package com.atlassian.webdriver.utils.element;
   
   import com.atlassian.webdriver.utils.Check;
   import org.apache.commons.lang.Validate;
   import org.openqa.selenium.By;
   import org.openqa.selenium.SearchContext;
   import org.openqa.selenium.WebDriver;
   import org.openqa.selenium.support.ui.ExpectedCondition;
   
  /**
   * Condition to wait for an element's presence.
   *
   */
  abstract class ElementLocationCondition implements ExpectedCondition<Boolean>
  {
      enum Locatable
      {
          LOCATED,
          NOTLOCATED
      }
  
      private final By by;
      private final SearchContext at;
      private final Locatable locatable;
  
      ElementLocationCondition(By by, Locatable locatable)
      {
          this(by, null, locatable);
      }
  
      ElementLocationCondition(By by, SearchContext at, Locatable locatable)
      {
          Validate.notNull(by, "by cannot be null.");
  
          this.by = by;
          this.at = at;
          this.locatable = locatable;
      }
  
      public Boolean apply(WebDriver webDriver)
      {
          if (locatable.equals(Locatable.LOCATED))
          {
              return Check.elementExists(by, at == null ? webDriver : at);
          }
          else
          {
              return !Check.elementExists(by, at == null ? webDriver : at);
          }
      }
  }