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// Copyright 2010 The Closure Library Authors. All Rights Reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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//      http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS-IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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/**
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 * @fileoverview Interface for a factory for creating XMLHttpRequest objects
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 * and metadata about them.
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 * @author [email protected] (David Barrett-Kahn)
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 */
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goog.provide('goog.net.XmlHttpFactory');
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/** @suppress {extraRequire} Typedef. */
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goog.require('goog.net.XhrLike');
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/**
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 * Abstract base class for an XmlHttpRequest factory.
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 * @constructor
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 */
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goog.net.XmlHttpFactory = function() {};
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/**
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 * Cache of options - we only actually call internalGetOptions once.
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 * @type {Object}
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 * @private
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 */
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goog.net.XmlHttpFactory.prototype.cachedOptions_ = null;
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/**
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 * @return {!goog.net.XhrLike.OrNative} A new XhrLike instance.
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 */
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goog.net.XmlHttpFactory.prototype.createInstance = goog.abstractMethod;
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/**
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 * @return {Object} Options describing how xhr objects obtained from this
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 *     factory should be used.
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 */
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goog.net.XmlHttpFactory.prototype.getOptions = function() {
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  return this.cachedOptions_ ||
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      (this.cachedOptions_ = this.internalGetOptions());
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};
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/**
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 * Override this method in subclasses to preserve the caching offered by
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 * getOptions().
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 * @return {Object} Options describing how xhr objects obtained from this
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 *     factory should be used.
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 * @protected
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 */
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goog.net.XmlHttpFactory.prototype.internalGetOptions = goog.abstractMethod;
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