content: /*
   * Copyright 2007-2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
   *
   * Licensed under the Apache License, Version 2.0 (the "License").
   * You may not use this file except in compliance with the License.
   * A copy of the License is located at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * or in the "license" file accompanying this file. This file is distributed
   * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
   * express or implied. See the License for the specific language governing
   * permissions and limitations under the License.
   */
  
  package com.amazon.ion.util;
  
  import static com.amazon.ion.facet.Facets.asFacet;
  
  import com.amazon.ion.Span;
  import com.amazon.ion.SpanProvider;
  
  /**
   * Utility methods for working with {@link Span}s.
   *
   */
  public final class Spans
  {
      /**
       * Attempts to get a {@link Span} from the given object, if it
       * supports {@link SpanProvider#currentSpan()}.
       *
       * @param spanProvider may be null.
       * @return null if there's not a current span.
       */
      public static Span currentSpan(Object spanProvider)
      {
          SpanProvider sp = asFacet(SpanProvider.class, spanProvider);
          Span span = (sp == null ? null : sp.currentSpan());
          return span;
      }
  
  
      /**
       * Attempts to get a {@link Span} facet from the given object, if it
       * supports {@link SpanProvider#currentSpan()}.
       *
       * @param spanProvider may be null.
       * @return null if there's not a current span supporting
       *  {@code spanFacetType}.
       */
      public static <T> T currentSpan(Class<T> spanFacetType,
                                      Object spanProvider)
      {
          Span span = currentSpan(spanProvider);
          T spanFacet = asFacet(spanFacetType, span);
          return spanFacet;
      }
  }
  