CODEWITHSUNDEEP
javaexceptionfinally
cang
cang

Reputation: 31

How to send exception and return a value in the same method in java

I know it's not possibile throw exception and return a value in the same method, but i need to do this in somehow. I was thinking to use finally block to throw the exception and after return the value. Something like:

public Type myMethod() {
try{
//some elaborations
return result;
} catch(MyException myException) {
    //do something 
    return result;
} finally {
if(myException != null) {
 throw myException ;
}
}

Is possible something like this, or how can i achieve this?

EDIT: Or can i split in different methods?

Upvotes: 1

Views: 72

Answers (3)

Reilas
Reilas

Reputation: 6256

"... I know it's not possibile throw exception and return a value in the same method, but i need to do this in somehow. ...

... Is possible something like this ... can i split in different methods?"

The simplest approach would be to use a class.

class Result<T> {
    T value;
    Throwable e;
}

Here is an example where r will always contain "abc".

Result x() {
    Result<String> r = new Result<>();
    try {
        Integer.parseInt(r.value = "abc");
    } catch (Exception e) {
        r.e = e;
    }
    return r;
}

You'll need to check whether e is null.

Result<String> r = x();
if (r.e != null) System.out.println(r.e);
System.out.println("r.value = " + r.value);

Upvotes: 0

vsfDawg
vsfDawg

Reputation: 1527

Consider creating a custom exception that contains the original Exception as a cause and the current value.

A naive example:

public class ValueException<T> extends Exception {
  private T value;
  public ValueException(T value, Exception cause) {
    super(cause);
    this.value = value;
  }
  ... stuff ...
}

Within your method...

public Type myMethod() throws ValueException {
  Type result = null;
  try {
    //some elaborations
    return result;
  } catch(Exception e) {
    throw new ValueException(result, e);
  }
}

Some caller...

public Type getType() {
  try {
    return myMethod();
  } catch (ValueException e) {
    if (isGoodEnough(e.getValue()) {
      return e.getValue();
    }
    throw new RuntimeException("Failed to get Type", e);
  }

Upvotes: 2

StackFlowed
StackFlowed

Reputation: 6816

Short answer yes. Create a class with 2 data types exception and return value.

public class ReturnExceptionResult {
    Object result;
    Exception ex;

...
}

public ReturnExceptionResult myMethod() {
    Object result;
    Exception ex;
    try{
        //some elaborations
        result=returnvalue;
    } catch(MyException myException) {
        //do something 
        ex=myException;
        result=returnvalue;
    }
        return new ReturnExceptionResult(result,ex);
}

Upvotes: 0

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