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.euphoria.core.translate.collector;
  
  import static java.util.Objects.requireNonNull;
  
  import java.io.Serializable;
  import org.apache.beam.sdk.extensions.euphoria.core.client.accumulators.AccumulatorProvider;
  import org.apache.beam.sdk.extensions.euphoria.core.client.accumulators.Counter;
  import org.apache.beam.sdk.extensions.euphoria.core.client.accumulators.Histogram;
  import org.apache.beam.sdk.extensions.euphoria.core.client.accumulators.Timer;
  import org.apache.beam.sdk.extensions.euphoria.core.client.io.Collector;
  import org.apache.beam.sdk.extensions.euphoria.core.client.io.Context;
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  /**
   * {@code Collector} for combinable functors.
   *
   * @deprecated Use Java SDK directly, Euphoria is scheduled for removal in a future release.
   */
  @SuppressWarnings({
    "nullness" // TODO(https://github.com/apache/beam/issues/20497)
  })
  @Deprecated
  public class SingleValueCollector<T> implements Collector<T>, Serializable {
  
    private static final String UNSUPPORTED = "Accumulators are supported for named operators only.";
  
    private final AccumulatorProvider accumulators;
    private final @Nullable String operatorName;
    private T elem;
  
    public SingleValueCollector(AccumulatorProvider accumulators, @Nullable String operatorName) {
      this.accumulators = accumulators;
      this.operatorName = operatorName;
    }
  
    public T get() {
      return elem;
    }
  
    @Override
    public void collect(T elem) {
      this.elem = elem;
    }
  
    @Override
    public Context asContext() {
      // this is not needed, the underlying functor does not have access to this
      throw new UnsupportedOperationException("Not supported.");
    }
  
    @Override
    public Counter getCounter(String name) {
      return accumulators.getCounter(requireNonNull(operatorName, UNSUPPORTED), name);
    }
  
    @Override
    public Histogram getHistogram(String name) {
      return accumulators.getHistogram(requireNonNull(operatorName, UNSUPPORTED), name);
    }
  
    @Override
    public Timer getTimer(String name) {
      return accumulators.getTimer(name);
    }
  }
  