Adding ability to easily create name thread factories with threads belonging to hierarchical thread groups.
Change-Id: Iaab3251c13e14b73c54a8edc945f5aa476a7ca54
diff --git a/utils/misc/src/main/java/org/onlab/util/GroupedThreadFactory.java b/utils/misc/src/main/java/org/onlab/util/GroupedThreadFactory.java
new file mode 100644
index 0000000..9001cf5
--- /dev/null
+++ b/utils/misc/src/main/java/org/onlab/util/GroupedThreadFactory.java
@@ -0,0 +1,88 @@
+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * 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 org.onlab.util;
+
+import org.apache.commons.lang3.concurrent.ConcurrentUtils;
+
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ThreadFactory;
+
+import static com.google.common.base.MoreObjects.toStringHelper;
+
+/**
+ * Thread factory for creating threads that belong to the specified thread group.
+ */
+public final class GroupedThreadFactory implements ThreadFactory {
+
+ public static final String DELIMITER = "/";
+
+ private final ThreadGroup group;
+
+ // Cache of created thread factories.
+ private static final ConcurrentHashMap<String, GroupedThreadFactory> FACTORIES =
+ new ConcurrentHashMap<>();
+
+ /**
+ * Returns thread factory for producing threads associated with the specified
+ * group name. The group name-space is hierarchical, based on slash-delimited
+ * name segments, e.g. {@code onos/intent}.
+ *
+ * @param groupName group name
+ * @return thread factory
+ */
+ public static GroupedThreadFactory groupedThreadFactory(String groupName) {
+ GroupedThreadFactory factory = FACTORIES.get(groupName);
+ if (factory != null) {
+ return factory;
+ }
+
+ // Find the parent group or root the group hierarchy under default group.
+ int i = groupName.lastIndexOf(DELIMITER);
+ if (i > 0) {
+ String name = groupName.substring(0, i);
+ ThreadGroup parentGroup = groupedThreadFactory(name).threadGroup();
+ factory = new GroupedThreadFactory(new ThreadGroup(parentGroup, groupName));
+ } else {
+ factory = new GroupedThreadFactory(new ThreadGroup(groupName));
+ }
+
+ return ConcurrentUtils.putIfAbsent(FACTORIES, groupName, factory);
+ }
+
+ // Creates a new thread group
+ private GroupedThreadFactory(ThreadGroup group) {
+ this.group = group;
+ }
+
+ /**
+ * Returns the thread group associated with the factory.
+ *
+ * @return thread group
+ */
+ public ThreadGroup threadGroup() {
+ return group;
+ }
+
+ @Override
+ public Thread newThread(Runnable r) {
+ return new Thread(group, r);
+ }
+
+ @Override
+ public String toString() {
+ return toStringHelper(this).add("group", group).toString();
+ }
+}