/**
* Copyright (c) 2014-present, Facebook, Inc. All rights reserved.
*
* You are hereby granted a non-exclusive, worldwide, royalty-free license to use,
* copy, modify, and distribute this software in source code or binary form for use
* in connection with the web services and APIs provided by Facebook.
*
* As with any software that integrates with the Facebook platform, your use of
* this software is subject to the Facebook Developer Principles and Policies
* [http://developers.facebook.com/policy/]. This copyright notice shall be
* included in all copies or substantial portions of the software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
package com.facebook.internal;
import com.facebook.FacebookSdk;
import java.util.concurrent.Callable;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.FutureTask;
public class LockOnGetVariable<T> {
private T value;
private CountDownLatch initLatch;
public LockOnGetVariable(T value) {
this.value = value;
}
public LockOnGetVariable(final Callable<T> callable) {
initLatch = new CountDownLatch(1);
FacebookSdk.getExecutor().execute(
new FutureTask<>(new Callable<Void>() {
@Override
public Void call() throws Exception {
try {
LockOnGetVariable.this.value = callable.call();
} finally {
initLatch.countDown();
}
return null;
}
}));
}
public T getValue() {
this.waitOnInit();
return this.value;
}
private void waitOnInit() {
if (initLatch == null) {
return;
}
try {
initLatch.await();
} catch (InterruptedException ex) {
// ignore
}
}
}