package com.atlassian.pageobjects.elements;
   
   import com.atlassian.annotations.PublicApi;
   import com.atlassian.webdriver.Elements;
   import com.google.common.base.Function;
   import com.google.common.base.Predicate;
   import org.apache.commons.lang.StringUtils;
   
   import javax.annotation.Nonnull;
  import java.util.Set;
  
  import static com.google.common.base.Preconditions.checkNotNull;
  
  /**
   * Predicates and functions for easier usage of {@link PageElement page elements}.
   *
   * @since 2.3
   */
  @PublicApi
  public final class PageElements
  {
      public static final String BODY = Elements.TAG_BODY;
      public static final String TR = Elements.TAG_TR;
      public static final String TD = Elements.TAG_TD;
  
      public static final String DATA_PREFIX = "data-";
  
      private PageElements()
      {
          throw new AssertionError("Do not instantiate " + getClass().getSimpleName());
      }
  
      @Nonnull
      public static Function<PageElement, String> getText()
      {
          return new Function<PageElement, String>()
          {
              @Override
              public String apply(PageElement input)
              {
                  return StringUtils.stripToNull(input.getText());
              }
          };
      }
  
      @Nonnull
      public static Predicate<PageElement> isVisible()
      {
          return new Predicate<PageElement>()
          {
              @Override
              public boolean apply(PageElement input)
              {
                  return input.isVisible();
              }
          };
      }
  
      @Nonnull
      public static Predicate<PageElement> hasClass(@Nonnull final String className)
      {
          checkNotNull(className, "className");
  
          return new Predicate<PageElement>()
          {
              @Override
              public boolean apply(PageElement input)
              {
                  return input.hasClass(className);
              }
          };
      }
  
      @Nonnull
      public static Predicate<PageElement> hasAttribute(@Nonnull final String attribute)
      {
          checkNotNull(attribute, "attribute");
  
          return new Predicate<PageElement>()
          {
              @Override
              public boolean apply(PageElement input)
              {
                  return input.getAttribute(attribute) != null;
              }
          };
      }
  
      @Nonnull
      public static Predicate<PageElement> hasAttribute(@Nonnull final String attribute, @Nonnull final String value)
      {
          checkNotNull(attribute, "attribute");
          checkNotNull(value, "value");
  
          return new Predicate<PageElement>()
          {
              @Override
              public boolean apply(PageElement input)
              {
                 return input.hasAttribute(attribute, value);
             }
         };
     }
 
     @Nonnull
     public static Predicate<PageElement> hasDataAttribute(@Nonnull final String attribute)
     {
         checkNotNull(attribute, "attribute");
 
         return hasAttribute(DATA_PREFIX + attribute);
     }
 
     @Nonnull
     public static Predicate<PageElement> hasDataAttribute(@Nonnull final String attribute, @Nonnull final String value)
     {
         checkNotNull(attribute, "attribute");
 
         return hasAttribute(DATA_PREFIX + attribute, value);
     }
 
     @Nonnull
     public static Predicate<PageElement> hasValue(@Nonnull final String value)
     {
         checkNotNull(value, "value");
 
         return new Predicate<PageElement>()
         {
             @Override
             public boolean apply(PageElement input)
             {
                 return value.equals(input.getValue());
             }
         };
     }
 
     @Nonnull
     public static Function<PageElement, Iterable<String>> getCssClasses()
     {
         return new Function<PageElement, Iterable<String>>()
         {
             @Override
             public Set<String> apply(PageElement input)
             {
                 return input.getCssClasses();
             }
         };
     }
 
     @Nonnull
     public static Function<PageElement, String> getAttribute(@Nonnull final String attributeName)
     {
         checkNotNull(attributeName, "attributeName");
 
         return new Function<PageElement, String>()
         {
             @Override
             public String apply(PageElement input)
             {
                 return input.getAttribute(attributeName);
             }
         };
     }
 
     @Nonnull
     public static Function<PageElement, String> getDataAttribute(@Nonnull final String attributeName)
     {
         checkNotNull(attributeName, "attributeName");
 
         return new Function<PageElement, String>()
         {
             @Override
             public String apply(PageElement input)
             {
                 return input.getAttribute(DATA_PREFIX + attributeName);
             }
         };
     }
 }