content: /*
   * 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);
    }
  
    @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}
     *
     * <p>{@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;
    }
  }
  