01: /*
02: * Copyright 2007 Tim Peierls
03: *
04: * Licensed under the Apache License, Version 2.0 (the "License");
05: * you may not use this file except in compliance with the License.
06: * You may obtain a copy of the License at
07: *
08: * http://www.apache.org/licenses/LICENSE-2.0
09: *
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 org.directwebremoting.guice;
17:
18: import com.google.inject.Provider;
19:
20: import java.util.concurrent.Callable;
21: import java.util.concurrent.ExecutionException;
22: import java.util.concurrent.FutureTask;
23:
24: /**
25: * A provider implementation that uses the FutureTask machinery.
26: * @author Tim Peierls [tim at peierls dot net]
27: */
28: class FutureTaskProvider<T> extends FutureTask<T> implements
29: InstanceProvider<T> {
30: FutureTaskProvider(final Provider<T> creator) {
31: super (new Callable<T>() {
32: public T call() {
33: return creator.get();
34: }
35: });
36: }
37:
38: @Override
39: public T get() {
40: try {
41: return super .get();
42: } catch (InterruptedException e) {
43: Thread.currentThread().interrupt();
44: return null;
45: } catch (ExecutionException e) {
46: Throwable t = e.getCause();
47: if (t instanceof RuntimeException) {
48: throw (RuntimeException) t;
49: } else if (t instanceof Error) {
50: throw (Error) t;
51: } else {
52: throw new IllegalStateException(
53: "unexpected Exception: " + t, t);
54: }
55: }
56: }
57: }
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