I am trying basic seda queue reader.
I need to use java.util.concurrent.DelayQueue. *Q1.* Is it possible to read
from this queue?
Especially because this page <http://camel.apache.org/seda.html> says
there are only three implementations of BlockingQueue are there:
LinkedBlockingQueueFactory, ArrayBlockingQueueFactory and
PriorityBlockingQueueFactory
DelayQueue objects need to implement Delayed interface. So I created
DelayObject class implementing it:
package com.mahesha999.examples.apachecamel.eg1;
import java.util.concurrent.Delayed;
import java.util.concurrent.TimeUnit;
public class DelayObject implements Delayed
{
private String data;
private long startTime;
public DelayObject(String data, long delay) {
this.data = data;
this.startTime = System.currentTimeMillis() + delay;
System.out.println(">>>>>>>>>>>>>>>>>> DelayObject created with
params: "
+ data + "(" + delay + ")");
}
public int compareTo(Delayed o) {
if (this.startTime < ((DelayObject) o).startTime) {
return -1;
}
if (this.startTime > ((DelayObject) o).startTime) {
return 1;
}
return 0;
}
public long getDelay(TimeUnit unit) {
long diff = startTime - System.currentTimeMillis();
return unit.convert(diff, TimeUnit.MILLISECONDS);
}
public String toString() {
return "{" +
"data='" + data + '\'' +
", startTime=" + startTime +
'}';
}
}
Next I have written basic application context xml as below. It creates a
DelayQueue loaded with single initial object. The camel route tries to read
from the queue and output to the standard output stream.
<beans xmlns="http://www.springframework.org/schema/beans";
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance";
xmlns:camel="http://camel.apache.org/schema/spring";
xmlns:util="http://www.springframework.org/schema/util";
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
http://camel.apache.org/schema/spring
http://camel.apache.org/schema/spring/camel-spring.xsd
http://www.springframework.org/schema/util
http://www.springframework.org/schema/util/spring-util-3.1.xsd";>
<bean id="delayQueue" class="java.util.concurrent.DelayQueue">
<constructor-arg>
<list>
<bean id="delayedObject1"
class="com.mahesha999.examples.apachecamel.eg1.DelayObject">
<constructor-arg
type="java.lang.String">
<value>Mahesh</value>
</constructor-arg>
<constructor-arg type="long">
<value>10</value>
</constructor-arg>
</bean>
</list>
</constructor-arg>
</bean>
<camelContext xmlns="http://camel.apache.org/schema/spring";>
<route>
<from uri="seda:array?queue=#delayQueue" />
<to uri="stream:out" />
</route>
</camelContext>
</beans>
Then my Main class looks like this:
package com.mahesha999.examples.apachecamel.eg1;
import java.util.concurrent.BlockingQueue;
import org.apache.camel.CamelContext;
import org.apache.camel.impl.DefaultCamelContext;
import org.springframework.context.support.AbstractXmlApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class App {
public static void main(String[] args) throws InterruptedException
{
AbstractXmlApplicationContext springCtx = new
ClassPathXmlApplicationContext("Eg1CamelContext.xml");
springCtx.start();
Thread.sleep(10000);
springCtx.stop();
springCtx.destroy();
}
}
The DelayObject is getting created and seems that its getting added to the
queue. But seda is not reading from it and outputing it to the standard
output as the output looks like this:
Jan 05, 2017 3:53:47 PM
org.springframework.context.support.AbstractApplicationContext
prepareRefresh
INFO: Refreshing
org.springframework.context.support.ClassPathXmlApplicationContext@31221be2:
startup date [Thu Jan 05 15:53:47 IST 2017]; root of context hierarchy
Jan 05, 2017 3:53:47 PM
org.springframework.beans.factory.xml.XmlBeanDefinitionReader
loadBeanDefinitions
INFO: Loading XML bean definitions from class path resource
[Eg1CamelContext.xml]
SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further
details.
Jan 05, 2017 3:53:48 PM
org.springframework.beans.factory.support.DefaultListableBeanFactory
preInstantiateSingletons
INFO: Pre-instantiating singletons in
org.springframework.beans.factory.support.DefaultListableBeanFactory@22e357dc:
defining beans
[delayQueue,template,consumerTemplate,camel-1:beanPostProcessor,camel-1];
root of factory hierarchy
>>>>>>>>>>>>>>>>>> DelayObject created with params: Mahesh(10)
Jan 05, 2017 3:54:00 PM
org.springframework.context.support.AbstractApplicationContext doClose
INFO: Closing
org.springframework.context.support.ClassPathXmlApplicationContext@31221be2:
startup date [Thu Jan 05 15:53:47 IST 2017]; root of context hierarchy
Jan 05, 2017 3:54:00 PM
org.springframework.beans.factory.support.DefaultSingletonBeanRegistry
destroySingletons
INFO: Destroying singletons in
org.springframework.beans.factory.support.DefaultListableBeanFactory@22e357dc:
defining beans
[delayQueue,template,consumerTemplate,camel-1:beanPostProcessor,camel-1];
root of factory hierarchy
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