AvroSchemaProvider.java

/**
 * Copyright 2016 Hortonworks.
 * <p>
 * Licensed 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
 * <p>
 * http://www.apache.org/licenses/LICENSE-2.0
 * <p>
 * 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 com.hortonworks.registries.schemaregistry.avro;

import com.hortonworks.registries.schemaregistry.AbstractSchemaProvider;
import com.hortonworks.registries.schemaregistry.CompatibilityResult;
import com.hortonworks.registries.schemaregistry.SchemaCompatibility;
import com.hortonworks.registries.schemaregistry.SchemaFieldInfo;
import com.hortonworks.registries.schemaregistry.errors.InvalidSchemaException;
import com.hortonworks.registries.schemaregistry.errors.SchemaNotFoundException;
import org.apache.avro.Schema;
import org.apache.avro.SchemaNormalization;
import org.apache.avro.SchemaParseException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.security.NoSuchAlgorithmException;
import java.util.List;

/**
 *
 */
public class AvroSchemaProvider extends AbstractSchemaProvider {
    private static final Logger LOG = LoggerFactory.getLogger(AvroSchemaProvider.class);

    public static final String TYPE = "avro";

    @Override
    public String getName() {
        return "Avro schema provider";
    }

    @Override
    public String getDescription() {
        return "This provider supports avro schemas. You can find more information about avro at http://avro.apache.org";
    }

    @Override
    public String getType() {
        return TYPE;
    }

    @Override
    public CompatibilityResult checkCompatibility(String toSchemaText,
                                                  String existingSchemaText,
                                                  SchemaCompatibility existingSchemaCompatibility) {
        return AvroSchemaValidator
                .of(existingSchemaCompatibility)
                .validate(new Schema.Parser().parse(toSchemaText),
                          new Schema.Parser().parse(existingSchemaText));
    }

    @Override
    public byte[] getFingerprint(String schemaText) throws InvalidSchemaException, SchemaNotFoundException {
        try {
            // generates fingerprint of canonical form of the given schema.
            Schema schema = new Schema.Parser().parse(getResultantSchema(schemaText));
            return SchemaNormalization.parsingFingerprint("MD5", schema);
        } catch (SchemaParseException e) {
            throw new InvalidSchemaException("Given schema is invalid", e);
        } catch (NoSuchAlgorithmException e) {
            throw new RuntimeException(e);
        }
    }

    @Override
    public String getResultantSchema(String schemaText) throws InvalidSchemaException, SchemaNotFoundException {
        AvroSchemaResolver avroSchemaResolver = new AvroSchemaResolver(getSchemaVersionRetriever());
        return avroSchemaResolver.resolveSchema(schemaText);
    }

    @Override
    public List<SchemaFieldInfo> generateFields(String schemaText) throws InvalidSchemaException, SchemaNotFoundException {
        AvroFieldsGenerator avroFieldsGenerator = new AvroFieldsGenerator();
        return avroFieldsGenerator.generateFields(new Schema.Parser().parse(getResultantSchema(schemaText)));
    }

}