/**
* Copyright 2017-2020 Plexus Interop Deutsche Bank AG
* SPDX-License-Identifier: Apache-2.0
*
* 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.
*/
import { Observer } from './Observer';
import { default as Queue } from 'typescript-collections/dist/lib/Queue';
import { Logger, LoggerFactory } from '../logger';
import { LimitedBufferQueue } from '../util/collections/LimitedBufferQueue';
/**
* Saves interraction with Observer, until real Observer arrives
*/
export class BufferedObserver<T> implements Observer<T> {
private baseObserver: Observer<T> | undefined;
private buffer: Queue<T>;
private receivedError: any;
private completed: boolean = false;
constructor(readonly limit: number = 1024 * 10, private readonly log: Logger = LoggerFactory.getLogger('BufferedObserver')) {
this.buffer = new LimitedBufferQueue<T>(limit);
}
public setObserver(observer: Observer<T>): void {
if (this.baseObserver) {
throw new Error('Base observer already defined');
}
this.baseObserver = observer;
while (!this.buffer.isEmpty()) {
observer.next(this.buffer.dequeue());
}
if (this.receivedError) {
observer.error(this.receivedError);
} else if (this.completed) {
observer.complete();
}
}
public next(value: T): void {
if (this.baseObserver) {
/* istanbul ignore if */
Iif (this.log.isTraceEnabled()) {
this.log.trace(`Passing frame to observer`);
}
this.baseObserver.next(value);
} else {
/* istanbul ignore if */
Iif (this.log.isTraceEnabled()) {
this.log.trace(`No observer, adding to buffer, buffer size ${this.buffer.size()}`);
}
this.buffer.enqueue(value);
}
}
public error(err: any): void {
if (this.baseObserver) {
this.baseObserver.error(err);
} else {
this.receivedError = err;
}
}
public complete(): void {
if (this.baseObserver) {
this.baseObserver.complete();
} else {
this.completed = true;
}
}
public clear(): void {
this.buffer.clear();
}
} |