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 android.util.Log; 20 21 import java.util.concurrent.CountDownLatch; 22 import java.util.concurrent.TimeUnit; 23 24 /** 25 * This class is a holder of the result of an asynchronous computation. 26 * 27 * @param <E> the type of the result. 28 */ 29 public class AsyncResultHolder<E> { 30 31 private final Object mLock = new Object(); 32 33 private E mResult; 34 private final String mTag; 35 private final CountDownLatch mLatch; 36 37 public AsyncResultHolder(final String tag) { 38 mTag = tag; 39 mLatch = new CountDownLatch(1); 40 } 41 42 /** 43 * Sets the result value of this holder. 44 * 45 * @param result the value to set. 46 */ 47 public void set(final E result) { 48 synchronized(mLock) { 49 if (mLatch.getCount() > 0) { 50 mResult = result; 51 mLatch.countDown(); 52 } 53 } 54 } 55 56 /** 57 * Gets the result value held in this holder. 58 * Causes the current thread to wait unless the value is set or the specified time is elapsed. 59 * 60 * @param defaultValue the default value. 61 * @param timeOut the maximum time to wait. 62 * @return if the result is set before the time limit then the result, otherwise defaultValue. 63 */ 64 public E get(final E defaultValue, final long timeOut) { 65 try { 66 return mLatch.await(timeOut, TimeUnit.MILLISECONDS) ? mResult : defaultValue; 67 } catch (InterruptedException e) { 68 Log.w(mTag, "get() : Interrupted after " + timeOut + " ms"); 69 return defaultValue; 70 } 71 } 72 } 73
