Java set default parameters

Java Default Parameters

In this short tutorial, we’ll demonstrate the use of method overloading to simulate default parameters in Java. Conclusion In this article, we looked at using method overloading to simulate default parameters in Java.

Java Default Parameters

This tutorial introduces how to implement default parameters in Java.

A default parameter is used when no value is passed. It is helpful when we want to pass limited arguments while the method accepts multiple arguments. For example, a method accepts three arguments, but if we wish to pass only two arguments during the method call, then the Java compiler uses the default value of the third argument to avoid any compilation error.

Java does not support default parameters value, but we can achieve it using some built-in solutions such as var-args or method overloading. Let’s see some examples.

Default Parameters in Java

In this example, we use the method overloading approach to set the default parameter value. However, this is not a fine solution but can be used as an alternative. Notice, we pass 0 as the default value while calling the add() method.

This approach doesn’t work if we have two optional parameters of the same type, and any of them can be omitted.

public class SimpleTesting < int add(int a, int b) < return a+b; >int add(int a, int b, int c) < return a+b+c; >public static void main(String[] args) < SimpleTesting test = new SimpleTesting(); int val1 = 10; int val2 = 20; int result1 = test.add(val1, 0); int result2 = test.add(val1, 0, val2); System.out.println("resutl1 : "+ result1); System.out.println("resutl2 : "+result2); >> 

Set Default Parameters using var-args in Java

This is another approach where we use the variable args feature to set Default Parameters. The var-args allows passing a variable length of arguments of the same type. See the example below.

public class SimpleTesting< int add(int a, int. b) < int b2 = b.length>0?b[0]:0; return a+b2; > int add(int a, int b, int c) < return a+b+c; >public static void main(String[] args) < SimpleTesting test = new SimpleTesting(); int val1 = 10; int val2 = 20; int result1 = test.add(val1); int result2 = test.add(val1, 0, val2); System.out.println("resutl1 : "+ result1); System.out.println("resutl2 : "+result2); >> 

Sett Default Parameters as Empty String in Java

In the case of string parameters, we can set an empty string to the parameters; however, this string holds null as the default value. See the example below.

public class SimpleTesting < String defaulPara(int a, String str1, String str2) < return str1+str2+a; >public static void main(String[] args) < SimpleTesting test = new SimpleTesting(); int val1 = 10; String result1 = test.defaulPara(val1,"","second"); String result2 = test.defaulPara(val1,"first",""); System.out.println("resutl1 : "+ result1); System.out.println("resutl2 : "+result2); >> 

resutl1 : second10 resutl2 : first10 

Set Default Parameters using var-args with any number of arguments in Java

In the case of var-args, we are free to provide any number of arguments while calling the method. So, if you want to provide only limited arguments, then it will work fine. See the example below.

public class SimpleTesting < int defaulPara(int. a) < int sum = 0; for (int i : a) < sum+=i; >return sum; > public static void main(String[] args) < SimpleTesting test = new SimpleTesting(); int val1 = 10; int val2 = 20; int result1 = test.defaulPara(); int result2 = test.defaulPara(val1); int result3 = test.defaulPara(val1, val2); System.out.println("resutl1 : "+ result1); System.out.println("resutl2 : "+result2); System.out.println("resutl3 : "+result3); >> 

resutl1 : 0 resutl2 : 10 resutl3 : 30 

Java Method

Java Default Parameters, This tutorial introduces how to implement default parameters in Java. A default parameter is used when no value is passed. It is helpful when we want to pass limited arguments while the method accepts multiple arguments. For example, a method accepts three arguments, but if we wish to pass only two arguments during the method call, then the

Java Default Parameters Using Method Overloading

1. Overview

In this short tutorial, we’ll demonstrate the use of method overloading to simulate default parameters in Java.

Here, we say simulate because unlike certain other OOP languages (like C++ and Scala), the Java specification doesn’t support assigning a default value to a method parameter .

2. Example

As an example, let’s make some tea! First, we’ll need a Tea POJO:

Here, the name is a required field, as our Tea has to have a name at least.

Then, there cannot be any tea without tea powder. So, we’ll assume that the user wants a standard 1 tbsp teaPowder in their tea, if it’s not provided at invocation time. This then is our first default parameter .

The other optional parameters are milk (in ml), herbs (to add or not to add), and sugar (in tbsp). If any of their values are not provided, we assume the user doesn’t want them.

Let’s see how to achieve this in Java using method overloading :

public Tea(String name, int milk, boolean herbs, int sugar, int teaPowder) < this.name = name; this.milk = milk; this.herbs = herbs; this.sugar = sugar; this.teaPowder = teaPowder; >public Tea(String name, int milk, boolean herbs, int sugar) < this(name, milk, herbs, sugar, DEFAULT_TEA_POWDER); >public Tea(String name, int milk, boolean herbs) < this(name, milk, herbs, 0); >public Tea(String name, int milk) < this(name, milk, false); >public Tea(String name)

As is evident, here we’re using constructor chaining, a form of overloading to provide the method parameters with some default values.

Now let’s add a simple test to see this in action:

@Test public void whenTeaWithOnlyName_thenCreateDefaultTea()

3. Alternatives

There are other ways to achieve default parameter Simulation in java. Some of them are:

Here’s how we can make use of the third way of allowing null arguments in our example:

public Tea(String name, Integer milk, Boolean herbs, Integer sugar, Integer teaPowder)

4. Conclusion

In this article, we looked at using method overloading to simulate default parameters in Java.

While there are other ways to achieve the same, overloading is most clean and simple. As always, code is available over on GitHub.

JavaScript Default Parameters, Test it Now. Output: In this example, We have created a function where we have assigned a default value to the parameter, and at the time of function call, we have passed undefined, and in the output, you can see that instead of taking the passed value, the function takes the default value and use it.; It means that whether the …

How to set default method argument values? [duplicate]

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?

doSomething(param1, param2); doSomething(); 

You can accomplish this via method overloading .

public int doSomething(int arg1, int arg2) < return 0; >public int doSomething()

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.

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 >0) < a = args[0]; >if (args.length > 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

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

The builder pattern allows you to add/remove parameters later on and you don’t need to create new overloaded methods for them.

No. Java doesn’t support default parameters like C++. You need to define a different method:

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()

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 default value to parameter Code Example, No, the structure you found is how Java handles it (that is, with overloading instead of default parameters). For constructors, See Effective Java: Programming Language Guide’s Item 1 tip (Consider static factory methods instead of constructors) if the overloading is getting complicated. For other methods, …

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Java Default Parameters

1. Default Parameters in Java
2. Set Default Parameters using var-args in Java
3. Set Default Parameters as Empty String in Java
4. Set Default Parameters using var-args with any number of arguments in Java

This tutorial introduces how to implement default parameters in Java.

A default parameter is used when no value is passed. It is helpful when we want to pass limited arguments while the method accepts multiple arguments. For example, a method accepts three arguments, but if we wish to pass only two arguments during the method call, then the Java compiler uses the default value of the third argument to avoid any compilation error.

Java does not support default parameters value, but we can achieve it using some built-in solutions such as var-args or method overloading. Let’s see some examples.

Default Parameters in Java

In this example, we use the method overloading approach to set the default parameter value. However, this is not a fine solution but can be used as an alternative. Notice, we pass 0 as the default value while calling the add() method.

This approach doesn’t work if we have two optional parameters of the same type, and any of them can be omitted.

public class SimpleTesting  int add(int a, int b)   return a+b;  >  int add(int a, int b, int c)   return a+b+c;  >  public static void main(String[] args)   SimpleTesting test = new SimpleTesting();  int val1 = 10;  int val2 = 20;  int result1 = test.add(val1, 0);  int result2 = test.add(val1, 0, val2);  System.out.println("resutl1 : "+ result1);  System.out.println("resutl2 : "+result2);  > > 

Set Default Parameters using var-args in Java

This is another approach where we use the variable args feature to set default parameters. The var-args allows passing a variable length of arguments of the same type. See the example below.

public class SimpleTesting  int add(int a, int. b)   int b2 = b.length>0?b[0]:0;  return a+b2;  >  int add(int a, int b, int c)   return a+b+c;  >  public static void main(String[] args)   SimpleTesting test = new SimpleTesting();  int val1 = 10;  int val2 = 20;  int result1 = test.add(val1);  int result2 = test.add(val1, 0, val2);  System.out.println("resutl1 : "+ result1);  System.out.println("resutl2 : "+result2);  > > 

Set Default Parameters as Empty String in Java

In the case of string parameters, we can set an empty string to the parameters; however, this string holds null as the default value. See the example below.

public class SimpleTesting  String defaulPara(int a, String str1, String str2)   return str1+str2+a;  >  public static void main(String[] args)   SimpleTesting test = new SimpleTesting();  int val1 = 10;  String result1 = test.defaulPara(val1,"","second");  String result2 = test.defaulPara(val1,"first","");  System.out.println("resutl1 : "+ result1);  System.out.println("resutl2 : "+result2);  > > 

resutl1 : second10 resutl2 : first10 

Set Default Parameters using var-args with any number of arguments in Java

In the case of var-args, we are free to provide any number of arguments while calling the method. So, if you want to provide only limited arguments, then it will work fine. See the example below.

public class SimpleTesting  int defaulPara(int. a)   int sum = 0;  for (int i : a)   sum+=i;  >  return sum;  >  public static void main(String[] args)   SimpleTesting test = new SimpleTesting();  int val1 = 10;  int val2 = 20;  int result1 = test.defaulPara();  int result2 = test.defaulPara(val1);  int result3 = test.defaulPara(val1, val2);  System.out.println("resutl1 : "+ result1);  System.out.println("resutl2 : "+result2);  System.out.println("resutl3 : "+result3);  > > 

resutl1 : 0 resutl2 : 10 resutl3 : 30 

Related Article — Java Method

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