package com.atlassian.sal.api.page;
   
   import com.google.common.base.Joiner;
   
   import javax.annotation.Nonnull;
   import javax.annotation.Nullable;
   import java.util.Arrays;
   import java.util.EnumSet;
   import java.util.Objects;
  import java.util.stream.Collectors;
  
  /**
   * Util class for creating empty enum set, parsing string and valueOf function
   */
  public abstract class PageCapabilities {
  
      public static final String SEPARATOR = ",";
  
      /**
       * @return Empty EnumSet
       */
      public static EnumSet<PageCapability> empty() {
          return EnumSet.noneOf(PageCapability.class);
      }
  
      /**
       * @param values {@code String} page capability names separated with {@link #SEPARATOR}
       * @return {@link java.util.EnumSet} of {@link com.atlassian.sal.api.page.PageCapability}
       * @throws IllegalArgumentException if any of parsed values is invalid
       */
      public static EnumSet<PageCapability> valueOf(@Nullable String values) {
          if (values == null || values.length() == 0) {
              return empty();
          }
  
          return Arrays.stream(values.split(SEPARATOR))
                  .map(value -> {
                      try {
                          return PageCapability.valueOf(value);
                      } catch (IllegalArgumentException e) {
                          return null;
                      }
                  })
                  .filter(Objects::nonNull)
                  .collect(Collectors.toCollection(() -> EnumSet.noneOf(PageCapability.class)));
      }
  
      /**
       * @param pageCaps enum set
       * @return Page capabilities separated with {@link #SEPARATOR}
       */
      public static String toString(@Nonnull EnumSet<PageCapability> pageCaps) {
          return Joiner.on(SEPARATOR).join(pageCaps.iterator());
      }
  }