Java String Capitalize capitalize(final String str)

Description

Capitalizes a String changing the first character to title case as per Character#toTitleCase(int) .

License

Apache License

Parameter

Parameter	Description
str	the String to capitalize, may be null

Return

the capitalized String, null if null String input

Declaration

public static String capitalize(final String str) 

Method Source Code

//package com.java2s;
/*//from   w w w .j a va 2s.  co  m
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

public class Main {
    /**
     * <p>Capitalizes a String changing the first character to title case as
     * per {@link Character#toTitleCase(int)}. No other characters are changed.
     *
     * A {@code null} input String returns {@code null}.
     *
     * <pre>
     * StringUtils.capitalize(null)  = null
     * StringUtils.capitalize("")    = ""
     * StringUtils.capitalize("cat") = "Cat"
     * StringUtils.capitalize("cAt") = "CAt"
     * StringUtils.capitalize("'cat'") = "'cat'"
     * </pre>
     *
     * @param str the String to capitalize, may be null
     * @return the capitalized String, {@code null} if null String input
     * @since 2.0
     */
    public static String capitalize(final String str) {
        int strLen;
        if (str == null || (strLen = str.length()) == 0) {
            return str;
        }

        final int firstCodepoint = str.codePointAt(0);
        final int newCodePoint = Character.toTitleCase(firstCodepoint);
        if (firstCodepoint == newCodePoint) {
            // already capitalized
            return str;
        }

        final int newCodePoints[] = new int[strLen]; // cannot be longer than the char array
        int outOffset = 0;
        newCodePoints[outOffset++] = newCodePoint; // copy the first codepoint
        for (int inOffset = Character.charCount(firstCodepoint); inOffset < strLen;) {
            final int codepoint = str.codePointAt(inOffset);
            newCodePoints[outOffset++] = codepoint; // copy the remaining ones
            inOffset += Character.charCount(codepoint);
        }
        return new String(newCodePoints, 0, outOffset);
    }

    /**
     * Gets a CharSequence length or {@code 0} if the CharSequence is
     * {@code null}.
     *
     * @param cs
     *            a CharSequence or {@code null}
     * @return CharSequence length or {@code 0} if the CharSequence is
     *         {@code null}.
     * @since 2.4
     * @since 3.0 Changed signature from length(String) to length(CharSequence)
     */
    public static int length(final CharSequence cs) {
        return cs == null ? 0 : cs.length();
    }
}

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