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.Closeable; 19 import java.io.IOException; 20 21 /** Ensures mutual exclusive access to a resource. */ 22 public interface Lock extends Closeable { 23 24 /** Releases the lock that is held. */ release()25 void release() throws IOException; 26 27 /** Returns true if lock is still held. */ isValid()28 boolean isValid(); 29 30 /** Returns true if lock is shared and false if it is exclusive. */ isShared()31 boolean isShared(); 32 } 33