core/org.eclipse.tigerstripe.core/src/main/java/org/eclipse/tigerstripe/workbench/internal/core/plugin/pluggable/JarInJarClassLoader.java

package org.eclipse.tigerstripe.workbench.internal.core.plugin.pluggable;

import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Map;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;

import org.eclipse.tigerstripe.workbench.TigerstripeException;
import org.eclipse.tigerstripe.workbench.internal.api.ITigerstripeRuntime;


@SuppressWarnings("deprecation")
public class JarInJarClassLoader extends URLClassLoader {
    
    private ITigerstripeRuntime runtime;

    public JarInJarClassLoader(ITigerstripeRuntime runtime, URL[] urls, ClassLoader parent) {
        super(urls, parent);
        this.runtime = runtime;

        try {
            for (URL url : urls) {
                if (isJar(url.getFile())) {
                    addJarResource(new File(url.getPath()));
                }
            }
        } catch (TigerstripeException e) {
            runtime.logErrorMessage(
                    "Error adding Jar entries to classpath",
                    e);
        }
    }

    private void addJarResource(File file) throws TigerstripeException {

        try (JarFile jarFile = new JarFile(file)) {
            addURL(file.toURL());
            Enumeration<JarEntry> jarEntries = jarFile.entries();
            while (jarEntries.hasMoreElements()) {
                JarEntry jarEntry = jarEntries.nextElement();
                if (!jarEntry.isDirectory() && isJar(jarEntry.getName())) {
                    addJarResource(TigerstripeJarUtils.jarEntryAsFile(jarFile, jarEntry));
                }
            }
        } catch (IOException e) {
            runtime.logErrorMessage("Error adding Jar resource to classpath", e);
        }
    }

    @Override
    protected Class<?> loadClass(String name, boolean resolve)
            throws ClassNotFoundException {

        synchronized (getClassLoadingLock(name)) {
            try {
                Class<?> clazz = findLoadedClass(name);
                if (clazz == null) {
                    clazz = findClass(name);
                }
                if (resolve) {
                    resolveClass(clazz);
                }
                return clazz;
            } catch (ClassNotFoundException e) {
                return super.loadClass(name, resolve);
            }
        }
    }

    private static boolean isJar(String fileName) {
        return fileName != null && (fileName.toLowerCase().endsWith(".jar"));
    }
    
    @Override
    public void close() throws IOException {
        this.runtime = null;
        super.close();
    }
}