Matches when the string is empty or contains only whitespace. Does not match null. The string to test.

Matches when the string has zero length. Does not match null. The string to test.

Matches when the string is null, empty, or whitespace. The string to test.

Matches when the string starts with any of the given values. The prefixes to check against. The string to test.

Matches when the string contains only whitespace characters and has length > 1. Does not match null. The string to test.

Matches when the string is exactly a single whitespace character. Does not match null. The string to test.