ceresdb-protocol/src/main/java/com/ceresdb/AvroMapper.java

/*
 * 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 com.ceresdb;

import java.io.IOException;

import org.apache.avro.AvroRuntimeException;
import org.apache.avro.Schema;
import org.apache.avro.generic.GenericDatumReader;
import org.apache.avro.generic.GenericRecord;
import org.apache.avro.io.BinaryDecoder;
import org.apache.avro.io.DatumReader;
import org.apache.avro.io.DecoderFactory;

/**
 * Avro mapper tool.
 *
 * @author jiachun.fjc
 */
public class AvroMapper {
    private final Schema  schema;
    private BinaryDecoder reuseDecoder;

    public AvroMapper(Schema schema) {
        this.schema = schema;
    }

    public GenericRecord mapTo(final byte[] bytes) {
        final DatumReader<GenericRecord> reader = new GenericDatumReader<>(this.schema);
        final BinaryDecoder decoder = DecoderFactory.get().binaryDecoder(bytes, this.reuseDecoder);
        if (this.reuseDecoder == null) {
            this.reuseDecoder = decoder;
        }
        try {
            return reader.read(null, decoder);
        } catch (final IOException e) {
            throw new AvroRuntimeException(e);
        }
    }
}