INDIP: sort a document collection in Java (Java heroes may skip this)

Update: the result of the blog below landed here. Thanks to Nathan Freeman, hihi, kudos to me???

In Lotus Script it was not a simple task to sort a document collection. In Java it sort of is.

Idea: use a comparator class, supply with an array of fields upon which the “sorting” should happen and let the Collections.sort do it’s magic:

Comparator class:

public class CollectionComparator implements Comparator<Document> {

String[] sortFields = null;

public CollectionComparator(String[] sortFields) {
this.sortFields = sortFields;

public int compare(Document doc1, Document doc2) {

try {
int compared = 0;
// loop all sortFields
for (String field : sortFields) {
Item item1 = doc1.getFirstItem(field);
Item item2 = doc2.getFirstItem(field);
switch (item1.getType()) {
case Item.TEXT:
case Item.AUTHORS:
case Item.NAMES:
case Item.READERS:
String val1 = doc1.getItemValueString(field);
String val2 = doc2.getItemValueString(field);
compared = val1.compareTo(val2);
if (0 != compared) {
return compared;
case Item.NUMBERS:
Double d1 = doc1.getItemValueDouble(field);
Double d2 = doc2.getItemValueDouble(field);
compared = d1.compareTo(d2);
if (0 != compared) {
return compared;

case Item.DATETIMES:

DateTime dt1 = item1.getDateTimeValue();
DateTime dt2 = item2.getDateTimeValue();
compared = dt2.timeDifference(dt1);
if (0 != compared) {
return compared;

return 0;
} catch (NotesException e) {

return 0;


Calling the sort:
// fill a list with the documents
List<Document> docs = new ArrayList<Document>();
doc = dc.getFirstDocument();
while (null != doc) {
doc = dc.getNextDocument(doc);

// sort the list
String[] sortFields = new String[] { “fieldName” }; // you can also supply multiple fields “field1”, “field2”
Collections.sort(docs, new CollectionComparator(sortFields));

// retrieve values
for (Document docSorted : docs) {
All code samples and downloads are copyright Michael Zischeck and licensed under Apache License 2.0 


  1. I will from now on add a line to the end of every post when it contains source code…

    have done so in this post… I hope this is okay

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