content: /*
   *  Licensed to the Apache Software Foundation (ASF) under one
   *  or more contributor license agreements.  See the NOTICE file
   *  distributed with this work for additional information
   *  regarding copyright ownership.  The ASF licenses this file
   *  to you under the Apache License, Version 2.0 (the
   *  "License"); you may not use this file except in compliance
   *  with the License.  You may obtain a copy of the License at
   *
   *        http://www.apache.org/licenses/LICENSE-2.0
   *
   *  Unless required by applicable law or agreed to in writing,
   *  software distributed under the License 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 org.apache.causeway.viewer.graphql.applib.marshallers;
  
  import graphql.schema.GraphQLScalarType;
  
  import org.springframework.lang.NonNull;
  
  /**
   * Provides an SPI to allow different scalar datatypes to be marshalled to and from GraphQL scalar types.
   *
   * <p>
   *     The implementations are called following a chain-of-responsibility pattern, first one matching is used.
   *     Use {@link jakarta.annotation.Priority} (with {@link org.apache.causeway.applib.annotation.PriorityPrecedence} values)
   *     to override the framework-provided defaults, earliest wins.
   * </p>
   *
   * @param <K>
   *
   * @since 2.0 {@index}
   */
  public interface ScalarMarshaller<K> {
  
      /**
       * Whether this marshaller is able to marshall/unmarshall the provided Java class.
       *
       * @param javaClass
       * @return
       */
      boolean handles(Class<?> javaClass);
  
      /**
       * The corresponding GraphQL scalar type for the Java-class.
       * @return
       */
      GraphQLScalarType getGqlScalarType();
  
      /**
       * Unmarshal the provided graphQL value into its Java equivalent.
       *
       * @param graphValue - to be unmarshalled.  This will never be null.
       * @param targetType - the required type.  Usually isn't required, though the fallback Object marshaller uses it to correctly marshal enums.
       * @return
       */
      K unmarshal(
              final Object graphValue,
              final @NonNull Class<?> targetType);
  }
  