Added usage of msg count in the generator node

@@ -54,6 +54,7 @@ public class TbMsgGeneratorNode implements TbNode {
     private ScriptEngine jsEngine;
     private long delay;
     private long lastScheduledTs;
+    private int currentMsgCount;
     private EntityId originatorId;
     private UUID nextTickId;
     private TbMsg prevMsg;
@@ -63,6 +64,7 @@ public class TbMsgGeneratorNode implements TbNode {
     public void init(TbContext ctx, TbNodeConfiguration configuration) throws TbNodeException {
         this.config = TbNodeUtils.convert(configuration, TbMsgGeneratorNodeConfiguration.class);
         this.delay = TimeUnit.SECONDS.toMillis(config.getPeriodInSeconds());
+        this.currentMsgCount = 0;
         if (!StringUtils.isEmpty(config.getOriginatorId())) {
             originatorId = EntityIdFactory.getByTypeAndUuid(config.getOriginatorType(), config.getOriginatorId());
         } else {
@@ -94,9 +96,10 @@ public class TbMsgGeneratorNode implements TbNode {
         if (initialized && msg.getType().equals(TB_MSG_GENERATOR_NODE_MSG) && msg.getId().equals(nextTickId)) {
             withCallback(generate(ctx),
                     m -> {
-                        if (initialized) {
+                        if (initialized && (config.getMsgCount() == TbMsgGeneratorNodeConfiguration.UNLIMITED_MSG_COUNT || currentMsgCount < config.getMsgCount())) {
                             ctx.tellNext(m, SUCCESS);
                             scheduleTickMsg(ctx);
+                            currentMsgCount++;
                         }
                     },
                     t -> {

@@ -19,11 +19,11 @@ import lombok.Data;
 import org.thingsboard.rule.engine.api.NodeConfiguration;
 import org.thingsboard.server.common.data.EntityType;
 
-import java.util.Map;
-
 @Data
 public class TbMsgGeneratorNodeConfiguration implements NodeConfiguration<TbMsgGeneratorNodeConfiguration> {
 
+    public static final int UNLIMITED_MSG_COUNT = 0;
+
     private int msgCount;
     private int periodInSeconds;
     private String originatorId;
@@ -33,7 +33,7 @@ public class TbMsgGeneratorNodeConfiguration implements NodeConfiguration<TbMsgG
     @Override
     public TbMsgGeneratorNodeConfiguration defaultConfiguration() {
         TbMsgGeneratorNodeConfiguration configuration = new TbMsgGeneratorNodeConfiguration();
-        configuration.setMsgCount(0);
+        configuration.setMsgCount(UNLIMITED_MSG_COUNT);
         configuration.setPeriodInSeconds(1);
         configuration.setJsScript("var msg = { temp: 42, humidity: 77 };\n" +
                 "var metadata = { data: 40 };\n" +