git.lttng.org Git - lttng-ust.git/blob

   1 /*
   2  * Copyright (C) 2015 - EfficiOS Inc., Alexandre Montplaisir <alexmonthy@efficios.com>
   3  *
   4  * This library is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU Lesser General Public License, version 2.1 only,
   6  * as published by the Free Software Foundation.
   7  *
   8  * This library is distributed in the hope that it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
  11  * for more details.
  12  *
  13  * You should have received a copy of the GNU Lesser General Public License
  14  * along with this library; if not, write to the Free Software Foundation,
  15  * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  16  */
  17
  18 package org.lttng.ust.agent.context;
  19
  20 import java.util.Set;
  21 import java.util.concurrent.CopyOnWriteArraySet;
  22
  23 /**
  24  * The singleton manager of {@link IContextInfoRetriever} objects.
  25  *
  26  * @author Alexandre Montplaisir
  27  */
  28 public final class ContextInfoManager {
  29
  30         private static final ContextInfoManager INSTANCE = new ContextInfoManager();
  31
  32         private final Set<IContextInfoRetriever> cirs = new CopyOnWriteArraySet<IContextInfoRetriever>();
  33
  34         /** Singleton class, constructor should not be accessed directly */
  35         private ContextInfoManager() {
  36         }
  37
  38         /**
  39          * Get the singleton instance.
  40          *
  41          * @return The singleton instance
  42          * @deprecated The context-retrieving facilities are not yet implemented.
  43          */
  44         @Deprecated
  45         public static ContextInfoManager getInstance() {
  46                 return INSTANCE;
  47         }
  48
  49         /**
  50          * Register a new context info retriever.
  51          *
  52          * This method has no effect if the exact same retriever is already
  53          * registered.
  54          *
  55          * @param cir
  56          *            The context info retriever to register
  57          */
  58         public void addContextInfoRetriever(IContextInfoRetriever cir) {
  59                 cirs.add(cir);
  60         }
  61
  62         /**
  63          * Unregister a previously added context info retriever.
  64          *
  65          * This method has no effect if the retriever was not already registered.
  66          *
  67          * @param cir
  68          *            The context info retriever to unregister
  69          */
  70         public void removeContextInfoRetriever(IContextInfoRetriever cir) {
  71                 cirs.remove(cir);
  72         }
  73
  74         /**
  75          * Return a read-only view (does not support
  76          * {@link java.util.Iterator#remove}) of the currently registered context
  77          * info retrievers.
  78          *
  79          * @return The current context info retrievers
  80          */
  81         public Iterable<IContextInfoRetriever> getContextInfoRetrievers() {
  82                 return cirs;
  83         }
  84 }