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INTSAMPLES-64 Poller Sample using custom Trigger

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For reference: https://jira.springsource.org/browse/INTSAMPLES-64

Shows how the polling period can be changed at runtime using a custom trigger.
This commit is contained in:
Gunnar Hillert
2012-02-14 17:06:30 -05:00
parent 66b25d3319
commit edd3f90299
7 changed files with 382 additions and 0 deletions
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36
intermediate/dynamic-poller/README.md Normal file
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Dynamic Poller Sample
=====================
By default this application will (poll) print out the current system time every 5 seconds. From the command line you can enter a non-negative numeric value to change the polling period (in milliseconds) at runtime.
Under the cover an **Inbound Channel Adapter** polls for the current system time. The **Poller** which is used by the **Inbound Channel Adapter** is configured with a custom trigger. The resulting message contains as payload the time in milliseconds and the message is sent to a **Logging Channel Adapter**, which will print the time to the command prompt.
You can run the application by either
* running the "Main" class from within STS (Right-click on Main class --> Run As --> Java Application)
* or from the command line using the [Exec Maven Plugin](http://mojo.codehaus.org/exec-maven-plugin/):
- mvn package exec:java
You should see output like the following:
INFO : org.springframework.integration.samples.poller.Main -
==========================================================
Welcome to the Spring Integration Dynamic Poller Sample!
For more information please visit:
http://www.springsource.org/spring-integration
==========================================================
INFO : org.springframework.integration.samples.poller.Main -
=========================================================
Please press 'q + Enter' to quit the application.
=========================================================
Please enter a non-negative numeric value and press <enter>: INFO : org.springframework.integration.samples.poller - 1329257519165
INFO : org.springframework.integration.samples.poller - 1329257524207
INFO : org.springframework.integration.samples.poller - 1329257529208
INFO : org.springframework.integration.samples.poller - 1329257534209
INFO : org.springframework.integration.samples.poller - 1329257539210

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<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/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>org.springframework.integration.samples</groupId>
<artifactId>dynamic-poller</artifactId>
<version>2.1.0.BUILD-SNAPSHOT</version>
<packaging>jar</packaging>
<name>dynamic-poller</name>
<url>http://www.springsource.org/spring-integration</url>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<spring.integration.version>2.1.0.RELEASE</spring.integration.version>
<log4j.version>1.2.16</log4j.version>
<junit.version>4.10</junit.version>
<java.main.class>org.springframework.integration.samples.poller.Main</java.main.class>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.integration</groupId>
<artifactId>spring-integration-core</artifactId>
<version>${spring.integration.version}</version>
</dependency>
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>${log4j.version}</version>
</dependency>
<!-- test-scoped dependencies -->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>${junit.version}</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>2.3.2</version>
<configuration>
<source>1.5</source>
<target>1.5</target>
<compilerArgument>-Xlint:all</compilerArgument>
<showWarnings>true</showWarnings>
<showDeprecation>true</showDeprecation>
</configuration>
</plugin>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>exec-maven-plugin</artifactId>
<version>1.2</version>
<configuration>
<mainClass>${java.main.class}</mainClass>
</configuration>
</plugin>
</plugins>
</build>
<repositories>
<repository>
<id>repo.springsource.org.milestone</id>
<name>Spring Framework Maven Milestone Repository</name>
<url>https://repo.springsource.org/milestone</url>
</repository>
</repositories>
</project>

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intermediate/dynamic-poller/src/main/java/org/springframework/integration/samples/poller/DynamicPeriodicTrigger.java Normal file
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/*
* Copyright 2002-2012 the original author or authors.
*
* Licensed 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.springframework.integration.samples.poller;
import java.util.Date;
import java.util.concurrent.TimeUnit;
import org.springframework.scheduling.Trigger;
import org.springframework.scheduling.TriggerContext;
import org.springframework.scheduling.support.PeriodicTrigger;
import org.springframework.util.Assert;
/**
* This is a dynamically changeable {@link Trigger}. It is based on the
* {@link PeriodicTrigger} implementations. However, the fields of this dynamic
* trigger are not final and the properties can be inspected and set via
* explicit getters and setters.
*
* @author Gunnar Hillert
*
*/
public class DynamicPeriodicTrigger implements Trigger {
private volatile long period;
private volatile TimeUnit timeUnit;
private volatile long initialDelay = 0;
private volatile boolean fixedRate = false;
/**
* Create a trigger with the given period in milliseconds.
*/
public DynamicPeriodicTrigger(long period) {
this(period, null);
}
/**
* Create a trigger with the given period and time unit. The time unit will
* apply not only to the period but also to any 'initialDelay' value, if
* configured on this Trigger later via {@link #setInitialDelay(long)}.
*/
public DynamicPeriodicTrigger(long period, TimeUnit timeUnit) {
Assert.isTrue(period >= 0, "period must not be negative");
this.timeUnit = (timeUnit != null) ? timeUnit : TimeUnit.MILLISECONDS;
this.period = this.timeUnit.toMillis(period);
}
/**
* Specify the delay for the initial execution. It will be evaluated in
* terms of this trigger's {@link TimeUnit}. If no time unit was explicitly
* provided upon instantiation, the default is milliseconds.
*/
public void setInitialDelay(long initialDelay) {
this.initialDelay = this.timeUnit.toMillis(initialDelay);
}
/**
* Specify whether the periodic interval should be measured between the
* scheduled start times rather than between actual completion times.
* The latter, "fixed delay" behavior, is the default.
*/
public void setFixedRate(boolean fixedRate) {
this.fixedRate = fixedRate;
}
/**
* Returns the time after which a task should run again.
*/
public Date nextExecutionTime(TriggerContext triggerContext) {
if (triggerContext.lastScheduledExecutionTime() == null) {
return new Date(System.currentTimeMillis() + this.initialDelay);
}
else if (this.fixedRate) {
return new Date(triggerContext.lastScheduledExecutionTime().getTime() + this.period);
}
return new Date(triggerContext.lastCompletionTime().getTime() + this.period);
}
public long getPeriod() {
return period;
}
public void setPeriod(long period) {
this.period = period;
}
public TimeUnit getTimeUnit() {
return timeUnit;
}
public void setTimeUnit(TimeUnit timeUnit) {
this.timeUnit = timeUnit;
}
public long getInitialDelay() {
return initialDelay;
}
public boolean isFixedRate() {
return fixedRate;
}
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (!(obj instanceof DynamicPeriodicTrigger)) {
return false;
}
DynamicPeriodicTrigger other = (DynamicPeriodicTrigger) obj;
return this.fixedRate == other.fixedRate
&& this.initialDelay == other.initialDelay
&& this.period == other.period;
}
@Override
public int hashCode() {
return (this.fixedRate ? 14 : 41) +
(int) (38 * this.period) +
(int) (43 * this.initialDelay);
}
}

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/*
* Copyright 2002-2012 the original author or authors.
*
* Licensed 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.springframework.integration.samples.poller;
import java.util.Scanner;
import org.apache.log4j.Logger;
import org.springframework.context.support.AbstractApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
/**
* Starts the Spring Context and will initialize the Spring Integration routes.
*
* @author Gunnar Hillert
* @version 1.0
*
*/
public final class Main {
private static final Logger LOGGER = Logger.getLogger(Main.class);
private Main() { }
/**
* Load the Spring Integration Application Context
*
* @param args - command line arguments
*/
public static void main(final String... args) {
LOGGER.info("\n=========================================================="
+ "\n "
+ "\n Welcome to the Spring Integration Dynamic Poller Sample! "
+ "\n "
+ "\n For more information please visit: "
+ "\n http://www.springsource.org/spring-integration "
+ "\n "
+ "\n==========================================================" );
final AbstractApplicationContext context =
new ClassPathXmlApplicationContext("classpath:META-INF/spring/integration/*-context.xml");
context.registerShutdownHook();
final Scanner scanner = new Scanner(System.in);
final DynamicPeriodicTrigger trigger = context.getBean(DynamicPeriodicTrigger.class);
LOGGER.info("\n========================================================="
+ "\n "
+ "\n Please press 'q + Enter' to quit the application. "
+ "\n "
+ "\n=========================================================" );
System.out.print("Please enter a non-negative numeric value and press <enter>: ");
while (!scanner.hasNext("q")) {
int triggerPeriod = scanner.nextInt();
System.out.println(String.format("Setting trigger period to '%s' ms", triggerPeriod));
trigger.setPeriod(triggerPeriod);
System.out.print("Please enter a non-negative numeric value and press <enter>: ");
}
LOGGER.info("Exiting application...bye.");
System.exit(0);
}
}

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intermediate/dynamic-poller/src/main/resources/META-INF/spring/integration/spring-integration-context.xml Normal file
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<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/integration http://www.springframework.org/schema/integration/spring-integration-2.1.xsd
http://www.springframework.org/schema/task http://www.springframework.org/schema/task/spring-task.xsd"
xmlns:int="http://www.springframework.org/schema/integration"
xmlns:task="http://www.springframework.org/schema/task">
<int:inbound-channel-adapter expression="T(java.lang.System).currentTimeMillis()" channel="logger">
<int:poller max-messages-per-poll="1" trigger="dynamicTrigger" />
</int:inbound-channel-adapter>
<bean id="dynamicTrigger" class="org.springframework.integration.samples.poller.DynamicPeriodicTrigger">
<constructor-arg name="period" value="5000"/>
</bean>
<int:logging-channel-adapter id="logger" logger-name="org.springframework.integration.samples.poller"/>
<task:executor id="executor" queue-capacity="20" pool-size="5-20"/>
</beans>

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<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
<log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/">
<!-- Appenders -->
<appender name="console" class="org.apache.log4j.ConsoleAppender">
<param name="Target" value="System.out" />
<layout class="org.apache.log4j.PatternLayout">
<param name="ConversionPattern" value="%-5p: %c - %m%n" />
</layout>
</appender>
<!-- Loggers -->
<logger name="org.springframework">
<level value="warn" />
</logger>
<logger name="org.springframework.integration.samples">
<level value="debug" />
</logger>
<!-- Root Logger -->
<root>
<priority value="warn" />
<appender-ref ref="console" />
</root>
</log4j:configuration>