Returns either the passed in String, or if the String is empty or null, the value of defaultStr. - Java java.lang

Java examples for java.lang:String Null Or Empty

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Description

Returns either the passed in String, or if the String is empty or null, the value of defaultStr.

Demo Code

/*/*  w ww .j  a  v  a2s  .  c  o  m*/
 * Copyright 2013 Guidewire Software, Inc.
 */
/**
 * This class is based, in part, on org.apache.commons.lang.StringUtils and is intended
 * to break the dependency on that project.
 *
 * @author <a href="http://jakarta.apache.org/turbine/">Apache Jakarta Turbine</a>
 * @author <a href="mailto:jon@latchkey.com">Jon S. Stevens</a>
 * @author Daniel L. Rall
 * @author <a href="mailto:gcoladonato@yahoo.com">Greg Coladonato</a>
 * @author <a href="mailto:ed@apache.org">Ed Korthof</a>
 * @author <a href="mailto:rand_mcneely@yahoo.com">Rand McNeely</a>
 * @author Stephen Colebourne
 * @author <a href="mailto:fredrik@westermarck.com">Fredrik Westermarck</a>
 * @author Holger Krauth
 * @author <a href="mailto:alex@purpletech.com">Alexander Day Chaffee</a>
 * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
 * @author Arun Mammen Thomas
 * @author Gary Gregory
 * @author Phil Steitz
 * @author Al Chou
 * @author Michael Davey
 * @author Reuben Sivan
 * @author Chris Hyzer
 *  Johnson

 */
public class Main {
  public static void main(String[] argv) {
    String str = "java2s.com";
    String defaultStr = "java2s.com";
    System.out.println(defaultIfEmpty(str, defaultStr));
  }

  /**
   * <p>
   * Returns either the passed in String, or if the String is empty or
   * <code>null</code>, the value of <code>defaultStr</code>.
   * </p>
   *
   * <pre>
   * defaultIfEmpty(null, "NULL")  = "NULL"
   * defaultIfEmpty("", "NULL")    = "NULL"
   * defaultIfEmpty("bat", "NULL") = "bat"
   * defaultIfEmpty("", null)      = null
   * </pre>
   *
   * @see GosuStringUtil#defaultString(String, String)
   * @param str
   *          the String to check, may be null
   * @param defaultStr
   *          the default String to return if the input is empty ("") or
   *          <code>null</code>, may be null
   * @return the passed in String, or the default
   */
  public static String defaultIfEmpty(String str, String defaultStr) {
    return isEmpty(str) ? defaultStr : str;
  }

  /**
   * <p>
   * Checks if a String is empty ("") or null.
   * </p>
   *
   * <pre>
   * StringUtils.isEmpty(null)      = true
   * StringUtils.isEmpty("")        = true
   * StringUtils.isEmpty(" ")       = false
   * StringUtils.isEmpty("bob")     = false
   * StringUtils.isEmpty("  bob  ") = false
   * </pre>
   *
   * <p>
   * NOTE: This method changed in Lang version 2.0. It no longer trims the String.
   * That functionality is available in isBlank().
   * </p>
   *
   * @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;
  }

  /**
   * Gets a String's length or <code>0</code> if the String is <code>null</code>.
   *
   * @param str
   *          a String or <code>null</code>
   * @return String length or <code>0</code> if the String is <code>null</code>.
   * @since 2.4
   */
  public static int length(String str) {
    return str == null ? 0 : str.length();
  }
}

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