Error while using ternary operator

Question

I'm writing my Code with Eclipse Juno and I'm using a hash table to set my dataImportObject depending on the entries in it. Could anyone please tell me whats wrong about this: ht is my hashTable with <String, Integer> pairs in it

(ht.containsKey("DEVICE_ADDRESS")) ? 
    dataImportObject.setDevice_Address(dataitems[ht.get("DEVICE_ADDRESS")]) : 
    dataImportObject.setDevice_Address("");

What error are you getting? On another note, consider using a full-blown `if-else`. Ternaries make code hard to read. — Vivin Paliath, Mar 12 '13 at 17:16
Welcome to Stack Overflow. Can you give us a little more to go on? What are you expecting to happen? — Zutty, Mar 12 '13 at 17:17
What is the return value for the setDevice_Address method? If it's void, ternary isn't an option. — Kenogu Labz, Mar 12 '13 at 17:17
Just use `if`, if you are not familiar with ternary operator. — Adam Stelmaszczyk, Mar 12 '13 at 17:18
It is considered bad practice to use `?:` as a *control-flow mechanism*, which is what you're doing here. Use `if`/`else` instead (or use the `?:` to evaluate the parameter to `setDevice_Address`). — Oliver Charlesworth, Mar 12 '13 at 17:19
You need to provide the community with far more input to gain high visibility and last but not least an answer. — Uwe Günther, Mar 12 '13 at 17:37

score 16 · Accepted Answer · answered Mar 12 '13 at 17:19

Could anyone please tell me whats wrong about this

Two things:

The conditional operator can't be used as a statement on its own, only as an expression
I assume these set methods have void return types, so they can't appear as operands in the conditional operator

Three options:

Use an if statement:

if (ht.containsKey("DEVICE_ADDRESS")) {
     dataImportObject.setDevice_Address(dataitems[ht.get("DEVICE_ADDRESS")]));
} else {
     dataImportObject.setDevice_Address("");
}

Use the conditional operator inside the setDevice_Address call, or even clearer, beforehand:

String address = ht.containsKey("DEVICE_ADDRESS") 
    ? dataitems[ht.get("DEVICE_ADDRESS")] : "";
dataImportObject.setDevice_Address(address);

If you know that your hashtable won't have any null values, you can avoid the double lookup:

Integer index = ht.get("DEVICE_ADDRESS");
String address = index == null ? "" : dataitems[index];
dataImportObject.setDevice_Address(address);

Yeah, that´s it. Seems like I've missunderstood the ternary operator ... I just wanted to use it to shorten my If statements, because I'm gonna need many of them but as my set functions return void, this won't work ... so I'll have to Use number 2. thanks very much — John Daniels, Mar 12 '13 at 17:24

score 0 · Answer 2 · edited May 23 '17 at 12:11

0

You can't set the return type of ternary condition to void.

Use if else for that.

Possible duplicate

edited May 23 '17 at 12:11

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answered Mar 12 '13 at 17:20

devBinnooh

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Error while using ternary operator

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