0N/A

0N/Aimport java.io.ByteArrayOutputStream;

0N/Aimport java.io.IOException;

0N/Aimport java.io.OutputStream;

0N/Aimport java.io.PrintWriter;

0N/Aimport java.io.StringWriter;

0N/A

0N/Aimport java.lang.reflect.Method;

0N/Aimport java.net.URI;

0N/Aimport java.util.Arrays;

0N/Aimport java.util.Vector;

0N/A

0N/Aimport javax.tools.Diagnostic;

0N/Aimport javax.tools.DiagnosticCollector;

0N/Aimport javax.tools.FileObject;

0N/Aimport javax.tools.ForwardingJavaFileManager;

0N/Aimport javax.tools.JavaCompiler;

0N/Aimport javax.tools.JavaCompiler.CompilationTask;

0N/Aimport javax.tools.JavaFileManager;

0N/Aimport javax.tools.JavaFileObject;

0N/Aimport javax.tools.JavaFileObject.Kind;

0N/Aimport javax.tools.SimpleJavaFileObject;

0N/Aimport javax.tools.StandardJavaFileManager;

0N/Aimport javax.tools.ToolProvider;

0N/A

0N/A

0N/Apublic class SortMethodsTest {

0N/A

0N/A static String createClass(String name, int nrOfMethods) {

0N/A StringWriter sw = new StringWriter();

0N/A PrintWriter pw = new PrintWriter(sw);

0N/A pw.println("public class " + name + "{");

0N/A for (int i = 0; i < nrOfMethods; i++) {

0N/A pw.println(" public void m" + i + "() {}");

0N/A }

0N/A pw.println(" public static String sayHello() {");

0N/A pw.println(" return \"Hello from class \" + " + name +

0N/A ".class.getName() + \" with \" + " + name +

0N/A ".class.getDeclaredMethods().length + \" methods\";");

0N/A pw.println(" }");

0N/A pw.println("}");

0N/A pw.close();

0N/A return sw.toString();

0N/A }

0N/A

0N/A public static void main(String args[]) {

0N/A

0N/A JavaCompiler comp = ToolProvider.getSystemJavaCompiler();

0N/A DiagnosticCollector<JavaFileObject> diags = new DiagnosticCollector<JavaFileObject>();

0N/A final String cName = new String("ManyMethodsClass");

0N/A Vector<Long> results = new Vector<Long>();

0N/A

0N/A for (int i = 6; i < 600000; i*=10) {

0N/A String klass = createClass(cName, i);

0N/A JavaMemoryFileObject file = new JavaMemoryFileObject(cName, klass);

0N/A MemoryFileManager mfm = new MemoryFileManager(comp.getStandardFileManager(diags, null, null), file);

0N/A CompilationTask task = comp.getTask(null, mfm, diags, null, null, Arrays.asList(file));

0N/A

0N/A if (task.call()) {

0N/A try {

0N/A MemoryClassLoader mcl = new MemoryClassLoader(file);

0N/A long start = System.nanoTime();

0N/A Class<? extends Object> c = Class.forName(cName, true, mcl);

0N/A long end = System.nanoTime();

0N/A results.add(end - start);

0N/A Method m = c.getDeclaredMethod("sayHello", new Class[0]);

0N/A String ret = (String)m.invoke(null, new Object[0]);

0N/A System.out.println(ret + " (loaded and resloved in " + (end - start) + "ns)");

0N/A } catch (Exception e) {

0N/A System.err.println(e);

0N/A }

0N/A }

0N/A else {

0N/A System.out.println(klass);

0N/A System.out.println();

0N/A for (Diagnostic diag : diags.getDiagnostics()) {

0N/A System.out.println(diag.getCode() + "\n" + diag.getKind() + "\n" + diag.getPosition());

0N/A System.out.println(diag.getSource() + "\n" + diag.getMessage(null));

0N/A }

0N/A }

0N/A }

0N/A

0N/A long lastRatio = 0;

0N/A for (int i = 2; i < results.size(); i++) {

3221N/A long normalized1 = Math.max(results.get(i-1) - results.get(0), 1);

0N/A long normalized2 = Math.max(results.get(i) - results.get(0), 1);

0N/A long ratio = normalized2/normalized1;

lastRatio = ratio;

System.out.println("10 x more methods requires " + ratio + " x more time");

}

// The following is just vague estimation but seems to work on current x86_64 and sparcv9 machines

if (lastRatio > 80) {

throw new RuntimeException("ATTENTION: it seems that class loading needs quadratic time with regard to the number of class methods!!!");

}

}

}

class JavaMemoryFileObject extends SimpleJavaFileObject {

private final String code;

private ByteArrayOutputStream byteCode;

JavaMemoryFileObject(String name, String code) {

super(URI.create("string:///" + name.replace('.','/') + Kind.SOURCE.extension), Kind.SOURCE);

this.code = code;

}

@Override

public CharSequence getCharContent(boolean ignoreEncodingErrors) {

return code;

}

@Override

public OutputStream openOutputStream() {

byteCode = new ByteArrayOutputStream();

return byteCode;

}

byte[] getByteCode() {

return byteCode.toByteArray();

}

}

class MemoryClassLoader extends ClassLoader {

private final JavaMemoryFileObject jfo;

public MemoryClassLoader(JavaMemoryFileObject jfo) {

this.jfo = jfo;

}

public Class findClass(String name) {

byte[] b = jfo.getByteCode();

return defineClass(name, b, 0, b.length);

}

}

class MemoryFileManager extends ForwardingJavaFileManager<JavaFileManager> {

private final JavaFileObject jfo;

public MemoryFileManager(StandardJavaFileManager jfm, JavaFileObject jfo) {

super(jfm);

this.jfo = jfo;

}

@Override

public FileObject getFileForInput(Location location, String packageName,

String relativeName) throws IOException {

return jfo;

}

@Override

public JavaFileObject getJavaFileForOutput(Location location, String qualifiedName,

Kind kind, FileObject outputFile) throws IOException {

return jfo;

}

}