Tag: Android

We are using SQLDroid to work as a JDBC driver for Android. However, SQLDroid is a container for Android API calls, and this API does not handle null values ​​well.

For us to use PreparedStatements we directly need to circumvent all setNull() (or some setString(idx, null) which may occur indirectly, such as when the variable is null), the first strategy was to do this verification while configuring query. For example, we made the following outline for the product search given a textual parameter (which can occasionally be null if called programmatically):

// String param é um parâmetro
String paramStr = Optional.ofNullable(param).orElse("");
String paramOrNullStr = Optional.ofNullable(param).map(p -> "'" + p + "'").orElse("null");

String query =  " SELECT " + 
                "   p.cd_produto, " + 
                "   ov.cd_cliente, " + 
                "   ov.cd_org_venda, " + 
                "   ov.cd_tab_preco " + 
                " FROM produto p " + 
                " CROSS JOIN org_venda ov " + 
                " WHERE " + 
                "   ( " + paramOrNullStr + " IS NULL) OR " + 
                "   ( " + 
                "       p.nm_produto LIKE '%" + paramStr + "%' OR " + 
                "       p.cd_produto LIKE '%" + paramStr + "%' OR " + 
                "       p.cd_referencia LIKE '%" + paramStr + "%' OR " + 
                "       p.cod_barras LIKE '%" + paramStr + "%' " +
                "    ) ";

But this is counterintuitive and counterproductive. Then I started working on implementing an outline for this. As Android offers JDBC interfaces, I opened any project in Java 8 and created a class to extend from PreparedStatement. Eclipse created for me the class with a great list of TODOs and when he confirmed the operation and put it to compile in the Android project, I found this:

C:UsersJefferson QuesadoDocumentsgeosales-nunumobileandroidappsrcmainjavacomexampleevo_mobilesqldroiddrivePstmtNullSafe.java:358: error: method does not override or implement a method from a supertype

    @Override

    ^

C:UsersJefferson QuesadoDocumentsgeosales-nunumobileandroidappsrcmainjavacomexampleevo_mobilesqldroiddrivePstmtNullSafe.java:360: error: invalid method reference

        putPreparer("closeOnCompletion", PreparedStatement::closeOnCompletion);

                                         ^

  cannot find symbol

    symbol:   method closeOnCompletion()

    location: interface PreparedStatement

When I went to see it, this function appeared in Java 7, along with isCloseOnCompletion, but did not enter Android (see definition of Statement)

So how do you make the compatibility of my class that implements PreparedStatement correctly to make it work on Android?

• Should I worry only about Android and eliminate these methods?
• Should I become a proxy and do routing according to the called methods?
• or should I just delete the note from @Override and leave a false return? (as SQLDroid did)

What factors should I take to decide the desired strategy?