diffusion/src/node_modules/routing/topic-cache.js

Diffusion JavaScript client

var TimeSeriesEntry = require('routing/topic-cache-time-series-entry');
var NoValueEntry = require('routing/topic-cache-no-value-entry');
var DatatypeEntry = require('routing/topic-cache-datatype-entry');

var UnsubscribeReason = require('../../topics/topics').UnsubscribeReason;
var TopicType = require('../../topics/topics').TopicType;

var TopicDetails = require('topics/details/topic-details');

module.exports = function TopicCache(datatypes) {
    var byPath = {};
    var byId = {};

    this.handleSubscription = function(info, registry) {
        var path = info.path;

        var streams = registry.streamsFor(path, info.specification);
        var entry;

        var details = TopicDetails.detailsFromSpecification(info.specification);

        switch (info.specification.type) {
            case TopicType.JSON :
            case TopicType.BINARY :
            case TopicType.STRING :
            case TopicType.DOUBLE :
            case TopicType.INT64 :
            case TopicType.RECORD_V2 :
                var datatype = datatypes.get(info.specification.type);
                entry = new DatatypeEntry(streams, path, details, info.specification, datatype);
                break;
            case TopicType.TIME_SERIES :
                var eventType = datatypes.get(info.specification.properties.TIME_SERIES_EVENT_VALUE_TYPE);
                entry = new TimeSeriesEntry(streams, path, details, info.specification, eventType);
                break;
            default :
                entry = new NoValueEntry(streams, path, details, info.specification);
        }

        var oldByPath = byPath[path];
        byPath[path] = entry;

        if (oldByPath) {
            throw new Error("Existing cache entry for " + path);
        }

        var oldById = byId[info.id];
        byId[info.id] = entry;

        if (oldById) {
            throw new Error("Existing cache entry for " + info.id);
        }

        entry.notifyInitialSubscription(registry);
    };

    this.notifyUnsubscriptionOfAllTopics = function(registry) {
        for (var id in byId) {
            byId[id].notifyUnsubscription(UnsubscribeReason.SUBSCRIPTION_REFRESH, registry);
        }

        byPath = {};
        byId = {};
    };

    this.handleValue = function(session, id, content, registry) {
        var errorHandler = session.getErrorHandler();
        var entry = byId[id];

        if (entry) {
            entry.handleValue(content, registry, errorHandler);
        } else {
            errorHandler(new Error("Data loss on topic with ID: " + id + " - possibly due to reconnection"));
        }
    };

    this.handleDelta = function(session, id, delta, registry) {
        var errorHandler = session.getErrorHandler();
        var entry = byId[id];

        if (entry) {
            entry.handleDelta(delta, registry, errorHandler);
        } else {
            errorHandler(new Error("Data loss on topic with ID: " + id + " - possibly due to reconnection"));
        }
    };

    this.handleUnsubscription = function(id, reason, registry) {
        var entry = byId[id];
        delete byId[id];

        if (entry) {
            var path = entry.getTopicPath();
            delete byPath[path];

            entry.notifyUnsubscription(reason, registry);
        }
    };

    this.newStream = function(selector, stream, registry) {
        for (var path in byPath) {
            var entry = byPath[path];
            var specification = entry.getTopicSpecification();

            if (selector.selects(path) && stream.selects(specification)) {
                entry.addStream(stream.adapter?stream.adapter(specification):stream, registry);
            }
        }
    };

    this.removeStream = function(stream, registry) {
        for (var path in byPath) {
            byPath[path].removeStream(stream, registry);
        }
    };

    this.removeAllStreams = function() {
        for (var path in byPath) {
            byPath[path].removeAllStreams();
        }
    };

    this.clear = function() {
        byPath = {};
        byId = {};
    };
};