-/*******************************************************************************\r
- * ============LICENSE_START==================================================\r
- * * org.onap.dmaap\r
- * * ===========================================================================\r
- * * Copyright © 2017 AT&T Intellectual Property. All rights reserved.\r
- * * ===========================================================================\r
- * * Licensed under the Apache License, Version 2.0 (the "License");\r
- * * you may not use this file except in compliance with the License.\r
- * * You may obtain a copy of the License at\r
- * * \r
- * * http://www.apache.org/licenses/LICENSE-2.0\r
- * * \r
- * * Unless required by applicable law or agreed to in writing, software\r
- * * distributed under the License is distributed on an "AS IS" BASIS,\r
- * * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\r
- * * See the License for the specific language governing permissions and\r
- * * limitations under the License.\r
- * * ============LICENSE_END====================================================\r
- * *\r
- * * ECOMP is a trademark and service mark of AT&T Intellectual Property.\r
- * *\r
- ******************************************************************************/\r
-\r
-\r
-package org.onap.dmaap.datarouter.node;\r
-\r
-import java.util.*;\r
-\r
-/**\r
- * Manage a list of tasks to be executed when an event occurs.\r
- * This makes the following guarantees:\r
- * <ul>\r
- * <li>Tasks can be safely added and removed in the middle of a run.</li>\r
- * <li>No task will be returned more than once during a run.</li>\r
- * <li>No task will be returned when it is not, at that moment, in the list of tasks.</li>\r
- * <li>At the moment when next() returns null, all tasks on the list have been returned during the run.</li>\r
- * <li>Initially and once next() returns null during a run, next() will continue to return null until startRun() is called.\r
- * </ul>\r
- */\r
-public class TaskList {\r
- private Iterator<Runnable> runlist;\r
- private HashSet<Runnable> tasks = new HashSet<Runnable>();\r
- private HashSet<Runnable> togo;\r
- private HashSet<Runnable> sofar;\r
- private HashSet<Runnable> added;\r
- private HashSet<Runnable> removed;\r
- /**\r
- * Construct a new TaskList\r
- */\r
- public TaskList() {\r
- }\r
- /**\r
- * Start executing the sequence of tasks.\r
- */\r
- public synchronized void startRun() {\r
- sofar = new HashSet<Runnable>();\r
- added = new HashSet<Runnable>();\r
- removed = new HashSet<Runnable>();\r
- togo = new HashSet<Runnable>(tasks);\r
- runlist = togo.iterator();\r
- }\r
- /**\r
- * Get the next task to execute\r
- */\r
- public synchronized Runnable next() {\r
- while (runlist != null) {\r
- if (runlist.hasNext()) {\r
- Runnable task = runlist.next();\r
- if (removed.contains(task)) {\r
- continue;\r
- }\r
- if (sofar.contains(task)) {\r
- continue;\r
- }\r
- sofar.add(task);\r
- return(task);\r
- }\r
- if (added.size() != 0) {\r
- togo = added;\r
- added = new HashSet<Runnable>();\r
- removed.clear();\r
- runlist = togo.iterator();\r
- continue;\r
- }\r
- togo = null;\r
- added = null;\r
- removed = null;\r
- sofar = null;\r
- runlist = null;\r
- }\r
- return(null);\r
- }\r
- /**\r
- * Add a task to the list of tasks to run whenever the event occurs.\r
- */\r
- public synchronized void addTask(Runnable task) {\r
- if (runlist != null) {\r
- added.add(task);\r
- removed.remove(task);\r
- }\r
- tasks.add(task);\r
- }\r
- /**\r
- * Remove a task from the list of tasks to run whenever the event occurs.\r
- */\r
- public synchronized void removeTask(Runnable task) {\r
- if (runlist != null) {\r
- removed.add(task);\r
- added.remove(task);\r
- }\r
- tasks.remove(task);\r
- }\r
-}\r
+/*******************************************************************************
+ * ============LICENSE_START==================================================
+ * * org.onap.dmaap
+ * * ===========================================================================
+ * * Copyright © 2017 AT&T Intellectual Property. All rights reserved.
+ * * ===========================================================================
+ * * 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.
+ * * ============LICENSE_END====================================================
+ * *
+ * * ECOMP is a trademark and service mark of AT&T Intellectual Property.
+ * *
+ ******************************************************************************/
+
+
+package org.onap.dmaap.datarouter.node;
+
+import java.util.HashSet;
+import java.util.Iterator;
+
+/**
+ * Manage a list of tasks to be executed when an event occurs. This makes the following guarantees:
+ * <ul>
+ * <li>Tasks can be safely added and removed in the middle of a run.</li>
+ * <li>No task will be returned more than once during a run.</li>
+ * <li>No task will be returned when it is not, at that moment, in the list of tasks.</li>
+ * <li>At the moment when next() returns null, all tasks on the list have been returned during the run.</li>
+ * <li>Initially and once next() returns null during a run, next() will continue to return null until startRun() is
+ * called.
+ * </ul>
+ */
+public class TaskList {
+
+ private Iterator<Runnable> runlist;
+ private HashSet<Runnable> tasks = new HashSet<>();
+ private HashSet<Runnable> togo;
+ private HashSet<Runnable> sofar;
+ private HashSet<Runnable> added;
+ private HashSet<Runnable> removed;
+
+ /**
+ * Start executing the sequence of tasks.
+ */
+ public synchronized void startRun() {
+ sofar = new HashSet<>();
+ added = new HashSet<>();
+ removed = new HashSet<>();
+ togo = new HashSet<>(tasks);
+ runlist = togo.iterator();
+ }
+
+ /**
+ * Get the next task to execute
+ */
+ public synchronized Runnable next() {
+ while (runlist != null) {
+ if (runlist.hasNext()) {
+ Runnable task = runlist.next();
+ if (addTaskToSoFar(task)) {
+ return task;
+ }
+ }
+ if (!added.isEmpty()) {
+ togo = added;
+ added = new HashSet<>();
+ removed.clear();
+ runlist = togo.iterator();
+ continue;
+ }
+ togo = null;
+ added = null;
+ removed = null;
+ sofar = null;
+ runlist = null;
+ }
+ return (null);
+ }
+
+ /**
+ * Add a task to the list of tasks to run whenever the event occurs.
+ */
+ public synchronized void addTask(Runnable task) {
+ if (runlist != null) {
+ added.add(task);
+ removed.remove(task);
+ }
+ tasks.add(task);
+ }
+
+ /**
+ * Remove a task from the list of tasks to run whenever the event occurs.
+ */
+ public synchronized void removeTask(Runnable task) {
+ if (runlist != null) {
+ removed.add(task);
+ added.remove(task);
+ }
+ tasks.remove(task);
+ }
+
+ private boolean addTaskToSoFar(Runnable task) {
+ if (removed.contains(task)) {
+ return false;
+ }
+ if (sofar.contains(task)) {
+ return false;
+ }
+ sofar.add(task);
+ return true;
+ }
+}
Code Review / dmaap / datarouter.git / blobdiff