Tutorial Mapping Query

From: Mikaël Cluseau (mc.isi.n..mail.com)
Date: Fri Oct 26 2007 - 18:53:05 EDT

  • Next message: Aristedes Maniatis: "Re: Tutorial Mapping Query"

    Hello there,

    I was going around 3.0M1, gone on the quick starts to see how it is ;-)

    I have been a bit disappointed by the "Main.java" code snippet :

    QueryChain chain = new QueryChain();
    chain.addQuery(new NamedQuery("DeleteAll", Collections.singletonMap(
                    "table",
                    "PAINTING")));
    chain.addQuery(new NamedQuery("DeleteAll", Collections.singletonMap(
                    "table",
                    "ARTIST")));
    chain.addQuery(new NamedQuery("DeleteAll", Collections.singletonMap(
                    "table",
                    "GALLERY")));

    context.performGenericQuery(chain);

    Its a lot of cut-and-paste, compared to the comment "we need to run the
    same query three times with different sets of parameters". Wouldn't the
    best code for this statement be :

    QueryChain chain = new QueryChain();

    for (String tableName : new String[] {
         "PAINTING", "ARTIST", "GALLERY"}) {
        chain.addQuery(new NamedQuery("DeleteAll", Collections.singletonMap(
                    "table", tableName)));
    }

    context.performGenericQuery(chain);

    Then we could even show people how easy it is to build good APIs with
    Cayenne ;-) :

    public static void emptyTables(String... tables) {
        QueryChain chain = new QueryChain();
        for (String tableName : tables) {
            chain.addQuery(new NamedQuery("DeleteAll", Collections.singletonMap(
                    "table", tableName)));
        }
        context.performGenericQuery(chain);
    }

    And in the "main" method :

    emptyTables("PAINTING", "ARTIST", "GALLERY");

    I may go to far for a quick start, but worth to post on the mailing list
    anyway ;-) 

    -- 
Mikaël Cluseau <mc.isi.n..mail.com>
ISI.NC

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