Nerot

Scheduled Caching Made Simple

Add this dependency to your pom.xml: 
<dependency>
    <groupId>nerot</groupId>
    <artifactId>nerot</artifactId>
    <version>3.4</version>
</dependency>
Add this repository to your pom.xml: 
<repository>
    <id>nerot-repository</id>
    <name>Nerot Repository</name>
    <url>http://garysweaver.github.com/nerot/m2/releases</url>
</repository>
Add the bean definitions in nerot.xml to your application's context: 
<bean name="nerotScheduleFactory" 
      class="org.springframework.scheduling.quartz.SchedulerFactoryBean">
   <property name="waitForJobsToCompleteOnShutdown" value="false"/>
</bean>

<bean name="nerotStore" class="nerot.store.MemoryStore" />

<bean name="nerot" class="nerot.Nerot">
   <property name="scheduler" ref="nerotScheduleFactory"/>
   <property name="store" ref="nerotStore"/>
</bean>
Add Nerot to your class:

import nerot.Nerot;

public class SomeClass {
  
  private Nerot nerot;
                
  public void setNerot(Nerot nerot) {
    this.nerot = nerot;
  }
}
Set Nerot on your bean: 
<bean name="someClass" class="SomeClass">
    <property name="nerot" ref="nerot"/>
</bean>

Defining a Schedule is Simple and Flexible

You can schedule refresh of the cache either via interval in milliseconds or Quartz CronTrigger syntax (similar to cron syntax).

RSS Feed Retrieval

// Get RSS feed every 15 seconds and cache if no error
nerot.scheduleRss(url, "0/15 * * * * ?");

// Retrieve the result from in-memory cache without delay
SyndFeed feed = nerot.getRssFromStore(url);

Webpage Retrieval

// Get webpage every 60 seconds and cache if no error
nerot.scheduleHttpGet(url, 60000L);

// Retrieve the result from in-memory cache without delay
String page = nerot.getHttpResponseBodyFromStore(url);

Static Methods

// Define Math.random()
GenericTask task = new GenericTask();
task.setStoreKey(key);
task.setActor(Math.class);
task.setMethod("random");

// Call Math.random() every 15 seconds
nerot.schedule("myJob", task, 15000L);

// Retrieve the result from in-memory cache without delay
Double random = (Double)nerot.getResultFromStore(key);

Instance Methods

// Define reporter.generate(...)
GenericTask task = new GenericTask();
task.setStoreKey(key);
task.setActor(new Reporter());
task.setMethod("generate");
task.setArgs(new Object[]{"s", y, true, 'c', 1.0D});

// Call report.generate(...) at 9:15pm every day
nerot.schedule("myJob", task, "0 15 21 * * ?");

// Retrieve the result from in-memory cache without delay
Report stats = (Report)nerot.getResultFromStore(key);

Schedule Methods via Spring Beans

Nerot includes classes for each type of schedule comment that schedule Nerot when the Spring bean is configured in the context. Just define a bean in the root application context and then get the result programmatically in the child context. 
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:p="http://www.springframework.org/schema/p"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xsi:schemaLocation="
         http://www.springframework.org/schema/beans 
         http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
         http://www.springframework.org/schema/context 
         http://www.springframework.org/schema/context/spring-context-2.5.xsd
         http://www.springframework.org/schema/tx 
         http://www.springframework.org/schema/tx/spring-tx-2.5.xsd">

    <context:annotation-config />

    <bean name="rssCronScheduler" class="nerot.spring.RssCronScheduler">
        <property name="url" value="http://news.acme.com/rss"/>
        <property name="cronSchedule" value="0/1 * * * * ?"/>
    </bean>
</beans>
@Autowired
Nerot nerot;

// Schedulers are Storers, so they provide a getStoreKey() method
@Autowired
Storer storer;
            
// Retrieve the result from in-memory cache without delay
SyndFeed feed = nerot.getRssFromStore(storer.getStoreKey());
See README for more info.