JAXB Custom Data Binding

In a previous post I experimented consuming WCF web services using various Java WS frameworks and tools. As pointed out by Alex, the one that I missed out was wsimport which is bundled as part of JSE6.

Like many other tools, it supports both Ant task and command line interface (CLI). The CLI for wsimport is quite simple - in my case I generated the source code and client stub library like so:

D:\Program Files\Java\jdk1.6.0_11\bin>wsimport -d /temp/generated -s /temp/gensrc -keep http://localhost/PromoService.svc?wsdl
parsing WSDL...


generating code...

D:\Program Files\Java\jdk1.6.0_11\bin>

All the rest is similar to the results of IntelliJ shown in my previous post. There are two problems with the generated PromoInfo.java which is a data/value object:

1. string fields are generated as JAXBElement<String>
2. dateTime fields are generated as XMLGregorianCalendar

I want to use core java data types on the data objects so that they can be easily integrated with other frameworks without having to do conversion. Examining my schema (on http://localhost/PromoService.svc?xsd=xsd2) the PromoInfo complex type is defined as

It is obvious that the xs:string and xs:dateTime were not converted into the desired java types. To solve my problems I specified customised JAXB binding rules in an external file - custombinding.xml like so

The attribute generateElementProperty="false" on line 2 tells wsimport not to generate JAXBElement but to generate native java data types instead.

The javaType element on line 3 defines the binding between "xs:dateTime" and "java.util.Date" because by default xml dateTime binds to javax.xml.datatype.XMLGregorianCalendar as shown here.

Once the binding is defined, rerunning the wsimport tool with the -b switch will produce the desired output:

D:\Program Files\Java\jdk1.6.0_11\bin>wsimport -d /temp/generated -s /temp/gensrc -b /temp/custombinding.xml http://localhost/PromoService.svc?wsdl
parsing WSDL...


generating code...
Note: D:\temp\gensrc\org\w3\_2001\xmlschema\Adapter1.java uses or overrides a deprecated API.
Note: Recompile with -Xlint:deprecation for details.

This time the generated PromoInfo.java looks much better:

...
public class PromoInfo {

    @XmlElement(name = "PromoDateTime", type = String.class)
    @XmlJavaTypeAdapter(Adapter1 .class)
    @XmlSchemaType(name = "dateTime")
    protected Date promoDateTime;
    @XmlElement(name = "PromoDescription", nillable = true)
    protected String promoDescription;
    @XmlElement(name = "PromoName", nillable = true)
    protected String promoName;
    @XmlElement(name = "PromoVenue", nillable = true)
    protected String promoVenue;
...

Consuming WCF Web Service Using Groovy Client

Last month, I developed some simple web services using WCF and consumed it using various web service frameworks in Java. Now I have implemented the web service client using GroovyWS, which is an add-on module to Groovy. It uses CXF under the hood.

To add the GroovyWS library, I simply copied its JAR file groovy-all-1.5.6.jar into the Groovy's lib directory (it can either go in {groovy.home}/lib or {user.home}/.groovy/lib according to the groovy-starter.conf file). Then run the following script from Groovy Console:

import groovyx.net.ws.WSClient
def proxy = new WSClient("http://localhost/PromoService.svc?wsdl", 
                this.class.classLoader)
        
def keywords = proxy.GetKeywordsFromMySpace("http://someurl/somepage.htm")
if(keywords!=null) {
    if (proxy.HasPromo(keywords)) {
        def promo = proxy.GetFirstPromo(keywords)
        println "Promo: ${promo?.promoName?.getValue()}, ${promo?.promoDateTime}"
    }
}

gives the result:

BindingInfo = [BindingInfo http://schemas.xmlsoap.org/wsdl/soap/]
o = SOAPBinding ({http://schemas.xmlsoap.org/wsdl/soap/}binding):
required=null
transportURI=http://schemas.xmlsoap.org/soap/http
Promo: Batman The Dark Knight, 2008-07-30T10:00:00

That's all!

I then re-did it using Eclipse 3.4 with Groovy Plug-in to create the Groovy project by following the instructions from the same web site. Then I added the JAR files into the dependency:

• ant.jar from Apache Ant 1.7.0 - this is needed by GroovyWS but not included in its distribution
• groovy-all-1.5.6.jar

The Groovy code for the test client is very simple:

package svdemo

import groovyx.net.ws.WSClient

/**
 * @author ROMENL
 *
 */
public class Program{

 /**
  * @param args
  */
 public static void main(def args){
  def proxy = new WSClient("http://localhost/PromoService.svc?wsdl", 
    Program.class.classLoader)
  
  def keywords = proxy.GetKeywordsFromMySpace("http://someurl/somepage.htm")
  if(keywords!=null) {
   if (proxy.HasPromo(keywords)) {
    def promo = proxy.GetFirstPromo(keywords)
    println "Promo: ${promo?.promoName?.getValue()}, ${promo?.promoDateTime}"
   }
  }
 }
}

Compiling then running the program yielded:

18/08/2008 12:19:33 PM org.apache.cxf.endpoint.dynamic.DynamicClientFactory outputDebug
INFO: Created classes: org.tempuri.GetFirstPromo, org.tempuri.GetFirstPromoResponse, org.tempuri.GetKeywordsFromMySpace, org.tempuri.GetKeywordsFromMySpaceResponse, org.tempuri.HasPromo, org.tempuri.HasPromoResponse, org.tempuri.ObjectFactory, com.microsoft.schemas._2003._10.serialization.ObjectFactory, org.datacontract.schemas._2004._07.svdemo.ObjectFactory, org.datacontract.schemas._2004._07.svdemo.PromoInfo
BindingInfo = [BindingInfo http://schemas.xmlsoap.org/wsdl/soap/]
o = SOAPBinding ({http://schemas.xmlsoap.org/wsdl/soap/}binding):
required=null
transportURI=http://schemas.xmlsoap.org/soap/http
Promo: Batman The Dark Knight, 2008-07-30T10:00:00

Much of the output was produced by CXF. Only the last line was produced by the test program. As you can see, the major difference between the Groovy version and the Java version using CXF is that in Java, you will use the wsdl2java tool to generate the Java client proxy and the data contract classes up front; but in Groovy, all that is automatic when you run the script. This makes the Groovy code very simple and small. However, the downside of this is that the IDE (Eclipse) cannot know the methods and members of the class up front. Therefore, there is no code-completion (intellisense) support for the business methods. Since I heavily rely on code-completion of the IDEs, this is a big disadvantage about dynamic languages for me (I do not memorise all the class members and methods names, and I do not read all the API docs either. I usually try to figure out the methods I need by looking at their names).

There are a couple of things I had to do for my code to run without errors:

1. I had to upgrade my JRE used by Eclipse to a 1.6.0_u10rc. Eclipse automatically addes a bunch of JARs from the JRE, including the resources.jar, which includes the JAXB classes. In an earlier version of my JRE (1.6.0_u2) the JAXB was version 2.0, but the CXF bundled in GroovyWS 0.3.1 requires v2.1. However, if you are not using Eclipse (e.g. using the Groovy Console directly), this step is not required
2. The CXF bundled with GroovyWS 0.3.1 had problem generating the code from WSDL - it complained about a namespace "doesnt contain ObjectFactory.class or jaxb.index". It turned out to be a CXF bug and had been fixed in CXF 2.1.1, thanks to a post by Bernie. After I replaced the org/apache/cxf branch of the groovyws-all-0.3.1.jar using the contents in cxf-2.1.1.jar, it was smooth sailing.

Related Posts:

• Consuming RESTful Service with Erlang
• Consuming Web Services from Android
• Consuming Web Services By JavaME
• Consuming WCF Web Service Using Java Client

Consuming WCF Web Service Using Java Client

[Updated on 2009-06-22] The JSE's native wsimport tool has been added along with custom binding in a more recent post - JAXB Custom Data Binding.

From the previous post I showed how to create a simple web service using WCF and consume it with a windows console application written in C#.

To have the same web services consumed by a Java client, I needed to make the web service WS-I Basic Profile 1.1 compliant so that it becomes portable cross-platforms. To do this, it is simply a matter of following instructions on MSDN. In my case, I modified Web.Config file: in <services> section I changed the wsHttpBinding into basicHttpBinding and removed the identity tags. The resulting snippet:

IntelliJ IDEA

To generate the Java web service client, I created a Java project in IDEA 7.0.2. Then right-click on the src tree to select New -> Web Service Client, then paste in the wsdl url (http://localhost/PromoService.svc?wsdl). Bingo, IDEA generates all the interface and class files, together with the client test code. I guess it is using JAXB under the hood. Adding the bits into the client test code resulted:

import svdemo.PromoService;
import svdemo.PromoInfo;

public class SvdemoClient {
  public static void main(String[] argv) {
      svdemo.IPromoService service = (new PromoService()).getBasicHttpBindingIPromoService();
      //invoke business method
      String keywords = "action";
      if(service.hasPromo(keywords)) {
          PromoInfo promo = service.getFirstPromo(keywords);
          System.out.println("promo:"+promo.getPromoName().getValue()
                  +","+promo.getPromoDateTime());
      }   else {
          System.out.println("nothing");
      }
  }
}

Notice how the service is instantiated (code not as nice as in C# version). Also, the PromoInfo class's members data type are of JAXBElement and XMLGregorianCalender..., which are not as nice as native primitive types. But it works - here is the output:

promo:Batman The Dark Knight,2008-07-30T10:00:00

NetBeans 6.0

I created a Java application project in NetBeans. From the project's source branch, right-clicking will bring up the New -> Web Service Client option. Providing the WSDL URI and selecting JAX-WS style will generate the WS client classes. The results are similar to IDEA, the exact same client code (see above) can be used to test the client. However, it is extremely slow so that I thought NetBeans froze. This happens to almost every step onwards. I eventually gave up on NetBeans. Maybe it is time to upgrade.

CXF

Apache CXF is the 2nd generation XFire. By default, it generates JAXB style binding. It came with wsdl2java utility. To generate the client code from wsdl, I used the following commands:

mkdir d:\projects\svdemocxf
wsdl2java -d d:\projects\svdemocxf -client -ant http://localhost/PromoService.svc?wsdl

I then moved all the source files into a src directory. Then build the project.

D:\projects\svdemocxf>ant build
D:\projects\svdemocxf>ant IPromoServiceClient
Buildfile: build.xml

compile:
    [javac] Compiling 15 source files to D:\projects\romen\build\classes

IPromoServiceClient:
     [java] Invoking hasPromo...
     [java] hasPromo.result=false
     [java] Invoking getFirstPromo...
     [java] getFirstPromo.result=null
     [java] Invoking getKeywordsFromMySpace...
     [java] getKeywordsFromMySpace.result=

BUILD SUCCESSFUL
Total time: 4 seconds

Note that the environment variable CXF_HOME had to be defined and point to the CXF installation directory for the ant build.xml file to work.

I added the client testing code similar to the one above:

package svdemo;
import org.datacontract.schemas._2004._07.svdemo.PromoInfo;
import org.tempuri.*;

public class Program {

 /**
  * @param args
  */
 public static void main(String[] args) {
  IPromoService service=(new PromoService()).getBasicHttpBindingIPromoService();
  String keywords="action";
  if(service.hasPromo(keywords)) {
   PromoInfo promo=service.getFirstPromo(keywords);
   System.out.println("promo:"+promo.getPromoName().getValue()
     +","+promo.getPromoDateTime());
  } else {
   System.out.println("nothing");
  }
 }
}

To run the test, I added the following target to the build.xml file:

Running the RunTest target yields:

D:\projects\svdemocxf>ant RunTest
Buildfile: build.xml

compile:
    [javac] Compiling 16 source files to D:\projects\svdemocxf\build\classes

RunTest:
     [java] promo:Batman The Dark Knight,2008-07-30T10:00:00

BUILD SUCCESSFUL
Total time: 4 seconds

Axis2

Apache Axis2 (v1.4) comes with the wsdl2java utility which generates java source code from WSDL file. Using the following command:

wsdl2java.bat -o \projects\svdemoAxis -p svdemoClient -uri http://localhost/PromoService.svc?wsdl

This generates the client stub class PromoServiceStub and dozens of inner classes - one for each input/output parameter and data type! The client test code ends up like this:

package svdemoClient;

import java.rmi.RemoteException;
import org.apache.axis2.AxisFault;
import svdemoClient.PromoServiceStub.PromoInfo;

public class Program {

 /**
  * @param args
  */
 public static void main(String[] args) {
  try {
   PromoServiceStub service=new PromoServiceStub();
   String keywords = "action";
   
   PromoServiceStub.HasPromo hasPromoPara=new PromoServiceStub.HasPromo();
   hasPromoPara.setKeyword(keywords);
   PromoServiceStub.HasPromoResponse hasPromoResp = service.HasPromo(hasPromoPara);
   if(hasPromoResp.getHasPromoResult()) {
    PromoServiceStub.GetFirstPromo firstPromoPara=new PromoServiceStub.GetFirstPromo();
    firstPromoPara.setKeyword(keywords);
    PromoServiceStub.GetFirstPromoResponse firstPromoResponse = service.GetFirstPromo(firstPromoPara);
    PromoInfo promo = firstPromoResponse.getGetFirstPromoResult();
    System.out.println("promo:"+promo.getPromoName()
      +","+promo.getPromoDateTime().getTime());
   } else {
    System.out.println("nothing");
   }
  } catch (Exception e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
  
 }

}

Compiling and running it in Eclipse 3.4 yields:

promo:Batman The Dark Knight,Wed Jul 30 10:00:00 EST 2008

As shown above, the code is very UGLY! For each input parameter and output response, a class has to be instantiated (even when the parameter is simply a string). This not only makes the code long, but also very hard to read. This is the ADB binding used by Axis2 by default. Changing the binding style into xmlbeans or jibx slightly improves the esthetic and readability of the code, but not much. The following test client code snippet is written against XMLBeans binding style from Axis:

String keywords = "action";
HasPromoDocument hasPromoDoc = HasPromoDocument.Factory.newInstance();
hasPromoDoc.getHasPromo().setKeyword(keywords);
HasPromoResponseDocument hasPromoResp;
hasPromoResp = service.HasPromo(hasPromoDoc);

if(hasPromoResp!=null && hasPromoResp.getHasPromoResponse().getHasPromoResult()) {
 GetFirstPromoDocument firstPromoDoc=GetFirstPromoDocument.Factory.newInstance();
 firstPromoDoc.getGetFirstPromo().setKeyword(keywords);
 GetFirstPromoResponseDocument firstPromoResp=
  service.GetFirstPromo(firstPromoDoc);
 if(firstPromoResp!=null) {
  PromoInfo promo=firstPromoResp.getGetFirstPromoResponse().getGetFirstPromoResult();
  System.out.println("promo:"+promo.getPromoName()
    +","+promo.getPromoDateTime().getTime());
 }
}

This article from DeveloperWorks gives more insights and examples on the different types of Axis2 bindings. As of Axis2 v1.4, it came with a JAXB experimental support. The above is just my feeble attempt on Axis2. However, Axis2's wsdl2java is quite capable of generating esthetic code - Eclipse 3.4 uses Axis under the hood (using JAXB I guess) to generate web service clients.

Eclipse Ganymede JEE Distribution

Eclipse Ganymede (v3.4) has an option to add new Web Service Client. However, it requires you to specify a Server - this is totally wrong, there is absolutely no need to have a server definition to generate WS client code. However, I just played along and defined a Tomcat 6.0 server. It allows me to continue with the WS Client wizard. Then, after I specified the WSDL URI, it gave me the error:

IWAB0503E Unable to update Java build path. Please check your system environment.
    Java Model Exception: Java Model Status [Build path contains duplicate entry: 'D:tools/eclipse/plugins/org.apache.axis_1.4.0.v200806030120/lib/axis.jar' for project 'svdemoAxis']
    ...

Days later, I upgraded one of the Eclipse plugins (which was auto-detected and suggested by Eclipse), then things were better. Retrying generating the web service client resulted in a new WebServiceProject project being created. I then added the testing client:

package svdemoClient;
import java.rmi.RemoteException;

import org.datacontract.schemas._2004._07.svdemo.PromoInfo;
import org.tempuri.*;

public class Program {

 /**
  * @param args
  */
 public static void main(String[] args) {
  String keywords="action";
  IPromoService service=(new IPromoServiceProxy()).getIPromoService();
  try {
   if(service.hasPromo(keywords)) {
    PromoInfo promo=service.getFirstPromo(keywords);
    System.out.println("promo:"+promo.getPromoName()
      +","+promo.getPromoDateTime().getTime());
   }
  } catch (Exception e) {
   e.printStackTrace();
  }
 }

}

Note that the promotDateTime field generated is of java.util.Calendar type, not XMLCalendar.

Related Posts:

• JAXB Custom Data Binding
• Consuming RESTful Service with Erlang
• Consuming Web Services from Android
• Consuming Web Services By JavaME
• Consuming WCF Web Service Using Groovy Client

WCF In 1 Hour

As part of a product concept study, I needed to prototype a web service to be consumed by a telephony service. This is to simulate a targeted promotion campaign in the telco environment.

The web service allows the consumer to check by keyword for any related promotions. If there are any, the consumer can retrieve the promotion and use the details of the promotion information - e.g. send a SMS or email to the subscriber to notify him/her about the promotion. I had the following in mind about the promotion web service:

1. to store the promotion data in an xml file
2. have a boolean service to check whether there are any promotions in the database with matching keyword
3. have another service method to return the promotion data (an object/composite type) with matching keyword
4. the promotion information need to be short and concise, making it suitable for sending in a SMS

The XML file I chose to create looked something like this:

 
  New Years Eve Concert
  The biggest event of the year. Artists from all around
  the country.
  Domain
  2008-12-31 20:00:00
  New Year's Eve
 
 
  Batman The Dark Knight
  
   Meet stars in Batman in person - Chritian Bale, Michael Caine.
  
  Star City
  2008-7-30 10:00:00
  Batman, action
 
 
  Jazz Night
  
   Jazz lovers' do not miss this once in a lifetime opportunity.
  
  The Jazz Club
  2008-10-30 21:00:00
  Jazz
 

After a short consideration, I decided to use .NET WCF for the web service and LINQ for the XML querying. The only problem is that I knew nothing about WCF and little about LINQ (I lived in the Java land). But it did not stop me. In fact, it made it more exciting.

The first thing I did was to create a WCF project in VS.2008. VS.2008 made it extremely easy. I then modified the auto-generated service interface and the service implementation files:

The serivce interface is IPromoService

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.Text;

namespace svdemo {
    [ServiceContract]
    public interface IPromoService {
        /// 

        /// Tests whether there are any promotions with matching keyword.
        /// 
        /// <param name="keyword">the keyword to be matched. Case in-sensitive, single word only</param>
        /// <returns>whether there are any promotions with matching keyword</returns>
        [OperationContract]
        bool HasPromo(string keyword);

        /// 

        /// Get the first promotion which matches the given keyword.
        /// 
        /// <param name="keyword">case in-sensitive, single word only.</param>
        /// <returns>The first promotion with matching keyword.</returns>
        [OperationContract]
        PromoInfo GetFirstPromo(string keyword);
    }


    // Use a data contract as illustrated in the sample below to add composite types to service operations.
    [DataContract]
    public class PromoInfo {
        string promoName;
        string promoDescription;
        string promoVenue;
        DateTime promoDateTime;

        public PromoInfo(string name, string desc, string venue, DateTime dt) {
            promoName = name;
            promoDescription = desc;
            promoVenue = venue;
            promoDateTime = dt;
        }
        [DataMember]
        public string PromoName {
            get { return promoName; }
            set { promoName = value; }
        }

        [DataMember]
        public string PromoDescription {
            get { return promoDescription; }
            set { promoDescription = value; }
        }

        [DataMember]
        public string PromoVenue {
            get { return promoVenue; }
            set { promoVenue = value; }
        }

        [DataMember]
        public DateTime PromoDateTime {
            get { return promoDateTime; }
            set { promoDateTime = value; }
        }
    }
}

The service implementation PromoService:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.Text;
using System.Xml.Linq;

namespace svdemo {
    public class PromoService : IPromoService {
        XDocument doc;
        public PromoService() {
            doc = XDocument.Load(@"D:\projects\SigvalueWS\svdemo\svdemo\data.xml");
        }

        public bool HasPromo(string keyword) {
            if (keyword == null)
                return false;

            string kw = keyword.ToUpper();
            var q = from p in doc.Descendants("Promotion")
                    where ((string) p.Element("Tags")).ToUpper().Contains(kw)
                    select p.Element("Name").Value;
            return (q.Count() > 0);
        }

        public PromoInfo GetFirstPromo(string keyword) {
            if (keyword == null)
                return null;
            string kw = keyword.ToUpper();
            var q = from p in doc.Descendants("Promotion")
                    where ((string) p.Element("Tags")).ToUpper().Contains(kw)
                    select new PromoInfo(p.Element("Name").Value,
                        p.Element("Description").Value,
                        p.Element("Venue").Value,
                        DateTime.Parse( p.Element("DateTime").Value));
            PromoInfo promo = q.First();
            return promo;
        }
    }
}

Running this project (Ctrl+F5) will deploy the web service onto a test web server and the wsdl can be obtained from the url http://localhost:2144/PromoService.svc?wsdl

To test the consumption of the web service, I created a console application project in C#. Adding a service reference (by copying the above URL into it) automatically generates the required web service client entry point code, client proxy, and the DTO PromoInfo class. So consuming the service is a no-brainer:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using svdemoClient.ServiceReference;

namespace svdemoClient {
    class Program {
        static void Main(string[] args) {
            PromoServiceClient client = new PromoServiceClient();
            string keyword="Jazz";
            if (client.HasPromo(keyword)){
                PromoInfo promo=client.GetFirstPromo(keyword);
                Console.WriteLine(
                    String.Format("got {0}, {1}", 
                    promo.PromoName, promo.PromoDateTime)
                );
            }else
                Console.WriteLine("nothing");
            System.Threading.Thread.Sleep(3000);
            client.Close();
        }
    }
}

Although this is my very first attempt to use WCF and LINQ to XML, the whole thing took me an hour and a bit and majority of the time was used in googling on how to use LINQ to XML.

Note: it is better to modify the transport setting to use Basic HTTP instead of TCP to improve interoperability. See here for more details.