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new 5d5cb49a camel-example-timer: Add Timer component example (#159)
5d5cb49a is described below
commit 5d5cb49ad760779282a16c9f02f5bedbf657e769
Author: Jomin <[email protected]>
AuthorDate: Tue Mar 3 14:01:08 2026 +0000
camel-example-timer: Add Timer component example (#159)
Adds a new beginner-level example demonstrating various Timer component
configurations:
- Simple periodic timer (300ms)
- Timer with initial delay (500ms delay, 300ms period)
- Timer with repeat count (3 times, 100ms interval)
- Fixed rate timer (500ms, with detailed timing explanation)
Co-authored-by: jomin mathew <>
---
README.adoc | 4 +-
pom.xml | 1 +
timer/README.adoc | 66 +++++++++++++++
timer/pom.xml | 99 ++++++++++++++++++++++
.../apache/camel/example/timer/TimerExample.java | 87 +++++++++++++++++++
timer/src/main/resources/log4j2.properties | 23 +++++
.../camel/example/timer/TimerExampleTest.java | 64 ++++++++++++++
7 files changed, 343 insertions(+), 1 deletion(-)
diff --git a/README.adoc b/README.adoc
index 0f59ad8e..7227e551 100644
--- a/README.adoc
+++ b/README.adoc
@@ -28,7 +28,7 @@ readme's instructions.
== Examples
// examples: START
-Number of Examples: 72 (0 deprecated)
+Number of Examples: 73 (0 deprecated)
[width="100%",cols="4,2,4",options="header"]
|===
@@ -66,6 +66,8 @@ Number of Examples: 72 (0 deprecated)
| link:spring/README.adoc[Spring] (spring) | Beginner | An example showing how
to work with Camel and Spring
+| link:timer/README.adoc[Timer] (timer) | Beginner | An example showing how to
work with Camel Timer component
+
| link:main/README.adoc[Main] (main) | Camel Standalone | An example for
showing standalone Camel
| link:main-endpointdsl/README.adoc[Main Endpointdsl] (main-endpointdsl) |
Camel Standalone | An example for showing standalone Camel with Endpoint DSL
diff --git a/pom.xml b/pom.xml
index c9824d6e..81fb857e 100644
--- a/pom.xml
+++ b/pom.xml
@@ -134,6 +134,7 @@
<module>spring-pulsar</module>
<module>spring-xquery</module>
<module>telegram</module>
+ <module>timer</module>
<module>transformer-demo</module>
<module>vault</module>
<module>whatsapp</module>
diff --git a/timer/README.adoc b/timer/README.adoc
new file mode 100644
index 00000000..8148ccd2
--- /dev/null
+++ b/timer/README.adoc
@@ -0,0 +1,66 @@
+== Camel Timer Example
+
+=== Introduction
+
+This example shows how to work with the Camel Timer component.
+
+The Timer component is used to generate message exchanges when a timer fires.
It's useful for:
+
+- Polling resources at regular intervals
+- Scheduling batch jobs
+- Triggering periodic tasks
+- Creating heartbeat mechanisms
+
+This example demonstrates various timer configurations including:
+
+- Simple periodic timer
+- Timer with initial delay
+- Timer with repeat count
+- Timer with fixed rate vs fixed delay
+
+The example is minimal and shows how to use the timer component in standalone
mode as a `public static void main` application.
+
+=== Build
+
+You will need to compile this example first:
+
+[source,sh]
+----
+$ mvn compile
+----
+
+=== Run
+
+To run the example type
+
+[source,sh]
+----
+$ mvn camel:run
+----
+
+The example will run for about 5 seconds demonstrating different timer
patterns.
+
+To stop the example hit `ctrl+c`
+
+You can also run the example from your editor such as Eclipse, IDEA etc,
+by opening the class
link:../timer/src/main/java/org/apache/camel/example/timer/TimerExample.java[org.apache.camel.example.timer.TimerExample]
+and then right click, and chose run java application.
+
+=== Configuration
+
+The example shows multiple timer configurations:
+
+- `timer:simple` - Fires every 300ms
+- `timer:withDelay` - Fires every 300ms after a 500ms initial delay
+- `timer:limited` - Fires only 3 times with 100ms interval
+- `timer:fixedRate` - Fires every 500ms at fixed rate regardless of processing
time
+
+=== Help and contributions
+
+If you hit any problem using Camel or have some feedback, then please
+https://camel.apache.org/community/support/[let us know].
+
+We also love contributors, so
+https://camel.apache.org/community/contributing/[get involved] :-)
+
+The Camel riders!
\ No newline at end of file
diff --git a/timer/pom.xml b/timer/pom.xml
new file mode 100644
index 00000000..eb3e941b
--- /dev/null
+++ b/timer/pom.xml
@@ -0,0 +1,99 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+
+ Licensed to the Apache Software Foundation (ASF) under one or more
+ contributor license agreements. See the NOTICE file distributed with
+ this work for additional information regarding copyright ownership.
+ The ASF licenses this file to You 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.
+
+-->
+<project xmlns="http://maven.apache.org/POM/4.0.0";
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance";
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
http://maven.apache.org/maven-v4_0_0.xsd";>
+
+ <modelVersion>4.0.0</modelVersion>
+
+ <parent>
+ <groupId>org.apache.camel.example</groupId>
+ <artifactId>camel-examples</artifactId>
+ <version>4.19.0-SNAPSHOT</version>
+ </parent>
+
+ <artifactId>camel-example-timer</artifactId>
+ <packaging>jar</packaging>
+ <name>Camel :: Example :: Timer</name>
+ <description>An example showing how to work with Camel Timer
component</description>
+
+ <properties>
+ <category>Beginner</category>
+ <title>Timer</title>
+ </properties>
+
+ <dependencyManagement>
+ <dependencies>
+ <!-- Add Camel BOM -->
+ <dependency>
+ <groupId>org.apache.camel</groupId>
+ <artifactId>camel-bom</artifactId>
+ <version>${camel.version}</version>
+ <type>pom</type>
+ <scope>import</scope>
+ </dependency>
+ </dependencies>
+ </dependencyManagement>
+
+ <dependencies>
+
+ <dependency>
+ <groupId>org.apache.camel</groupId>
+ <artifactId>camel-core</artifactId>
+ </dependency>
+
+ <!-- logging -->
+ <dependency>
+ <groupId>org.apache.logging.log4j</groupId>
+ <artifactId>log4j-core</artifactId>
+ <scope>runtime</scope>
+ <version>${log4j2-version}</version>
+ </dependency>
+ <dependency>
+ <groupId>org.apache.logging.log4j</groupId>
+ <artifactId>log4j-slf4j2-impl</artifactId>
+ <scope>runtime</scope>
+ <version>${log4j2-version}</version>
+ </dependency>
+
+ <!-- for testing -->
+ <dependency>
+ <groupId>org.apache.camel</groupId>
+ <artifactId>camel-test-junit6</artifactId>
+ <scope>test</scope>
+ </dependency>
+ </dependencies>
+
+ <build>
+ <plugins>
+
+ <!-- Allows the routes to be run via 'mvn camel:run' -->
+ <plugin>
+ <groupId>org.apache.camel</groupId>
+ <artifactId>camel-maven-plugin</artifactId>
+ <version>${camel.version}</version>
+ <configuration>
+
<mainClass>org.apache.camel.example.timer.TimerExample</mainClass>
+ </configuration>
+ </plugin>
+
+ </plugins>
+
+ </build>
+
+</project>
\ No newline at end of file
diff --git
a/timer/src/main/java/org/apache/camel/example/timer/TimerExample.java
b/timer/src/main/java/org/apache/camel/example/timer/TimerExample.java
new file mode 100644
index 00000000..2f444db8
--- /dev/null
+++ b/timer/src/main/java/org/apache/camel/example/timer/TimerExample.java
@@ -0,0 +1,87 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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.
+ */
+package org.apache.camel.example.timer;
+
+import org.apache.camel.CamelContext;
+import org.apache.camel.builder.RouteBuilder;
+import org.apache.camel.impl.DefaultCamelContext;
+
+/**
+ * An example showing how to use the Timer component in various configurations.
+ * <p>
+ * The timer component is used to generate message exchanges at regular
intervals.
+ * This is useful for polling, scheduling, and triggering periodic tasks.
+ */
+public final class TimerExample {
+
+ public static void main(String[] args) throws Exception {
+ // create a CamelContext
+ try (CamelContext camel = new DefaultCamelContext()) {
+
+ // add routes demonstrating different timer patterns
+ camel.addRoutes(createTimerRoutes());
+
+ // start is not blocking
+ camel.start();
+
+ // run for 5 seconds to demonstrate the timers
+ Thread.sleep(5_000);
+
+ System.out.println("\nShutting down...");
+ }
+ }
+
+ static RouteBuilder createTimerRoutes() {
+ return new RouteBuilder() {
+ @Override
+ public void configure() {
+
+ // Simple timer - fires every 300ms
+ from("timer:simple?period=300")
+ .routeId("simple-timer")
+ .setBody(simple("Simple timer fired at
${date:now:yyyy-MM-dd HH:mm:ss}"))
+ .log("${body}");
+
+ // Timer with initial delay - waits 500ms before first fire,
then every 300ms
+ from("timer:withDelay?delay=500&period=300")
+ .routeId("delayed-timer")
+ .setBody(simple("Delayed timer fired at
${date:now:yyyy-MM-dd HH:mm:ss}"))
+ .log("${body}");
+
+ // Timer with repeat count - fires only 3 times
+ from("timer:limited?period=100&repeatCount=3")
+ .routeId("limited-timer")
+ .setBody(simple("Limited timer fired
(${header.CamelTimerCounter} of 3) at ${date:now:yyyy-MM-dd HH:mm:ss}"))
+ .log("${body}");
+
+ // Fixed rate timer - uses scheduleAtFixedRate (start-to-start
timing)
+ // Attempts to maintain fixed intervals. If processing time <
period, fires at regular intervals.
+ // vs fixedRate=false (default) - uses scheduleWithFixedDelay
(end-to-start timing)
+ // Waits for completion + full period before next execution.
+ from("timer:fixedRate?period=500&fixedRate=true")
+ .routeId("fixed-rate-timer")
+ .setBody(simple("Fixed-rate timer fired at
${date:now:yyyy-MM-dd HH:mm:ss}"))
+ .log("${body}")
+ // simulate some processing time
+ .process(exchange -> {
+ // This 50ms delay is less than the 500ms period,
demonstrating fixed-rate timing
+ Thread.sleep(50);
+ });
+ }
+ };
+ }
+}
\ No newline at end of file
diff --git a/timer/src/main/resources/log4j2.properties
b/timer/src/main/resources/log4j2.properties
new file mode 100644
index 00000000..dde96bbd
--- /dev/null
+++ b/timer/src/main/resources/log4j2.properties
@@ -0,0 +1,23 @@
+## ---------------------------------------------------------------------------
+## Licensed to the Apache Software Foundation (ASF) under one or more
+## contributor license agreements. See the NOTICE file distributed with
+## this work for additional information regarding copyright ownership.
+## The ASF licenses this file to You 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.
+## ---------------------------------------------------------------------------
+
+appender.out.type = Console
+appender.out.name = out
+appender.out.layout.type = PatternLayout
+appender.out.layout.pattern = [%30.30t] %-30.30c{1} %-5p %m%n
+rootLogger.level = INFO
+rootLogger.appenderRef.out.ref = out
\ No newline at end of file
diff --git
a/timer/src/test/java/org/apache/camel/example/timer/TimerExampleTest.java
b/timer/src/test/java/org/apache/camel/example/timer/TimerExampleTest.java
new file mode 100644
index 00000000..80689cba
--- /dev/null
+++ b/timer/src/test/java/org/apache/camel/example/timer/TimerExampleTest.java
@@ -0,0 +1,64 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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.
+ */
+package org.apache.camel.example.timer;
+
+import org.apache.camel.RoutesBuilder;
+import org.apache.camel.builder.NotifyBuilder;
+import org.apache.camel.test.junit6.CamelTestSupport;
+import org.junit.jupiter.api.Test;
+
+import java.util.concurrent.TimeUnit;
+
+import static org.apache.camel.example.timer.TimerExample.createTimerRoutes;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+/**
+ * A unit test verifying that timer routes work correctly.
+ */
+class TimerExampleTest extends CamelTestSupport {
+
+ @Test
+ void should_fire_simple_timer() {
+ // Wait for at least 2 messages from the simple timer (fires every
300ms)
+ NotifyBuilder notify = new NotifyBuilder(context)
+ .from("timer:simple*")
+ .whenCompleted(2)
+ .create();
+
+ assertTrue(
+ notify.matches(20, TimeUnit.SECONDS), "Simple timer should
fire at least twice"
+ );
+ }
+
+ @Test
+ void should_respect_repeat_count() {
+ // The limited timer should fire exactly 3 times
+ NotifyBuilder notify = new NotifyBuilder(context)
+ .from("timer:limited*")
+ .whenExactlyCompleted(3)
+ .create();
+
+ assertTrue(
+ notify.matches(20, TimeUnit.SECONDS), "Limited timer should
fire exactly 3 times"
+ );
+ }
+
+ @Override
+ protected RoutesBuilder createRouteBuilder() {
+ return createTimerRoutes();
+ }
+}
\ No newline at end of file
