blob: 96fb9222c8bc944acfd7248d3377a22ad23a9eb5 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
|
/**
* Copyright (C) 2008 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.inject.internal;
import com.google.inject.internal.util.Function;
import com.google.inject.internal.util.MapMaker;
import com.google.inject.internal.util.Nullable;
import java.util.Map;
/**
* Lazily creates (and caches) values for keys. If creating the value fails (with errors), an
* exception is thrown on retrieval.
*
* @author jessewilson@google.com (Jesse Wilson)
*/
public abstract class FailableCache<K, V> {
private final Map<K, Object> delegate = new MapMaker().makeComputingMap(
new Function<K, Object>() {
public Object apply(@Nullable K key) {
Errors errors = new Errors();
V result = null;
try {
result = FailableCache.this.create(key, errors);
} catch (ErrorsException e) {
errors.merge(e.getErrors());
}
return errors.hasErrors() ? errors : result;
}
});
protected abstract V create(K key, Errors errors) throws ErrorsException;
public V get(K key, Errors errors) throws ErrorsException {
Object resultOrError = delegate.get(key);
if (resultOrError instanceof Errors) {
errors.merge((Errors) resultOrError);
throw errors.toException();
} else {
@SuppressWarnings("unchecked") // create returned a non-error result, so this is safe
V result = (V) resultOrError;
return result;
}
}
boolean remove(K key) {
return delegate.remove(key) != null;
}
}
|
