| /* |
| * 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.extensions.protobuf; |
| |
| import com.google.protobuf.ByteString; |
| import java.io.IOException; |
| import java.io.InputStream; |
| import java.io.OutputStream; |
| import org.apache.beam.sdk.coders.AtomicCoder; |
| import org.apache.beam.sdk.coders.Coder; |
| import org.apache.beam.sdk.coders.CoderException; |
| import org.apache.beam.sdk.util.VarInt; |
| import org.apache.beam.sdk.values.TypeDescriptor; |
| import org.apache.beam.vendor.guava.v20_0.com.google.common.io.ByteStreams; |
| |
| /** |
| * A {@link Coder} for {@link ByteString} objects based on their encoded Protocol Buffer form. |
| * |
| * <p>When this code is used in a nested {@link Coder.Context}, the serialized {@link ByteString} |
| * objects are first delimited by their size. |
| */ |
| public class ByteStringCoder extends AtomicCoder<ByteString> { |
| |
| public static ByteStringCoder of() { |
| return INSTANCE; |
| } |
| |
| /** ************************ */ |
| private static final ByteStringCoder INSTANCE = new ByteStringCoder(); |
| |
| private static final TypeDescriptor<ByteString> TYPE_DESCRIPTOR = |
| new TypeDescriptor<ByteString>() {}; |
| |
| private ByteStringCoder() {} |
| |
| @Override |
| public void encode(ByteString value, OutputStream outStream) throws IOException, CoderException { |
| encode(value, outStream, Context.NESTED); |
| } |
| |
| @Override |
| public void encode(ByteString value, OutputStream outStream, Context context) |
| throws IOException, CoderException { |
| if (value == null) { |
| throw new CoderException("cannot encode a null ByteString"); |
| } |
| |
| if (!context.isWholeStream) { |
| // ByteString is not delimited, so write its size before its contents. |
| VarInt.encode(value.size(), outStream); |
| } |
| value.writeTo(outStream); |
| } |
| |
| @Override |
| public ByteString decode(InputStream inStream) throws IOException { |
| return decode(inStream, Context.NESTED); |
| } |
| |
| @Override |
| public ByteString decode(InputStream inStream, Context context) throws IOException { |
| if (context.isWholeStream) { |
| return ByteString.readFrom(inStream); |
| } |
| |
| int size = VarInt.decodeInt(inStream); |
| // ByteString reads to the end of the input stream, so give it a limited stream of exactly |
| // the right length. Also set its chunk size so that the ByteString will contain exactly |
| // one chunk. |
| return ByteString.readFrom(ByteStreams.limit(inStream, size), size); |
| } |
| |
| @Override |
| protected long getEncodedElementByteSize(ByteString value) throws Exception { |
| int size = value.size(); |
| return (long) VarInt.getLength(size) + size; |
| } |
| |
| @Override |
| public void verifyDeterministic() {} |
| |
| /** |
| * {@inheritDoc} |
| * |
| * <p>Returns true; the encoded output of two invocations of {@link ByteStringCoder} in the same |
| * {@link Coder.Context} will be identical if and only if the original {@link ByteString} objects |
| * are equal according to {@link Object#equals}. |
| */ |
| @Override |
| public boolean consistentWithEquals() { |
| return true; |
| } |
| |
| /** |
| * {@inheritDoc} |
| * |
| * <p>Returns true. {@link ByteString#size} returns the size of an array and a {@link VarInt}. |
| */ |
| @Override |
| public boolean isRegisterByteSizeObserverCheap(ByteString value) { |
| return true; |
| } |
| |
| @Override |
| public TypeDescriptor<ByteString> getEncodedTypeDescriptor() { |
| return TYPE_DESCRIPTOR; |
| } |
| } |