Reducing cyclic complexity, multiple if statements

Question

I have the following code:

private Facility updateFacility(Facility newFacility, Facility oldFacility) {
    if (newFacility.getCity() != null)
        oldFacility.setCity(newFacility.getCity());
    if (newFacility.getContactEmail() != null) 
        oldFacility.setContactEmail(newFacility.getContactEmail());
    if (newFacility.getContactFax() != null) 
        oldFacility.setContactFax(newFacility.getContactFax());
    if (newFacility.getContactName() != null) 
        oldFacility.setContactName(newFacility.getContactName());
    // ......
}

There are about 14 such checks and assignments. That is, with the exception of a few, I need to change all the fields of the oldFacility object. I get the cyclic complexity of this code 14, which is “over 10 authorized” according to SonarQube. Any ideas on how to reduce cyclomatic complexity?

Answer 1

At some point in your program, you will have to implement the logic:

• If the new tool has a specific property, update the old object accordingly.
• If not, do not override the previous value from the old object.

, :

public class Facility {

    public void setSomething(String something) {
        if (something != null) {
            this.something = something;
        }
    }

}

, update :

private Facility updateFacility(Facility newFacility, Facility oldFacility) {
    oldFacility.setSomething(newFacility.getSomething());
    // etc for the rest
}

Answer 2

, Builder , if. .

Answer 3

hashCode equals Facility :

if(!newFacility.equals(oldFacility))
 {
    //only when something is changed in newFacility, this condition will be excecuted
    oldFacility = newFacility;
 }
 return oldFacility;
 //This is just and example, you can return newFacility directly

: , . . , !

Answer 4

oldFacility, , , oldFacility , , . .

private Facility updateFacility(Facility newFacility, Facility oldFacility){
    String contentNotToBeModified; // or whatever variable type
    contentNotToBeModified = oldFacility.getCity();
    // Do the same for all data that you want to keep

    oldFacility = newFacility;
    newFacility.setCity(contentNotToBeModified);
}

, oldFacility, oldFacility newFacility newFacility oldFacility.

Answer 5

, NullPointerException , :

private Facility updateFacility(Facility newFacility, Facility oldFacility) {

if (newFacility != null) {

    oldFacility.setCity(newFacility.getCity());
    oldFacility.setContactEmail(newFacility.getContactEmail());
    oldFacility.setContactFax(newFacility.getContactFax());
    oldFacility.setContactName(newFacility.getContactName());
    ...
}

, , , .

, - newFacility.getCity().toString(), .

Answer 6

Java Reflection, //- :

public Facility updateFacility(Facility newFacility, Facility oldFacility)
{
    String[] properties = {"City", "ContactEmail", "ContactFax", "ContactName"};
    for(String prop : properties) {
        try {
            Method getter = Facility.class.getMethod("get"+prop);
            Method setter = Facility.class.getMethod("set"+prop, getter.getReturnType());
            Object newValue = getter.invoke(newFacility);
            if (newValue != null)
                setter.invoke(oldFacility, newValue);
        } catch (NoSuchMethodException | 
                SecurityException | 
                IllegalAccessException | 
                InvocationTargetException ex) {
             throw new RuntimeException(ex);
        }
    }
    ...
}

properties [], Facility , .

: getter setter, , Facility .

CAVEATS: ! , Facility. Facility, , , .