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 java.util.Collections;
  import java.util.List;
  import org.apache.beam.sdk.util.VarInt;
  import org.apache.beam.sdk.values.TypeDescriptor;
  
  /**
   * A {@link Coder} that encodes {@link Long Longs} using between 1 and 10 bytes. Negative numbers
   * always take 10 bytes, so {@link BigEndianLongCoder} may be preferable for longs that are known to
   * often be large or negative.
   */
  public class VarLongCoder extends StructuredCoder<Long> {
    public static VarLongCoder of() {
      return INSTANCE;
    }
  
    /////////////////////////////////////////////////////////////////////////////
  
    private static final VarLongCoder INSTANCE = new VarLongCoder();
    private static final TypeDescriptor<Long> TYPE_DESCRIPTOR = new TypeDescriptor<Long>() {};
  
    private VarLongCoder() {}
  
    @Override
    public void encode(Long value, OutputStream outStream) throws IOException, CoderException {
      if (value == null) {
        throw new CoderException("cannot encode a null Long");
      }
      VarInt.encode(value, outStream);
    }
  
    @Override
    public Long decode(InputStream inStream) throws IOException, CoderException {
      try {
        return VarInt.decodeLong(inStream);
      } catch (EOFException | UTFDataFormatException exn) {
        // These exceptions correspond to decoding problems, so change
        // what kind of exception they're branded as.
        throw new CoderException(exn);
      }
    }
  
    @Override
    public List<? extends Coder<?>> getCoderArguments() {
      return Collections.emptyList();
    }
  
    @Override
    public void verifyDeterministic() {}
  
    /**
     * {@inheritDoc}
     *
     * @return {@code true}. {@link VarLongCoder} is injective.
     */
    @Override
    public boolean consistentWithEquals() {
      return true;
    }
  
    /**
     * {@inheritDoc}
     *
     * @return {@code true}. {@link #getEncodedElementByteSize} is cheap.
     */
    @Override
    public boolean isRegisterByteSizeObserverCheap(Long value) {
      return true;
    }
  
    @Override
    public TypeDescriptor<Long> getEncodedTypeDescriptor() {
      return TYPE_DESCRIPTOR;
    }
  
    @Override
    protected long getEncodedElementByteSize(Long value) throws Exception {
      if (value == null) {
        throw new CoderException("cannot encode a null Long");
      }
      return VarInt.getLength(value);
    }
  }
  