Number of Parameters -- A Question of Style and Form

Discussion in 'Java' started by Hal Vaughan, Jun 15, 2007.

  1. Hal Vaughan

    Hal Vaughan Guest

    While I don't see that there would be an actual "right" answer to this, I'm
    sure experienced programmers can say what tends to work and what doesn't.

    I have a situation where I will be passing one object to another so it can
    be configured and used internally. I could pass it with a number of
    parameters, probably 5 or 6, or I could pass it with only a few parameters
    and have all the rest specified with different method calls.

    Does it tend to be easier, in the long run, to have one call with a lot of
    parameters (which can be hard to keep track of without an IDE prompting
    you) or does it tend to work better to keep the parameter list short and
    use several calls? My thought is that the former wold probably work
    better, especially if I use the class I'm writing months later, after
    having forgotten the internals, since it's easier to keep the parameters
    straight than to remember that several calls have to be made to set
    everything up.

    I'm wondering if more experienced programmers have any experience or
    comments that indicates whether a long list of parameters or a number of
    different method calls tend to work better.


    Hal Vaughan, Jun 15, 2007
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  2. One consideration is whether the parameters have usable defaults.

    I tend to do non-optional parameters in one call, but then allow
    additional calls for optionals. Languages without keyword=value syntax
    do not do well for calls with large numbers of optional parameters.

    In either case, when it comes to using the class months later, I prefer
    to rely on Javadoc rather than memory.

    Patricia Shanahan, Jun 15, 2007
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  3. Hal Vaughan

    Tom Hawtin Guest

    Or you could create an argument object. Call several methods on that to
    set it up. Then use one call to apply those arguments.

    Tom Hawtin
    Tom Hawtin, Jun 15, 2007
  4. Hal Vaughan

    Hal Vaughan Guest

    That's a point I had not thought about. Thanks for making it.
    I used to use Kate in KDE for all my programming. I'm self taught, other
    than a few classes in BASIC and one in VAX 11/780 Assembler back in the
    early 1980s, so when I had to start programming again, I was programming
    for 4 years before I found out about an IDE. I'm using Eclipse and have
    found it is a HUGE help when it prompts me when I'm typing out method
    That was my thought and that I'd be better off with one call with the params
    documented than having multiple calls and having to document the need to
    make all the successive calls.

    Hal Vaughan, Jun 15, 2007
  5. Hal Vaughan

    Roedy Green Guest

    Shorter lists work better.

    There is only one way to get the order wrong for 2 parms. For 3 parms
    here are 5 wrong ways. For 7 parms there are 7!-1 = 5039 wrong ways.

    You see how your odds of hitting the exact perfect order get worse and
    worse as the number of parameters expands.

    The problem is exacerbated when there are two or more parameters of
    the same type without an obvious natural ordering. e.g. x,y

    The one that nails me frequently is this:

    new Font ("Dialog", 15, Font.BOLD);

    It compiles just fine since Font.BOLD is an int, not an enum.

    for other Font gotchas see:
    Roedy Green, Jun 15, 2007
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