content: package com.alibaba.smart.framework.engine.common.util;
  
  /**
   * Created by 高海军 帝奇 74394 on 2017 February  10:23.
   *
   * reduced from apache StringUtils
   */
  public abstract  class StringUtil {
  
      public static final String EMPTY = "";
      public static final int INDEX_NOT_FOUND = -1;
  
      public static boolean equals(String a, String b) {
          if (a == null) {
              return b == null;
          }
          return a.equals(b);
      }
  
      public static boolean isEmpty(String value) {
          if (value == null || value.length() == 0) {
              return true;
          }
  
          return false;
      }
  
      public static boolean isNotEmpty(String value) {
          return !isEmpty(value);
      }
  
      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;
      }
      public static String removeStart(final String str, final String remove) {
          if (isEmpty(str) || isEmpty(remove)) {
              return str;
          }
          if (str.startsWith(remove)){
              return str.substring(remove.length());
          }
          return str;
      }
  
      public static String substringBefore(String str, String separator) {
          if (isEmpty(str) || separator == null) {
              return str;
          }
          if (separator.length() == 0) {
              return EMPTY;
          }
          int pos = str.indexOf(separator);
          if (pos == INDEX_NOT_FOUND) {
              return str;
          }
          return str.substring(0, pos);
      }
  
  
      public static String substringAfter(String str, String separator) {
          if (isEmpty(str)) {
              return str;
          }
          if (separator == null) {
              return EMPTY;
          }
          int pos = str.indexOf(separator);
          if (pos == INDEX_NOT_FOUND) {
              return EMPTY;
          }
          return str.substring(pos + separator.length());
      }
  }
  
  