Deploy WSDL file as OSGI Bundle in Apache Karaf

Introduction

WSDL file describes webservices. Java classes are often generated from WSDL. For this purpose, we could use command line tools (e. g. wsdl2Java or wsimport) or using maven plugin.

From the other side, we have Apache Karaf which is OSGI container. Karaf has installed by default many deployers for creating OSGi bundles from files, e. g. Blueprint deployer, Spring deployer or War deployer.

It is easy to generate java classes from WSDL file and also to create custom deployer for Karaf, so why do not join these two features?

Installation of WSDL deployer

Source code of my WSDL deployer is provided here. You can download and build it:

mvn clean install

We also need Karaf. I will use the newest version 4.0.5. It could be download from Karaf website. When you download and unpack it, you can run it:

$ cd PUT_PATH_TO_KARAF_DIR_HERE
$ ./bin/karaf
    __ __                  ____      
   / //_/____ __________ _/ __/      
  / ,<  / __ / ___/ __ / /_        
 / /| |/ /_/ / /  / /_/ / __/        
/_/ |_|\__,_/_/   \__,_/_/         

Apache Karaf (4.0.5)

Hit '<tab>' for a list of available commands
and '[cmd] --help' for help on a specific command.
Hit '<ctrl-d>' or type 'system:shutdown' or 'logout' to shutdown Karaf.

karaf@root()>

and install commons-io and wsdl-delpoyer bundles:

karaf@root()> install -s mvn:org.apache.servicemix.bundles/org.apache.servicemix.bundles.commons-io/1.4_3
Bundle ID: 52
karaf@root()> install -s mvn:com.github.alien11689.karaf/wsdl-deployer/1.0.0-SNAPSHOT
Bundle ID: 53

Install WSDL from Karaf shell

I will test deployer using WSDL file named exampleService-2.0.0.wsdl (provided WSDL is similar to this, but has another namespace in types schama for testing purpose):

<?xml version="1.0"?>
<wsdl:definitions
    xmlns:soap="http://schemas.xmlsoap.org/wsdl/soap/"
    xmlns:wsu="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd"
    xmlns:soapenc="http://schemas.xmlsoap.org/soap/encoding/"
    xmlns:tns="http://Example.org"
    xmlns:sns="http://Example.org/schema"
    xmlns:wsa="http://schemas.xmlsoap.org/ws/2004/08/addressing"
    xmlns:wsp="http://schemas.xmlsoap.org/ws/2004/09/policy"
    xmlns:wsap="http://schemas.xmlsoap.org/ws/2004/08/addressing/policy"
    xmlns:xsd="http://www.w3.org/2001/XMLSchema"
    xmlns:msc="http://schemas.microsoft.com/ws/2005/12/wsdl/contract"
    xmlns:wsaw="http://www.w3.org/2006/05/addressing/wsdl"
    xmlns:soap12="http://schemas.xmlsoap.org/wsdl/soap12/"
    xmlns:wsa10="http://www.w3.org/2005/08/addressing"
    xmlns:wsx="http://schemas.xmlsoap.org/ws/2004/09/mex"
  targetNamespace="http://Example.org"
    xmlns:wsdl="http://schemas.xmlsoap.org/wsdl/">
    <wsdl:types>
        <xsd:schema targetNamespace="http://Example.org/schema" elementFormDefault="qualified" >
            <xsd:element name="Add">
                <xsd:complexType>
                    <xsd:sequence>
                        <xsd:element minOccurs="0" name="a" type="xsd:int" />
                        <xsd:element minOccurs="0" name="b" type="xsd:int" />
                    </xsd:sequence>
                </xsd:complexType>
            </xsd:element>
            <xsd:element name="AddResponse">
                <xsd:complexType>
                    <xsd:sequence>
                        <xsd:element minOccurs="0" name="result" type="xsd:int" />
                    </xsd:sequence>
                </xsd:complexType>
            </xsd:element>
            <xsd:element name="Subtract">
                <xsd:complexType>
                    <xsd:sequence>
                        <xsd:element minOccurs="0" name="a" type="xsd:int" />
                        <xsd:element minOccurs="0" name="b" type="xsd:int" />
                    </xsd:sequence>
                </xsd:complexType>
            </xsd:element>
            <xsd:element name="SubtractResponse">
                <xsd:complexType>
                    <xsd:sequence>
                        <xsd:element minOccurs="0" name="result" type="xsd:int" />
                    </xsd:sequence>
                </xsd:complexType>
            </xsd:element>
        </xsd:schema>
    </wsdl:types>
    <wsdl:message name="ICalculator_Add_InputMessage">
        <wsdl:part name="parameters" element="sns:Add" />
    </wsdl:message>
    <wsdl:message name="ICalculator_Add_OutputMessage">
        <wsdl:part name="parameters" element="sns:AddResponse" />
    </wsdl:message>
    <wsdl:message name="ICalculator_Subtract_InputMessage">
        <wsdl:part name="parameters" element="sns:Subtract" />
    </wsdl:message>
    <wsdl:message name="ICalculator_Subtract_OutputMessage">
        <wsdl:part name="parameters" element="sns:SubtractResponse" />
    </wsdl:message>
    <wsdl:portType name="ICalculator">
        <wsdl:operation name="Add">
            <wsdl:input wsaw:Action="http://Example.org/ICalculator/Add" message="tns:ICalculator_Add_InputMessage" />
            <wsdl:output wsaw:Action="http://Example.org/ICalculator/AddResponse" message="tns:ICalculator_Add_OutputMessage" />
        </wsdl:operation>
        <wsdl:operation name="Subtract">
            <wsdl:input wsaw:Action="http://Example.org/ICalculator/Subtract" message="tns:ICalculator_Subtract_InputMessage" />
            <wsdl:output wsaw:Action="http://Example.org/ICalculator/SubtractResponse" message="tns:ICalculator_Subtract_OutputMessage" />
        </wsdl:operation>
    </wsdl:portType>
    <wsdl:binding name="DefaultBinding_ICalculator" type="tns:ICalculator">
        <soap:binding transport="http://schemas.xmlsoap.org/soap/http" />
        <wsdl:operation name="Add">
            <soap:operation soapAction="http://Example.org/ICalculator/Add" style="document" />
            <wsdl:input>
                <soap:body use="literal" />
            </wsdl:input>
            <wsdl:output>
                <soap:body use="literal" />
            </wsdl:output>
        </wsdl:operation>
        <wsdl:operation name="Subtract">
            <soap:operation soapAction="http://Example.org/ICalculator/Subtract" style="document" />
            <wsdl:input>
                <soap:body use="literal" />
            </wsdl:input>
            <wsdl:output>
                <soap:body use="literal" />
            </wsdl:output>
        </wsdl:operation>
    </wsdl:binding>
    <wsdl:service name="CalculatorService">
        <wsdl:port name="ICalculator" binding="tns:DefaultBinding_ICalculator">
            <soap:address location="http://localhost/ICalculator" />
        </wsdl:port>
    </wsdl:service>
</wsdl:definitions>

We could install it via command:

karaf@root()> install -s wsdl:file:PUT_PATH_TO_WSDL_HERE/exampleService-2.0.0.wsdl\$package=org.github.alien11689.example&s1=http://Example.org/schema&t1=org.github.alien11689.example.schema
Bundle ID: 54

File must have format ${bundleSymbolicName}-${version}.wsdl.

Provided options are:

  • package – allows to change package of generated interface
  • pair s1 and t1 – maps schema in WSDL to package (WSDL deployer is in draft verion nowadays provides options to map only one schema).

Karaf has installed this file:

karaf@root()> headers 54

Bundle 54
---------
Manifest-Version = 2

Bundle-ManifestVersion = 2
Bundle-SymbolicName = exampleService-2.0.0.wsdl
Bundle-Version = 2.0.0

Export-Package =
    org.github.alien11689.example.schema;version=2.0.0,
    org.github.alien11689.example;version=2.0.0
Import-Package =
    javax.jws,
    javax.jws.soap,
    javax.xml.bind.annotation,
    javax.xml.namespace,
    javax.xml.ws

Install WSDL by putting it into Karaf drop folder

You can also install WSDL file by copying it to deploy directory:

cp PUT_PATH_TO_WSDL_HERE/exampleService-2.0.0.wsdl PUT_PATH_TO_KARAF_DIR_HERE/deploy/deployedExampleService-2.0.0.wsdl

It is much more simple to do, but do not allow for customization (e. g. namespace to package mapping). It creates bundle:

karaf@root()> list | grep deployedExampleService
55 | Active |  80 | 2.0.0          | deployedExampleService-2.0.0.wsdl
karaf@root()> headers 55

Bundle 55
---------
Manifest-Version = 2

Bundle-ManifestVersion = 2
Bundle-SymbolicName = deployedExampleService-2.0.0.wsdl
Bundle-Version = 2.0.0

Export-Package =
    org.example;version=2.0.0,
    org.example.schema;version=2.0.0
Import-Package =
    javax.jws,
    javax.jws.soap,
    javax.xml.bind.annotation,
    javax.xml.namespace,
    javax.xml.ws

How does it work?

Deployer uses wsimport command to create in temporary directory and compile generated java classes. Compiled class are packed with MANIFEST.MF into service.jar and such jar is really installed in OSGi container. For example, my temporary directory is /tmp/4ff81631-3c08-487a-b731-1f95c568026f:

$ tree /tmp/4ff81631-3c08-487a-b731-1f95c568026f
/tmp/4ff81631-3c08-487a-b731-1f95c568026f
├── Jaxb-binding.xml
├── Jaxws-binding.xml
├── service.wsdl
├── src
│   └── org
│       └── github
│           └── alien11689
│               └── example
│                   ├── CalculatorService.java
│                   ├── ICalculator.java
│                   └── schema
│                       ├── Add.java
│                       ├── AddResponse.java
│                       ├── ObjectFactory.java
│                       ├── package-info.java
│                       ├── Subtract.java
│                       └── SubtractResponse.java
└── target
    ├── org
    │   └── github
    │       └── alien11689
    │           └── example
    │               ├── CalculatorService.class
    │               ├── ICalculator.class
    │               └── schema
    │                   ├── Add.class
    │                   ├── AddResponse.class
    │                   ├── ObjectFactory.class
    │                   ├── package-info.class
    │                   ├── Subtract.class
    │                   └── SubtractResponse.class
    └── service.jar

And my service.jar contains:

$ jar tf /tmp/4ff81631-3c08-487a-b731-1f95c568026f/target/service.jar
META-INF/
META-INF/MANIFEST.MF
org/
org/github/
org/github/alien11689/
org/github/alien11689/example/
org/github/alien11689/example/schema/
org/github/alien11689/example/schema/Add.class
org/github/alien11689/example/schema/ObjectFactory.class
org/github/alien11689/example/schema/Subtract.class
org/github/alien11689/example/schema/SubtractResponse.class
org/github/alien11689/example/schema/package-info.class
org/github/alien11689/example/schema/AddResponse.class
org/github/alien11689/example/ICalculator.class
org/github/alien11689/example/CalculatorService.class

Conclusion

WSDL generation and Karaf deployers could be easily joined and simplified creation of OSGi bundles without explicite creation of jar. Provided WSDL deployer is just draft, but could be very useful when we have many WSDLs and do not want to create separate artifacts for them.

Source code of WSDL deployer is provided here.

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Inconsistent Dependency Injection to domains with Grails

I've encountered strange behavior with a domain class in my project: services that should be injected were null. I've became suspicious as why is that? Services are injected properly in other domain classes so why this one is different?

Constructors experiment

I've created an experiment. I've created empty LibraryService that should be injected and Book domain class like this:

class Book {
def libraryService

String author
String title
int pageCount

Book() {
println("Finished constructor Book()")
}

Book(String author) {
this()
this.@author = author
println("Finished constructor Book(String author)")
}

Book(String author, String title) {
super()
this.@author = author
this.@title = title
println("Finished constructor Book(String author, String title)")
}

Book(String author, String title, int pageCount) {
this.@author = author
this.@title = title
this.@pageCount = pageCount
println("Finished constructor Book(String author, String title, int pageCount)")
}

void logInjectedService() {
println(" Service libraryService is injected? -> $libraryService")
}
}
class LibraryService {
def serviceMethod() {
}
}

Book has 4 explicit constructors. I want to check which constructor is injecting dependecies. This is my method that constructs Book objects and I called it in controller:

class BookController {
def index() {
constructAndExamineBooks()
}

static constructAndExamineBooks() {
println("Started constructAndExamineBooks")
Book book1 = new Book().logInjectedService()
Book book2 = new Book("foo").logInjectedService()
Book book3 = new Book("foo", 'bar').logInjectedService()
Book book4 = new Book("foo", 'bar', 100).logInjectedService()
Book book5 = new Book(author: "foo", title: 'bar')
println("Finished constructor Book(Map params)")
book5.logInjectedService()
}
}

Analysis

Output looks like this:

Started constructAndExamineBooks
Finished constructor Book()
Service libraryService is injected? -> eu.spoonman.refaktor.LibraryService@2affcce2
Finished constructor Book()
Finished constructor Book(String author)
Service libraryService is injected? -> eu.spoonman.refaktor.LibraryService@2affcce2
Finished constructor Book(String author, String title)
Service libraryService is injected? -> null
Finished constructor Book(String author, String title, int pageCount)
Service libraryService is injected? -> null
Finished constructor Book()
Finished constructor Book(Map params)
Service libraryService is injected? -> eu.spoonman.refaktor.LibraryService@2affcce2

What do we see?

  1. Empty constructor injects dependencies.
  2. Constructor that invokes empty constructor explicitly injects dependencies.
  3. Constructor that invokes parent's constructor explicitly does not inject dependencies.
  4. Constructor without any explicit call declared does not call empty constructor thus it does not inject dependencies.
  5. Constructor provied by Grails with a map as a parameter invokes empty constructor and injects dependencies.

Conclusion

Always explicitily invoke empty constructor in your Grail domain classes to ensure Dependency Injection! I didn't know until today either!