I'm sure there are lots of current solutions. I'm simply suggesting
that there is value in being able to do this easily in the build file.
David Dabbs wrote:
>
> David,
>
> Here's one possibility. I've successfuly employed this for 'aggregating'
> together several tasks I wanted to 'drive' with a fixed list of files loaded
> from a Manifest file.
>
> Create a new, custom task called <TGZ>. It should extend MatchingTask and
> accept whatever common attributes you're interested in passing, e.g.
> filename.
>
> Define the following methods:
> createGunzip()
> getGunzip() // may not be necessary
> createUntar()
> getUntar() // may not be necessary
> execute();
>
> The createXXX() methods will create and return an instance of the requested
> task.
> They should also use the requested task object's setXX() method(s) to set
> common parameters such as filename, destination, etc.
>
> Execute will call, in sequence, unzip.execute() and untar.execute();
>
> To use the aggregate task without having to retype the tags verytime you
> with to use it, simply create a dummy target and id the <TGZ> tag with a
> reference id. Any target wishing to <tgz> will simply use
>
> <tgz refid="foo" option="bar" option="baz" />
>
> Here's a sample. Note I just banged this out and did not try to compile it.
>
> /***************************************************************/
> package org.apache.tools.ant.taskdefs.optional;
>
> import org.apache.tools.ant.*;
> import org.apache.tools.ant.taskdefs.GUnzip;
> import org.apache.tools.ant.taskdefs.Untar;
> import org.apache.tools.ant.taskdefs.MatchingTask;
>
> public class TGZ extends MatchingTask {
>
> private GUnzip gunzip;
> private Untar untar;
>
> public GUnzip createGunzip() {
> if (gunzip == null) {
> gunzip = (GUnzip) project.createTask("gunzip"); //XX
> } else {
> //XX error if more than one gunzip encountered
> }
> return gunzip;
> }
>
> public Untar createUntar() {
> if (untar == null) {
> untar = (untar) project.createTask("untar"); //XX
> } else {
> //XX error if more than one untar encountered
> }
> return untar;
> }
>
> /*
> setXXX methods for attributes this task (TGZ) defines. setFile( File
> file), for example
> */
>
> public void execute() throws BuildException
> {
> checkParameters();
> /*
> set appropriate options on gunzip and untar task objects
> for each file specified ("fileset" instance variable)...
> gunzip.execute();
> untar.execute();
>
> See MatchingTask-derived clases such as Javac.java or others for
> examples of how to scan filesets for pattern matched files.
> */
> }
>
> private void checkParameters() throws BuildException
> {
> /*
>
> YOUR ATTRIBUTE VALIDATION HERE....
>
> if ( javac==null) {
> throw new BuildException("javac element is required.",
> location);
> }
> if ( jspc != null ) {
> //log("JSP precompilation enabled.", Project.MSG_INFO);
> }
> */
> }
>
> /*
> * Returns whether the given String parameter has been defined.
> */
> private boolean checkParam(String param)
> {
> return !((param == null) || (param.length()==0) ||
> (param.equals("null")) ) ;
> }
> }
>
> This is a lot of hassle to simply avoid copying two task definitions, but
> with more complex "functions" it might be worth it I suppose.
>
> Hope this helps,
>
> David
>
> ----- Original Message -----
> From: "David Corbin" <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>
> Sent: Wednesday, January 10, 2001 6:47 AM
> Subject: Re: Parameterized "task-function"
>
> > > David Dabbs wrote:
> > >
> > > > Has any thought been given to being able to construct a task from
> > > > several tasks, and have it parameterized? I realize this can be
> > > cobbled
> > > > together with targets and properties, but we all know that's a lousy
> > >
> > > > solution, don't we?
> > >
> > > Do you have a use case? I'm not sure what you're looking for. I could
> > > see a generic task that, given a list of refIds, could execute() them
> > > in series assuming they've already been defined. Not sure if that
> > > would buy you much ovcer the ugly way.
> > >
> > > David Dabbs
> >
> > A) I have dozens of .tgz files I want to extract. To do this, I have to
> > specify two tasks <gunzip> and <untar>. I'd like to make one task that
> > incorporates both.
> >
> > B) eventually, I hope ANT will support an include. When it does, I'll
> > want to be able to "pass arguments" for standard actions.
> >
> > (That's just starters). As was pointed out to me, ANT is a scripting
> > language. I want function/procedures. Is that so odd?
> >
> > --
> > David Corbin
> > Mach Turtle Technologies, Inc.
> > http://www.machturtle.com
> > [EMAIL PROTECTED]
> >
--
David Corbin
Mach Turtle Technologies, Inc.
http://www.machturtle.com
[EMAIL PROTECTED]
