package com.atlassian.marketplace.client.api;
   
   import java.lang.reflect.Method;
   
   import com.atlassian.fugue.Option;
   
   import static com.atlassian.fugue.Option.none;
   import static com.atlassian.fugue.Option.some;
   import static com.google.common.base.Preconditions.checkNotNull;
  
  /**
   * Common interface for {@code enum} types that have a unique string key for each possible value.
   * @since 2.0.0
   */
  public interface EnumWithKey
  {
      /**
       * The string key that represents this value in the Marketplace API.
       */
      public String getKey();
      
      /**
       * Helper class that can get allowable values or match a key string for any {@link EnumWithKey} type.
       */
      public static class Parser<A extends EnumWithKey>
      {
          private final A[] values;
          
          private Parser(A[] values)
          {
              this.values = checkNotNull(values);
          }
          
          public A[] getValues()
          {
              return values;
          }
          
          public Option<A> valueForKey(String key)
          {
              for (A v: values)
              {
                  if (v.getKey().equalsIgnoreCase(key))
                  {
                      return some(v);
                  }
              }
              return none();
          }
          
          public static <A extends EnumWithKey> Parser<A> forType(Class<A> enumClass)
          {
              try
              {
                  // This is ugly, but unfortunately Java's built-in {@code Enum} doesn't provide
                  // any *generic* way to get the list of allowed values.
                  Method method = enumClass.getDeclaredMethod("values");
                  @SuppressWarnings("unchecked")
                  A[] values = (A[]) method.invoke(null);
                  return new Parser<A>(values);
              }
              catch (Exception e)
              {
                  throw new IllegalStateException(e);
              }
          }
      }
  }