Java 8 Date equivalent to Joda's DateTimeFormatterBuilder with multiple parser formats?

Question

I currently have a Joda date parser that uses the DateTimeFormatterBuilder with half a dozen different date formats that I may receive.

I\'m migrating to Java 8\'s D

Answer 1

Iterating over @Tunaki's solution, using streams, when the code need to accept different patterns in a configurable way :

DateTimeFormatter dateTimeFormatter = dateFormats.stream()
        .map(DateTimeFormatter::ofPattern)
        .reduce(new DateTimeFormatterBuilder(), 
                DateTimeFormatterBuilder::appendOptional, 
                (f1, f2) -> f1.append(f2.toFormatter()))
        .toFormatter();

In this case I don't care about the combiner part of the reducer, but I need it in the signature so I made the combiner correct.

This code would virtually equivalent to if the above patterns (yyyy/MM/dd HH:mm:ss.SSSSSS, yyyy-MM-dd HH:mm:ss[.SSS], ddMMMyyyy:HH:mm:ss.SSS[ Z]) would be fed to the stream :

DateTimeFormatter formatter = new DateTimeFormatterBuilder()
    .appendOptional(DateTimeFormatter.ofPattern("yyyy/MM/dd HH:mm:ss.SSSSSS")
    .appendOptional(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss[.SSS]"
    .appendOptional(DateTimeFormatter.ofPattern("ddMMMyyyy:HH:mm:ss.SSS[ Z]")
    .toFormatter();