Java tutorial
/** * This file is part of pwt. * * pwt is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser * General Public License as published by the Free Software Foundation, either version 3 of the * License, or (at your option) any later version. * * pwt is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the * implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser * General Public License for more details. * * You should have received a copy of the GNU Lesser General Public License along with pwt. If not, * see <http://www.gnu.org/licenses/>. */ package fr.putnami.pwt.core.widget.client.helper; import com.google.gwt.text.shared.Parser; import java.text.ParseException; public final class StringParser implements Parser<String> { private static StringParser instance; private StringParser() { } @Override public String parse(CharSequence object) throws ParseException { if (object == null || "".equals(object.toString().trim())) { return null; } return object.toString(); } public static StringParser get() { if (StringParser.instance == null) { StringParser.instance = new StringParser(); } return StringParser.instance; } }