openmct/src/utils/staleness.js

/*****************************************************************************
 * Open MCT, Copyright (c) 2014-2022, United States Government
 * as represented by the Administrator of the National Aeronautics and Space
 * Administration. All rights reserved.
 *
 * Open MCT is licensed under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * http://www.apache.org/licenses/LICENSE-2.0.
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 *
 * Open MCT includes source code licensed under additional open source
 * licenses. See the Open Source Licenses file (LICENSES.md) included with
 * this source code distribution or the Licensing information page available
 * at runtime from the About dialog for additional information.
 *****************************************************************************/

export default class StalenessUtils {
    constructor(openmct, domainObject) {
        this.openmct = openmct;
        this.domainObject = domainObject;
        this.metadata = this.openmct.telemetry.getMetadata(domainObject);
        this.lastStalenessResponseTime = 0;

        this.setTimeSystem(this.openmct.time.timeSystem());
        this.watchTimeSystem();
    }

    shouldUpdateStaleness(stalenessResponse, id) {
        const stalenessResponseTime = this.parseTime(stalenessResponse);

        if (stalenessResponseTime > this.lastStalenessResponseTime) {
            this.lastStalenessResponseTime = stalenessResponseTime;

            return true;
        } else {
            return false;
        }
    }

    watchTimeSystem() {
        this.openmct.time.on('timeSystem', this.setTimeSystem, this);
    }

    unwatchTimeSystem() {
        this.openmct.time.off('timeSystem', this.setTimeSystem, this);
    }

    setTimeSystem(timeSystem) {
        let metadataValue = { format: timeSystem.key };

        if (this.metadata) {
            metadataValue = this.metadata.value(timeSystem.key) ?? metadataValue;
        }

        const valueFormatter = this.openmct.telemetry.getValueFormatter(metadataValue);

        this.parseTime = (stalenessResponse) => {
            const stalenessDatum = {
                ...stalenessResponse,
                source: stalenessResponse[timeSystem.key]
            };

            return valueFormatter.parse(stalenessDatum);
        };
    }

    destroy() {
        this.unwatchTimeSystem();
    }
}