Loops in Ant

[Jay Damon]

Is there any way to perform a looping action of any type in Ant? If so, can someone provide an examples? Thanks

[Lewin Chan]

Hi,
I don't believe you can with the core ant tasks, I did have rather an extensive look at this. One thing you have to remember is that.

ant is not a scripting language.

You can of course write you own task and execute some another task multiple times within it...
L

[Jay Damon]

Actually, I am now looking at performing looping tasks using JavaScript. It was relatively easy to get JavaScript enabled and I now have some working JavaScript in my Ant script file. However, I am still trying to work out how Ant targets can call JavaScript and vice versa.

[Adam Hardy]

Hi Jay,
What do you actually want to do?

[Jay Damon]

I am working on some Ant scripts designed to be run inside the WebSphere Studio Application Developer (v4.0.3) IDE. Because there are a number of tasks, e.g. refresh, rebuild, etc., that are applicable to all projects, what I want to do is 1) declare all my project names in one place (so I do not have to create task-specific code for each of the refresh, rebuild, etc. tasks), and 2) use a looping mechanism to execute each of these tasks for each project.
I have managed to get JavaScript working inside my Ant scripts and it appears this may solve my problems by 1) declaring the project types and names within JavaScript arrays, and 2) using a for loop within JavaScript to execute Ant targets repeatedly.
However, I am still working on some issues related to the execution of JavaScript from Ant targets and vice versa. But I am fairly confident that I will be able to get the Ant scripts to do what I want now although I still have to work out the details.

[Tim Holloway]

Welcome to the club. I too have multiple similar subprojects that I'd like to be able to iterate Ant sub-builds over without having to change the master build.xml every time I add one. Even just running over a list from a property would suffice.
Not now, and, as far as I can tell, so time soon. I don't know if if's something the Ant people don't feel a need for or if it's just something they object to

[Jay Damon]

Check out Using JavaScript with Ant at:
http://www.sitepen.com/ant/javascript.html
As I indicated, I am currently looking at JavaScript as a solution to this problem. I'm still working out the details but the following Ant script, as an example, works once you add the bsf.jar (Bean Scripting Framework) and js.jar (JavaScript) files to your classpath.
Unfortunately, I am currently locked into Ant v1.3 because I am using IBM WebSphere Studio Application Developer v4.0.3. I think some of my problems would be solved if I could move to Ant v1.4 or v1.5.

<?xml version="1.0" encoding="UTF-8"?>
<!-- ================================================================ -->
<!--                                                                  -->
<!-- Name:        Test JavaScript                                     -->
<!--                                                                  -->
<!-- Summary:     Test Ant JavaScript execution.                      -->
<!--                                                                  -->
<!-- Version:     1.0                                                 -->
<!--                                                                  -->
<!-- Install: (1) Add the following Java Archive (JAR) files and      -->
<!--              replace the plugin.xml file in the Ant plugin       -->
<!--              folder named org.eclipse.ant.core:                  -->
<!--                                                                  -->
<!--                    bsf.jar    (Bean Scripting Framework)         -->
<!--                    js.jar     (JavaScript)                       -->
<!--                    plugin.xml                                    -->
<!--                                                                  -->
<!--              The plugin.xml file included has been modified to   -->
<!--              include the JAR files as runtime dependencies.      -->
<!--                                                                  -->
<!--          (2) Set an environment variable named ANT_HOME to:      -->
<!--                                                                  -->
<!--              C:\Progra~1\IBM\Applic~1\plugins\org.eclipse.ant.core       -->
<!--                                                                  -->
<!--          (3) Set an environment variable named JAVA_HOME to:     -->
<!--                                                                  -->
<!--              C:\Progra~1\IBM\Applic~1\plugins\com.ibm.etools.server.jdk  -->
<!--                                                                  -->
<!-- ================================================================ -->
<project name="JavaScript" default="TestJavaScript" basedir=".">
<target name="Initialize">
<property name="Property1" value="This is property 1."/>
<property name="Property2" value="This is property 2."/>
</target>

<target name="CreateJavaScriptTask" depends="Initialize">
<script language="javascript"> <![CDATA[
// Import does not work; is this an Ant v1.3 limitation ?
//importClass(java.io.File);   // Java class needed for file creation
// Declare project attributes.
var size   = 100;
var type   = new Array(size);
var name   = new Array(size);
var modify = new Array(size);

// WebSphere Studio Application Developer project names.
type[ 1] = "java  "; name[ 1] = "projectJava01        "; modify[ 1] = "no "; 
type[ 2] = "client"; name[ 2] = "projectClient01      "; modify[ 2] = "yes"; 
type[ 3] = "client"; name[ 3] = "projectClient02      "; modify[ 3] = "no "; 
type[ 4] = "ejb   "; name[ 4] = "projectEJB01         "; modify[ 4] = "no "; 
type[ 5] = "ejb   "; name[ 5] = "projectEJB02         "; modify[ 5] = "no "; 
type[ 6] = "client"; name[ 6] = "projectClient03      "; modify[ 6] = "no "; 
type[ 7] = "client"; name[ 7] = "projectClient04      "; modify[ 7] = "no "; 
type[ 8] = "ejb   "; name[ 8] = "projectEJB03         "; modify[ 8] = "no "; 
type[ 9] = "client"; name[ 9] = "projectClient05      "; modify[ 9] = "no "; 
type[10] = "web   "; name[10] = "projectWeb01         "; modify[10] = "yes"; 
type[11] = "client"; name[11] = "projectClient06      "; modify[11] = "no "; 
type[12] = "client"; name[12] = "projectClient07      "; modify[12] = "no "; 
type[13] = "client"; name[13] = "projectClient08      "; modify[13] = "no "; 
type[14] = "web   "; name[14] = "projectWeb02         "; modify[14] = "no "; 
// Get Ant script initialization properties.
echo = JavaScript.createTask("echo");
 echo.setMessage(JavaScript.getProperty("Property1"));
 echo.execute();
 echo.setMessage(JavaScript.getProperty("Property2"));
 echo.execute();
// Get Ant script property (passed as parameter).
 var action = JavaScript.getProperty("Action");
 if (action == null || action == "") {
 action = "Test";
 }
// Get project and target. (does not work, at least in Ant v1.3)
//project = getProject();
//target  = JavaScript.getTarget("TestJavaScriptDone");
// Interate thru projects.
  for (index=0; index<name.length; index++) {
  
  if (type[index] != null && name[index] != null) {
  type[index]   = trim(type[index]);
  name[index]   = trim(name[index]);
  modify[index] = trim(modify[index]);
  if (type[index] != "" && name[index] != "") {
  
  var projectType = getProjectType(type[index]);
  var projectName = name[index];
  
echoLoop = JavaScript.createTask("echo");
 TestJavaScript.addTask(echoLoop);
  var message = action + "ing project " + index + " = " + projectType + " + " + projectName + " + " + modify[index];
  echoLoop.setMessage(message);
  echoLoop.execute();
  }
 } 
    }
// Execute an Ant target using the antcall task; A NullPointerException 
// is received using this procedure for executing a target in Ant v1.3.
//testDone = JavaScript.createTask("antcall");
 //testDone.setTarget("TestJavaScriptDone");
//testDone.execute();

// Execute an Ant target directly; specify the target name attribute.
 TestJavaScriptDone.execute();
 
// Make directory does not work; needs import declaration.
            makeDirectory = JavaScript.createTask("mkdir");
        //  directory = new File(C:\temp\anttest);
        //  makeDirectory.setDir(directory);
        //  makeDirectory.execute();
// Get project type description.
        function getProjectType(type) {
 if      (type == "client") {
 return "Application Client";
 }
 else if (type == "ejb"   ) {
 return "Enterprise Javabean";
 }
 else if (type == "web"   ) {
 return "Web Application";
 }
 else {
 return "Java";
 }
  
        }
// Trim leading and trailing blanks.
        function trim(string) {
            var startIndex = 0;
  for (var index=0; index<string.length; index++) {
  if (string.charAt(index) != ' ') {
  startIndex = index;
  break;
  }
  }
  if (startIndex < string.length) {
            var endIndex = 0;
  for (var index=(string.length-1); index>=0; index--) {
  if (string.charAt(index) != ' ') {
  endIndex = index;
  break;
  }
  }
  if (startIndex <= endIndex) {
  return string.substring(startIndex, (endIndex+1));
  }
  else {
  return "";
  }
}
else {
return "";
}
        }
    ]]> </script>
</target>
<target name="TestJavaScript">
<antcall target="CreateJavaScriptTask">
  <param name="Action" value="Refresh"/>
  </antcall>
<antcall target="CreateJavaScriptTask">
  <param name="Action" value="Rebuild"/>
  </antcall>
<antcall target="CreateJavaScriptTask">
  </antcall>
<antcall target="CreateJavaScriptTask">
  <param name="Action" value=""/>
  </antcall>
</target>
<target name="TestJavaScriptDone">
<echo message="Done!"/>
</target>
</project>

[Paul Done]

In a recent project I used a different method. In a master buildfile I included an Xslt/Style task which generated another buildfile on the fly and then executed it. This generated buildfile would include a series of tasks derived from a list in an XML config file I had in my source project. This may seem convoluted and obviously depends on having an XML metadata file to drive it in the first place. However, in my case, once set up, it worked really easily - the XML file was actually a J2EE deployment descriptor in my situation.
[ January 07, 2003: Message edited by: Paul Done ]

[Jay Damon]

Paul, can you provide examples of your solution?

[Paul Done]

Unfortunately I don't have the orginal buildscripts at hand - this was done for a customer last year - however I have found the XSL which I called from the XLS/Style ant task in the master buildfile - not sure if this is any help?....

<!DOCTYPE stylesheet [ 
    <!ENTITY dollar  "$" ><!-- dollar-sign --> 
    <!ENTITY lbrace  "{" ><!-- left-brace  --> 
    <!ENTITY rbrace  "}" ><!-- right-brace --> 
]>
<xsl:stylesheet version = '1.0' xmlns:xsl='http://www.w3.org/1999/XSL/Transform'>
    <xsl :-o	 utput indent="yes" method="xml"/> 
    <xsl:template match="*|text()|@*"/>
    <xsl:template match="/dynamic-projects">
        <project name="GeneratedPortalMerge" default="package">
            <target name="init" unless="TSTAMP">
                <tstamp/>
                <echo>Build of ${ant.project.name} started at ${TSTAMP} on ${TODAY}</echo>
            </target>
            <target name="package" depends="init">
                <echo>Running ${ant.project.name} to generate super portal war from seperate portal subprojects</echo>
                <xsl:apply-templates select="project"/>
            </target>
            <target name="clean" depends="init">
                <xsl:apply-templates select="project"/>
            </target>
        </project>
    </xsl:template>
    <xsl:template match="project[@type='web']">        
        <xsl:element name="ant">
            <xsl:attribute name="dir">../<xsl:value-of select="."/></xsl:attribute>
            <xsl:attribute name="target">${subproject.target}</xsl:attribute>
        </xsl:element>
    </xsl:template>    
</xsl:stylesheet>  

...which generated the buildfile....

  
<?xml version="1.0" encoding="UTF-8"?>
<project default="package" name="GeneratedPortalMerge">
<target unless="TSTAMP" name="init">
<tstamp/>
<echo>Build of ${ant.project.name} started at ${TSTAMP} on ${TODAY}</echo>
</target>
<target depends="init" name="package">
<echo>Running ${ant.project.name} to generate super portal war from seperate portal subprojects</echo>
<ant dir="../DirectorWebProj1" target="${subproject.target}"/>
<ant dir="../DirectorWebProj2" target="${subproject.target}"/>
<ant dir="../DirectorWebProj3" target="${subproject.target}"/>
</target>
<target depends="init" name="clean">
<ant dir="../DirectorWebProj1" target="${subproject.target}"/>
<ant dir="../DirectorWebProj2" target="${subproject.target}"/>
<ant dir="../DirectorWebProj3" target="${subproject.target}"/>
</target>
</project>

Not sure if this helps because its very specific to the problem at the time. Basically I was creating a large WAR web component from lots of smaller ones developed by different developers in source control. Each sub project had its own buildfile, but there was not way to automate the build of the master web component from these smaller web components until I used this method (a single web component was required for production, rather than an EAR containing multiple WARs, because the servlet context needed to be shared). In fact, this example didn't use a deployment descriptor as input to the XSL, it used a custom XML config file that was also source controlled - but the principle is the same.
Paul

[Jay Damon]

Thanks, Paul.

[Nicolas Brasseur]

Hello,
I tried to implement Paul's solution, unfortunately I get some problems when using the $ { } characters ...
Here is a code snippet of my stylesheet :

<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE stylesheet [
     <!ENTITY dollar  "$" >
     <!ENTITY lbrace  "{" >
     <!ENTITY rbrace  "}" >
]>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl :-o	 utput indent="yes" method="xml"/> 
<xsl:template match="/">
 ...
  <target name="pvcs" description="get fdo project with pvcs">
    <echo message="Tomcat :[B] $ { env.TOMCAT_HOME } [/B] "/>
    <pvcs repository="${argDBLocation}" updateonly="false" force="yes" workspace="/@/Public/batch" >
      <pvcsproject name="/${argProjectName}/src"/>
    </pvcs>
  </target>
...

As Paul did I tried to use internal entities replacing the $ { } characters ... the result I get is quite dispointing :

...
<target name="pvcs" description="get fdo project with pvcs">
<echo message="Tomcat :[B] $ [/B]  " />
<pvcs repository="$" updateonly="false" force="yes" workspace="/@/Public/batch">
<pvcsproject name="/$/src" />
</pvcs>
</target>
...

I only get a single dollar sign. I saw Paul was nopt always using the entities in his stylesheet ... is there any rule I am not respecting ?
Thanks in advance
Nicolas
PS : I know my question is more about XSLT than ant but it directly concerns people who are trying to build Ant xml files using XSLT to solve some problems (cfr. my yesterday post)

[Nicolas Brasseur]

Actually entities work well when unsed in elements ... and don't when used in attributes ...
will I be forced to use <xsl:element> <xsl:attribute> everywhere or is it a solution to use entities as attributes values ?
Thanks in advance ...