/Java/Java how to make a parameter optional

Java how to make a parameter optional

void foo(String a, Optional<Integer> bOpt) {
    Integer b = bOpt.isPresent() ? bOpt.get() : 0;
    //...
}

foo("a", Optional.of(2));
foo("a", Optional.<Integer>absent());

Source: stackoverflow.com

Java how to make a parameter optional

void foo(String a, Integer... b) {
    Integer b1 = b.length > 0 ? b[0] : 0;
    Integer b2 = b.length > 1 ? b[1] : 0;
    //...
}

foo("a");
foo("a", 1, 2);

Source: stackoverflow.com

Java how to make a parameter optional

 class Foo {
     private final String a; 
     private final Integer b;

     Foo(String a, Integer b) {
       this.a = a;
       this.b = b;
     }

     //...
 }

 class FooBuilder {
   private String a = ""; 
   private Integer b = 0;

   FooBuilder setA(String a) {
     this.a = a;
     return this;
   }

   FooBuilder setB(Integer b) {
     this.b = b;
     return this;
   }

   Foo build() {
     return new Foo(a, b);
   }
 }

 Foo foo = new FooBuilder().setA("a").build();

Source: stackoverflow.com

Java how to make a parameter optional

void foo(Map<String, Object> parameters) {
    String a = ""; 
    Integer b = 0;
    if (parameters.containsKey("a")) { 
        if (!(parameters.get("a") instanceof Integer)) { 
            throw new IllegalArgumentException("...");
        }
        a = (Integer)parameters.get("a");
    }
    if (parameters.containsKey("b")) { 
        //... 
    }
    //...
}

foo(ImmutableMap.<String, Object>of(
    "a", "a",
    "b", 2, 
    "d", "value"));

Source: stackoverflow.com

Similar codes

4 votes379 views1 answer
Source option 5 is no longer supported. Use 7 or later
Java
0 vote380 views3 answers
Diiferent ways to run spring boot
Java
0 vote400 views1 answer
Send message bukkit
Java
0 vote359 views2 answers
Finding the ASCII value of a Character in java
Java
0 vote371 views1 answer
Rxjava dependencies
Java
4 votes333 views2 answers
Java create directory if not exists
Java
0 vote329 views1 answer
Align button to the left in JPanel
Java
9 votes347 views5 answers
Flutter image
Java
1 vote396 views2 answers
Java for loop increment by 3
Java
0 vote447 views1 answer
Why cant we have primitive types in generixs
Java