Solve #1701, Add one-shot rule support

smart-common/src/main/java/org/smartdata/model/rule/TimeBasedScheduleInfo.java

@@ -57,6 +57,6 @@ public long getEvery() {
   }
 
   public boolean isOneShot() {
-    return startTime == endTime && every == 0;
+    return startTime == endTime && startTime == 0 && every == 0;
   }
 }

smart-engine/src/main/java/org/smartdata/server/engine/rule/ExecutorScheduler.java

@@ -38,8 +38,15 @@ public ExecutorScheduler(int numThreads) {
   public void addPeriodicityTask(RuleExecutor re) {
     TimeBasedScheduleInfo si = re.getTranslateResult().getTbScheduleInfo();
     long now = System.currentTimeMillis();
-    service.scheduleAtFixedRate(re, si.getStartTime() - now,
-        si.getEvery(), TimeUnit.MILLISECONDS);
+    long startDelay = si.getStartTime() - now;
+    if (startDelay < 0) {
+      startDelay = 0;
+    }
+    long every = si.getEvery();
+    if (every <= 0) {
+      every = 5000;
+    }
+    service.scheduleAtFixedRate(re, startDelay, every, TimeUnit.MILLISECONDS);
   }
 
   public void addPeriodicityTask(ScheduleInfo schInfo, Runnable work) {

smart-engine/src/main/java/org/smartdata/server/engine/rule/RuleExecutor.java

@@ -266,9 +266,8 @@ public void run() {
       TimeBasedScheduleInfo scheduleInfo = tr.getTbScheduleInfo();
 
       if (scheduleInfo.getEndTime() != TimeBasedScheduleInfo.FOR_EVER
-          // TODO: tricky here, time passed
+          && !scheduleInfo.isOneShot()
           && startCheckTime - scheduleInfo.getEndTime() > 0) {
-        // TODO: special for scheduleInfo.isOneShot()
         LOG.info("Rule " + ctx.getRuleId() + " exit rule executor due to time passed or finished");
         ruleManager.updateRuleInfo(rid, RuleState.FINISHED, System.currentTimeMillis(), 0, 0);
         exitSchedule();
@@ -288,12 +287,8 @@ public void run() {
         numCmdSubmitted = submitCmdlets(info, files);
       }
       ruleManager.updateRuleInfo(rid, null, System.currentTimeMillis(), 1, numCmdSubmitted);
-      if (exited) {
-        exitSchedule();
-      }
-      // System.out.println(this + " -> " + System.currentTimeMillis());
-      long endProcessTime = System.currentTimeMillis();
 
+      long endProcessTime = System.currentTimeMillis();
       if (endProcessTime - startCheckTime > 2000 || LOG.isDebugEnabled()) {
         LOG.warn(
             "Rule "
@@ -309,6 +304,14 @@ public void run() {
                 + ".");
       }
 
+      if (scheduleInfo.isOneShot()) {
+        ruleManager.updateRuleInfo(rid, RuleState.FINISHED, System.currentTimeMillis(), 0, 0);
+        exitSchedule();
+      }
+
+      if (exited) {
+        exitSchedule();
+      }
     } catch (IOException e) {
       LOG.error("Rule " + ctx.getRuleId() + " exception", e);
     }

smart-rule/src/main/antlr4/org/smartdata/rule/parser/SmartRule.g4

@@ -33,6 +33,7 @@ trigger
     : AT timepointexpr                      #triTimePoint
     | EVERY timeintvalexpr duringexpr?      #triCycle
     | ON fileEvent duringexpr?              #triFileEvent
+    | ONCE                                  #triOnce
     ;
 
 duringexpr : FROM timepointexpr (TO timepointexpr)? ;
@@ -175,6 +176,7 @@ AND : 'and' ;
 EVERY : 'every' ;
 FROM : 'from' ;
 ON : 'on' ;
+ONCE : 'once' ;
 OR : 'or' ;
 NOW : 'now' ;
 NOT : 'not' ;

smart-rule/src/main/java/org/smartdata/rule/parser/SmartRuleVisitTranslator.java

@@ -96,6 +96,12 @@ public TreeNode visitConditions(SmartRuleParser.ConditionsContext ctx) {
     return conditions;
   }
 
+  @Override
+  public TreeNode visitTriOnce(SmartRuleParser.TriOnceContext ctx) {
+    timeBasedScheduleInfo = new TimeBasedScheduleInfo();
+    return null;
+  }
+
   @Override
   public TreeNode visitTriTimePoint(SmartRuleParser.TriTimePointContext ctx) {
     timeBasedScheduleInfo = new TimeBasedScheduleInfo();