refactor DefaultFunctionCallExpr

[hduelme]

I made the fields prefix and functionName final.
Gentrified all lists and replaced the for loop by the foreach loop (available size Java 5).

The foreach loop is easier to read and faster, compared to the normal for loop.

[elharo]

This is a potentially code breaking public API change, which we won't do. (Consider subclasses that override this method.) Ditto for other signature changes below.

[hduelme]

I have done a little test.
I have written an class OverwriteTest like so:

package org.jaxen.expr;

import java.util.List;

public class OverwriteTest extends DefaultFunctionCallExpr {
    public OverwriteTest(String prefix, String functionName) {
        super(prefix, functionName);
    }

    @Override
    public List getParameters() {
        return super.getParameters();
    }
}

No Problem for the Java Compiler. Indeed it is not a good practice to drop the generics, but it is possible without an API break.

If you agree the signature in the interface FunctionCallExpr should also be changed.

[elharo]

foreach might be clearer. There's no proof it's faster.

[hduelme]

You are right. This is possibly a flawed assumption on my part, but still it's also not slower. The compiler should optimize both to the same speed.