1 /* 2 * Copyright (C) 2014 The Android Open Source Project 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 17 package com.android.camera.async; 18 19 import java.util.concurrent.TimeUnit; 20 import java.util.concurrent.TimeoutException; 21 22 /** 23 * An input stream of objects which can be closed from either the producer or 24 * the consumer. 25 */ 26 public interface BufferQueue<T> extends SafeCloseable { 27 @Override close()28 public void close(); 29 30 /** 31 * Blocks, returning the next available value. 32 * 33 * @return The next available value. 34 * @throws InterruptedException If interrupted while waiting for the next 35 * value. 36 * @throws com.android.camera.async.BufferQueue.BufferQueueClosedException If the stream is closed and no more values 37 * will be available. 38 */ getNext()39 public T getNext() throws InterruptedException, BufferQueueClosedException; 40 41 /** 42 * Blocks, returning the next available value. 43 * 44 * @param timeout The maximum amount of time to wait. 45 * @param unit The unit associated with the timeout. 46 * @return The next available value. 47 * @throws InterruptedException If interrupted while waiting for the next 48 * value. 49 * @throws com.android.camera.async.BufferQueue.BufferQueueClosedException If the stream is closed and no more values 50 * will be available. 51 * @throws TimeoutException If no new value is made available within the 52 * specified time limit. 53 */ getNext(long timeout, TimeUnit unit)54 public T getNext(long timeout, TimeUnit unit) throws InterruptedException, TimeoutException, 55 BufferQueueClosedException; 56 57 /** 58 * Immediately returns the next available value without removing it from the 59 * stream. 60 * 61 * @return The next available value if one exists, or null if no value 62 * exists yet or the stream is closed. 63 */ peekNext()64 public T peekNext(); 65 66 /** 67 * Immediately discards the next available value, if one exists. 68 */ discardNext()69 public void discardNext(); 70 71 /** 72 * @return True if the stream has been closed by either the producer or the 73 * consumer. 74 */ isClosed()75 public boolean isClosed(); 76 77 /** 78 * Indicates that the stream is closed and no more results are available. 79 */ 80 public static class BufferQueueClosedException extends Exception { 81 } 82 } 83