java method optional parameter code example
Example 1: java how to make a parameter optional
void foo(String a, Integer b) {
}
void foo(String a) {
foo(a, 0);
}
foo("a", 2);
foo("a");
Example 2: 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());
Example 3: java how to make a parameter optional
void foo(String a, Integer b, Integer c) {
b = b != null ? b : 0;
c = c != null ? c : 0;
}
foo("a", null, 2);
Example 4: 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);
Example 5: 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();