/*
* 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.beam.sdk.coders;
import java.io.EOFException;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.UTFDataFormatException;
import org.apache.beam.sdk.values.TypeDescriptor;
/**
* A {@link ByteCoder} encodes {@link Byte} values in 1 byte using Java serialization.
*/
public class ByteCoder extends AtomicCoder<Byte> {
public static ByteCoder of() {
return INSTANCE;
}
/////////////////////////////////////////////////////////////////////////////
private static final ByteCoder INSTANCE = new ByteCoder();
private static final TypeDescriptor<Byte> TYPE_DESCRIPTOR = new TypeDescriptor<Byte>() {};
private ByteCoder() {}
@Override
public void encode(Byte value, OutputStream outStream)
throws IOException, CoderException {
if (value == null) {
throw new CoderException("cannot encode a null Byte");
}
outStream.write(value.byteValue());
}
@Override
public Byte decode(InputStream inStream)
throws IOException, CoderException {
try {
// value will be between 0-255, -1 for EOF
int value = inStream.read();
if (value == -1) {
throw new EOFException("EOF encountered decoding 1 byte from input stream");
}
return (byte) value;
} catch (EOFException | UTFDataFormatException exn) {
// These exceptions correspond to decoding problems, so change
// what kind of exception they're branded as.
throw new CoderException(exn);
}
}
/**
* {@inheritDoc}
*
* {@link ByteCoder} will never throw a {@link Coder.NonDeterministicException}; bytes can always
* be encoded deterministically.
*/
@Override
public void verifyDeterministic() {}
/**
* {@inheritDoc}
*
* @return {@code true}. This coder is injective.
*/
@Override
public boolean consistentWithEquals() {
return true;
}
/**
* {@inheritDoc}
*
* @return {@code true}. {@link ByteCoder#getEncodedElementByteSize} returns a constant.
*/
@Override
public boolean isRegisterByteSizeObserverCheap(Byte value) {
return true;
}
@Override
public TypeDescriptor<Byte> getEncodedTypeDescriptor() {
return TYPE_DESCRIPTOR;
}
/**
* {@inheritDoc}
*
* @return {@code 1}, the byte size of a {@link Byte} encoded using Java serialization.
*/
@Override
protected long getEncodedElementByteSize(Byte value)
throws Exception {
if (value == null) {
throw new CoderException("cannot estimate size for unsupported null value");
}
return 1;
}
}