lib/goog/net/xmlhttpfactory.js

1// Copyright 2010 The Closure Library Authors. All Rights Reserved.
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7// http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS-IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15/**
16 * @fileoverview Interface for a factory for creating XMLHttpRequest objects
17 * and metadata about them.
18 * @author dbk@google.com (David Barrett-Kahn)
19 */
20
21goog.provide('goog.net.XmlHttpFactory');
22
23/** @suppress {extraRequire} Typedef. */
24goog.require('goog.net.XhrLike');
25
26
27
28/**
29 * Abstract base class for an XmlHttpRequest factory.
30 * @constructor
31 */
32goog.net.XmlHttpFactory = function() {
33};
34
35
36/**
37 * Cache of options - we only actually call internalGetOptions once.
38 * @type {Object}
39 * @private
40 */
41goog.net.XmlHttpFactory.prototype.cachedOptions_ = null;
42
43
44/**
45 * @return {!goog.net.XhrLike.OrNative} A new XhrLike instance.
46 */
47goog.net.XmlHttpFactory.prototype.createInstance = goog.abstractMethod;
48
49
50/**
51 * @return {Object} Options describing how xhr objects obtained from this
52 * factory should be used.
53 */
54goog.net.XmlHttpFactory.prototype.getOptions = function() {
55 return this.cachedOptions_ ||
56 (this.cachedOptions_ = this.internalGetOptions());
57};
58
59
60/**
61 * Override this method in subclasses to preserve the caching offered by
62 * getOptions().
63 * @return {Object} Options describing how xhr objects obtained from this
64 * factory should be used.
65 * @protected
66 */
67goog.net.XmlHttpFactory.prototype.internalGetOptions = goog.abstractMethod;