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.runners.flink.translation.wrappers.streaming;
  
  import static org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.base.Preconditions.checkNotNull;
  import static org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.base.Preconditions.checkState;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.nio.ByteBuffer;
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.List;
  import java.util.Locale;
  import org.apache.beam.sdk.coders.ByteArrayCoder;
  import org.apache.beam.sdk.coders.Coder;
  import org.apache.beam.sdk.coders.StructuredCoder;
  import org.apache.beam.sdk.util.CoderUtils;
  import org.apache.beam.vendor.grpc.v1p69p0.com.google.protobuf.ByteString;
  
  /**
   * Utility functions for dealing with key encoding. Beam requires keys to be compared in binary
   * format. The helpers here ensure that a consistent encoding is used.
   */
  public class FlinkKeyUtils {
  
    /** Encodes a key to a byte array wrapped inside a ByteBuffer. */
    public static <K> ByteBuffer encodeKey(K key, Coder<K> keyCoder) {
      checkNotNull(keyCoder, "Provided coder must not be null");
      final byte[] keyBytes;
      try {
        keyBytes = CoderUtils.encodeToByteArray(keyCoder, key, Coder.Context.NESTED);
      } catch (Exception e) {
        throw new RuntimeException(String.format(Locale.ENGLISH, "Failed to encode key: %s", key), e);
      }
      return ByteBuffer.wrap(keyBytes);
    }
  
    /** Decodes a key from a ByteBuffer containing a byte array. */
    public static <K> K decodeKey(ByteBuffer byteBuffer, Coder<K> keyCoder) {
      checkNotNull(byteBuffer, "Provided ByteBuffer must not be null");
      checkNotNull(keyCoder, "Provided coder must not be null");
      checkState(byteBuffer.hasArray(), "ByteBuffer key must contain an array.");
      @SuppressWarnings("ByteBufferBackingArray")
      final byte[] keyBytes = byteBuffer.array();
      try {
        return CoderUtils.decodeFromByteArray(keyCoder, keyBytes, Coder.Context.NESTED);
      } catch (Exception e) {
        throw new RuntimeException(
            String.format(
                Locale.ENGLISH, "Failed to decode encoded key: %s", Arrays.toString(keyBytes)),
            e);
      }
    }
  
    static ByteBuffer fromEncodedKey(ByteString encodedKey) {
      return ByteBuffer.wrap(encodedKey.toByteArray());
    }
  
    /** The Coder for the Runner's encoded representation of a key. */
    static class ByteBufferCoder extends StructuredCoder<ByteBuffer> {
  
      public static ByteBufferCoder of() {
        return INSTANCE;
      }
  
      private static final ByteBufferCoder INSTANCE = new ByteBufferCoder();
  
      private ByteBufferCoder() {}
  
      @Override
      public void encode(ByteBuffer value, OutputStream outStream) throws IOException {
        @SuppressWarnings("ByteBufferBackingArray")
        byte[] array = value.array();
        ByteArrayCoder.of().encode(array, outStream);
      }
  
      @Override
      public ByteBuffer decode(InputStream inStream) throws IOException {
        byte[] decode = ByteArrayCoder.of().decode(inStream);
        return ByteBuffer.wrap(decode);
      }
  
      @Override
      public List<? extends Coder<?>> getCoderArguments() {
        return Collections.emptyList();
      }
  
      @Override
      public void verifyDeterministic() {}
    }
  }
  