Suppose I have an Iterator<Class1> object. Class1 provides a method stringFunction() that returns a String.
Is there a way to use String.join in a way that calls stringFunction() on every Class1 returned by the iterator, and concatenates the function results separated by a delimiter?
There's a String.join overload that takes an Iterable<CharSequence>; is it possible to create one from the Iterator<Class1> and the stringFunction, so that join can use it?
How about using
streamOfCharSequence.collect(Collectors.joining(delimiter)) instead of String.join(delimiter, Iterable<CharSequence>.
You can try something like
String result = StreamSupport
.stream(Spliterators.spliteratorUnknownSize(iterator,
Spliterator.ORDERED), false)
.map(e -> e.stringFunction()).collect(Collectors.joining(", "));
StreamSupport.stream(Spliterators.spliteratorUnknownSize(iterator, Spliterator.ORDERED), false) and just use stream().map(e -> e.stringFunction()).collect(Collectors.joining(", ")).Using Guava, you should be able to do something like this:
Iterator<Class1> iter = ...
String result = Joiner.on("//").join(Iterators.transform(iter, x -> x.stringFunction()));
The following works, but seems a little clunky.
Iterator<Class1> iterator = ...;
Iterator<CharSequence> funcIterator =
StreamSupport.stream(
Spliterators.spliteratorUnknownSize(iterator, Spliterator.ORDERED), false)
.map(x -> (CharSequence)x.stringFunction())
.iterator();
String result = String.join("//", () -> funcIterator);
It doesn't work to create an Iterator<String> because join doesn't
accept it; thus it's necessary to declare the type as
Iterator<CharSequence>, and also to cast the String to a
CharSequence in the lambda. The syntax () -> idIterator works for
creating an Iterable whose iterator is the given iterator.
Is there a simpler way?
