Axis Developer's Guide

1.0 Version

Table of Contents

Introduction
General Guidelines
Development Environment
Pluggable-Components
   Discovery
   Logging/Tracing
Configuration Properties
Exception Handling
Compile and Run
Internationalization
   Extending Message Files
Adding Testcases
Test and Samples Structure
Adding Source Code Checks
Debugging
Running the JAX-RPC Compatibility Tests
 

Introduction

This guide is a collection of topics related to developing code for Axis.

General Guidelines

Development Environment

The following packages are required for axis development:


The axis jar files are built in the xml-axis/java/build/lib directory.   Here is an example CLASSPATH, which I use when developing code:

D:\\xerces\\xerces-1_4_2\\xerces.jar
G:\\junit3.7\\junit.jar
G:\\xml-axis\\java\\build\\lib\\commons-discovery.jar
G:\\xml-axis\\java\\build\\lib\\commons-logging.jar
G:\\xml-axis\\java\\build\\lib\\wsdl4j.jar
G:\\xml-axis\\java\\build\\lib\\axis.jar
G:\\xml-axis\\java\\build\\lib\\log4j-1.2.4.jar
G:\\xml-axis\\java\\build\\classes
If you access the internet via a proxy server, you'll need to set an environment variable so that the Axis tests do the same. Set ANT_OPTS to, for example:
-Dhttp.proxyHost=proxy.somewhere.com -Dhttp.proxyPort=80 -Dhttp.nonProxyHosts="localhost"

Pluggable-Components

The Axis Architecture Guide explains the requirements for pluggable components.

Discovery

An axis-specific component factory should be created of the form:
    org.apache.axis.components.<componentType>.<factoryClassName>
For example, org.apache.axis.components.logger.LogFactory is the factory, or discovery mechanism, for the logger component/service.

The org.apache.axis.components.image package demonstrates both a factory, and supporting classes for different image tools used by AXIS. This is representative of a pluggable component that uses external tooling, isolating it behind a 'thin' wrapper to AXIS that provides only a limited interface to meet AXIS minimal requirements. This allows future designers and implementors to gain an explicit understanding of the AXIS's specific requirements on these tools.

Logging/Tracing

AXIS logging and tracing is based on the Logging component of the Jakarta Commons project, or the Jakarta Commons Logging (JCL) SPI. The JCL provides a Log interface with thin-wrapper implementations for other logging tools, including Log4J, Avalon LogKit, and JDK 1.4. The interface maps closely to Log4J and LogKit.

Using the Logger SPI

To use the JCL SPI from a Java class, include the following import statements:

For each class definition, declare and initialize a log attribute as follows:

Messages are logged to a logger, such as log by invoking a method corresponding to priority: The Log interface defines the following methods for use in writing log/trace messages to the log:

While semantics for these methods are ultimately defined by the implementation of the Log interface, it is expected that the severity of messages is ordered as shown in the above list.

In addition to the logging methods, the following are provided:

These are typically used to guard code that only needs to execute in support of logging, and that introduces undesirable runtime overhead in the general case (logging disabled).

Guidelines

Message Priorities
It is important to ensure that log message are appropriate in content and severity. The following guidelines are suggested:

Configuring the Logger

The Jakarta Commons Logging (JCL) SPI can be configured to use different logging toolkits. To configure which logger is used by the JCL, see the AXIS System Integration Guide.

Configuration of the behavior of the JCL ultimately depends upon the logging toolkit being used. The JCL SPI (and hence AXIS) uses Log4J by default if it is available (in the CLASSPATH).

Log4J
As Log4J is the prefered/default logger for AXIS, a few details are presented herein to get the developer going.

Configure Log4J using system properties and/or a properties file:

Configuration Properties

AXIS is in the process of moving away from using system properties as the primary point of internal configuration. Avoid calling System.getProperty(), and instead call AxisProperties.getProperty. AxisProperties.getProperty will call System.getProperty, and will (eventually) query other sources of configuration information.

Using this central point of access will allow the global configuration system to be redesigned to better support multiple AXIS engines in a single JVM.

Exception Handling

Guidelines for AXIS Exception Handling are based on best-practices for Exception Handling. While there are details specific to AXIS in these guidelines, they apply in principle to any project; they are included here for two reasons. First, because they are not listed elsewhere in the Apache/Jakarta guidelines (or haven't been found). Second, because adherence to these guidelines is considered crucial to enterprise ready middleware.

These guidelines are fundamentally independent of programming language. They are based on experience, but proper credit must be given to More Effective C++, by Scott Meyers, for opening the eyes of the innocent(?) many years ago.

Finally, these are guidelines. There will always be exceptions to these guidelines, in which case all that can be asked (as per these guidelines) is that they be logged in the form of comments in the code.

Compile and Run

The xml-axis/java/build.xml file is the primary 'make' file used by ant to build the application and run the tests.  The build.xml file defines ant build targets.  Read the build.xml file for more information.  Here are some of the useful targets:
  To compile the source code:
cd xml-axis/java
ant compile
To run the tests:
cd xml-axis/java
ant functional-tests
Note: these tests start a server on port 8080. If this clashes with the port used by your web application server (such as Tomcat), you'll need to change one of the ports or stop your web application server when running the tests.

Please run ant functional-tests and ant all-tests before checking in new code.

Internationalization

If you make changes to the source code that results in the generation of text (error messages or debug information), you must follow the following guidelines to ensure that your text is properly translated.

Developer Guidelines

  1. Your text string should be added as a property to the resource.properties file (xml-axis/java/src/org/apache/axis/i18n/resource.properties).  Note that some of the utility applications (i.e. tcpmon) have their own resource property files (tcpmon.properties).

  2.  
  3. The resource.properties file contains translation and usage instructions.  Entries in a message resource file are of the form <key>=<message>. Here is an example message:
  4. sample00=My name is {0}, and my title is {1}.
     

    1. sample00 is the key that the code will use to access this message.
    2. The text after the = is the message text.
    3. The {number} syntax defines the location for inserts.
  5. The code should use the static method org.apache.axis.i18n.Messages.getMessage to obtain the text and add inserts.  Here is an example usage:
  6. Messages.getMessage("sample00", "Rich Scheuerle", "Software Developer");
     

  7. All keys in the properties file should use the syntax <string><2-digit-suffix>.

  8.  
    1. Never change the message text in the properties file. The message may be used in multiple places in the code.  Plus translation is only done on new keys.

    2.  
    3. If a code change requires a change to a message, create a new entry with an incremented 2-digit suffix.

    4.  
    5. All new entries should be placed at the bottom of the file to ease translation.

    6.  
    7. We may occasionally want to trim the properties file of old data, but this should only be done on major releases.

Example

Consider the following statement:

        if ( operationName == null )
            throw new AxisFault( "No operation name specified" );

We will add an entry into org/apache/axis/i18n/resource.properties:

       noOperation=No operation name specified.

And change the code to read:

        if ( operationName == null )
            throw new AxisFault(Messages.getMessage("noOperation"));

Interface

AXIS uses the standard Java internationalization class java.util.ResourceBundle to access property files and message strings, and uses java.text.MessageFormat to format the strings using variables. AXIS provides a single class org.apache.axis.i18n.Messages that manages both ResourceBundle and MessageFormat classes. Messages methods are:

public static java.util.ResourceBundle getResourceBundle();

public static String getMessage(String key) throws java.util.MissingResourceException;

public static String getMessage(String key, String var) throws java.util.MissingResourceException;

public static String getMessage(String key, String var1, String var2) throws java.util.MissingResourceException;

public static String getMessage(String key, String[] vars) throws java.util.MissingResourceException;

AXIS programmers can work with the resource bundle directly via a call to Messages.getResourceBundle(), but the getMessage() methods should be used instead for two reasons:

  1. It's a shortcut. It is cleaner to call
    1. Messages.getMessage("myMsg00");
    than
      Messages.getResourceBundle().getString("myMsg00");

  2. The getMessage methods enable messages with variables.

The getMessage methods

If you have a message with no variables
    myMsg00=This is a string.
then simply call
    Messages.getMessage("myMsg00");


If you have a message with variables, use the syntax "{X}" where X is the number of the variable, starting at 0. For example:

    myMsg00=My {0} is {1}.
then call:
    Messages.getMessage("myMsg00","name", "Russell");
and the resulting string will be:  "My name is Russell."

You could also call the String array version of getMessage:

    Messages.getMessage("myMsg00", new String[] {"name", "Russell"});


The String array version of getMessage is all that is necessary, but the vast majority of messages will have 0, 1 or 2 variables, so the other getMessage methods are provided as a convenience to avoid the complexity of the String array version.

Note that the getMessage methods throw MissingResourceException if the resource cannot be found.  And ParseException if there are more {X} entries than arguments.  These exceptions are RuntimeException's, so the caller doesn't have to explicitly catch them.

The resource bundle properties file is org/apache/axis/i18n/resource.properties.

Extending Message Files

Generally, within AXIS all messages are placed in org.apache.axis.i18n.resource.properties. There are facilities for extending the messages without modifying this file for integration or 3rd party extensions to AXIS. See the Integration Guide for details.

Adding Testcases

See Also: Test and Samples Structure

Editor's Note: We need more effort to streamline and simplify the addition of tests.  We also need to think about categorizing tests as the test bucket grows.
 

If you make changes to Axis, please add a test that uses your change.  Why?


Some general principles:


One way to build a test is to "cut and paste" and existing tests, and then modify the test to suit your needs.  This approach is becoming more complicated as the different kinds of tests grow.

A good "non-wsdl" test for reference is test/saaj.

Creating a WSDL Test

Here are the steps that I used to create the sequence test, which generates code from a wsdl file and runs a sequence validation test:
 
  1. Created a xml-axis/java/test/wsdl/sequence directory.

  2. Created a SequenceTest.wsdl file defining the webservice.

  3. Ran the Wsdl2java emitter to create java files:
  4. java org.apache.axis.wsdl.Wsdl2java -t -s SequenceTest.wsdl

    1. The -t option causes the emitter to generate a *TestCase.java file that hooks into the test harness. This file is operational without any additional changes.  Copy the *TestCase.java file into the same directory as your wsdl file.  (Ideally only the java files that are changed need to be in your directory.  So this file is not needed, but please make sure to modify your <wsdl2java ...> clause (described below) to emit a testcase.
    2. The -s option causes the emitter to generate a *SOAPBindingImpl.java file.  The java file contains empty methods for the service.  You probably want to fill them in with your own logic.  Copy the *SOAPBindingImpl.java file into the same directory as your wsdl file.  (If no changes are needed in the java file, you don't need to save it.  But you will need to make sure that your <wsdl2java ...> clause generates a skeleton).
    3. Remove all of the java files that don't require modification.  So you should have three files in your directory (wsdl file, *TestCase.java, and *SOAPBindingImpl.java).  My sequence test has an another file due to some additional logic that I needed.

  5. The test/wsdl/sequence/build.xml file controls the building of this test.  Locate the "compile" target.  Add a clause that runs the Wsdl2java code. I would recommend stealing something from the test/wsdl/roundtrip/build.xml file (it does a LOT of wsdl2java and java2wsdl calls). Here is the one for SequenceTest:
  6.     <!-- Sequence Test -->
        <wsdl2java url="${axis.home}/test/wsdl/sequence/SequenceTest.wsdl"
                   output="${axis.home}/build/work"
                   deployscope="session"
                   skeleton="yes"
                   messagecontext="no"
                   noimports="no"
                   verbose="no"
                   testcase="no">
            <mapping namespace="urn:SequenceTest2" package="test.wsdl.sequence"/>
        </wsdl2java>

  7. Enable the run target in the new build.xml file. You need to choose from the execute-Component and the (soon to be introduced) execute-Simple-Test target. These control HOW the test is invoked when run as a single component. The execute-Component sets up the tcp-server and http-server prior to running the test, as well as handles deploying and services that may be needed. The execute-Simple-test simply invokes the raw test class file.

  8. Done.  Run ant functional-tests to verify.  Check in your test.

  9.  

Test Structure

The Test and Samples Redesign Document is here

As of Axis 1.0, RC1, we have moved to a "componentized" test structure. Instead of having one high-level large recursive function, there are smaller, simple "component" build.xml files in the leaf level of the test/** and samples/** trees.

These "component" files have a common layout. Their primary targets are:

A "sample" test xml file can be found in test/templateTest

Adding Source Code Checks

The Axis build performs certain automated checks of the files in the source directory (java/src) to make sure certain conventions are followed such as using internationalised strings when issuing messages.

If a convention can be reduced to a regular expression match, it can be enforced at build time by updating java/test/utils/TestSrcContent.java.

All that is necessary is to add a pattern to the static FileNameContentPattern array. Each pattern has three parameters:

  1. a pattern that matches filenames that are to be checked,
  2. a pattern to be searched for in the chosen files, and
  3. a boolean indicating whether the pattern is to be allowed (typically false indicating not allowed).

A reasonable summary of the regular expression notation is provided in the Jakarta ORO javadocs.

Debugging

Using tcpmon to Monitor Functional Tests.

Here is an easy way to monitor the messages while running functional-tests (or all-tests).
Start up tcpmon listening on 8080 and forwarding to a different port:

java org.apache.axis.utils.tcpmon 8080 localhost 8011
Run your tests, but use the forwarded port for the SimpleAxisServer, and indicate that functional-tests should continue if a failure occurs.
ant functional-tests -Dtest.functional.SimpleAxisPort=8011 -Dtest.functional.fail=no
The SOAP messages for all of the tests should appear in the tcpmon window.

tcpmon is described in more detail in the AXIS User's Guide.

Using SOAP Monitor to Monitor Functional Tests.

If you are debugging code that is running as a web application using a web application server (such as Tomcat) then you may also use the SOAP Monitor utility to view the SOAP request and response messages.
Start up the SOAP monitor utility by loading the SOAP monitor applet in your web browser window:

http://localhost:<port>/axis/SOAPMonitor
. As you run your tests, the SOAP messages should appear in the SOAP monitor window.

SOAP Monitor is described in more detail in the AXIS User's Guide.

Running a Single Functional Test

In one window start the server:
java org.apache.axis.transport.http.SimpleAxisServer -p 8080
In another window, first deploy the service you're testing:
java org.apache.axis.client.AdminClient deploy.wsdd
Then bring up the JUnit user interface with your test. For example, to run the the multithread test case:
java junit.swingui.TestRunner -noloading test.wsdl.multithread.MultithreadTestCase

Turning on Debug Output

This section is oriented to the AXIS default logger: Log4J. For additional information on Log4J, see the section Configuring the Logger.

Writing Temporary Output

Remember that AXIS is targetted for use in a number of open-source and other web applications, and so it needs to be a good citizen. Writing output using System.out.println or System.err.println should be avoided.

Developers may be tempted to use System.out.println while debugging or analyzing a system. If you choose to do this, you will need to disable the util/TestSrcContent test, which enforces avoidance of System.out.println and System.err.println. It follows that you will need to remove your statements before checking the code back in.

As an alternative, we strongly encourage you to take a few moments and introduce debug statements: log.debug("reasonably terse and meaningful message"). If a debug message is useful for understanding a problem now, it may be useful again in the future to you or a peer.

Running the JAX-RPC Compatibility Tests

As well as a specification, JAX-RPC has a Technology Compatibility Kit (TCK) which is available to members of the JAX-RPC Expert Group (and others?).

The kit comes as a zip file which you should unzip into a directory of your choosing. The installation instructions are in the JAX-RPC Release Notes document which is stored in the docs directory. If you open the index.html file in the docs directory using a web browser, you'll see a list of all the documents supplied with the kit.

Note that the kit includes the JavaTest test harness which is used for running the compatibility tests.

If any more information is needed about running these tests, please add it here!