rdf-dataset-fragmenter/lib/strategy/FragmentationStrategyResourceObject.js

Fragments an RDF dataset into multiple parts

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.FragmentationStrategyResourceObject = void 0;
const FragmentationStrategyStreamAdapter_1 = require("./FragmentationStrategyStreamAdapter");
/**
 * A fragmentation strategy that groups triples by (subject) resources,
 * and places quads into the document identified by the given predicate value.
 *
 * Blank nodes are not supported.
 */
class FragmentationStrategyResourceObject extends FragmentationStrategyStreamAdapter_1.FragmentationStrategyStreamAdapter {
    constructor(targetPredicateRegex) {
        super();
        this.targetPredicate = new RegExp(targetPredicateRegex, 'u');
        this.resourceBuffer = {};
    }
    async handleQuad(quad, quadSink) {
        // Create buffer if one doesn't exist yet
        if (!this.resourceBuffer[quad.subject.value]) {
            this.resourceBuffer[quad.subject.value] = [];
        }
        // Handle remaining quads
        const buffer = this.resourceBuffer[quad.subject.value];
        if (Array.isArray(buffer)) {
            // Buffer remaining quads
            buffer.push(quad);
        }
        else {
            // If the target predicate was already set, flush immediately
            await quadSink.push(buffer.value, quad);
        }
        // Match the target predicate
        if (this.targetPredicate.test(quad.predicate.value)) {
            if (quad.object.termType !== 'NamedNode') {
                throw new Error(`Expected target predicate value of type NamedNode on resource '${quad.subject.value}', but got '${quad.object.value}' (${quad.object.termType})`);
            }
            // Flush the buffer of this resource
            await this.flushResourceBuffer(quadSink, quad.subject.value, quad.object.value);
            // Indicate that further triples of this resource should be emitted immediately
            this.resourceBuffer[quad.subject.value] = quad.object;
        }
    }
    async flush(quadSink) {
        await super.flush(quadSink);
        for (const resourceIri of Object.keys(this.resourceBuffer)) {
            if (Array.isArray(this.resourceBuffer[resourceIri])) {
                // eslint-disable-next-line no-console
                console.warn(`Detected quads of the resource ${resourceIri} without a defined target predicate.`);
            }
        }
    }
    async flushResourceBuffer(quadSink, resourceIri, targetIri) {
        const quads = this.resourceBuffer[resourceIri];
        if (Array.isArray(quads)) {
            for (const quad of quads) {
                await quadSink.push(targetIri, quad);
            }
        }
    }
}
exports.FragmentationStrategyResourceObject = FragmentationStrategyResourceObject;
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