Right pad a String with a specified String. : String Format « Data Type « Java Tutorial






/* 
 * 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 {
  /**
   * The maximum size to which the padding constant(s) can expand.
   */
  private static final int PAD_LIMIT = 8192;


  /**
   * Right pad a String with a specified character.
   *
   * The String is padded to the size of <code>size</code>.
   *
   * <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</code> if null String input
   * @since 2.0
   */
  public static String rightPad(String str, int size, char padChar) {
      if (str == null) {
          return null;
      }
      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(padding(pads, padChar));
  }

  /**
   * Right pad a String with a specified String.
   *
   * The String is padded to the size of <code>size</code>.
   *
   * <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</code> if null String input
   */
  public static String rightPad(String str, int size, String padStr) {
      if (str == null) {
          return null;
      }
      if (isEmpty(padStr)) {
          padStr = " ";
      }
      int padLen = padStr.length();
      int strLen = str.length();
      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 {
          char[] padding = new char[pads];
          char[] padChars = padStr.toCharArray();
          for (int i = 0; i < pads; i++) {
              padding[i] = padChars[i % padLen];
          }
          return str.concat(new String(padding));
      }
  }
  /**
   * Returns padding using the specified delimiter repeated
   * to a given length.
   *
   * <pre>
   * StringUtils.padding(0, 'e')  = ""
   * StringUtils.padding(3, 'e')  = "eee"
   * StringUtils.padding(-2, 'e') = IndexOutOfBoundsException
   * </pre>
   *
   * 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</code>s to be represented.
   * If you are needing to support full I18N of your applications
   * consider using {@link #repeat(String, int)} instead. 
   * 
   *
   * @param repeat  number of times to repeat delim
   * @param padChar  character to repeat
   * @return String with repeated character
   * @throws IndexOutOfBoundsException if <code>repeat &lt; 0</code>
   * @see #repeat(String, int)
   */
  private static String padding(int repeat, char padChar) throws IndexOutOfBoundsException {
      if (repeat < 0) {
          throw new IndexOutOfBoundsException("Cannot pad a negative amount: " + repeat);
      }
      final char[] buf = new char[repeat];
      for (int i = 0; i < buf.length; i++) {
          buf[i] = padChar;
      }
      return new String(buf);
  }

  // Empty checks
  //-----------------------------------------------------------------------
  /**
   * Checks if a String is empty ("") or null.
   *
   * <pre>
   * StringUtils.isEmpty(null)      = true
   * StringUtils.isEmpty("")        = true
   * StringUtils.isEmpty(" ")       = false
   * StringUtils.isEmpty("bob")     = false
   * StringUtils.isEmpty("  bob  ") = false
   * </pre>
   *
   * NOTE: This method changed in Lang version 2.0.
   * It no longer trims the String.
   * That functionality is available in isBlank().
   *
   * @param str  the String to check, may be null
   * @return <code>true</code> if the String is empty or null
   */
  public static boolean isEmpty(String str) {
      return str == null || str.length() == 0;
  }
}








2.30.String Format
2.30.1.Format Calendar with String.format()
2.30.2.Format strings into table
2.30.3.String.format(): right pad a string
2.30.4.String.format(): left pad a string
2.30.5.Format a String (JDK1.5)
2.30.6.Pass value array to String.format()
2.30.7.Remove/collapse multiple newline characters.
2.30.8.Abbreviate string
2.30.9.Capital and uncapital strings
2.30.10.Transforms words to singular, plural, humanized (human readable), underscore, camel case, or ordinal form
2.30.11.Replace New Lines
2.30.12.Fix Line Separator
2.30.13.Abbreviates a String using ellipses in both sides.
2.30.14.Abbreviates a String using ellipses.
2.30.15.Capitalize the first character of the given string
2.30.16.Centers a String in a larger String of size size using the space character (' ').
2.30.17.Centers a String in a larger String of size size. Uses a supplied String as the value to pad the String with.
2.30.18.Centers a String in a larger String of size size. Uses a supplied character as the value to pad the String with.
2.30.19.Convert string to uppercase
2.30.20.Left pad a String with a specified String.
2.30.21.Left pad a String with a specified character.
2.30.22.Left pad a String with spaces (' ').
2.30.23.Makes the first letter caps and the rest lowercase.
2.30.24.Put quotes around the given String if necessary.
2.30.25.Quote a string so that it can be used as an identifier or a string literal in SQL statements.
2.30.26.Right pad a String with a specified String.
2.30.27.Right pad a String with a specified character.
2.30.28.Right pad a String with spaces (' ').
2.30.29.Trim off trailing blanks but not leading blanks
2.30.30.Truncate a String to the given length with no warnings or error raised if it is bigger.
2.30.31.Uncapitalizes a String changing the first letter to title case as per Character.toLowerCase(char). No other letters are changed.
2.30.32.Repeat String
2.30.33.Repeat a String repeat times to form a new String.
2.30.34.Strip Line Breaks
2.30.35.Trim any of the characters
2.30.36.Removes one newline from end of a String if it's there, otherwise leave it alone.
2.30.37.Removes newline, carriage return and tab characters from a string
2.30.38.Remove the leading and trailing quotes from str.