Return a value present in loop in java -

i want return value loop. code follows:

public long findlocationid(string location) throws systemexception     {          long locid = 1;          list<location> locationlist = locationlocalserviceutil.getlocations(-1,-1);              for(location findloc : locationlist)  {                 if(location == findloc.getlocationname())  {                     locid = findloc.getlocationid();                      **return locid;**                 }             }      } 

when try put return value in loop error saying include return statement.

how should change code can return value loop itself?

i want return new locid value in loop , not value set locid = 1; want return new value of locid loop

there various approach problem.

1. use while loop
2. use loop additional stop condition
3. use break key word.

let first create template before introduce our logic:

public long findlocationid(string locationname) throws systemexception     {          if(locationname == null) { //here cover first issue.              throw new illegalargumentexception("the locationname must not null");         }          long locid = long.min_value; //we declare default value returned if none match found.           collection<location> locationlist = getlocationlist(); //the location can read method not binded field.          if(locationlist == null || locationlist.isempty()) {             return locid; // or throw exception invalid state.         }           //place logic           return locid;      } 

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typically when not know when want stop iteration, sign should start while loop.

so lets try it.

solution 1 - while way.

 iterator<location> iterator = locationlist.iterator();          while(iterator.hasnext() && long.min_value != locid) {              location location = iterator.next();              if(locationname.equalsignorecase(location.getlocationname())) {                 locid = location.getlocationid(); // change locid, second condition no longer true , loop end.             }          } 

the pros: - works

the cons: - leave iterator

we should not leave iterators, error prone. lead next solution.

solution 2 - use pattern iterator instead of while.

 for(iterator<location> iterator2 = locationlist.iterator();iterator.hasnext() && long.min_value != locid;) {              location location = iterator.next();              if(locationname.equalsignorecase(location.getlocationname())) {                 locid = location.getlocationid(); // change locid, second condition no longer true , loop end.             }         } 

pros - works

cons - complicated, must thing stop, when reading code.

as above solution not easy read should removed.

solution 3 - why break useful.

for(location location : locationlist) {              if(locationname.equalsignorecase(location.getlocationname())) {                 locid = location.getlocationid();                 break;             }          } 

pros - works - readable

cons - none

conclusion code should readable. using break, point found match , not want progress anymore.

fine. case when location found ?

op example return 1l. not best choice value used id.

in previous examples have used min value of long. acceptable cases but, still need validate method result, , document it.

the final solution present additional loop exit, return key word.

public long findlocationid(string locationname) throws systemexception     {          if(locationname == null) { //here cover fist issue.              throw new illegalargumentexception("the locationname must not null");         }          collection<location> locationlist = getlocationlist(); //the location can read method not binded field.          if(locationlist == null) {             throw new illegalstateexception("the location list not initialized");          }          for(location location : locationlist) {              if(locationname.equalsignorecase(location.getlocationname())) {                 return location.getlocationid(); //we exit method.             }          }          throw new systemexception("could not found location name:" + locationname);       } 

additional note

in example op have location == findloc.getlocationname(), problem code should not use == compare objects types (details). deal string class recommended method use method string#equals(object) or 'string#equalsignorecase(string)'. example have used second option.