package com.atlassian.webdriver;
   
   import com.atlassian.annotations.PublicApi;
   import com.google.common.base.Function;
   import com.google.common.base.Predicates;
   import com.google.common.collect.FluentIterable;
   import com.google.common.collect.ImmutableSet;
   import org.apache.commons.lang.StringUtils;
   
  import javax.annotation.Nonnull;
  import javax.annotation.Nullable;
  import java.util.Collections;
  import java.util.Set;
  
  import static com.google.common.base.Preconditions.checkNotNull;
  
  /**
   * Utilities related to manipulating/querying of web elements (of any sort).
   * <p/>
   * NOTE: this class does not directly depend on any flavour of elements (e.g. WebDriver's
   * {@link org.openqa.selenium.WebElement}).
   *
   * @since 2.3
   */
  @PublicApi
  public final class Elements
  {
      public static final String TAG_BODY = "body";
      public static final String TAG_DIV = "div";
      public static final String TAG_TR = "tr";
      public static final String TAG_TD = "td";
      public static final String TAG_UL = "ul";
      public static final String TAG_LI = "li";
  
      public static final String ATTRIBUTE_CLASS = "class";
      public static final String ATTRIBUTE_ID = "id";
  
      private Elements()
      {
          throw new AssertionError("Do not instantiate " + getClass().getSimpleName());
      }
  
      /**
       * Extract CSS class names from the CSS "class" attribute value.
       *
       * @param rawClassValue the CSS "class" attribute value
       * @return set extracted CSS class names, or an empty set, if {@code rawClassValue} is {@code null},
       * or a blank string; all extracted class names will be lower cased
       */
      @Nonnull
      @SuppressWarnings("ConstantConditions")
      public static Set<String> getCssClasses(@Nullable String rawClassValue)
      {
          if (StringUtils.isBlank(rawClassValue))
          {
              return Collections.emptySet();
          }
  
          return FluentIterable.from(ImmutableSet.copyOf(rawClassValue.split("\\s+")))
                  .transform(new Function<String, String>()
                  {
                      @Nullable
                      @Override
                      public String apply(@Nullable String cssClass)
                      {
                          return StringUtils.isBlank(cssClass) ? null : cssClass.toLowerCase();
                      }
                  })
                  .filter(Predicates.notNull())
                  .toSet();
      }
  
      /**
       * Checks to see if a raw {@code rawClassValue} contains a specific class of not. The check is case-insensitive.
       *
       * @param expectedClassName CSS class name to check for
       * @param rawClassValue raw value of the "class" attribute
       * @return {@code true}, if {@code rawClassValue} contains CSS {@code expectedClassName} (case-insensitive),
       * {@code false} otherwise
       */
      public static boolean hasCssClass(@Nonnull String expectedClassName, @Nullable String rawClassValue)
      {
          checkNotNull(expectedClassName, "className");
  
          return rawClassValue != null && getCssClasses(rawClassValue).contains(expectedClassName.toLowerCase());
      }
  }