engine: Add setters for the trait interfaces

Turns out it's useful to wholesale set the entire struct.

engine/autoedge.go

@@ -31,6 +31,10 @@ type EdgeableRes interface {
 	// trait.
 	AutoEdgeMeta() *AutoEdgeMeta
 
+	// SetAutoEdgeMeta lets you set all of the meta params for the automatic
+	// edges trait in a single call.
+	SetAutoEdgeMeta(*AutoEdgeMeta)
+
 	// UIDs includes all params to make a unique identification of this
 	// object.
 	UIDs() []ResUID // most resources only return one

engine/autogroup.go

@@ -34,6 +34,10 @@ type GroupableRes interface {
 	// grouping trait.
 	AutoGroupMeta() *AutoGroupMeta
 
+	// SetAutoGroupMeta lets you set all of the meta params for the
+	// automatic grouping trait in a single call.
+	SetAutoGroupMeta(*AutoGroupMeta)
+
 	// GroupCmp compares two resources and decides if they're suitable for
 	//grouping. This usually needs to be unique to your resource.
 	GroupCmp(res GroupableRes) error

engine/metaparams.go

@@ -44,6 +44,10 @@ var DefaultMetaParams = &MetaParams{
 type MetaRes interface {
 	// MetaParams lets you get or set meta params for the resource.
 	MetaParams() *MetaParams
+
+	// SetMetaParams lets you set all of the meta params for the resource in
+	// a single call.
+	SetMetaParams(*MetaParams)
 }
 
 // MetaParams provides some meta parameters that apply to every resource.

engine/traits/autoedge.go

@@ -40,3 +40,9 @@ func (obj *Edgeable) AutoEdgeMeta() *engine.AutoEdgeMeta {
 	}
 	return obj.meta
 }
+
+// SetAutoEdgeMeta lets you set all of the meta params for the automatic edges
+// trait in a single call.
+func (obj *Edgeable) SetAutoEdgeMeta(meta *engine.AutoEdgeMeta) {
+	obj.meta = meta
+}

engine/traits/autogroup.go

@@ -47,6 +47,12 @@ func (obj *Groupable) AutoGroupMeta() *engine.AutoGroupMeta {
 	return obj.meta
 }
 
+// SetAutoGroupMeta lets you set all of the meta params for the automatic
+// grouping trait in a single call.
+func (obj *Groupable) SetAutoGroupMeta(meta *engine.AutoGroupMeta) {
+	obj.meta = meta
+}
+
 // GroupCmp compares two resources and decides if they're suitable for grouping.
 // You'll probably want to override this method when implementing a resource...
 // This base implementation assumes not, so override me!

engine/traits/meta.go

@@ -38,3 +38,9 @@ func (obj *Meta) MetaParams() *engine.MetaParams {
 	}
 	return obj.meta
 }
+
+// SetMetaParams lets you set all of the meta params for the resource in a
+// single call.
+func (obj *Meta) SetMetaParams(meta *engine.MetaParams) {
+	obj.meta = meta
+}