how to set default method argument values

Question

Is it possible to set the default method parameter values in Java   Example  If there is a method  public int doSomething int arg1  int arg2      some logic here     return 0      is it possible to modify the given method in order to be able to call it with and without parameters   example   doSomething param1  param2   doSomething      Thanks

User · Answer

You can overload the method with different parameters    public int doSomething int arg1  int arg2      some logic here         return 0     public int doSomething    doSomething 0 0

User · Answer

If your arguments are the same type you could use varargs   public int something int    args        int a   0      int b   0      if  args length  gt  0          a   args 0             if  args length  gt  1          b   args 1             return a   b     but this way you lose the semantics of the individual arguments  or  have a method overloaded which relays the call to the parametered version  public int something       return something 1  2       or if the method is part of some kind of initialization procedure  you could use the builder pattern instead   class FoodBuilder      int saltAmount     int meatAmount     FoodBuilder setSaltAmount int saltAmount           this saltAmount   saltAmount         return this          FoodBuilder setMeatAmount int meatAmount           this meatAmount   meatAmount         return this          Food build            return new Food saltAmount  meatAmount           Food f   new FoodBuilder   setSaltAmount 10  build    Food f2   new FoodBuilder   setSaltAmount 10  setMeatAmount 5  build      Then work with the Food object  int doSomething Food f        return f getSaltAmount     f getMeatAmount        The builder pattern allows you to add remove parameters later on and you don t need to create new overloaded methods for them

User · Answer

It s not possible to default values in Java   My preferred way to deal with this is to overload the method so you might have something like   public class MyClass     public int doSomething int arg1  int arg2                     public int doSomething           return doSomething  lt default value gt    lt default value gt

User · Answer

Hopefully I am not misunderstanding this document  but if your using Java 1 8  in theory  you could accomplish something like this by defining a working implementation of a default method   defender methods   within an interface that you implement   interface DoInterface       void doNothing        public default void remove            throw new UnsupportedOperationException  remove              public default int doSomething  int arg1  int arg2            val   arg1   arg2   arg1          log   Value is      val            return val          class DoIt extends DoInterface       DoIt             log  Called DoIt constructor               public int doSomething             int val   doSomething  0  100            return val            Then  call it either way   DoIt d   new DoIt    d doSomething    d soSomething  5  45

User · Answer

No  Java doesn t support default parameters like C    You need to define a different method   public int doSomething        return doSomething value1  value2

User · Answer

You can accomplish this via method overloading   public int doSomething int arg1  int arg2            return 0     public int doSomething             return doSomething defaultValue0  defaultValue1       By creating this parameterless method you are allowing the user to call the parameterfull method with the default arguments you supply within the implementation of the parameterless method   This is known as overloading the method

User · Answer

You can t declare default values for the parameters like C   I believe  lets you  but you could simply just create an overload   public int doSomething int arg1  int arg2          some logic here     return 0       overload supplies default values of 1 and 2 public int doSomething         return doSomething 1  2       If you are going to do something like this please do everyone else who works with your code a favor and make sure you mention in Javadoc comments what the default values you are using are

[java] how to set default method argument values?

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