/**
*
*/
package org.activejpa.enhancer;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* A class loader that emulates the functionality of the agent. To be used for testing in an environment where loading agent is not possible
*
* WARNING: Use it only for testing. Not recommended for production use.
*
* @author ganeshs
*
*/
public class MyClassLoader extends ClassLoader {
private DomainClassEnhancer enhancer;
private boolean initialzed;
private List<String> excludedPackages = new ArrayList<String>(Arrays.asList("java.", "javax.", "sun.", "org.mockito"));
private Logger logger = LoggerFactory.getLogger(MyClassLoader.class);
public MyClassLoader() {
this(Thread.currentThread().getContextClassLoader());
}
public MyClassLoader(ClassLoader loader) {
this(loader, null);
}
public MyClassLoader(ClassLoader loader, List<String> excludedPackages) {
super(loader);
if (excludedPackages != null) {
this.excludedPackages.addAll(excludedPackages);
}
}
private void init() {
enhancer = new DomainClassEnhancer();
initialzed = true;
}
@Override
protected Class<?> loadClass(String name, boolean resolve) throws ClassNotFoundException {
if (! initialzed) {
init();
}
logger.trace("Loading the class " + name);
for (String excluded : excludedPackages) {
if (name.startsWith(excluded)) {
return super.loadClass(name, resolve);
}
}
Class<?> clazz = findLoadedClass(name);
if (clazz != null) {
logger.trace("Class " + name + " is already loaded");
return clazz;
}
byte[] bytes = null;
if (enhancer.canEnhance(name)) {
bytes = enhancer.enhance(this, name);
} else {
InputStream classData = getResourceAsStream(name.replace('.', '/') + ".class");
if(classData == null) {
return super.loadClass(name, resolve);
}
try {
bytes = toByteArray(classData);
} catch (Exception e) {
logger.debug("Failed while converting classdata to bytes for the class " + name, e);
return super.loadClass(name, resolve);
} finally {
if (classData != null) {
try {
classData.close();
} catch (IOException e) {
// Ignore. Can't do much
logger.trace("Failed while closing the classData for the class " + name, e);
}
}
}
}
clazz = defineClass(name, bytes, 0, bytes.length);
if (resolve) {
resolveClass(clazz);
}
return clazz;
}
private static byte[] toByteArray(InputStream is) throws IOException {
ByteArrayOutputStream os = new ByteArrayOutputStream();
byte[] bytes = new byte[4096];
int n = 0;
while (-1 != (n = is.read(bytes))) {
os.write(bytes, 0, n);
}
return os.toByteArray();
}
}