Laszlo – Simple Web Service

This post shows a simple example of a Laszlo web service. It uses the xfire web service created in this post. The user enters a symbol and clicks Get Quote, laszlo makes a call to the webservice to retrieve a quote for the symbol. The laszlo documentation describes the use of soap in laszlo applications.

This is a screenshot of the laszlo page:

<canvas debug="true">

<soap name="stockquote"
  wsdl="http://localhost:8080/xfire-stockquote/services/StockQuote?wsdl">

<!-- Method to make a document for SOAP message requests -->
<method name="makegetQuoteDoc" args="symbol">
	Debug.write('Entering makegetQuoteDoc function');
<![CDATA[
    var s =  '<getStockQuote xmlns="http://localhost:8080/xfire-stockquote/services/stockQuote" ><security>'+symbol+'</security></getStockQuote>';

Debug.write(s);
    return s;
]]>
</method>

<handler name="onload">
    // make buttons visible once SOAP object is loaded
		canvas.buttons.setAttribute('visible', true);
		Debug.write('StockQuote soap service loaded');
    Debug.write('StockQuote WSDL at ' + this.wsdl);
    Debug.write('proxy:');
    Debug.inspect(this.proxy);
</handler>

<handler name="onerror" args="error">
    Debug.write('error:', error);
</handler>

<handler name="ontimeout" args="error">
    Debug.write('timeout:', error);
</handler>

<remotecall funcname="getStockQuote" >
  <param value="${ canvas.stockquote.makegetQuoteDoc(symbol.text) }" />
  <method event="ondata" args="value">
		    Debug.write("Got data!");
		    result.setText(value);
  </method>
</remotecall>

</soap>

<view name="buttons" x="10" y="10" visible="false" layout="spacing: 10" >
<text><b>Stock Quote Service</b></text>
<view layout="axis: x" ><text y="3">Symbol:</text><edittext id="symbol" text="IBM"/></view>
<view layout="axis: x" ><text>Result:</text><text id="result"/></view>

<button text="Get Quote" onclick="canvas.stockquote.getStockQuote.invoke()" />

</view>

</canvas>

Web Service with Spring and XFire

In a previous post I looked at how a simple quote web service with XFire. This post will implement the same webservice using XFire and Spring.

WEB-INF/web.xml

Configure the xfire dispatcher servlet and the spring config files in the web.xml

<context-param>
	<param-name>contextConfigLocation</param-name>
	<param-value>/WEB-INF/applicationContext.xml
	classpath:org/codehaus/xfire/spring/xfire.xml</param-value>
</context-param>

<listener>
	<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>

<servlet>
	<servlet-name>xfire</servlet-name>
	<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
</servlet>

<servlet-mapping>
	<servlet-name>xfire</servlet-name>
	<url-pattern>/*</url-pattern>
</servlet-mapping>

WEB-INF/applicationContext.xml

Configure the service class in the applicationContext.xml file:

<beans>
    <bean id="stockQuoteService" class="demo.xfire.service.StockQuoteServiceImpl"/>
</beans>

WEB-INF/xfire-servlet.xml

Configure a SimpleUrlHandlerMapping and an XFireExporter to expose the methods of our service class:

<bean class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping">
	<property name="urlMap">
		<map>
			<entry key="/StockQuoteService">
				<ref bean="stockQuote"/>
			</entry>
		</map>
	</property>
</bean>

<bean id="stockQuote" class="org.codehaus.xfire.spring.remoting.XFireExporter">
	<property name="serviceFactory">
		<ref bean="xfire.serviceFactory"/>
	</property>
	<property name="xfire">
		<ref bean="xfire"/>
	</property>
	<property name="serviceBean">
		<ref bean="stockQuoteService"/>
	</property>
	<property name="serviceClass">
		<value>demo.xfire.service.StockQuoteService</value>
	</property>
</bean>

Service interface

public interface StockQuoteService {
  public Float getStockQuote(String security);
}

Service Implementation

public class StockQuoteServiceImpl {

protected final Log log = LogFactory.getLog(getClass());

public Float getStockQuote(String security)
  {
    Random rand = new Random();
    log.debug("Retrieving quote for "+ security);
    return new Float(rand.nextInt(101));
  }
}

Testing

After the demo application has been deployed the url will be similar to http://localhost:8080/xfire-spring-demo/StockQuoteService?wsdl for tomcat.

To run requests against the web service you could use soapUI.

The Code

You can download the war file with the code here xfire-spring-stockquote.war

If you are not using Tomcat you need to change the location of the log file in the log4j.properties file.

Using Properties Files in Mule Configuration

In a previous post I looked at how to use quartz to trigger events in mule – we had a cron expression which dictated when an event occurred. This post explains how to externalise this cron expression to a properties file.

We create a properties file (application.properties) with the cron expression. This properties file should be on the classpath.

cron.expression=0 24 15 * * ?

First we reference our properties file in the mule config:

<environment-properties>
  <file-properties location="application.properties"/>
</environment-properties>

We can then use the same syntax as Spring to acces the parameter in the properties file:

<endpoint name="quartz.in" address="quartz:/myService">
  <properties>
    <property name="cronExpression" value="${cron.expression}" />
  </properties>
</endpoint>

This example shows how to externalise configuration properties to a properties file.

Using environment variable to control the location of log files in Tomcat

You can control the location of log files in Tomcat using the ${catalina.home} environment variable.

Example:

log4j.rootLogger=DEBUG, file

log4j.appender.file=org.apache.log4j.RollingFileAppender

log4j.appender.file.layout=org.apache.log4j.PatternLayout
log4j.appender.file.layout.ConversionPattern=%d{dd-MMM HH:mm:ss.SSS} %p - %C.%M(%L) | %m%n
log4j.appender.file.File=${catalina.home}/logs/applicationname.log

Log4j – Reporting application errors by email

This post shows how you can setup log4j to send email when errors occur in your application. log4j.properties extract:

# Root category priority: DEBUG, Appender:mail
log4j.rootCategory=debug, mail

# Configuration for receiving e-mails when ERROR messages occur.
log4j.appender.mail=org.apache.log4j.net.SMTPAppender
log4j.appender.mail.To=admin@company.com
log4j.appender.mail.From=error@application-name.com
log4j.appender.mail.SMTPHost=smtp.company.com
log4j.appender.mail.Threshold=ERROR
log4j.appender.mail.BufferSize=1
log4j.appender.mail.Subject=Application Error Occurred
log4j.appender.mail.layout=org.apache.log4j.HTMLLayout

Using Quartz to trigger events in Mule

This posts shows how to use Quartz to trigger events in Mule.
Simple Trigger

Simple triggers allows you to execute a component repeatedly after a number of miliseconds. This component will be triggered 20 seconds after the application starts (startDelay=20000) and then every 10 seconds (repeatInterval=10000)

<global-endpoints>
  <endpoint name="quartz.in" address="quartz:/myService">
    <properties>
      <property name="repeatInterval" value="10000" />
      <property name="startDelay" value="20000" />
      <property name="payloadClassName" value="java.lang.String" />
    </properties>
  </endpoint>
</global-endpoints>

<mule-descriptor name="sampleComponent"
	inboundEndpoint="quartz.in"
	implementation="demo.mule.example7.SampleComponent"/>

Cron Trigger

Cron trigger allows us to execute a component based on a cron trigger (more information on cron triggers can be found here ). This component will be triggered every day at 8:00.

<global-endpoints>
  <endpoint name="quartz.in" address="quartz:/myService">
    <properties>
      <property name="cronExpression" value="0 00 08 * * ?" />
    </properties>
  </endpoint>
</global-endpoints>

<mule-descriptor name="sampleComponent"
	inboundEndpoint="quartz.in"
	implementation="demo.mule.SampleComponent"/>