Update project structure to org.onap

[dmaap/datarouter.git] / datarouter-node / src / main / java / org / onap / dmaap / datarouter / node / RateLimitedOperation.java

diff --git a/datarouter-node/src/main/java/org/onap/dmaap/datarouter/node/RateLimitedOperation.java b/datarouter-node/src/main/java/org/onap/dmaap/datarouter/node/RateLimitedOperation.java
new file mode 100644 (file)
index 0000000..5890e19
--- /dev/null
+++ b/datarouter-node/src/main/java/org/onap/dmaap/datarouter/node/RateLimitedOperation.java
@@ -0,0 +1,102 @@
+/*******************************************************************************\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
+ *     Execute an operation no more frequently than a specified interval\r
+ */\r
+\r
+public abstract class RateLimitedOperation implements Runnable {\r
+       private boolean marked; // a timer task exists\r
+       private boolean executing;      // the operation is currently in progress\r
+       private boolean remark; // a request was made while the operation was in progress\r
+       private Timer   timer;\r
+       private long    last;   // when the last operation started\r
+       private long    mininterval;\r
+       /**\r
+        *      Create a rate limited operation\r
+        *      @param mininterval      The minimum number of milliseconds after the last execution starts before a new execution can begin\r
+        *      @param timer    The timer used to perform deferred executions\r
+        */\r
+       public RateLimitedOperation(long mininterval, Timer timer) {\r
+               this.timer = timer;\r
+               this.mininterval = mininterval;\r
+       }\r
+       private class deferred extends TimerTask        {\r
+               public void run() {\r
+                       execute();\r
+               }\r
+       }\r
+       private synchronized void unmark() {\r
+               marked = false;\r
+       }\r
+       private void execute() {\r
+               unmark();\r
+               request();\r
+       }\r
+       /**\r
+        *      Request that the operation be performed by this thread or at a later time by the timer\r
+        */\r
+       public void request() {\r
+               if (premark()) {\r
+                       return;\r
+               }\r
+               do {\r
+                       run();\r
+               } while (demark());\r
+       }\r
+       private synchronized boolean premark() {\r
+               if (executing) {\r
+                       // currently executing - wait until it finishes\r
+                       remark = true;\r
+                       return(true);\r
+               }\r
+               if (marked) {\r
+                       // timer currently running - will run when it expires\r
+                       return(true);\r
+               }\r
+               long now = System.currentTimeMillis();\r
+               if (last + mininterval > now) {\r
+                       // too soon - schedule a timer\r
+                       marked = true;\r
+                       timer.schedule(new deferred(), last + mininterval - now);\r
+                       return(true);\r
+               }\r
+               last = now;\r
+               executing = true;\r
+               // start execution\r
+               return(false);\r
+       }\r
+       private synchronized boolean demark() {\r
+               executing = false;\r
+               if (remark) {\r
+                       remark = false;\r
+                       return(!premark());\r
+               }\r
+               return(false);\r
+       }\r
+}\r