caching features

Cache used to store temporary data on mobile (RSS feed, news, ...). Data are stored in RMS or in memory.

Advantages:

data are loaded only at first access. After, we use the cached data.
cache access are quickly than HTTP or file access.

Warning:
The cache does not know whether the data are outdated.
The lifetime of the data must be managed by the developer.

Questions on the data to be registered in cache:

are the data often accessed by user? if not: registering the data in record store can be useless.
quantity of data? if there is a lot of data: registering them in record store can slow the application.
is the lifecycle of data short? if it is short: you should configure a short cache delay so cache may not be often used

The cache access is done through Javacript APIs.

To use cache, use an URL in two part, separated by a comma.

first part, the cache resource URL (cache://...)
second part, the resource URL (file://..., http://... or other URL)
third part (optional), asynchronous access (a boolean - true = synchronous / false = asynchronous)

example:

//File access
File.open ('cache://mypicture.png,file://mypicture.png');
//HTTP loading
Http.get ('cache://mypicture.png,http://server/mypicture.png', on PictureLoaded);
//XML loading
XML.open ('cache://myXmlFile.xml,http://server/myXmlFile.xml', XML.URL, onXmlLoaded);

The cache is dependent on the widget. A widget cannot read another widget cache.
The cache scope is the current widget.

We cannot reuse data in cache between two widgets.