My Java Tips

Ant provides various core and optional tasks which you use to automate the build process. Very seldom, you need to define your own customized tasks.

---

To implement a simple custom task, you need to extend the org.apache.tools.ant.Task class and override the execute() method. Follow the sample below:

Java Code:

import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.Task;
public class FileSorter extends Task {
// The method executing the task
public void execute() throws BuildException {}
}

The execute() method is throws BuildException which will thrown to signal the failure back.

Example follows:

Java Code:

import java.io.*;
import java.util.*;
import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.Task;
/**
* A simple example task to sort a file
*/
public class FileSorter extends Task {
private File file, tofile;
// The method executing the task
public void execute() throws BuildException {
System.out.println("Sorting file="+file);
try {
BufferedReader from =
new BufferedReader(new FileReader(file));
BufferedWriter to =
new BufferedWriter(new FileWriter(tofile));
List allLines = new ArrayList();
// read in the input file
String line = from.readLine();
while (line != null) {
allLines.add(line);
line = from.readLine();
}
from.close();
// sort the list
Collections.sort(allLines);
// write out the sorted list
for (ListIterator i=allLines.listIterator(); i.hasNext(); ) {
String s = (String)i.next();
to.write(s); to.newLine();
}
to.close();
} catch (FileNotFoundException e) {
throw new BuildException(e);
} catch (IOException e) {
throw new BuildException(e);
}
}
// The setter for the "file" attribute
public void setFile(File file) {
this.file = file;
}
// The setter for the "tofile" attribute
public void setTofile(File tofile) {
this.tofile = tofile;
}
}

Do try this.