| /* |
| * 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.nemo.compiler.frontend.beam.coder; |
| |
| import org.apache.beam.sdk.coders.Coder; |
| import org.apache.beam.sdk.coders.CoderException; |
| import org.apache.beam.sdk.coders.VoidCoder; |
| import org.apache.nemo.common.coder.DecoderFactory; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import java.io.IOException; |
| import java.io.InputStream; |
| |
| /** |
| * {@link DecoderFactory} from {@link org.apache.beam.sdk.coders.Coder}. |
| * |
| * @param <T> the type of element to decode. |
| */ |
| public final class BeamDecoderFactory<T> implements DecoderFactory<T> { |
| private static final Logger LOG = LoggerFactory.getLogger(BeamDecoderFactory.class); |
| |
| private final Coder<T> beamCoder; |
| |
| /** |
| * Constructor of BeamDecoderFactory. |
| * |
| * @param beamCoder actual Beam coder to use. |
| */ |
| public BeamDecoderFactory(final Coder<T> beamCoder) { |
| this.beamCoder = beamCoder; |
| } |
| |
| @Override |
| public Decoder<T> create(final InputStream inputStream) { |
| if (beamCoder instanceof VoidCoder) { |
| return new BeamVoidDecoder<>(inputStream, beamCoder); |
| } else { |
| return new BeamDecoder<>(inputStream, beamCoder); |
| } |
| } |
| |
| @Override |
| public String toString() { |
| return beamCoder.getClass().getName(); |
| } |
| |
| /** |
| * Abstract class for Beam Decoder. |
| * |
| * @param <T2> the type of element to decode. |
| */ |
| private abstract class BeamAbstractDecoder<T2> implements Decoder<T2> { |
| |
| private final Coder<T2> beamCoder; |
| private final transient InputStream inputStream; |
| |
| /** |
| * Constructor. |
| * |
| * @param inputStream the input stream to decode. |
| * @param beamCoder the actual beam coder to use. |
| */ |
| protected BeamAbstractDecoder(final InputStream inputStream, |
| final Coder<T2> beamCoder) { |
| this.inputStream = inputStream; |
| this.beamCoder = beamCoder; |
| } |
| |
| /** |
| * Decode the actual data internally. |
| * |
| * @return the decoded data. |
| * @throws IOException if fail to decode. |
| */ |
| protected T2 decodeInternal() throws IOException { |
| try { |
| return beamCoder.decode(inputStream); |
| } catch (final CoderException e) { |
| throw new IOException(e); |
| } |
| } |
| |
| /** |
| * @return the input stream. |
| */ |
| protected InputStream getInputStream() { |
| return inputStream; |
| } |
| } |
| |
| /** |
| * Beam Decoder for non void objects. |
| * |
| * @param <T2> the type of element to decode. |
| */ |
| private final class BeamDecoder<T2> extends BeamAbstractDecoder<T2> { |
| |
| /** |
| * Constructor. |
| * |
| * @param inputStream the input stream to decode. |
| * @param beamCoder the actual beam coder to use. |
| */ |
| private BeamDecoder(final InputStream inputStream, |
| final Coder<T2> beamCoder) { |
| super(inputStream, beamCoder); |
| } |
| |
| @Override |
| public T2 decode() throws IOException { |
| return decodeInternal(); |
| } |
| |
| @Override |
| public String toString() { |
| return "BeamDecoder: {" + beamCoder.toString() + "}"; |
| } |
| } |
| |
| /** |
| * Beam Decoder for {@link VoidCoder}. |
| * |
| * @param <T2> the type of element to decode. |
| */ |
| private final class BeamVoidDecoder<T2> extends BeamAbstractDecoder<T2> { |
| |
| /** |
| * Constructor. |
| * |
| * @param inputStream the input stream to decode. |
| * @param beamCoder the actual beam coder to use. |
| */ |
| private BeamVoidDecoder(final InputStream inputStream, |
| final Coder<T2> beamCoder) { |
| super(inputStream, beamCoder); |
| } |
| |
| @Override |
| public T2 decode() throws IOException { |
| if (getInputStream().read() == -1) { |
| throw new IOException("End of stream reached"); |
| } |
| return decodeInternal(); |
| } |
| } |
| } |