org.apache.avro.message.MessageDecoder Maven / Gradle / Ivy
/*
* 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.message;
import org.apache.avro.util.ReusableByteArrayInputStream;
import org.apache.avro.util.ReusableByteBufferInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;
/**
* Deserializes a single datum from a ByteBuffer, byte array, or InputStream.
*
* @param a datum class
*/
public interface MessageDecoder {
/**
* Deserialize a single datum from an InputStream.
*
* @param stream stream to read from
* @return a datum read from the stream
* @throws BadHeaderException If the payload's header is not recognized.
* @throws MissingSchemaException If the payload's schema cannot be found.
* @throws IOException
*/
D decode(InputStream stream) throws IOException;
/**
* Deserialize a single datum from an InputStream.
*
* @param stream stream to read from
* @param reuse a datum instance to reuse, avoiding instantiation if possible
* @return a datum read from the stream
* @throws BadHeaderException If the payload's header is not recognized.
* @throws MissingSchemaException If the payload's schema cannot be found.
* @throws IOException
*/
D decode(InputStream stream, D reuse) throws IOException;
/**
* Deserialize a single datum from a ByteBuffer.
*
* @param encoded a ByteBuffer containing an encoded datum
* @return a datum read from the stream
* @throws BadHeaderException If the payload's header is not recognized.
* @throws MissingSchemaException If the payload's schema cannot be found.
* @throws IOException
*/
D decode(ByteBuffer encoded) throws IOException;
/**
* Deserialize a single datum from a ByteBuffer.
*
* @param encoded a ByteBuffer containing an encoded datum
* @param reuse a datum instance to reuse, avoiding instantiation if possible
* @return a datum read from the stream
* @throws BadHeaderException If the payload's header is not recognized.
* @throws MissingSchemaException If the payload's schema cannot be found.
* @throws IOException
*/
D decode(ByteBuffer encoded, D reuse) throws IOException;
/**
* Deserialize a single datum from a byte array.
*
* @param encoded a byte array containing an encoded datum
* @return a datum read from the stream
* @throws BadHeaderException If the payload's header is not recognized.
* @throws MissingSchemaException If the payload's schema cannot be found.
* @throws IOException
*/
D decode(byte[] encoded) throws IOException;
/**
* Deserialize a single datum from a byte array.
*
* @param encoded a byte array containing an encoded datum
* @param reuse a datum instance to reuse, avoiding instantiation if possible
* @return a datum read from the stream
* @throws BadHeaderException If the payload's header is not recognized.
* @throws MissingSchemaException If the payload's schema cannot be found.
* @throws IOException
*/
D decode(byte[] encoded, D reuse) throws IOException;
/**
* Base class for {@link MessageEncoder} implementations that provides default
* implementations for most of the {@code DatumEncoder} API.
*
* Implementations provided by this base class are thread-safe.
*
* @param a datum class
*/
abstract class BaseDecoder implements MessageDecoder {
private static final ThreadLocal BYTE_ARRAY_IN = ThreadLocal
.withInitial(ReusableByteArrayInputStream::new);
private static final ThreadLocal BYTE_BUFFER_IN = ThreadLocal
.withInitial(ReusableByteBufferInputStream::new);
@Override
public D decode(InputStream stream) throws IOException {
return decode(stream, null);
}
@Override
public D decode(ByteBuffer encoded) throws IOException {
return decode(encoded, null);
}
@Override
public D decode(byte[] encoded) throws IOException {
return decode(encoded, null);
}
@Override
public D decode(ByteBuffer encoded, D reuse) throws IOException {
ReusableByteBufferInputStream in = BYTE_BUFFER_IN.get();
in.setByteBuffer(encoded);
return decode(in, reuse);
}
@Override
public D decode(byte[] encoded, D reuse) throws IOException {
ReusableByteArrayInputStream in = BYTE_ARRAY_IN.get();
in.setByteArray(encoded, 0, encoded.length);
return decode(in, reuse);
}
}
}