https://openjdk.java.net/ 
/*
 * Copyright (c) 2005, 2015, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

/*
 *******************************************************************************
 * (C) Copyright IBM Corp. 1996-2005 - All Rights Reserved                     *
 *                                                                             *
 * The original version of this source code and documentation is copyrighted   *
 * and owned by IBM, These materials are provided under terms of a License     *
 * Agreement between IBM and Sun. This technology is protected by multiple     *
 * US and International patents. This notice and attribution to IBM may not    *
 * to removed.                                                                 *
 *******************************************************************************
 */

package java.text;

import sun.text.normalizer.NormalizerBase;


This class provides the method normalize which transforms Unicode
text into an equivalent composed or decomposed form, allowing for easier
sorting and searching of text.
The normalize method supports the standard normalization forms
described in

Unicode Standard Annex #15 — Unicode Normalization Forms.


Characters with accents or other adornments can be encoded in
several different ways in Unicode.  For example, take the character A-acute.
In Unicode, this can be encoded as a single character (the "composed" form):

     U+00C1    LATIN CAPITAL LETTER A WITH ACUTE

or as two separate characters (the "decomposed" form):

     U+0041    LATIN CAPITAL LETTER A
     U+0301    COMBINING ACUTE ACCENT

To a user of your program, however, both of these sequences should be
treated as the same "user-level" character "A with acute accent".  When you
are searching or comparing text, you must ensure that these two sequences are
treated as equivalent.  In addition, you must handle characters with more than
one accent. Sometimes the order of a character's combining accents is
significant, while in other cases accent sequences in different orders are
really equivalent.


Similarly, the string "ffi" can be encoded as three separate letters:

     U+0066    LATIN SMALL LETTER F
     U+0066    LATIN SMALL LETTER F
     U+0069    LATIN SMALL LETTER I

or as the single character

     U+FB03    LATIN SMALL LIGATURE FFI

The ffi ligature is not a distinct semantic character, and strictly speaking
it shouldn't be in Unicode at all, but it was included for compatibility
with existing character sets that already provided it.  The Unicode standard
identifies such characters by giving them "compatibility" decompositions
into the corresponding semantic characters.  When sorting and searching, you
will often want to use these mappings.


The normalize method helps solve these problems by transforming
text into the canonical composed and decomposed forms as shown in the first
example above. In addition, you can have it perform compatibility
decompositions so that you can treat compatibility characters the same as
their equivalents.
Finally, the normalize method rearranges accents into the
proper canonical order, so that you do not have to worry about accent
rearrangement on your own.


The W3C generally recommends to exchange texts in NFC.
Note also that most legacy character encodings use only precomposed forms and
often do not encode any combining marks by themselves. For conversion to such
character encodings the Unicode text needs to be normalized to NFC.
For more usage examples, see the Unicode Standard Annex.

Since:1.6
/**
 * This class provides the method <code>normalize</code> which transforms Unicode
 * text into an equivalent composed or decomposed form, allowing for easier
 * sorting and searching of text.
 * The <code>normalize</code> method supports the standard normalization forms
 * described in
 * <a href="http://www.unicode.org/unicode/reports/tr15/tr15-23.html">
 * Unicode Standard Annex #15 &mdash; Unicode Normalization Forms</a>.
 * <p>
 * Characters with accents or other adornments can be encoded in
 * several different ways in Unicode.  For example, take the character A-acute.
 * In Unicode, this can be encoded as a single character (the "composed" form):
 *
 * <pre>
 *      U+00C1    LATIN CAPITAL LETTER A WITH ACUTE</pre>
 *
 * or as two separate characters (the "decomposed" form):
 *
 * <pre>
 *      U+0041    LATIN CAPITAL LETTER A
 *      U+0301    COMBINING ACUTE ACCENT</pre>
 *
 * To a user of your program, however, both of these sequences should be
 * treated as the same "user-level" character "A with acute accent".  When you
 * are searching or comparing text, you must ensure that these two sequences are
 * treated as equivalent.  In addition, you must handle characters with more than
 * one accent. Sometimes the order of a character's combining accents is
 * significant, while in other cases accent sequences in different orders are
 * really equivalent.
 * <p>
 * Similarly, the string "ffi" can be encoded as three separate letters:
 *
 * <pre>
 *      U+0066    LATIN SMALL LETTER F
 *      U+0066    LATIN SMALL LETTER F
 *      U+0069    LATIN SMALL LETTER I</pre>
 *
 * or as the single character
 *
 * <pre>
 *      U+FB03    LATIN SMALL LIGATURE FFI</pre>
 *
 * The ffi ligature is not a distinct semantic character, and strictly speaking
 * it shouldn't be in Unicode at all, but it was included for compatibility
 * with existing character sets that already provided it.  The Unicode standard
 * identifies such characters by giving them "compatibility" decompositions
 * into the corresponding semantic characters.  When sorting and searching, you
 * will often want to use these mappings.
 * <p>
 * The <code>normalize</code> method helps solve these problems by transforming
 * text into the canonical composed and decomposed forms as shown in the first
 * example above. In addition, you can have it perform compatibility
 * decompositions so that you can treat compatibility characters the same as
 * their equivalents.
 * Finally, the <code>normalize</code> method rearranges accents into the
 * proper canonical order, so that you do not have to worry about accent
 * rearrangement on your own.
 * <p>
 * The W3C generally recommends to exchange texts in NFC.
 * Note also that most legacy character encodings use only precomposed forms and
 * often do not encode any combining marks by themselves. For conversion to such
 * character encodings the Unicode text needs to be normalized to NFC.
 * For more usage examples, see the Unicode Standard Annex.
 *
 * @since 1.6
 */
public final class Normalizer {

   private Normalizer() {};

    
This enum provides constants of the four Unicode normalization forms
that are described in

Unicode Standard Annex #15 — Unicode Normalization Forms
and two methods to access them.

Since:1.6
/**
     * This enum provides constants of the four Unicode normalization forms
     * that are described in
     * <a href="http://www.unicode.org/unicode/reports/tr15/tr15-23.html">
     * Unicode Standard Annex #15 &mdash; Unicode Normalization Forms</a>
     * and two methods to access them.
     *
     * @since 1.6
     */
    public static enum Form {

        
Canonical decomposition.

/**
         * Canonical decomposition.
         */
        NFD,

        
Canonical decomposition, followed by canonical composition.

/**
         * Canonical decomposition, followed by canonical composition.
         */
        NFC,

        
Compatibility decomposition.

/**
         * Compatibility decomposition.
         */
        NFKD,

        
Compatibility decomposition, followed by canonical composition.

/**
         * Compatibility decomposition, followed by canonical composition.
         */
        NFKC
    }

    
Normalize a sequence of char values.
The sequence will be normalized according to the specified normalization
from.

Params:
Throws:
Returns:The normalized String
/**
     * Normalize a sequence of char values.
     * The sequence will be normalized according to the specified normalization
     * from.
     * @param src        The sequence of char values to normalize.
     * @param form       The normalization form; one of
     *                   {@link java.text.Normalizer.Form#NFC},
     *                   {@link java.text.Normalizer.Form#NFD},
     *                   {@link java.text.Normalizer.Form#NFKC},
     *                   {@link java.text.Normalizer.Form#NFKD}
     * @return The normalized String
     * @throws NullPointerException If <code>src</code> or <code>form</code>
     * is null.
     */
    public static String normalize(CharSequence src, Form form) {
        return NormalizerBase.normalize(src.toString(), form);
    }

    
Determines if the given sequence of char values is normalized.

Params:
Throws:
Returns:true if the sequence of char values is normalized;
false otherwise.
/**
     * Determines if the given sequence of char values is normalized.
     * @param src        The sequence of char values to be checked.
     * @param form       The normalization form; one of
     *                   {@link java.text.Normalizer.Form#NFC},
     *                   {@link java.text.Normalizer.Form#NFD},
     *                   {@link java.text.Normalizer.Form#NFKC},
     *                   {@link java.text.Normalizer.Form#NFKD}
     * @return true if the sequence of char values is normalized;
     * false otherwise.
     * @throws NullPointerException If <code>src</code> or <code>form</code>
     * is null.
     */
    public static boolean isNormalized(CharSequence src, Form form) {
        return NormalizerBase.isNormalized(src.toString(), form);
    }
}