99 lines
No EOL
3.6 KiB
TypeScript
99 lines
No EOL
3.6 KiB
TypeScript
/**
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* Merges features from different featureSources for a single layer
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* Uses the freshest feature available in the case multiple sources offer data with the same identifier
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*/
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import {UIEventSource} from "../../UIEventSource";
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import FeatureSource, {FeatureSourceForLayer, IndexedFeatureSource, Tiled} from "../FeatureSource";
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import FilteredLayer from "../../../Models/FilteredLayer";
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import {Tiles} from "../../../Models/TileRange";
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import {BBox} from "../../BBox";
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export default class FeatureSourceMerger implements FeatureSourceForLayer, Tiled, IndexedFeatureSource {
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public features: UIEventSource<{ feature: any; freshness: Date }[]> = new UIEventSource<{ feature: any; freshness: Date }[]>([]);
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public readonly name;
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public readonly layer: FilteredLayer
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public readonly tileIndex: number;
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public readonly bbox: BBox;
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public readonly containedIds: UIEventSource<Set<string>> = new UIEventSource<Set<string>>(new Set())
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private readonly _sources: UIEventSource<FeatureSource[]>;
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constructor(layer: FilteredLayer, tileIndex: number, bbox: BBox, sources: UIEventSource<FeatureSource[]>) {
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this.tileIndex = tileIndex;
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this.bbox = bbox;
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this._sources = sources;
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this.layer = layer;
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this.name = "FeatureSourceMerger(" + layer.layerDef.id + ", " + Tiles.tile_from_index(tileIndex).join(",") + ")"
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const self = this;
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const handledSources = new Set<FeatureSource>();
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sources.addCallbackAndRunD(sources => {
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let newSourceRegistered = false;
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for (let i = 0; i < sources.length; i++) {
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let source = sources[i];
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if (handledSources.has(source)) {
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continue
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}
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handledSources.add(source)
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newSourceRegistered = true
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source.features.addCallback(() => {
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self.Update();
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});
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if (newSourceRegistered) {
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self.Update();
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}
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}
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})
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}
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private Update() {
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let somethingChanged = false;
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const all: Map<string, { feature: any, freshness: Date }> = new Map<string, { feature: any; freshness: Date }>();
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// We seed the dictionary with the previously loaded features
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const oldValues = this.features.data ?? [];
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for (const oldValue of oldValues) {
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all.set(oldValue.feature.id, oldValue)
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}
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for (const source of this._sources.data) {
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if (source?.features?.data === undefined) {
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continue;
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}
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for (const f of source.features.data) {
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const id = f.feature.properties.id;
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if (!all.has(id)) {
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// This is a new feature
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somethingChanged = true;
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all.set(id, f);
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continue;
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}
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// This value has been seen already, either in a previous run or by a previous datasource
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// Let's figure out if something changed
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const oldV = all.get(id);
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if (oldV.freshness < f.freshness) {
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// Jup, this feature is fresher
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all.set(id, f);
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somethingChanged = true;
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}
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}
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}
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if (!somethingChanged) {
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// We don't bother triggering an update
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return;
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}
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const newList = [];
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all.forEach((value, _) => {
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newList.push(value)
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})
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this.containedIds.setData(new Set(all.keys()))
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this.features.setData(newList);
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}
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} |