Add API stubs for the Java context info retrievers

[lttng-ust.git] / liblttng-ust-java-agent / java / lttng-ust-agent-common / org / lttng / ust / agent / context / ContextInfoManager.java

diff --git a/liblttng-ust-java-agent/java/lttng-ust-agent-common/org/lttng/ust/agent/context/ContextInfoManager.java b/liblttng-ust-java-agent/java/lttng-ust-agent-common/org/lttng/ust/agent/context/ContextInfoManager.java
new file mode 100644 (file)
index 0000000..90a79ac
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+++ b/liblttng-ust-java-agent/java/lttng-ust-agent-common/org/lttng/ust/agent/context/ContextInfoManager.java
@@ -0,0 +1,84 @@
+/*
+ * Copyright (C) 2015 - EfficiOS Inc., Alexandre Montplaisir <alexmonthy@efficios.com>
+ *
+ * This library is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License, version 2.1 only,
+ * as published by the Free Software Foundation.
+ *
+ * This library is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+package org.lttng.ust.agent.context;
+
+import java.util.Set;
+import java.util.concurrent.CopyOnWriteArraySet;
+
+/**
+ * The singleton manager of {@link IContextInfoRetriever} objects.
+ *
+ * @author Alexandre Montplaisir
+ */
+public final class ContextInfoManager {
+
+       private static final ContextInfoManager INSTANCE = new ContextInfoManager();
+
+       private final Set<IContextInfoRetriever> cirs = new CopyOnWriteArraySet<IContextInfoRetriever>();
+
+       /** Singleton class, constructor should not be accessed directly */
+       private ContextInfoManager() {
+       }
+
+       /**
+        * Get the singleton instance.
+        *
+        * @return The singleton instance
+        * @deprecated The context-retrieving facilities are not yet implemented.
+        */
+       @Deprecated
+       public static ContextInfoManager getInstance() {
+               return INSTANCE;
+       }
+
+       /**
+        * Register a new context info retriever.
+        *
+        * This method has no effect if the exact same retriever is already
+        * registered.
+        *
+        * @param cir
+        *            The context info retriever to register
+        */
+       public void addContextInfoRetriever(IContextInfoRetriever cir) {
+               cirs.add(cir);
+       }
+
+       /**
+        * Unregister a previously added context info retriever.
+        *
+        * This method has no effect if the retriever was not already registered.
+        *
+        * @param cir
+        *            The context info retriever to unregister
+        */
+       public void removeContextInfoRetriever(IContextInfoRetriever cir) {
+               cirs.remove(cir);
+       }
+
+       /**
+        * Return a read-only view (does not support
+        * {@link java.util.Iterator#remove}) of the currently registered context
+        * info retrievers.
+        *
+        * @return The current context info retrievers
+        */
+       public Iterable<IContextInfoRetriever> getContextInfoRetrievers() {
+               return cirs;
+       }
+}