Guava Splitter with multiple split parameters

Question

Playing with Guava I can either set the split to be a single character, a string or a regular expression.

What I want is to split on multiple inputs without having to resort to using regular expressions as I want to built up the separators using method calls.

What I'm trying to do is to get it to let me do something like:

Splitter.on(',')
    .on('.')
    .on('|')
    .on("BREAK")
    .splitToList(test);

So for the input "a,b,c.d|e BREAK f" would produce a list containing a/b/c/d/e/f.

This is done within a class I'm writing so maybe construct a regular expression from the inputs when the call is made to finally process the data and use this as the one and only .on() call?

Thanks.

I'm not sure this is doable generally -- what if you did .on('B').on("BREAK"), how would that even work? -- but regexes are certainly the only way to approximate this with Guava's Splitter. — Louis Wasserman
.on is static so doesn't allow it and without looking at the code it seems that it stores a single item for the split, i.e. one of char, string, regex — Neil Walker

Ray Ray · Accepted Answer · 2014-01-14T01:57:03

As @Louis Wasserman pointed out, you want to use a regular expression here. You can either use Splitter.on(Pattern) or Splitter.onPattern(String) to accomplish this, and construct a regular expression to match the separators, like ([,.|]|BREAK).

Here is my method with a test. This test fails for the CharMatcher approach, and succeeds with the regular expression.

public class SplitterTest {
    public String splitAndRejoin(String pre) {
        return Joiner.on("/").join(
            Splitter
                .onPattern("([,.|]|BREAK)")
                .trimResults()
                .omitEmptyStrings()
                .split(pre));
    }

    @Test
    public void test1() {
        assertEquals("a/b/c/d/e/f", splitAndRejoin("a,b,c.d|e BREAK f"));
        assertEquals("A/B/C/D/E/F", splitAndRejoin("A,B,C.D|E BREAK F"));
    }
}

Guava Splitter with multiple split parameters

1 Answers