WOProjectClassLoader.java

package org.objectstyle.wolips.jrebel.utils;

/* BSD Licensed : Originally from http://pmd.svn.sourceforge.net/svnroot/pmd as JavaProjectClassLoader */

import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.HashSet;
import java.util.Set;

import org.eclipse.core.resources.IProject;
import org.eclipse.core.resources.IWorkspaceRoot;
import org.eclipse.core.runtime.IPath;
import org.eclipse.jdt.core.IClasspathEntry;
import org.eclipse.jdt.core.IJavaProject;
import org.eclipse.jdt.core.JavaCore;
import org.eclipse.jdt.core.JavaModelException;

/**
 * This is a ClassLoader for the Build Path of an IJavaProject.
 */
public class WOProjectClassLoader extends URLClassLoader {
  // private static final Logger log = Logger.getLogger(JavaProjectClassLoader.class);

  private Set<IJavaProject> javaProjects = new HashSet<IJavaProject>();
  private Set<URL> urls = new HashSet<URL>();

  private IWorkspaceRoot workspaceRoot;

  public WOProjectClassLoader(ClassLoader parent, IJavaProject javaProject) {
    super(new URL[0], parent);
    workspaceRoot = javaProject.getProject().getWorkspace().getRoot();
    addURLs(javaProject, false);

    // No longer need these things, drop references
    javaProjects = null;
    workspaceRoot = null;
    urls = null;
  }

  private void addURLs(IJavaProject javaProject, boolean exportsOnly) {
    if (!javaProjects.contains(javaProject)) {
      javaProjects.add(javaProject);

      try {
        // Add default output location
        addURL(javaProject.getOutputLocation());

        // Add each classpath entry
        IClasspathEntry[] classpathEntries = javaProject.getResolvedClasspath(true);
        for (IClasspathEntry classpathEntry : classpathEntries) {
          if (classpathEntry.isExported() || !exportsOnly) {
            switch (classpathEntry.getEntryKind()) {

            // Recurse on projects
            case IClasspathEntry.CPE_PROJECT:
              IProject project = javaProject.getProject().getWorkspace().getRoot().getProject(classpathEntry.getPath().toString());
              IJavaProject javaProj = JavaCore.create(project);
              if (javaProj != null) {
                addURLs(javaProj, true);
              }
              break;

            // Library
            case IClasspathEntry.CPE_LIBRARY:
              addURL(classpathEntry);
              break;

            // Only Source entries with custom output location need to be added
            case IClasspathEntry.CPE_SOURCE:
              IPath outputLocation = classpathEntry.getOutputLocation();
              if (outputLocation != null) {
                addURL(outputLocation);
              }
              break;

            // Variable and Container entries should not be happening, because
            // we've asked for resolved entries.
            case IClasspathEntry.CPE_VARIABLE:
            case IClasspathEntry.CPE_CONTAINER:
              break;
            }
          }
        }
      } catch (JavaModelException e) {
        e.printStackTrace();
        // log.debug("MalformedURLException occurred: " + e.getLocalizedMessage(),e);
      }
    }
  }

  private void addURL(IClasspathEntry classpathEntry) {
    addURL(classpathEntry.getPath());
  }

  private void addURL(IPath path) {
    try {
      if (workspaceRoot.exists(path)) {
        path = workspaceRoot.getLocation().append(path);
      }
      if (isBundleFramework(path)) {
        URL url = path.removeLastSegments(3).toFile().getAbsoluteFile().toURL();
        addURL(url);
      }
      URL url = path.toFile().getAbsoluteFile().toURL();
      addURL(url);
    } catch (MalformedURLException e) {
      e.printStackTrace();
      // log.debug("MalformedURLException occurred: " + e.getLocalizedMessage(),e);
    }
  }

  @Override
  protected void addURL(URL url) {
    if (!urls.contains(url)) {
      urls.add(url);
      super.addURL(url);
    }
  }

  private boolean isBundleFramework(IPath path) {
    int count = path.segmentCount() - 1;
    if ("jar".equals(path.getFileExtension()) && "Java".equals(path.segment(--count)) && "Resources".equals(path.segment(--count)))
      return true;
    return false;
  }
}