content: /*
   * Copyright (C) 2020 ActiveJ LLC.
   *
   * Licensed 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 io.activej.datastream.stats;
  
  import io.activej.bytebuf.ByteBuf;
  
  import java.util.Collection;
  
  @FunctionalInterface
  public interface StreamStatsSizeCounter<T> {
  	int size(T item);
  
  	static StreamStatsSizeCounter<ByteBuf> forByteBufs() {
  		return ByteBuf::readRemaining;
  	}
  
  	static <T extends Collection<?>> StreamStatsSizeCounter<T> forCollections() {
  		return Collection::size;
  	}
  
  	static <T> StreamStatsSizeCounter<T[]> forArrays() {
  		return item -> item.length;
  	}
  
  	static StreamStatsSizeCounter<String> forStrings() {
  		return String::length;
  	}
  }
  