Question

I’m using the JDO Query class and I need to conditionally pass certain parameters to the execute method, as demonstrated in the code below.

I don’t know how to do this in Java.

query.declareParameters("String alphaP");
query.declareParameters("String bravoP");
query.declareParameters("String charlieP");

if (condition) {
    if (othercondition) {
        query.declareParameters("List<String> stringList");
    }
    else {
        query.declareParameters("String simpleString");
    }
}

if (someothercondition) {
    query.declareParameters("int deltaP");
}

if (yetanothercondition) {
    query.declareParameters("int echoP");
}

if (thelastcondition) {
    query.declareParameters("int foxtrotP");
}

List<ResultClass> results = (List<ResultClass>) query.execute(
    alphaP, 
    bravoP, 
    charlieP,

    // ... and whatever other parameters are required based on 
    // which conditions are true above

    );

Answer 1

I would suggest using the executeWithArray method: dynamically build up the array of parameters using an instance of java.util.ArrayList which you can then convert to an array using the toArray method. The code might look something like the following:

ArrayList<Object> args = new ArrayList<Object>();
args.add(alphaP);
args.add(bravoP);
args.add(charlieP);
// Add other arguments here...

List<ResultClass> results = (List<ResultClass>) query.executeWithArray(args.toArray());