@sap/odata-v4/lib/deserializer/Reader.js

OData V4.0 server library

'use strict';

/**
 * Parent class of all readers
 */
class Reader {

    /**
     */
    constructor() {
        this._emitter = null;
    }

    /**
     * Sets the event emitter
     *
     * @param {EventEmitter} emitter - Emitter used for emitting events
     * @param {string} [prefix] - Prefix to be appended to event name
     * @returns {Reader} this instance
     */
    setEmitter(emitter, prefix) {
        this._emitter = emitter;
        this._prefix = prefix ? prefix + '.' : '';
        return this;
    }

    /**
     * Emits an event via the internal emitter
     * @param {string} event - Event name
     * @param {*} data1 data send to event receiver
     * @param {*} data2 data send to event receiver
     * @param {*} data3 data send to event receiver
     */
    emit(event, data1, data2, data3) {
        this._emitter.emit(this._prefix + event, data1, data2, data3);
    }

    /**
     * Emit consumed bytes data from the caches read position onwards and advance the cache position
     *
     * @param {Cache} cache - Cache
     * @param {number} consumed - Amount of bytes to consume
     * @param {string} event - Event to be emitted
     */
    emitAndConsume(cache, consumed, event) {
        if (this._emitter && consumed) {
            this.emit(event, cache.getBytes(consumed));

        }
        cache.advance(consumed);
    }
}

module.exports = Reader;