# Tutorial: Tasks using Properties, Filesets & Paths

After reading the tutorial about writing tasks [1] this tutorial explains how to get and set properties and how to use nested filesets and paths. Finally it explains how to contribute tasks to Ant.

## Content

- The goal
- Build environment
- Property access
- Using filesets
- Using nested paths
- Returning a list
- Documentation
- Contribute the new task
- Resources

## The goal

The goal is to write a task, which searchs in a path for a file and saves the location of that file in a property.

## Build environment

We can use the buildfile from the other tutorial and modify it a little bit. That's the advantage of using properties - we can reuse nearly the whole script. :-)

    <?xml version="1.0" encoding="ISO-8859-1"?>
    <project name="FindTask" basedir="." default="test">
        ...
        <target name="use.init" description="Taskdef's the Find-Task" depends="jar">
            <taskdef name="find" classname="Find" classpath="apache-ant.jar"/>
        </target>

        <!-- the other use.* targets are deleted -->
        ...
    </project>

The buildfile is in the archive tutorial-tasks-filesets-properties.zip [2] in `/build.xml.01-propertyaccess` (future version saved as *.02..., final version as build.xml; same for sources).

## Property access

Our first step is to set a property to a value and print the value of that property. So our scenario would be

        <find property="test" value="test-value"/>
        <find print="test"/>

ok, can be rewritten with the core tasks

        <property name="test" value="test-value"/>
        <echo message="${test}"/>

but I have to start on known ground :-)

So what to do? Handling three attributes (property, value, print) and an execute method. Because this is only an introduction example I don't do much checking:

    import org.apache.tools.ant.BuildException;

    public class Find extends Task {

        private String property;
        private String value;
        private String print;

        public void setProperty(String property) {
            this.property = property;
        }

        // setter for value and print

        public void execute() {
            if (print != null) {
                String propValue = getProject().getProperty(print);
                log(propValue);
            } else {
                if (property == null) throw new BuildException("property not set");
                if (value    == null) throw new BuildException("value not set");
                getProject().setNewProperty(property, value);
            }
        }
    }

As said in the other tutorial, the property access is done via Project instance. We get this instance via the public `getProject()` method which we inherit from `Task` (more precise from ProjectComponent). Reading a property is done via `getProperty(propertyname)` (very simple, isn't it?). This property returns the value as String or null if not set.
Setting a property is ... not really difficult, but there is more than one setter. You can use the `setProperty()` method which will do the job like expected. But there is a golden rule in Ant: properties are immutable. And this method sets the property to the specified value - whether it has a value before that or not. So we use another way. `setNewProperty()` sets the property only if there is no property with that name. Otherwise a message is logged.

(by the way: a short word to ants "namespaces" (don't be confused with xml namespaces: an `<antcall>` creates a new space for property names. All properties from the caller are passed to the callee, but the callee can set its own properties without notice by the caller.)

There are some other setter, too (but I haven't used them, so I can't say something to them, sorry :-)

After putting our two line example from above into a target names `use.simple` we can call that from our testcase:

    import org.apache.tools.ant.BuildFileTest;

    public class FindTest extends BuildFileTest {

        public FindTest(String name) {
            super(name);
        }

        public void setUp() {
            configureProject("build.xml");
        }

        public void testSimple() {
            expectLog("use.simple", "test-value");
        }
    }

and all works fine.

## Using filesets

Ant provides a common way of bundling files: the fileset. Because you are reading this tutorial I think you know them and I don't have to spend more explanations about their usage in buildfiles. Our goal is to search a file in path. And on this step the path is simply a fileset (or more precise: a collection of filesets). So our usage would be

        <find file="ant.jar" location="location.ant-jar">
            <fileset dir="/Users/antoine/dev/asf/ant-core/bootstrap" includes="**/*.jar"/>
        </find>

What do we need? A task with two attributes (file, location) and nested filesets. Because we had attribute handling already explained in the example above and the handling of nested elements is described in the other tutorial the code should be very easy:

    public class Find extends Task {

        private String file;
        private String location;
        private Vector filesets = new Vector();

        public void setFile(String file) {
            this.file = file;
        }

        public void setLocation(String location) {
            this.location = location;
        }

        public void addFileset(FileSet fileset) {
            filesets.add(fileset);
        }

        public void execute() {
        }
    }

Ok - that task wouldn't do very much, but we can use it in the described manner without failure. On next step we have to implement the execute method. And before that we will implement the appropriate testcases (TDD - test driven development).

In the other tutorial we have reused the already written targets of our buildfile. Now we will configure most of the testcases via java code (sometimes it's much easier to write a target than doing it via java coding). What can be tested?

- not valid configured task (missing file, missing location, missing fileset)
- don't find a present file
- behaviour if file can't be found

Maybe you find some more testcases. But this is enough for now.
For each of these points we create a `testXX` method.

    public class FindTest extends BuildFileTest {

        ... // constructor, setUp as above

        public void testMissingFile() {
            Find find = new Find();
            try {
                find.execute();
                fail("No 'no-file'-exception thrown.");
            } catch (Exception e) {
                // exception expected
                String expected = "file not set";
                assertEquals("Wrong exception message.", expected, e.getMessage());
            }
        }

        public void testMissingLocation() {
            Find find = new Find();
            find.setFile("ant.jar");
            try {
                find.execute();
                fail("No 'no-location'-exception thrown.");
            } catch (Exception e) {
                ... // similar to testMissingFile()
            }
        }

        public void testMissingFileset() {
            Find find = new Find();
            find.setFile("ant.jar");
            find.setLocation("location.ant-jar");
            try {
                find.execute();
                fail("No 'no-fileset'-exception thrown.");
            } catch (Exception e) {
                ... // similar to testMissingFile()
            }
        }

        public void testFileNotPresent() {
            executeTarget("testFileNotPresent");
            String result = getProject().getProperty("location.ant-jar");
            assertNull("Property set to wrong value.", result);
        }

        public void testFilePresent() {
            executeTarget("testFilePresent");
            String result = getProject().getProperty("location.ant-jar");
            assertNotNull("Property not set.", result);
            assertTrue("Wrong file found.", result.endsWith("ant.jar"));
        }
    }

If we run this test class all test cases (except testFileNotPresent) fail. Now we can implement our task, so that these test cases will pass.

        protected void validate() {
            if (file==null) throw new BuildException("file not set");
            if (location==null) throw new BuildException("location not set");
            if (filesets.size()<1) throw new BuildException("fileset not set");
        }

        public void execute() {
            validate();                                                             // 1
            String foundLocation = null;
            for(Iterator itFSets = filesets.iterator(); itFSets.hasNext(); ) {      // 2
                FileSet fs = (FileSet)itFSets.next();
                DirectoryScanner ds = fs.getDirectoryScanner(getProject());         // 3
                String[] includedFiles = ds.getIncludedFiles();
                for(int i=0; i<includedFiles.length; i++) {
                    String filename = includedFiles[i].replace('\\','/');           // 4
                    filename = filename.substring(filename.lastIndexOf("/")+1);
                    if (foundLocation==null && file.equals(filename)) {
                        File base  = ds.getBasedir();                               // 5
                        File found = new File(base, includedFiles[i]);
                        foundLocation = found.getAbsolutePath();
                    }
                }
            }
            if (foundLocation!=null)                                                // 6
                getProject().setNewProperty(location, foundLocation);
        }

On //1 we check the prerequisites for our task. Doing that in a `validate`-method is a common way, because we separate the prerequisites from the real work. On //2 we iterate over all nested filesets. If we don't want to handle multiple filesets, the `addFileset()` method has to reject the further calls. We can get the result of a fileset via its DirectoryScanner like done in //3. After that we create a plattform independend String representation of the file path (//4, can be done in other ways of course). We have to do the `replace()`, because we work with a simple string comparison. Ant itself is platform independant and can therefore run on filesystems with slash (/, e.g. Linux) or backslash (\, e.g. Windows) as path separator. Therefore we have to unify that. If we found our file we create an absolute path representation on //5, so that we can use that information without knowing the basedir. (This is very important on use with multiple filesets, because they can have different basedirs and the return value of the directory scanner is relative to its basedir.) Finally we store the location of the file as property, if we had found one (//6).

Ok, much more easier in this simple case would be to add the file as additional include element to all filesets. But I wanted to show how to handle complex situations whithout being complex :-)

The test case uses the ant property ant.home as reference. This property is set by the `Launcher` class which starts ant. We can use that property in our buildfiles as a build-in property [3]. But if we create a new ant environment we have to set that value for our own. And we use the `<junit>` task in fork-mode. Therefore we have do modify our buildfile:

        <target name="junit" description="Runs the unit tests" depends="jar">
            <delete dir="${junit.out.dir.xml}"/>
            <mkdir  dir="${junit.out.dir.xml}"/>
            <junit printsummary="yes" haltonfailure="no">
                <classpath refid="classpath.test"/>
                <sysproperty key="ant.home" value="/Users/antoine/dev/asf/ant-core/bootstrap"/>
                <formatter type="xml"/>
                <batchtest fork="yes" todir="${junit.out.dir.xml}">
                    <fileset dir="src" includes="**/*Test.java"/>
                </batchtest>
            </junit>
        </target>

## Using nested paths

A task providing support for filesets is a very comfortable one. But there is another possibility of bundling files: the `<path>`. Fileset are easy if the files are all under a common base directory. But if this is not the case you have a problem. Another disadvantage is its speed: if you have only a few files in a huge directory structure, why not use a `<filelist>` instead? `<path>`s combines these datatypes in that way that a path contains other paths, filesets, dirsets and filelists. This is why Ant-Contribs [4] `<foreach>` task is modified to support paths instead of filesets. So we want that, too.

Changing from fileset to path support is very easy:

    Change java code from:
        private Vector filesets = new Vector();
        public void addFileset(FileSet fileset) {
            filesets.add(fileset);
        }
    to:
        private Vector paths = new Vector();                      *1
        public void addPath(Path path) {                          *2
            paths.add(path);
        }
    and build file from:
        <find file="ant.jar" location="location.ant-jar">
            <fileset dir="/Users/antoine/dev/asf/ant-core/bootstrap" includes="**/*.jar"/>
        </find>
    to:
        <find file="ant.jar" location="location.ant-jar">
            <path>                                                *3
                <fileset dir="/Users/antoine/dev/asf/ant-core/bootstrap" includes="**/*.jar"/>
            </path>
        </find>

On *1 we rename only the vector. It�s just for better reading the source. On *2 we have to provide the right method: an addName(Type t). Therefore replace the fileset with path here. Finally we have to modify our buildfile on *3 because our task doesn�t support nested filesets any longer. So we wrap the fileset inside a path.

And now we modify the testcase. Oh, not very much to do :-) Renaming the `testMissingFileset()` (not really a must-be but better it�s named like the think it does) and update the expected-String in that method (now a `path not set` message is expected). The more complex test cases base on the buildscript. So the targets `testFileNotPresent` and `testFilePresent` have to be modified in the manner described above.

The test are finished. Now we have to adapt the task implementation. The easiest modification is in the `validate()` method where we change le last line to `if (paths.size()<1) throw new BuildException("path not set");`. In the `execute()` method we have a little more work. ... mmmh ... in reality it's lesser work, because the Path class does the whole DirectoryScanner-handling and creating-absolute-paths stuff for us. So the execute method is just:

        public void execute() {
            validate();
            String foundLocation = null;
            for(Iterator itPaths = paths.iterator(); itPaths.hasNext(); ) {
                Path path = (Path)itPaths.next();                                // 1
                String[] includedFiles = path.list();                            // 2
                for(int i=0; i<includedFiles.length; i++) {
                    String filename = includedFiles[i].replace('\\','/');
                    filename = filename.substring(filename.lastIndexOf("/")+1);
                    if (foundLocation==null && file.equals(filename)) {
                        foundLocation = includedFiles[i];                        // 3
                    }
                }
            }
            if (foundLocation!=null)
                getProject().setNewProperty(location, foundLocation);
        }

Of course we have to do the typecase to Path on //1. On //2 and //3 we see that the Path class does the work for us: no DirectoryScanner (was at 2) and no creating of the absolute path (was at 3).

## Returning a list

So far so good. But could a file be on more than one place in the path? - Of course.
And would it be good to get all of them? - It depends on ...

In this section we will extend that task to support returning a list of all files. Lists as property values are not supported by Ant natively. So we have to see how other tasks use lists. The most famous task using lists is Ant-Contribs `<foreach>`. All list elements are concatenated and separated with a customizable separator (default ',').

So we do the following:

        <find ... delimiter=""/> ... </find>

If the delimiter is set we will return all found files as list with that delimiter.

Therefore we have to

- provide a new attribute
- collect more than the first file
- delete duplicates
- create the list if necessary
- return that list

So we add as testcase:

    in the buildfile:
        <target name="test.init">
            <mkdir dir="test1/dir11/dir111"/>                             *1
            <mkdir dir="test1/dir11/dir112"/>
            ...
            <touch file="test1/dir11/dir111/test"/>
            <touch file="test1/dir11/dir111/not"/>
            ...
            <touch file="test1/dir13/dir131/not2"/>
            <touch file="test1/dir13/dir132/test"/>
            <touch file="test1/dir13/dir132/not"/>
            <touch file="test1/dir13/dir132/not2"/>
            <mkdir dir="test2"/>
            <copy todir="test2">                                          *2
                <fileset dir="test1"/>
            </copy>
        </target>

        <target name="testMultipleFiles" depends="use.init,test.init">    *3
            <find file="test" location="location.test" delimiter=";">
                <path>
                    <fileset dir="test1"/>
                    <fileset dir="test2"/>
                </path>
            </find>
            <delete>                                                      *4
                <fileset dir="test1"/>
                <fileset dir="test2"/>
            </delete>
        </target>

    in the test class:
        public void testMultipleFiles() {
            executeTarget("testMultipleFiles");
            String result = getProject().getProperty("location.test");
            assertNotNull("Property not set.", result);
            assertTrue("Only one file found.", result.indexOf(";") > -1);
        }

Now we need a directory structure where we CAN find files with the same name in different directories. Because we can't sure to have one we create one on *1 and *2. And of course we clean up that on *4. The creation can be done inside our test target or in a separate one, which will be better for reuse later (*3).

The task implementation is modified as followed:

        private Vector foundFiles = new Vector();
        ...
        private String delimiter = null;
        ...
        public void setDelimiter(String delim) {
            delimiter = delim;
        }
        ...
        public void execute() {
            validate();
            // find all files
            for(Iterator itPaths = paths.iterator(); itPaths.hasNext(); ) {
                Path path = (Path)itPaths.next();
                String[] includedFiles = path.list();
                for(int i=0; i<includedFiles.length; i++) {
                    String filename = includedFiles[i].replace('\\','/');
                    filename = filename.substring(filename.lastIndexOf("/")+1);
                    if (file.equals(filename) && !foundFiles.contains(includedFiles[i])) {   // 1
                        foundFiles.add(includedFiles[i]);
                    }
                }
            }

            // create the return value (list/single)
            String rv = null;
            if (foundFiles.size() > 0) {                                        // 2
                if (delimiter==null) {
                    // only the first
                    rv = (String)foundFiles.elementAt(0);
                } else {
                    // create list
                    StringBuffer list = new StringBuffer();
                    for(Iterator it=foundFiles.iterator(); it.hasNext(); ) {    // 3
                        list.append(it.next());
                        if (it.hasNext()) list.append(delimiter);               // 4
                    }
                    rv = list.toString();
                }
            }

            // create the property
            if (rv!=null)
                getProject().setNewProperty(location, rv);
        }

The algorithm does: finding all files, creating the return value depending on the users wish, returning the value as property. On //1 we eliminates the duplicates. //2 ensures that we create the return value only if we have found one file. On //3 we iterate over all found files and //4 ensures that the last entry has no trailing delimiter.

Ok, first searching for all files and then returning only the first one ... You can tune the performance of your own :-)

## Documentation

A task is useless if the only who is able to code the buildfile is the task developer (and he only the next few weeks :-). So documentation is also very important. In which form you do that depends on your favourite. But inside Ant there is a common format and it has advantages if you use that: all task users know that form, this form is requested if you decide to contribute your task. So we will doc our task in that form.

If you have a look at the manual page of the java [5] task you will see

- it is plain html
- starts with the name
- has sections: description, parameters, nested elements, (maybe return codes) and (most important :-) examples
- parameters are listed in a table with columns for attribute name, its description and whether it's required (if you add a feature after an Ant release, provide a `since Ant xx` statement when it's introduced)
- describe the nested elements (since-statement if necessary)
- provide one or more useful examples; first code then description

As a template we have:

    <html>

    <head>
    <meta http-equiv="Content-Language" content="en-us">
    <title> Taskname Task</title>
    </head>

    <body>

    <h2><a name="taskname">Taskname</a></h2>
    <h3>Description</h3>
    <p> Describe the task.</p>

    <h3>Parameters</h3>
    <table border="1" cellpadding="2" cellspacing="0">
      <tr>
        <td valign="top"><b>Attribute</b></td>
        <td valign="top"><b>Description</b></td>
        <td align="center" valign="top"><b>Required</b></td>
      </tr>

      do this html row for each attribute (including inherited attributes)
      <tr>
        <td valign="top">classname</td>
        <td valign="top">the Java class to execute.</td>
        <td align="center" valign="top">Either jar or classname</td>
      </tr>

    </table>

    <h3>Parameters specified as nested elements</h3>

    Describe each nested element (including inherited)
    <h4>your nested element</h4>
    <p> description </p>
    <p><em>since Ant 1.6</em>.</p>

    <h3>Examples</h3>
    <pre>
        A code sample; don't forget to escape the < of the tags with &lt;
    </pre>
    what should that example do?

    </body>
    </html>

For our task we have that [6]:

    <html>

    <head>
    <meta http-equiv="Content-Language" content="en-us">
    <title> Find Task</title>
    </head>

    <body>

    <h2><a name="find">Find</a></h2>
    <h3>Description</h3>
    <p>Searchs in a given path for a file and returns the absolute to it as property.
    If delimiter is set this task returns all found locations.</p>

    <h3>Parameters</h3>
    <table border="1" cellpadding="2" cellspacing="0">
      <tr>
        <td valign="top"><b>Attribute</b></td>
        <td valign="top"><b>Description</b></td>
        <td align="center" valign="top"><b>Required</b></td>
      </tr>
      <tr>
        <td valign="top">file</td>
        <td valign="top">The name of the file to search.</td>
        <td align="center" valign="top">yes</td>
      </tr>
      <tr>
        <td valign="top">location</td>
        <td valign="top">The name of the property where to store the location</td>
        <td align="center" valign="top">yes</td>
      </tr>
      <tr>
        <td valign="top">delimiter</td>
        <td valign="top">A delimiter to use when returning the list</td>
        <td align="center" valign="top">only if the list is required</td>
      </tr>
    </table>

    <h3>Parameters specified as nested elements</h3>

    <h4>path</h4>
    <p>The path where to search the file.</p>

    <h3>Examples</h3>
    <pre>
        <find file="ant.jar" location="loc">
            <path>
                <fileset dir="/Users/antoine/dev/asf/ant-core/bootstrap"/>
            <path>
        </find>
    </pre>
    Searches in Ants home directory for a file <i>ant.jar</i> and stores its location in
    property <i>loc</i> (should be ANT_HOME/bin/ant.jar).

    <pre>
        <find file="ant.jar" location="loc" delimiter=";">
            <path>
                <fileset dir="C:/"/>
            <path>
        </find>
        <echo>ant.jar found in: ${loc}</echo>
    </pre>
    Searches in Windows C: drive for all <i>ant.jar</i> and stores their locations in
    property <i>loc</i> delimited with <i>';'</i>. (should need a long time :-)
    After that it prints out the result (e.g. C:/ant-1.5.4/bin/ant.jar;C:/ant-1.6/bin/ant.jar).

    </body>
    </html>

## Contribute the new task

If we decide to contribute our task, we should do some things:

- is our task welcome? :-) Simply ask on the user list
- is the right package used?
- is the code conform to the styleguide?
- do all tests pass?
- does the code compile on JDK 1.2 (and passes all tests there)?
- code under Apache license
- create a patch file
- publishing that patch file

The Ant Task Guidelines [7] support additional information on that.

Now we will check the "Checklist before submitting a new task" described in that guideline.

- Java file begins with Apache license statement. must do that
- Task does not depend on GPL or LGPL code. ok
- Source code complies with style guidelines have to check (checkstyle)
- Code compiles and runs on Java1.2 have to try
- Member variables are private, and provide public accessor methods if access is actually needed. have to check (checkstyle)
- Maybe Task has failonerror attribute to control failure behaviour hasn't
- New test cases written and succeed passed on JDK 1.4, have to try on JDK 1.2
- Documentation page written ok
- Example task declarations in the documentation tested. ok (used in tests)
- Patch files generated using cvs diff -u to do
- patch files include a patch to defaults.properties to register the tasks to do
- patch files include a patch to coretasklist.html or optionaltasklist.html to link to the new task page to do
- Message to dev contains [SUBMIT] and task name in subject to do
- Message body contains a rationale for the task to do
- Message attachments contain the required files -source, documentation, test and patches zipped up to escape the HTML filter. to do

### Package / Directories

This task does not depend on any external library. Therefore we can use this as a core task. This task contains only one class. So we can use the standard package for core tasks: `org.apache.tools.ant.taskdefs`. Implementations are in the directory `src/main`, tests in `src/testcases` and buildfiles for tests in `src/etc/testcases`.

Now we integrate our work into Ants distribution. So first we do an update of our cvs tree. If not done yet, you have to checkout the ant module from Apaches cvs server as described in Access the Source Tree (AnonCVS) [8] (password is anoncvs):

    cvs -d :pserver:anoncvs@cvs.apache.org:/home/cvspublic login                 //1
    cvs -d :pserver:anoncvs@cvs.apache.org:/home/cvspublic checkout ant          //2

If you have a local copy of Ants sources just do an update

    cvs -d :pserver:anoncvs@cvs.apache.org:/home/cvspublic login
    cd ant                                                                       //3
    cvs -d :pserver:anoncvs@cvs.apache.org:/home/cvspublic update                //4

We use the -d flag on //1 to specifiy the cvs directory. You can specify the environment variable CVSROOT with that value and after that you haven�t to use that flag any more. On //2 we get the whole cvs tree of ant. (Sorry, but that uses a lot of time ... 10 up to 30 minutes are not unusual ... but this has to be done only once :-). A cvs update doesn't use a modulename but you have to be inside the directory. Therefore we go into that on //3 and do the update on //4.

Now we will build our Ant distribution and do a test. So we can see if there are any tests failing on our machine. (We can ignore these failing tests on later steps; windows syntax used here- translate to xNIX if needed):

    ANTHOME> build                                                    // 1
    ANTHOME> set ANT_HOME=%CD%\dist                                   // 2
    ANTHOME> ant test -Dtest.haltonfailure=false                      // 3

First we have to build our Ant distribution (//1). On //2 we set the ANT_HOME environment variable to the directory where the new created distribution is stored (%CD% is expanded to the current directory on Windows 2000 and XP, on 9x and NT write it out). On //3 we let Ant do all the tests (which enforced a compile of all tests) without stopping on first failure.

Next we apply our work onto Ants sources. Because we haven't modified any, this is a relative simple step. (Because I have a local copy of Ant and usually contribute my work, I work on the local copy just from the beginning. The advantage: this step isn't necessary and saves a lot of work if you modify existing source :-).

- move the Find.java to ANTHOME/src/main/org/apache/tools/ant/taskdefs/Find.java
- move the FindTest.java to ANTHOME/src/testcases/org/apache/tools/ant/taskdefs/FindTest.java
- move the build.xml to ANTHOME/src/etc/testcases/taskdefs/find.xml (!!! renamed !!!)
- add a `package org.apache.tools.ant.taskdefs;` at the beginning of the two java files
- delete all stuff from find.xml keeping the targets "testFileNotPresent", "testFilePresent", "test.init" and "testMultipleFiles"
- delete the dependency to "use.init" in the find.xml
- in FindTest.java change the line `configureProject("build.xml");` to `configureProject("src/etc/testcases/taskdefs/find.xml");`
- move the find.html to ANTHOME/docs/manual/CoreTasks/find.html
- add a `<a href="CoreTasks/find.html">Find</a><br>` in the ANTHOME/docs/manual/coretasklist.html

Now our modifications are done and we will retest it:

    ANTHOME> build
    ANTHOME> ant run-single-test                                      // 1
                 -Dtestcase=org.apache.tools.ant.taskdefs.FindTest    // 2
                 -Dtest.haltonfailure=false

Because we only want to test our new class, we use the target for single tests, specify the test to use and configure not to halt on the first failure - we want to see all failures of our own test (//1 + 2).

And ... oh, all tests fail: Ant could not find the task or a class this task relies upon.

Ok: in the earlier steps we told Ant to use the Find class for the `<find>` task (remember the `<taskdef>` statement in the "use.init" target). But now we want to introduce that task as a core task. And nobody wants to taskdef the javac, echo, ... So what to do? The answer is the src/main/.../taskdefs/default.properties. Here is the mapping between taskname and implementing class done. So we add a `find=org.apache.tools.ant.taskdefs.Find` as the last core task (just before the `# optional tasks` line). Now a second try:

    ANTHOME> build                                                    // 1
    ANTHOME> ant run-single-test
                 -Dtestcase=org.apache.tools.ant.taskdefs.FindTest
                 -Dtest.haltonfailure=false

We have to rebuild (//1) Ant because the test look in the %ANT_HOME%\lib\ant.jar (more precise: on the classpath) for the properties file. And we have only modified it in the source path. So we have to rebuild that jar. But now all tests pass and we check whether our class breaks some other tests.

    ANTHOME> ant test -Dtest.haltonfailure=false

Because there are a lot of tests this step requires a little bit of time. So use the run-single-test during development and do the test only at the end (maybe sometimes during development too). We use the -Dtest.haltonfailure=false here because there could be other tests fail and we have to look into them.

This test run should show us two things: our test will run and the number of failing tests is the same as directly after the cvs update (without our modifications).

### Apache license statement

Simply copy the license text from one the other source from the Ant source tree.

### Test on JDK 1.2

Until version 1.5 Ant must be able to run on a JDK 1.1. With version 1.6 this is not a requisite any more. But JDK 1.2 is a must-to-work-with. So we have to test that. You can download older JDKs from Sun [9].

Clean the ANT_HOME variable, delete the build, bootstrap and dist directory and point JAVA_HOME to the JDK 1.2 home directory. Then do the `build`, set ANT_HOME and run `ant test` (like above).

Our test should pass.

### Checkstyle

There are many things we have to ensure. Indentation with 4 spaces, blanks here and there, ... (all described in the Ant Task Guidelines [7] which includes the Sun code style [10]). Because there are so many things we would be happy to have a tool for do the checks. There is one: checkstyle. Checkstyle is available at Sourceforge [11] and Ant provides with the `check.xml` a buildfile which will do the job for us.

Download it and put the checkstyle-*-all.jar into your %USERPROFILE%\.ant\lib directory. All jar's stored there are available to Ant so you haven't to add it to you %ANT_HOME%\lib directory (this feature was added with Ant 1.6).

So we will run the tests with

    ANTHOME> ant -f check.xml checkstyle htmlreport

I prefer the HTML report because there are lots of messages and we can navigate faster. Open the ANTHOME/build/reports/checkstyle/html/index.html and navigate to the Find.java. Now we see that there are some errors: missing whitespaces, unused imports, missing javadocs. So we have to do that.

Hint: start at the buttom of the file so the line numbers in the report will keep up to date and you will find the next error place much more easier without redoing the checkstyle.

After cleaning up the code according to the messages we delete the reports directory and do a second checkstyle run. Now our task isn't listed. That's fine :-)

### Publish the task

Finally we publish that archive. As described in the Ant Task Guidelines [7] we can post it on the developer mailinglist or we create a BugZilla entry. For both we need some information:

subject | short description | Task for finding files in a path
body | more details about the path | This new task looks inside a nested `<path/>` for occurrences of a file and stores all locations as a property. See the included manual for details.
attachements | all files needed to apply the path | Archive containing a patch with the new and modified resources

Sending an email with these information is very easy and I think I haven't to show that. The other way - BugZilla - is slightly more difficult. But it has the advantage that entries will not be forgotten (once per week a report is generated). So I will show this way.

You must have a BugZilla account for that. So open the BugZilla Main Page [12] and follow the link Open a new Bugzilla account [13] and the steps described there if you haven't one.

1. From the BugZilla main page choose Enter a new bug report [14]
2. Choose "Ant" as product
3. Version is the last "Alpha (nightly)" (at this time 1.7)
4. Component is "Core tasks"
5. Plattform and Severity are ok with "Other" and "Normal"
6. Initial State is ok with "New"
7. Same with the empy "Assigned to"
8. It is not required to add yourself as CC, because you are the reporter and therefore will be informed on changes
9. URL: no url required
10. Summary: add the subject from the table
11. Description: add the body from the table
12. Then press "Commit"
13. After redirecting to the new created bug entry click "Create a New Attachment"
14. Enter the path to your local path file into "File" or choose it via the "File"'s button.
15. Enter a short description into "Description", so that you could guess, what the path file includes. Here we could add "Initial Patch".
16. The "Content Type" is "auto-detect". You could use the "patch" type, if you only provide a single path file, but we want do upload more that one, included in our patch.zip.
17. Then press "Commit"

Now the new task is uploaded into the bug database.

## Resources

[1] tutorial-writing-tasks.html
[2] tutorial-tasks-filesets-properties.zip
[3] using.html#built-in-props
[4] http://ant-contrib.sourceforge.net/
[5] CoreTasks/java.html
[6] CoreTasks/find.html
[7] ../ant_task_guidelines.html
[8] http://ant.apache.org/cvs.html
[9] http://java.sun.com/products/archive/index.html
[10] http://java.sun.com/docs/codeconv/html/CodeConvTOC.doc.html
[11] http://checkstyle.sourceforge.net/
[12] http://issues.apache.org/bugzilla/
[13] http://issues.apache.org/bugzilla/createaccount.cgi
[14] http://issues.apache.org/bugzilla/enter_bug.cgi