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.core;
  
  import org.apache.beam.sdk.util.common.ElementByteSizeObserver;
  
  /**
   * An interface for things that allow observing the size in bytes of encoded values of type {@code
   * T}.
   *
   * @param <T> the type of the values being observed
   */
  public interface ElementByteSizeObservable<T> {
    /**
     * Returns whether {@link #registerByteSizeObserver} is cheap enough to call for every element,
     * that is, if this {@code ElementByteSizeObservable} can calculate the byte size of the element
     * to be coded in roughly constant time (or lazily).
     */
    boolean isRegisterByteSizeObserverCheap(T value);
  
    /**
     * Notifies the {@code ElementByteSizeObserver} about the byte size of the encoded value using
     * this {@code ElementByteSizeObservable}.
     */
    void registerByteSizeObserver(T value, ElementByteSizeObserver observer) throws Exception;
  }
  