Styjun

How can we create a list of lists based on the size in bytes of the elements in the list?

Given I have List values. I want to split this list into multiple lists based on the sum of the byte size of the elements.

List<List<String>> splitList(List<String> listToSplit, int maxByteSize)

Assuming I have a ListlistToSplit = Arrays.asList("Value1", "Value2", "Value3"));

And the maxByteSize = 12.

Then I would expect to get 2 Lists - one list containing Value1 and Value2 and the other Value3

This is what I have tried so far

 private List<List<String>> splitList( List<String> values, int maxByteSize) 
 List<List<String>> returnList = new ArrayList<>();
 returnList = buildValuesList(maxByteSize, values.size(), values, returnList);
 return returnList;


 private List<List<String>> buildList(int availableSize, int noOfValues, List<String> values,
 List<List<String>> returnList) 
 List<String> valuesList = new ArrayList<>();
 List<String> remainderValues = new ArrayList<>(values);
 returnList.add(valuesList);
 int currentSize = 0;
 for (String val : values) 
 int valueSize = val.getBytes().length;
 if (currentSize < availableSize && (currentSize + valueSize < availableSize)) 
 currentSize += valueSize;
 valuesList.add(val);
 remainderValues.remove(val);
 else 
 buildValuesList(availableSize, noOfValues, remainderValues, returnList);
 
 
 return returnList;

Iterate over the listToSplit and if the sum between the bytes length of the current element and the bytes length of previous elements is greater than the maxByteSize then add the current list to the list to return and reset the length counter of the strings added to the list to return

public List<List<String>> splitList(List<String> listToSplit, int maxByteSize) 
 List<List<String>> splittedList = new ArrayList<>();
 List<String> currentList = new ArrayList<>();
 int currentSize = 0;
 for (String in : listToSplit) 

 if (currentSize + in.getBytes().length > maxByteSize) 
 splittedList.add(currentList);
 currentList = new ArrayList<>();
 splittedList.add(currentList); // add the new list to the list to return
 currentSize = 0;
 
 currentSize += in.getBytes().length;
 currentList.add(in);
 
 return splittedList;