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;
  
  import org.apache.beam.sdk.extensions.euphoria.core.annotation.audience.Audience;
  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;
  
  /**
   * A {@code Context} that holds only single value. There is no window associated with the value, so
   * the {@code getWindow()} will always throw {@code UnsupportedOperationException}. This context
   * will free the value as soon as {@code getAndResetValue()} is called.
   *
   * @deprecated Use Java SDK directly, Euphoria is scheduled for removal in a future release.
   */
  @Audience(Audience.Type.EXECUTOR)
  @SuppressWarnings({
    "nullness" // TODO(https://github.com/apache/beam/issues/20497)
  })
  @Deprecated
  public class SingleValueContext<T> implements Context, Collector<T> {
  
    private final @Nullable Context wrap;
    private T value;
  
    public SingleValueContext() {
      this(null);
    }
  
    public SingleValueContext(@Nullable Context wrap) {
      this.wrap = wrap;
    }
  
    /**
     * Replace the stored value with given one.
     *
     * @param elem the element to store
     */
    @Override
    public void collect(T elem) {
      value = elem;
    }
  
    @Override
    public Context asContext() {
      return this;
    }
  
    @Override
    public Counter getCounter(String name) {
      if (wrap == null) {
        throw new UnsupportedOperationException("Accumulators not supported in this context");
      }
      return wrap.getCounter(name);
    }
  
    @Override
    public Histogram getHistogram(String name) {
      if (wrap == null) {
        throw new UnsupportedOperationException("Accumulators not supported in this context");
      }
      return wrap.getHistogram(name);
    }
  
    @Override
    public Timer getTimer(String name) {
      if (wrap == null) {
        throw new UnsupportedOperationException("Accumulators not supported in this context");
      }
      return wrap.getTimer(name);
    }
  
    /**
     * Retrieve and reset the stored value to null.
     *
     * @return the stored value
     */
    public T getAndResetValue() {
      T ret = value;
      value = null;
      return ret;
    }
  
    /**
     * Retrieve value of this context.
     *
     * @return value
     */
    public T get() {
      return value;
    }
  }
  