Java String Pad Right rightPad(final String str, final int size, final char padChar)

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  5. rightPad(final String str, final int size, final char padChar)

Description

Right pad a String with a specified character.

The String is padded to the size of size .

 StringUtils.rightPad(null, *, *)     = null StringUtils.rightPad("", 3, 'z')     = "zzz" StringUtils.rightPad("bat", 3, 'z')  = "bat" StringUtils.rightPad("bat", 5, 'z')  = "batzz" StringUtils.rightPad("bat", 1, 'z')  = "bat" StringUtils.rightPad("bat", -1, 'z') = "bat"

License

Open Source License

Parameter

Parameter Description
str the String to pad out, may be null
size the size to pad to
padChar the character to pad with

Return

right padded String or original String if no padding is necessary, null if null String input

Declaration 

public static String rightPad(final String str, final int size, final char padChar)

Method Source Code

//package com.java2s;
/* ************************************************************************
#
#  DivConq//  w  w  w .j a va  2s.  com
#
#  http://divconq.com/
#
#  Copyright:
#    Copyright 2014 eTimeline, LLC. All rights reserved.
#
#  License:
#    See the license.txt file in the project's top-level directory for details.
#
#  Authors:
#    * Andy White
#
************************************************************************ */

public class Main {
    private static final int PAD_LIMIT = 8192;

    /**
     * <p>Right pad a String with spaces (' ').</p>
     *
     * <p>The String is padded to the size of {@code size}.</p>
     *
     * <pre>
     * StringUtils.rightPad(null, *)   = null
     * StringUtils.rightPad("", 3)     = "   "
     * StringUtils.rightPad("bat", 3)  = "bat"
     * StringUtils.rightPad("bat", 5)  = "bat  "
     * StringUtils.rightPad("bat", 1)  = "bat"
     * StringUtils.rightPad("bat", -1) = "bat"
     * </pre>
     *
     * @param str  the String to pad out, may be null
     * @param size  the size to pad to
     * @return right padded String or original String if no padding is necessary,
     *  {@code null} if null String input
     */
    public static String rightPad(final String str, final int size) {
        return rightPad(str, size, ' ');
    }

    /**
     * <p>Right pad a String with a specified character.</p>
     *
     * <p>The String is padded to the size of {@code size}.</p>
     *
     * <pre>
     * StringUtils.rightPad(null, *, *)     = null
     * StringUtils.rightPad("", 3, 'z')     = "zzz"
     * StringUtils.rightPad("bat", 3, 'z')  = "bat"
     * StringUtils.rightPad("bat", 5, 'z')  = "batzz"
     * StringUtils.rightPad("bat", 1, 'z')  = "bat"
     * StringUtils.rightPad("bat", -1, 'z') = "bat"
     * </pre>
     *
     * @param str  the String to pad out, may be null
     * @param size  the size to pad to
     * @param padChar  the character to pad with
     * @return right padded String or original String if no padding is necessary,
     *  {@code null} if null String input
     * @since 2.0
     */
    public static String rightPad(final String str, final int size, final char padChar) {
        if (str == null) {
            return null;
        }
        final int pads = size - str.length();
        if (pads <= 0) {
            return str; // returns original String when possible
        }
        if (pads > PAD_LIMIT) {
            return rightPad(str, size, String.valueOf(padChar));
        }
        return str.concat(repeat(padChar, pads));
    }

    /**
     * <p>Right pad a String with a specified String.</p>
     *
     * <p>The String is padded to the size of {@code size}.</p>
     *
     * <pre>
     * StringUtils.rightPad(null, *, *)      = null
     * StringUtils.rightPad("", 3, "z")      = "zzz"
     * StringUtils.rightPad("bat", 3, "yz")  = "bat"
     * StringUtils.rightPad("bat", 5, "yz")  = "batyz"
     * StringUtils.rightPad("bat", 8, "yz")  = "batyzyzy"
     * StringUtils.rightPad("bat", 1, "yz")  = "bat"
     * StringUtils.rightPad("bat", -1, "yz") = "bat"
     * StringUtils.rightPad("bat", 5, null)  = "bat  "
     * StringUtils.rightPad("bat", 5, "")    = "bat  "
     * </pre>
     *
     * @param str  the String to pad out, may be null
     * @param size  the size to pad to
     * @param padStr  the String to pad with, null or empty treated as single space
     * @return right padded String or original String if no padding is necessary,
     *  {@code null} if null String input
     */
    public static String rightPad(final String str, final int size, String padStr) {
        if (str == null) {
            return null;
        }
        if (isEmpty(padStr)) {
            padStr = " ";
        }
        final int padLen = padStr.length();
        final int strLen = str.length();
        final int pads = size - strLen;
        if (pads <= 0) {
            return str; // returns original String when possible
        }
        if (padLen == 1 && pads <= PAD_LIMIT) {
            return rightPad(str, size, padStr.charAt(0));
        }

        if (pads == padLen) {
            return str.concat(padStr);
        } else if (pads < padLen) {
            return str.concat(padStr.substring(0, pads));
        } else {
            final char[] padding = new char[pads];
            final char[] padChars = padStr.toCharArray();
            for (int i = 0; i < pads; i++) {
                padding[i] = padChars[i % padLen];
            }
            return str.concat(new String(padding));
        }
    }

    /**
     * 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();
    }

    /**
     * <p>Repeat a String {@code repeat} times to form a
     * new String.</p>
     *
     * <pre>
     * StringUtils.repeat(null, 2) = null
     * StringUtils.repeat("", 0)   = ""
     * StringUtils.repeat("", 2)   = ""
     * StringUtils.repeat("a", 3)  = "aaa"
     * StringUtils.repeat("ab", 2) = "abab"
     * StringUtils.repeat("a", -2) = ""
     * </pre>
     *
     * @param str  the String to repeat, may be null
     * @param repeat  number of times to repeat str, negative treated as zero
     * @return a new String consisting of the original String repeated,
     *  {@code null} if null String input
     */
    public static String repeat(final String str, final int repeat) {
        // Performance tuned for 2.0 (JDK1.4)

        if (str == null) {
            return null;
        }
        if (repeat <= 0) {
            return " ";
        }
        final int inputLength = str.length();
        if (repeat == 1 || inputLength == 0) {
            return str;
        }
        if (inputLength == 1 && repeat <= PAD_LIMIT) {
            return repeat(str.charAt(0), repeat);
        }

        final int outputLength = inputLength * repeat;
        switch (inputLength) {
        case 1:
            return repeat(str.charAt(0), repeat);
        case 2:
            final char ch0 = str.charAt(0);
            final char ch1 = str.charAt(1);
            final char[] output2 = new char[outputLength];
            for (int i = repeat * 2 - 2; i >= 0; i--, i--) {
                output2[i] = ch0;
                output2[i + 1] = ch1;
            }
            return new String(output2);
        default:
            final StringBuilder buf = new StringBuilder(outputLength);
            for (int i = 0; i < repeat; i++) {
                buf.append(str);
            }
            return buf.toString();
        }
    }

    /**
     * <p>Repeat a String {@code repeat} times to form a
     * new String, with a String separator injected each time. </p>
     *
     * <pre>
     * StringUtils.repeat(null, null, 2) = null
     * StringUtils.repeat(null, "x", 2)  = null
     * StringUtils.repeat("", null, 0)   = ""
     * StringUtils.repeat("", "", 2)     = ""
     * StringUtils.repeat("", "x", 3)    = "xxx"
     * StringUtils.repeat("?", ", ", 3)  = "?, ?, ?"
     * </pre>
     *
     * @param str        the String to repeat, may be null
     * @param separator  the String to inject, may be null
     * @param repeat     number of times to repeat str, negative treated as zero
     * @return a new String consisting of the original String repeated,
     *  {@code null} if null String input
     * @since 2.5
     */
    public static String repeat(final String str, final String separator, final int repeat) {
        if (str == null || separator == null) {
            return repeat(str, repeat);
        }
        // given that repeat(String, int) is quite optimized, better to rely on it than try and splice this into it
        final String result = repeat(str + separator, repeat);
        return removeEnd(result, separator);
    }

    /**
     * <p>Returns padding using the specified delimiter repeated
     * to a given length.</p>
     *
     * <pre>
     * StringUtils.repeat('e', 0)  = ""
     * StringUtils.repeat('e', 3)  = "eee"
     * StringUtils.repeat('e', -2) = ""
     * </pre>
     *
     * <p>Note: this method doesn't not support padding with
     * <a href="http://www.unicode.org/glossary/#supplementary_character">Unicode Supplementary Characters</a>
     * as they require a pair of {@code char}s to be represented.
     * If you are needing to support full I18N of your applications
     * consider using {@link #repeat(String, int)} instead.
     * </p>
     *
     * @param ch  character to repeat
     * @param repeat  number of times to repeat char, negative treated as zero
     * @return String with repeated character
     * @see #repeat(String, int)
     */
    public static String repeat(final char ch, final int repeat) {
        final char[] buf = new char[repeat];
        for (int i = repeat - 1; i >= 0; i--) {
            buf[i] = ch;
        }
        return new String(buf);
    }

    /**
     * check to see if characters contains only whitespace
     *  
     * @param str string to check
     * @return true if contains only whitespace
     */
    public static boolean isEmpty(CharSequence str) {
        if (str == null)
            return true;

        int strLen = str.length();

        for (int i = 0; i < strLen; i++)
            if (!Character.isWhitespace(str.charAt(i)))
                return false;

        return true;
    }

    /**
     * <p>Removes a substring only if it is at the end of a source string,
     * otherwise returns the source string.</p>
     *
     * <p>A {@code null} source string will return {@code null}.
     * An empty ("") source string will return the empty string.
     * A {@code null} search string will return the source string.</p>
     *
     * <pre>
     * StringUtils.removeEnd(null, *)      = null
     * StringUtils.removeEnd("", *)        = ""
     * StringUtils.removeEnd(*, null)      = *
     * StringUtils.removeEnd("www.domain.com", ".com.")  = "www.domain.com"
     * StringUtils.removeEnd("www.domain.com", ".com")   = "www.domain"
     * StringUtils.removeEnd("www.domain.com", "domain") = "www.domain.com"
     * StringUtils.removeEnd("abc", "")    = "abc"
     * </pre>
     *
     * @param str  the source String to search, may be null
     * @param remove  the String to search for and remove, may be null
     * @return the substring with the string removed if found,
     *  {@code null} if null String input
     * @since 2.1
     */
    public static String removeEnd(final String str, final String remove) {
        if (isEmpty(str) || isEmpty(remove)) {
            return str;
        }
        if (str.endsWith(remove)) {
            return str.substring(0, str.length() - remove.length());
        }
        return str;
    }
}

Related

  1. rightPad(byte[] bytes, int length, byte padByte)
  2. rightPad(final String input, final int size)
  3. rightPad(String _str, int _size, char _padChar)
  4. rightPad(String csIn, int nRequiredLength, char cFill)
  5. rightPad(String field, char padding, int width)
  6. rightPad(String in, char padding, int length)