/*
 * 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.pulsar.broker.service.schema;

import org.apache.avro.Schema;
import org.apache.avro.SchemaValidationException;
import org.apache.avro.SchemaValidator;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * An avro schema validator that always reports as incompatible, if there is an existing schema.
 */
class NeverSchemaValidator implements SchemaValidator {
    private static final Logger log = LoggerFactory.getLogger(NeverSchemaValidator.class);
    static final NeverSchemaValidator INSTANCE = new NeverSchemaValidator();

    @Override
    public void validate(Schema toValidate, Iterable<Schema> existing)
            throws SchemaValidationException {
        for (Schema s : existing) {
            // only throw exception if there are existing schemas
            throw new SchemaValidationException(toValidate, toValidate);
        }
    }
}
