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Labs/Jetpack/JEP/11: Difference between revisions
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Because of the asynchronous nature of this API, its operations communicate their statuses and results to callers via callbacks. In the context of simple storage, a callback is either a function or an object that defines the methods <code>onResult</code> and <code>onError</code>. If a callback is a function, it is called when its associated asynchronous operation successfully completes. If a callback is an object, its <code>onResult</code> method (if defined) is called when the operation successfully completes, and its <code>onError</code> method (if defined) is called when an error occurs during the operation. This allows callers to provide a simple function in the common case; only if callers wish to be notified of errors do they need to use the more verbose object form. | Because of the asynchronous nature of this API, its operations communicate their statuses and results to callers via callbacks. In the context of simple storage, a callback is either a function or an object that defines the methods <code>onResult</code> and <code>onError</code>. If a callback is a function, it is called when its associated asynchronous operation successfully completes. If a callback is an object, its <code>onResult</code> method (if defined) is called when the operation successfully completes, and its <code>onError</code> method (if defined) is called when an error occurs during the operation. This allows callers to provide a simple function in the common case; only if callers wish to be notified of errors do they need to use the more verbose object form. | ||
In this proposal, <code>onResult</code> | In the remainder of this proposal, <code>onResult</code> is shorthand for either the function form or the <code>object.onResult</code> form. Since there is only one form for errors, <code>onError</code> is shorthand for the <code>object.onError</code> form. | ||
The arguments passed to <code>onResult</code> and <code>onError</code> depend on the API method to which the callback is passed. Each method's description below indicates how it calls its callback. | The arguments passed to <code>onResult</code> and <code>onError</code> depend on the API method to which the callback is passed. Each method's description below indicates how it calls its callback. | ||