/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

0 vote135 views1 answer
How to convert line into string java
Java
0 vote132 views1 answer
Change string into binary uding java
Java
0 vote172 views1 answer
Spring boot intellij auto reload
Java Spring
10 votes108 views3 answers
Android studio start activity
Java
1 vote127 views1 answer
Not supported for DML operations
Java
0 vote120 views1 answer
How to convert string to int android studio kotlin
Java
0 vote130 views2 answers
Sealed class in kotlin example
Java
0 vote90 views1 answer
Uri.builder in android studio
Java
1 vote117 views1 answer
Java stream limit items
Java
0 vote121 views1 answer
What is java.io example
Java