Method: static {...}

1: /*
2: * *************************************************************************************************************************************************************
3: *
4: * TheseFoolishThings: Miscellaneous utilities
5: * http://tidalwave.it/projects/thesefoolishthings
6: *
7: * Copyright (C) 2009 - 2025 by Tidalwave s.a.s. (http://tidalwave.it)
8: *
9: * *************************************************************************************************************************************************************
10: *
11: * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License.
12: * You may obtain a copy of the License at
13: *
14: * http://www.apache.org/licenses/LICENSE-2.0
15: *
16: * 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
17: * CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
18: *
19: * *************************************************************************************************************************************************************
20: *
21: * git clone https://bitbucket.org/tidalwave/thesefoolishthings-src
22: * git clone https://github.com/tidalwave-it/thesefoolishthings-src
23: *
24: * *************************************************************************************************************************************************************
25: */
26: package it.tidalwave.role.impl;
27:
28: import javax.annotation.Nonnull;
29: import java.util.Collections;
30: import java.util.List;
31: import java.util.concurrent.CopyOnWriteArrayList;
32: import it.tidalwave.util.ContextManager;
33: import it.tidalwave.util.Task;
34: import lombok.extern.slf4j.Slf4j;
35: import static it.tidalwave.util.ShortNames.*;
36:
37: /***************************************************************************************************************************************************************
38: *
39: * A facility that takes a snapshot of the contexts that are current at creation time and make them available later.
40: *
41: * @author Fabrizio Giudici
42: *
43: **************************************************************************************************************************************************************/
44: @Slf4j
45: public class ContextSnapshot
46: {
47: private final ContextManager contextManager = ContextManager.getInstance();
48:
49: // TODO: should be weak references? Should a context be alive as soon as all the objects created with it are
50: // alive?
51: private final List<Object> contexts = Collections.unmodifiableList(contextManager.getContexts());
52:
53: /***********************************************************************************************************************************************************
54: * Creates a new instance and samples the currently available contexts.
55: *
56: * @param owner the owner
57: **********************************************************************************************************************************************************/
58: public ContextSnapshot (@Nonnull final Object owner)
59: {
60: if (log.isTraceEnabled())
61: {
62: log.trace(">>>> contexts for {} at construction time: {}", shortId(owner), shortIds(contexts));
63: }
64: }
65:
66: /***********************************************************************************************************************************************************
67: * Returns the previously sampled contexts.
68: *
69: * @return the contexts
70: **********************************************************************************************************************************************************/
71: @Nonnull
72: public List<Object> getContexts()
73: {
74: return new CopyOnWriteArrayList<>(contexts);
75: }
76:
77: /***********************************************************************************************************************************************************
78: * Runs a {@link Task} associated with the sampled contexts.
79: *
80: * @param <V> the type of the result value
81: * @param <T> the type of the exception
82: * @param task the task
83: * @return the value produced by the task
84: * @throws T the exception(s) thrown by the task
85: **********************************************************************************************************************************************************/
86: public <V, T extends Throwable> V runWithContexts (@Nonnull final Task<V, T> task)
87: throws T
88: {
89: return contextManager.runWithContexts(contexts, task);
90: }
91:
92: /***********************************************************************************************************************************************************
93: * {@inheritDoc}
94: **********************************************************************************************************************************************************/
95: @Override @Nonnull
96: public String toString()
97: {
98: return String.format("ContextSnapshot%s", shortIds(contexts));
99: }
100: }