CAMEL-23279: fix SamplingDefinition.description() NumberFormatException with property placeholders

Avoid premature parsing of samplePeriod through TimeUtils.toDuration()
in description(), which fails when the value contains unresolved
property placeholders like {{sample.period}}. Return the raw string
value instead, consistent with ThrottleDefinition.description().

Author: Croway

core/camel-core-model/src/main/java/org/apache/camel/model/SamplingDefinition.java

@@ -86,7 +86,7 @@ protected String description() {
         if (messageFrequency != null) {
             return "1 Exchange per " + getMessageFrequency() + " messages received";
         } else {
-            return "1 Exchange per " + TimeUtils.printDuration(TimeUtils.toDuration(samplePeriod));
+            return "1 Exchange per " + getSamplePeriod() + " millis";
         }
     }
 

core/camel-core/src/test/java/org/apache/camel/processor/SamplingThrottlerTest.java

@@ -20,6 +20,7 @@
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
+import java.util.Properties;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 
@@ -100,6 +101,17 @@ public void run() {
         executor.shutdownNow();
     }
 
+    @Test
+    public void testSamplingWithPropertyPlaceholder() throws Exception {
+        MockEndpoint mock = getMockEndpoint("mock:result");
+        mock.expectedMinimumMessageCount(1);
+        mock.setResultWaitTime(3000);
+
+        template.sendBody("direct:sample-placeholder", "<message>placeholder test</message>");
+
+        mock.assertIsSatisfied();
+    }
+
     @Test
     public void testSamplingUsingMessageFrequency() throws Exception {
         long totalMessages = 100;
@@ -156,6 +168,13 @@ private void validateDroppedExchanges(List<Exchange> sentExchanges, int expected
         assertEquals(expectedNotDroppedCount, notDropped);
     }
 
+    @Override
+    protected Properties useOverridePropertiesWithPropertiesComponent() {
+        Properties props = new Properties();
+        props.put("sample.period", "1000");
+        return props;
+    }
+
     @Override
     protected RouteBuilder createRouteBuilder() {
         return new RouteBuilder() {
@@ -171,6 +190,8 @@ public void configure() {
 
                 from("direct:sample-messageFrequency-via-dsl").sample().sampleMessageFrequency(5).to("mock:result");
 
+                from("direct:sample-placeholder").sample("{{sample.period}}").to("mock:result");
+
                 // END SNIPPET: e1
             }
         };