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
   *
   *     https://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.avro;
  
  import java.io.IOException;
  
  import org.apache.avro.io.parsing.ResolvingGrammarGenerator;
  import org.apache.avro.io.parsing.Symbol;
  
  /**
   * A {@link SchemaValidationStrategy} that checks that the {@link Schema} to
   * validate and the existing schema can mutually read each other according to
   * the default Avro schema resolution rules.
   *
   */
  class ValidateMutualRead implements SchemaValidationStrategy {
  
    /**
     * Validate that the schemas provided can mutually read data written by each
     * other according to the default Avro schema resolution rules.
     *
     * @throws SchemaValidationException if the schemas are not mutually compatible.
     */
    @Override
    public void validate(Schema toValidate, Schema existing) throws SchemaValidationException {
      canRead(toValidate, existing);
      canRead(existing, toValidate);
    }
  
    /**
     * Validates that data written with one schema can be read using another, based
     * on the default Avro schema resolution rules.
     *
     * @param writtenWith The "writer's" schema, representing data to be read.
     * @param readUsing   The "reader's" schema, representing how the reader will
     *                    interpret data.
     * @throws SchemaValidationException if the schema <b>readUsing<b/> cannot be
     *                                   used to read data written with
     *                                   <b>writtenWith<b/>
     */
    static void canRead(Schema writtenWith, Schema readUsing) throws SchemaValidationException {
      boolean error;
      try {
        error = Symbol.hasErrors(new ResolvingGrammarGenerator().generate(writtenWith, readUsing));
      } catch (IOException e) {
        throw new SchemaValidationException(readUsing, writtenWith, e);
      }
      if (error) {
        throw new SchemaValidationException(readUsing, writtenWith);
      }
    }
  
  }
  