1 /* 2 * Copyright (C) 2013 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.inputmethod.latin.utils; 18 19 import java.util.concurrent.CountDownLatch; 20 import java.util.concurrent.TimeUnit; 21 22 /** 23 * This class is a holder of a result of asynchronous computation. 24 * 25 * @param <E> the type of the result. 26 */ 27 public class AsyncResultHolder<E> { 28 29 private final Object mLock = new Object(); 30 31 private E mResult; 32 private final CountDownLatch mLatch; 33 AsyncResultHolder()34 public AsyncResultHolder() { 35 mLatch = new CountDownLatch(1); 36 } 37 38 /** 39 * Sets the result value to this holder. 40 * 41 * @param result the value which is set. 42 */ set(final E result)43 public void set(final E result) { 44 synchronized(mLock) { 45 if (mLatch.getCount() > 0) { 46 mResult = result; 47 mLatch.countDown(); 48 } 49 } 50 } 51 52 /** 53 * Gets the result value held in this holder. 54 * Causes the current thread to wait unless the value is set or the specified time is elapsed. 55 * 56 * @param defaultValue the default value. 57 * @param timeOut the time to wait. 58 * @return if the result is set until the time limit then the result, otherwise defaultValue. 59 */ get(final E defaultValue, final long timeOut)60 public E get(final E defaultValue, final long timeOut) { 61 try { 62 if(mLatch.await(timeOut, TimeUnit.MILLISECONDS)) { 63 return mResult; 64 } else { 65 return defaultValue; 66 } 67 } catch (InterruptedException e) { 68 return defaultValue; 69 } 70 } 71 } 72