Issue: Spring Component Annotation scan not picking up the class annotated in the external jar which is not included in pom.xml. But i need to scan for classes with specific annotation from external jars. These external jars will be placed in the classpath but will not be known to my application during compile time.
1) We have a maven module(artifactId="metric_processor") which produces a jar file(metric_processor.jar) and has following classes
package com.metric;
@Target({ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
public @interface ProcessMetric {
String name();
}
package com.metric;
public interface MetricProcessor {
int computeMetric();
}
package com.metric;
@ProcessMetric(name="LATENCY")
@Component
public class LatencyMetricProcessor implements MetricProcessor {
.....
}
2) We have another maven module ("artifactId="metric_processor_external") which produces a jar(metric_processor_external.jar) and includes "metric_processor" module as compile time scope.
package com.metric;
@ProcessMetric(name="TEST_METRIC_EXTERNAL")
@Component
public class TestMetricProcessor implements MetricProcessor {
....
}
3) We have a third(main) maven module(artifactId="main_application") which is a stand alone application(uses spring) which includes module "metric_processor" in compile scope. (But does not include "metric_processor_external"). The build plugin for the third module is
<build>
<plugins>
<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<version>2.4</version>
<configuration>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
<archive>
<manifest>
<mainClass>com.main.TriggerMetricProcessor</mainClass>
</manifest>
</archive>
</configuration>
<executions>
<execution>
<id>make-assembly</id>
<phase>package</phase>
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
Application context xml for this module is
<beans>
<context:component-scan base-package="com.metric">
<context:include-filter type="annotation" expression="com.metric.ProcessMetric" />
</context:component-scan>
<bean id="triggerMetricProcessor" class="com.main.TriggerMetricProcessor" />
</beans>
I have the following class which is the starting point of the application
package com.main;
import ...
public class TriggerMetricProcessor {
public static void main(String[] args) throws Exception {
ApplicationContext context =
new ClassPathXmlApplicationContext("application-context.xml");
TriggerMetricProcessor triggerMetricProcessor = (TriggerMetricProcessor) context.getBean("triggerMetricProcessor");
triggerMetricProcessor.initMetricProcessor(context);
}
private void initMetricProcessor(ApplicationContext context) {
GenericBeanFactoryAccessor beanFactoryAccessor = new GenericBeanFactoryAccessor(context);
final Map<String, Object> metricProcessors = beanFactoryAccessor.getBeansWithAnnotation(ProcessMetric.class);
for (final Object metricProcessor : metricProcessors.values()) {
final Class<? extends MetricProcessor> metricProcessorClass = (Class<? extends MetricProcessor>)metricProcessor.getClass();
final ProcessMetric annotation = metricProcessorClass.getAnnotation(ProcessMetric.class);
System.out.println("Found MetricProcessor class: " + metricProcessorClass + ", with name: " + annotation.name());
}
}
}
we compile the third module as
maven clean install assembly:single
This produces the jar file "main_application-with-dependencies.jar"
Then we run its as
java -cp "metric_process_external.jar" -jar main_application-with-dependencies.jar
Now the application finds only "LatencyMetricProcessor" and does not find the "TestMetricProcessor".
Can someone please help?
