Forwarding database

ForwardingDatabase is a mechanism to perform additional logic before executing a query against a database. One example is to create a forwarding database that prevents returning cached query results, as in the following snippet.

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ForwardingDatabase noCacheDatabase = new ForwardingDatabase() {
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    @Override
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    protected <T> Query<T> filterQuery(Query<T> query) {
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        return query.clone().noCache();
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    }
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};

You can then use the no-cache forwarding database by specifying it in Query#using:

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Query.from(User.class).using(noCacheDatabase).selectAll();

Because this query specified noCacheDatabase, Dari invokes the filterQuery method before executing the query.

Both Dari and Brightspot use ForwardingDatabase for a variety of scenarios. Here are a few examples:

• Dari’s Caching Database
• Brightspot’s Preview Database
• Brightspot’s Authentication Filter