

Tells to register node/collection of nodes this TF had produced with a given mapping label XXX is there need in indirection TEE provides or I can do it directly through e.g. ITemplateGenerator?

Parameters:

templateContext - not null

label - not null

See Also:

TemplateExecutionEnvironment.registerLabel(SNode, SNode, String), TemplateExecutionEnvironment.registerLabel(SNode, Iterable, String)

reportTo

public abstract void reportTo(Collection<SNode> collection)

Report node/collection of nodes this TF has produced to supplied collection

Parameters:

collection - never null

addTo

public abstract void addTo(SNode parent)

Insert node/collection of nodes into supplied parent into fragment's aggregation link. XXX Perhaps, it's worth to pass TemplateContext/TEE so that we can validate a child (proper concept/role)?

Parameters:

parent - never null

weaveWith

public abstract FragmentResult weaveWith(NodeWeaveFacility weaveFacility)
                                  throws GenerationFailureException

Code similar to addTo(SNode) intended for weave scenario, where anchor query has to be respected.

Parameters:

weaveFacility - knows parent and how to find out anchor for newly injected node

Returns:

this for convenience

Throws:

GenerationFailureException - rethrows one from NodeWeaveFacility.weaveNode(SContainmentLink, SNode)