Reload problem for Rythm

gistfile1.txt

java.lang.StringIndexOutOfBoundsException: String index out of range: -1
	at java.lang.String.substring(String.java:1937)
	at com.greenlaw110.rythm.internal.CodeBuilder.setExtended_deprecated(CodeBuilder.java:280)
	at com.greenlaw110.rythm.internal.CodeBuilder.setExtended(CodeBuilder.java:258)
	at com.greenlaw110.rythm.internal.parser.build_in.ExtendsParser$1$1.call(ExtendsParser.java:67)
	at com.greenlaw110.rythm.internal.CodeBuilder.invokeDirectives(CodeBuilder.java:388)
	at com.greenlaw110.rythm.internal.CodeBuilder.build(CodeBuilder.java:365)
	at com.greenlaw110.rythm.internal.compiler.TemplateClass.buildSourceCode(TemplateClass.java:320)
	at com.greenlaw110.rythm.internal.compiler.TemplateClass.refresh(TemplateClass.java:417)
	at com.greenlaw110.rythm.internal.compiler.TemplateClass.refresh(TemplateClass.java:311)
	at com.greenlaw110.rythm.internal.compiler.TemplateClassLoader.detectChange(TemplateClassLoader.java:355)
	at com.greenlaw110.rythm.internal.compiler.TemplateClassManager.checkUpdate(TemplateClassManager.java:91)
	at com.greenlaw110.rythm.internal.compiler.TemplateClassManager.getByTemplate(TemplateClassManager.java:80)
	at com.greenlaw110.rythm.RythmEngine.getTemplate(RythmEngine.java:407)
	at com.greenlaw110.rythm.RythmEngine.render(RythmEngine.java:456)
	at com.greenlaw110.rythm.Rythm.render(Rythm.java:94)
	at rythm.test.ReloadTest.reload(ReloadTest.java:36)

ReloadTest.java

package rythm.test;

import static org.hamcrest.Matchers.*;
import static org.junit.Assert.*;

import java.io.File;
import java.util.Properties;

import org.junit.Test;

import com.greenlaw110.rythm.Rythm;
import com.greenlaw110.rythm.utils.IO;

public class ReloadTest {
	@Test
	public void reload() throws Exception {
		File d = new File(System.getProperty("java.io.tmpdir"));
		Properties p = new Properties();
		p.setProperty("rythm.root", d.getAbsolutePath());
		p.setProperty("rythm.mode", "dev");
		Rythm.init(p);

		File f1 = new File(d, "f1.html");
		IO.writeContent("@extends(f2)@set(title=\"foo\")", f1);
		File f2 = new File(d, "f2.html");
		IO.writeContent("@get(title)", f2);
		assertThat(Rythm.render("f1.html"), is("foo\n"));

		IO.writeContent("@extends(f2)@set(title=\"bar\")", f1);
		assertThat(Rythm.render("f1.html"), is("foo\n"));

		for (int i = 0; i < 5; ++i) {
			sleep(6);
			IO.writeContent("@extends(f2)@set(title=\"baz\")", f1);
			assertThat(Rythm.render("f1.html"), is("baz\n"));
		}
	}

	private void sleep(int n) throws InterruptedException {
		for (int i = 0; i < n; ++i) {
			Thread.sleep(1000L);
			System.out.print(".");
		}
		System.out.println();
	}
}