Java String Normalize normalizeWhitespace(final String str)

Description

Utility to normalize whitespace in a String, i.e.

License

Open Source License

Parameter

Parameter	Description
str	String to normalize

Return

normalized version of str.

Declaration

public static String normalizeWhitespace(final String str) 

Method Source Code

//package com.java2s;
/*/*from  w ww .j a v  a2 s. c  om*/
 * Copyright (C) 2014 Christian P. Lerch <christian.p.lerch[at]gmail.com>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

import java.text.CharacterIterator;

import java.text.StringCharacterIterator;

import javax.annotation.Nullable;

public class Main {
    /**
     * Utility to normalize whitespace in a String, i.e. collapses any sequence
     * whitespaces (spaces, tabs, linefeeds etc) into a single ' ' (blank) character.
     * Note: doesn't trim() the string, however, whitespace at the beginning and end
     * is normalized too.
     * @param str String to normalize
     * @return normalized version of str.
     */
    public static String normalizeWhitespace(final String str) {
        if (isNullOrEmpty(str))
            return str;
        final StringBuilder buf = new StringBuilder();
        final CharacterIterator iter = new StringCharacterIterator(str);
        boolean inWhitespace = false; // Flag set if we're in a second consecutive whitespace
        for (char c = iter.first(); c != CharacterIterator.DONE; c = iter.next()) {
            if (Character.isWhitespace(c)) {
                if (!inWhitespace) {
                    buf.append(' ');
                    inWhitespace = true;
                }
            } else {
                inWhitespace = false;
                buf.append(c);
            }
        }
        return buf.toString();
    }

    /**
     * Checks whether the given CharSequence is null or has zero length.
     *
     * <p>Consider normalizing all of your your string references with {@link #nullToEmpty}.
     * If you do, you can use {@link String#isEmpty()} instead of this
     * method, and you won't need special null-safe forms of methods like {@link
     * String#toUpperCase} either.
     *
     * @param str the CharSequence reference to check (may be {@code null})
     * @return {@code true} if the CharSequence is null or is the empty string
     */
    public static boolean isNullOrEmpty(@Nullable final CharSequence str) {
        return str == null || str.length() == 0;
    }

    public static boolean isNullOrEmpty(@Nullable final String str) {
        return isNullOrEmpty((CharSequence) str);
    }
}

Related

1. normalizeUnicode(CharSequence text)
2. normalizeUnicode(final String str)
3. normalizeUnicode(String input)
4. normalizeUnicode(String str)
5. normalizeUnicodeDiacritics(String text)
6. normalizeWhiteSpace(String str)
7. normalizeWidth(String text)
8. normalizeWord(String word)