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Commons for lang, crypto, xml, dom, text, csv, reflection, annotations, parsing, ...

There is a newer version: 4.4.0

/*
 * tksCommons
 *
 * Author : Thomas Kuhlmann (ThK-Systems, http://www.thk-systems.de) License : LGPL (https://www.gnu.org/licenses/lgpl.html)
 */
package de.thksystems.util.lang;

public final class StringUtils {

    private StringUtils() {
    }

    /**
     * Extract all capitals (uppercase characters) of a string.
     * 
     * "hello" -> ""
     * "Hello" -> "H"
     * "HelLo" -> "HL"
     * "hello World. Here I am." -> "WHI"
     * null -> null
     * 
     */
    public static String getCapitals(String s) {
        if (s == null) {
            return null;
        }
        return s.chars().filter(Character::isUpperCase)
                .collect(StringBuilder::new,
                        StringBuilder::appendCodePoint,
                        StringBuilder::append)
                .toString();
    }

}