import java.io.*;
import org.codehaus.plexus.util.FileUtils;


File f = new File( basedir, "pom.xml" );
if ( !f.exists() )
{
    throw new RuntimeException( "file does not exists: " + f );
}
if ( f.lastModified() <  new File( basedir, "timestamp" ).lastModified())
{
    throw new RuntimeException( "file not recreated: " + f );
}