42 lines
1.4 KiB
JavaScript
42 lines
1.4 KiB
JavaScript
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// Copyright (c) 2012 Mathieu Turcotte
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// Licensed under the MIT license.
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var util = require('util');
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var precond = require('precond');
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var BackoffStrategy = require('./strategy');
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// Exponential backoff strategy.
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function ExponentialBackoffStrategy(options) {
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BackoffStrategy.call(this, options);
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this.backoffDelay_ = 0;
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this.nextBackoffDelay_ = this.getInitialDelay();
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this.factor_ = ExponentialBackoffStrategy.DEFAULT_FACTOR;
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if (options && options.factor !== undefined) {
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precond.checkArgument(options.factor > 1,
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'Exponential factor should be greater than 1 but got %s.',
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options.factor);
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this.factor_ = options.factor;
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}
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}
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util.inherits(ExponentialBackoffStrategy, BackoffStrategy);
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// Default multiplication factor used to compute the next backoff delay from
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// the current one. The value can be overridden by passing a custom factor as
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// part of the options.
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ExponentialBackoffStrategy.DEFAULT_FACTOR = 2;
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ExponentialBackoffStrategy.prototype.next_ = function() {
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this.backoffDelay_ = Math.min(this.nextBackoffDelay_, this.getMaxDelay());
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this.nextBackoffDelay_ = this.backoffDelay_ * this.factor_;
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return this.backoffDelay_;
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};
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ExponentialBackoffStrategy.prototype.reset_ = function() {
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this.backoffDelay_ = 0;
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this.nextBackoffDelay_ = this.getInitialDelay();
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};
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module.exports = ExponentialBackoffStrategy;
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