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.extensions.zetasketch;
  
  import static org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.base.Preconditions.checkNotNull;
  
  import com.google.zetasketch.HyperLogLogPlusPlus;
  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.ByteArrayCoder;
  import org.apache.beam.sdk.coders.Coder;
  import org.apache.beam.sdk.coders.CoderException;
  
  /** Coder for the {@link HyperLogLogPlusPlus} class with generic type parameter {@code T}. */
  class HyperLogLogPlusPlusCoder<T> extends AtomicCoder<HyperLogLogPlusPlus<T>> {
  
    private static final HyperLogLogPlusPlusCoder<?> INSTANCE = new HyperLogLogPlusPlusCoder<>();
  
    private static final Coder<byte[]> BYTE_ARRAY_CODER = ByteArrayCoder.of();
  
    // Generic singleton factory pattern; the coder works for all HyperLogLogPlusPlus objects at
    // runtime regardless of type T
    @SuppressWarnings("unchecked")
    static <T> HyperLogLogPlusPlusCoder<T> of() {
      return (HyperLogLogPlusPlusCoder<T>) INSTANCE;
    }
  
    @Override
    public void encode(HyperLogLogPlusPlus<T> value, OutputStream outStream) throws IOException {
      checkNotNull(value, new CoderException("Cannot encode a null HyperLogLogPlusPlus value."));
      BYTE_ARRAY_CODER.encode(value.serializeToByteArray(), outStream);
    }
  
    @Override
    @SuppressWarnings("unchecked")
    public HyperLogLogPlusPlus<T> decode(InputStream inStream) throws IOException {
      return (HyperLogLogPlusPlus<T>) HyperLogLogPlusPlus.forProto(BYTE_ARRAY_CODER.decode(inStream));
    }
  
    @Override
    public void verifyDeterministic() throws NonDeterministicException {
      BYTE_ARRAY_CODER.verifyDeterministic();
    }
  
    // TODO: check if we can know the sketch size without serializing it
    // If so, isRegisterByteSizeObserverCheap() and registerByteSizeObserver() can be overridden
  }
  