public static String stripToEmpty(final String str) {
        return N.isNullOrEmpty(str) ? N.EMPTY_STRING : strip(str, null);
    }
public static String stripToEmpty ( final String str ) { return N . isNullOrEmpty ( str ) ? N . EMPTY_STRING : strip ( str , null ) ; }
<p>
Strips whitespace from the start and end of a String returning an empty
String if {@code null} input.
</p>

<p>
This is similar to {@link #trimToEmpty(String)} but removes whitespace.
Whitespace is defined by {@link Character#isWhitespace(char)}.
</p>

<pre>
N.stripToEmpty(null)     = ""
N.stripToEmpty("")       = ""
N.stripToEmpty("   ")    = ""
N.stripToEmpty("abc")    = "abc"
N.stripToEmpty("  abc")  = "abc"
N.stripToEmpty("abc  ")  = "abc"
N.stripToEmpty(" abc ")  = "abc"
N.stripToEmpty(" ab c ") = "ab c"
</pre>

@param str
the String to be stripped, may be null
@return the trimmed String, or an empty String if {@code null} input
@since 2.0