001/*
002 * Sonar, open source software quality management tool.
003 * Copyright (C) 2008-2012 SonarSource
004 * mailto:contact AT sonarsource DOT com
005 *
006 * Sonar is free software; you can redistribute it and/or
007 * modify it under the terms of the GNU Lesser General Public
008 * License as published by the Free Software Foundation; either
009 * version 3 of the License, or (at your option) any later version.
010 *
011 * Sonar is distributed in the hope that it will be useful,
012 * but WITHOUT ANY WARRANTY; without even the implied warranty of
013 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014 * Lesser General Public License for more details.
015 *
016 * You should have received a copy of the GNU Lesser General Public
017 * License along with Sonar; if not, write to the Free Software
018 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02
019 */
020package org.sonar.batch.bootstrapper;
021
022import java.io.IOException;
023import java.net.URL;
024import java.net.URLClassLoader;
025import java.util.Enumeration;
026
027/**
028 * Special {@link URLClassLoader} to execute Sonar, which restricts loading from parent.
029 */
030public class BootstrapClassLoader extends URLClassLoader {
031
032  private String[] unmaskedPackages;
033
034  public BootstrapClassLoader(ClassLoader parent, String... unmaskedPackages) {
035    super(new URL[0], parent);
036    this.unmaskedPackages = unmaskedPackages;
037  }
038
039  /**
040   * {@inheritDoc} Visibility of a method has been relaxed to public.
041   */
042  @Override
043  public void addURL(URL url) {
044    super.addURL(url);
045  }
046
047  /**
048   * {@inheritDoc} Visibility of a method has been relaxed to public.
049   */
050  @Override
051  public Class<?> findClass(String name) throws ClassNotFoundException {
052    return super.findClass(name);
053  }
054
055  /**
056   * @return true, if class can be loaded from parent ClassLoader
057   */
058  boolean canLoadFromParent(String name) {
059    for (String pkg : unmaskedPackages) {
060      if (name.startsWith(pkg + ".")) {
061        return true;
062      }
063    }
064    return false;
065  }
066
067  /**
068   * Same behavior as in {@link URLClassLoader#loadClass(String, boolean)}, except loading from parent.
069   */
070  @Override
071  protected synchronized Class<?> loadClass(String name, boolean resolve) throws ClassNotFoundException {
072    // First, check if the class has already been loaded
073    Class<?> c = findLoadedClass(name);
074    if (c == null) {
075      try {
076        // Load from parent
077        if ((getParent() != null) && canLoadFromParent(name)) {
078          c = getParent().loadClass(name);
079        } else {
080          // Load from system
081          c = getSystemClassLoader().loadClass(name);
082        }
083      } catch (ClassNotFoundException e) {
084        // If still not found, then invoke findClass in order
085        // to find the class.
086        c = findClass(name);
087      }
088    }
089    if (resolve) {
090      resolveClass(c);
091    }
092    return c;
093  }
094
095  /**
096   * Unlike {@link URLClassLoader#getResource(String)} don't return resource from parent.
097   * See http://jira.codehaus.org/browse/SONAR-2276
098   */
099  @Override
100  public URL getResource(String name) {
101    return findResource(name);
102  }
103
104  /**
105   * Unlike {@link URLClassLoader#getResources(String)} don't return resources from parent.
106   * See http://jira.codehaus.org/browse/SONAR-2276
107   */
108  @Override
109  public Enumeration<URL> getResources(String name) throws IOException {
110    return findResources(name);
111  }
112
113}