How to remove if else condition from loop?

Question

I have a code snippet similar to the one below,

public ArrayList getReport(reportJDOList,accountType)
{
    String abc = "";

    for(ReportJDO reportJDO : reportJDOList)
    {
        if(accountType.equals("something")
           abc = reportJDO.getThis();
        else
           abc = reportJDO.getThat();

        //somecode goes here
    }

    returning List;
}

As I know the value of accountType before the iteration, I dont want this check to happen, for every entry in a list as it would cause numerous number of checks if the size of reportJDOList is 10000 for an instance. How we remove this thing from happening? Thanks in Advance :)

boolean typeIsSomething = accountType.equals("something"); Now you have a boolean value which you can use within the loop — schubakah
– schubakah, Commented Dec 1, 2015 at 10:04

AlexR · Accepted Answer · 2015-12-01 09:35:06Z

6

You can indeed peform check once and implement 2 loops:

if(accountType.equals("something") {
   for(ReportJDO reportJDO : reportJDOList) {
       abc = reportJDO.getThis();
   }
} else {
   for(ReportJDO reportJDO : reportJDOList) {
       abc = reportJDO.getThat();
   }
}

Obviously you can improve your design by either

separating you loops into 2 different methods
Using command pattern, i.e. implementing loop body in different command and executing it to loop.
Using Guava's Function (it is just improvement of #2)
Using java 8 streams.

answered Dec 1, 2015 at 9:35

AlexR

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2 Comments

Karthik Amar Over a year ago

Hi Alex, Thanks for the answer, I actually aware of the #1 solution, But the thing is "//some code goes here" part has lot of codes which I think putting into two loops will make lot of redundancy.

Aaron Over a year ago

To avoid duplicating the code in "some code goes here" extract it into a method that can be called from both places. The accepted answer by @Eran still has an if condition inside the loop.

Eran · Accepted Answer · 2015-12-01 09:31:25Z

4

IF you want to save the String comparison, make it once before the loop and store the result in a boolean variable :

String abc = "";
boolean isThis = accountType.equals("something");
for(ReportJDO reportJDO : reportJDOList) {  
    abc = isThis ? reportJDO.getThis() : reportJDO.getThat();
    //somecode goes here
}

answered Dec 1, 2015 at 9:31

Eran

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Comments

Jan · Accepted Answer · 2015-12-01 09:37:54Z

0

I'd vote for clean coding this - perform the check once and delegate the logic into private methods, each performing the loop individually. This duplicates code for the loop but gives greatest flexibility if at some point you need to do something more in SomethingReport that's not duplicated in OtherReport.

   public ArrayList getReport(reportJDOList,accountType) {
     if("soemthing".equals(accountType)) {
       return getSomethingReport(reportJDOList);
     } else {
       return getOtherReport(reportJDOList); 
     }
   }

   private ArrayList getSomethingReport(reportJDOList) {
     [...] 
   }

answered Dec 1, 2015 at 9:37

Jan

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Comments

Mihail Laftchiyski · Accepted Answer · 2015-12-03 18:31:21Z

0

interface AccountHandler {
    String get(Report r);
}

AccountHandler thisHandler= new AccountHandler() {
    @Override
    public String get(Report r) {
        return r.getThis();
    }
};  
AccountHandler thatHandler= new AccountHandler() {
    @Override
    public String get(Report r) {
        return r.getThat();
    }
};

//...............
AccountHandler ah;
ah = (what.equalsIgnoreCase("this")) ? thisHandler : thatHandler;
Report r=new Report();
// loop
ah.get(r);

answered Dec 3, 2015 at 18:31

Mihail Laftchiyski

1

1 Comment

Adam Michalik Over a year ago

A few words of additional comment are always appreciated next to the raw code.

Mihail Laftchiyski · Accepted Answer · 2015-12-03 18:47:48Z

0

//Using reflection:
Report r = new Report();
Method thisMethod = r.getClass().getDeclaredMethod("getThis");
Method thatMethod = r.getClass().getDeclaredMethod("getThat");
Method m =  (what.equalsIgnoreCase("this")) ? thisMethod : thatMethod;
m.invoke(r);

answered Dec 3, 2015 at 18:47

Mihail Laftchiyski

1

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