mandatory parameters taken by all functions in java code example
Example 1: java how to make a parameter optional
@SuppressWarnings("unchecked")
static <T> T getParm(Map<String, Object> map, String key, T defaultValue)
{
return (map.containsKey(key)) ? (T) map.get(key) : defaultValue;
}
void foo(Map<String, Object> parameters) {
String a = getParm(parameters, "a", "");
int b = getParm(parameters, "b", 0);
}
foo(Map.of("a","a", "b",2, "d","value"));
Example 2: 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"));