1 /* 2 * Copyright 2022 Google LLC 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 package com.google.android.libraries.mobiledatadownload.file.common; 17 18 import java.io.IOException; 19 import javax.annotation.Nullable; 20 21 /** Interface for accessing the size of a data behind a stream. */ 22 public interface Sizable { 23 24 /** 25 * Return the logical size of the stream or null if it is unknown. The logical size is defined as 26 * the total number of bytes required to store all of the data in the stream after applying the 27 * transform. This is expected to be an efficient operation. In particular, if it is O(filesize) 28 * to compute the logical size, implementor should return null rather than perform that 29 * calculation. 30 */ 31 @Nullable size()32 Long size() throws IOException; 33 } 34