SONAR-2106: Improve sonar-batch-bootstrapper

* Add BootstrapClassLoader

* Instead of RuntimeException use BootstrapException

* Improve quality according to Sonar report

6 files changed, 212 insertions, 27 deletions

diff --git a/sonar-batch-bootstrapper/src/main/java/org/sonar/batch/bootstrapper/BootstrapClassLoader.java b/sonar-batch-bootstrapper/src/main/java/org/sonar/batch/bootstrapper/BootstrapClassLoader.java
new file mode 100644
index 00000000000..c61a238df04
--- /dev/null
+++ b/sonar-batch-bootstrapper/src/main/java/org/sonar/batch/bootstrapper/BootstrapClassLoader.java
@@ -0,0 +1,93 @@
+/*
+ * Sonar, open source software quality management tool.
+ * Copyright (C) 2009 SonarSource SA
+ * mailto:contact AT sonarsource DOT com
+ *
+ * Sonar is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * Sonar is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with Sonar; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02
+ */
+package org.sonar.batch.bootstrapper;
+
+import java.net.URL;
+import java.net.URLClassLoader;
+
+/**
+ * Special {@link URLClassLoader} to execute Sonar, which restricts loading from parent.
+ */
+public class BootstrapClassLoader extends URLClassLoader {
+
+  private String[] unmaskedPackages;
+
+  public BootstrapClassLoader(ClassLoader parent, String... unmaskedPackages) {
+    super(new URL[0], parent);
+    this.unmaskedPackages = unmaskedPackages;
+  }
+
+  /**
+   * {@inheritDoc} Visibility of a method has been relaxed to public.
+   */
+  @Override
+  public void addURL(URL url) {
+    super.addURL(url);
+  }
+
+  /**
+   * {@inheritDoc} Visibility of a method has been relaxed to public.
+   */
+  @Override
+  public Class<?> findClass(String name) throws ClassNotFoundException {
+    return super.findClass(name);
+  }
+
+  /**
+   * @return true, if class can be loaded from parent ClassLoader
+   */
+  boolean canLoadFromParent(String name) {
+    for (String pkg : unmaskedPackages) {
+      if (name.startsWith(pkg + ".")) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  /**
+   * Same behavior as in {@link URLClassLoader#loadClass(String, boolean)}, except loading from parent.
+   */
+  @Override
+  protected synchronized Class<?> loadClass(String name, boolean resolve) throws ClassNotFoundException {
+    // First, check if the class has already been loaded
+    Class<?> c = findLoadedClass(name);
+    if (c == null) {
+      try {
+        // Load from parent
+        if ((getParent() != null) && canLoadFromParent(name)) {
+          c = getParent().loadClass(name);
+        } else {
+          // Load from system
+          c = getSystemClassLoader().loadClass(name);
+        }
+      } catch (ClassNotFoundException e) {
+        // If still not found, then invoke findClass in order
+        // to find the class.
+        c = findClass(name);
+      }
+    }
+    if (resolve) {
+      resolveClass(c);
+    }
+    return c;
+  }
+
+}
diff --git a/sonar-batch-bootstrapper/src/main/java/org/sonar/batch/bootstrapper/BootstrapException.java b/sonar-batch-bootstrapper/src/main/java/org/sonar/batch/bootstrapper/BootstrapException.java
new file mode 100644
index 00000000000..8b75b61c97a
--- /dev/null
+++ b/sonar-batch-bootstrapper/src/main/java/org/sonar/batch/bootstrapper/BootstrapException.java
@@ -0,0 +1,36 @@
+/*
+ * Sonar, open source software quality management tool.
+ * Copyright (C) 2009 SonarSource SA
+ * mailto:contact AT sonarsource DOT com
+ *
+ * Sonar is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * Sonar is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with Sonar; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02
+ */
+package org.sonar.batch.bootstrapper;
+
+public class BootstrapException extends RuntimeException {
+
+  public BootstrapException(String message) {
+    super(message);
+  }
+
+  public BootstrapException(Throwable cause) {
+    super(cause);
+  }
+
+  public BootstrapException(String message, Throwable cause) {
+    super(message, cause);
+  }
+
+}
diff --git a/sonar-batch-bootstrapper/src/main/java/org/sonar/batch/bootstrapper/BatchDownloader.java b/sonar-batch-bootstrapper/src/main/java/org/sonar/batch/bootstrapper/Bootstrapper.java
index eead8dc6d5e..065c193c7d2 100644
--- a/sonar-batch-bootstrapper/src/main/java/org/sonar/batch/bootstrapper/BatchDownloader.java
+++ b/sonar-batch-bootstrapper/src/main/java/org/sonar/batch/bootstrapper/Bootstrapper.java
@@ -21,11 +21,12 @@ package org.sonar.batch.bootstrapper;
 
 import java.io.*;
 import java.net.HttpURLConnection;
+import java.net.MalformedURLException;
 import java.net.URL;
 import java.util.ArrayList;
 import java.util.List;
 
-public class BatchDownloader {
+public class Bootstrapper {
 
   private static final String VERSION_PATH = "/api/server/version";
   private static final String BATCH_PATH = "/batch/";
@@ -33,10 +34,13 @@ public class BatchDownloader {
   public static final int CONNECT_TIMEOUT_MILLISECONDS = 30000;
   public static final int READ_TIMEOUT_MILLISECONDS = 60000;
 
+  private File bootDir;
   private String serverUrl;
   private String serverVersion;
 
-  public BatchDownloader(String serverUrl) {
+  public Bootstrapper(String serverUrl, File workDir) {
+    bootDir = new File(workDir, "batch");
+    bootDir.mkdirs();
     if (serverUrl.endsWith("/")) {
       this.serverUrl = serverUrl.substring(0, serverUrl.length() - 1);
     } else {
@@ -59,33 +63,34 @@ public class BatchDownloader {
       try {
         serverVersion = remoteContent(VERSION_PATH);
       } catch (IOException e) {
-        throw new RuntimeException(e.getMessage(), e);
+        throw new BootstrapException(e.getMessage(), e);
       }
     }
     return serverVersion;
   }
 
   /**
+   * Download batch files from server and creates {@link BootstrapClassLoader}.
    * To use this method version of Sonar should be at least 2.6.
    * 
-   * @return list of downloaded files
+   * @param urls additional URLs for loading classes and resources
+   * @param parent parent ClassLoader
+   * @param unmaskedPackages only classes and resources from those packages would be available for loading from parent
    */
-  public List<File> downloadBatchFiles(File toDir) {
-    try {
-      List<File> files = new ArrayList<File>();
-
-      String libs = remoteContent(BATCH_PATH);
-
-      for (String lib : libs.split(",")) {
-        File file = new File(toDir, lib);
-        remoteContentToFile(BATCH_PATH + lib, file);
-        files.add(file);
+  public BootstrapClassLoader createClassLoader(URL[] urls, ClassLoader parent, String... unmaskedPackages) {
+    BootstrapClassLoader classLoader = new BootstrapClassLoader(parent, unmaskedPackages);
+    List<File> files = downloadBatchFiles();
+    for (URL url : urls) {
+      classLoader.addURL(url);
+    }
+    for (File file : files) {
+      try {
+        classLoader.addURL(file.toURI().toURL());
+      } catch (MalformedURLException e) {
+        throw new BootstrapException(e);
       }
-
-      return files;
-    } catch (Exception e) {
-      throw new RuntimeException(e);
     }
+    return classLoader;
   }
 
   private void remoteContentToFile(String path, File toFile) {
@@ -97,10 +102,10 @@ public class BatchDownloader {
       output = new FileOutputStream(toFile, false);
       input = connection.getInputStream();
       BootstrapperIOUtils.copyLarge(input, output);
-    } catch (Exception e) {
+    } catch (IOException e) {
       BootstrapperIOUtils.closeQuietly(output);
       BootstrapperIOUtils.deleteFileQuietly(toFile);
-      throw new RuntimeException("Fail to download the file: " + fullUrl, e);
+      throw new BootstrapException("Fail to download the file: " + fullUrl, e);
     } finally {
       BootstrapperIOUtils.closeQuietly(input);
       BootstrapperIOUtils.closeQuietly(output);
@@ -133,4 +138,18 @@ public class BatchDownloader {
     return connection;
   }
 
+  private List<File> downloadBatchFiles() {
+    try {
+      List<File> files = new ArrayList<File>();
+      String libs = remoteContent(BATCH_PATH);
+      for (String lib : libs.split(",")) {
+        File file = new File(bootDir, lib);
+        remoteContentToFile(BATCH_PATH + lib, file);
+        files.add(file);
+      }
+      return files;
+    } catch (Exception e) {
+      throw new BootstrapException(e);
+    }
+  }
 }
diff --git a/sonar-batch-bootstrapper/src/main/java/org/sonar/batch/bootstrapper/BootstrapperIOUtils.java b/sonar-batch-bootstrapper/src/main/java/org/sonar/batch/bootstrapper/BootstrapperIOUtils.java
index e7d4ec42e1a..d400bc8c40d 100644
--- a/sonar-batch-bootstrapper/src/main/java/org/sonar/batch/bootstrapper/BootstrapperIOUtils.java
+++ b/sonar-batch-bootstrapper/src/main/java/org/sonar/batch/bootstrapper/BootstrapperIOUtils.java
@@ -21,9 +21,10 @@ package org.sonar.batch.bootstrapper;
 
 import java.io.*;
 
-final class BootstrapperIOUtils {
+public final class BootstrapperIOUtils {
 
   private BootstrapperIOUtils() {
+    // only static methods
   }
 
   /**
@@ -39,8 +40,7 @@ final class BootstrapperIOUtils {
       if (closeable != null) {
         closeable.close();
       }
-    } catch (IOException ioe) {
-      // ignore
+    } catch (IOException ioe) { // NOSONAR
     }
   }
 
diff --git a/sonar-batch-bootstrapper/src/test/java/org/sonar/batch/bootstrapper/BootstrapClassLoaderTest.java b/sonar-batch-bootstrapper/src/test/java/org/sonar/batch/bootstrapper/BootstrapClassLoaderTest.java
new file mode 100644
index 00000000000..b8a13d50173
--- /dev/null
+++ b/sonar-batch-bootstrapper/src/test/java/org/sonar/batch/bootstrapper/BootstrapClassLoaderTest.java
@@ -0,0 +1,36 @@
+/*
+ * Sonar, open source software quality management tool.
+ * Copyright (C) 2009 SonarSource SA
+ * mailto:contact AT sonarsource DOT com
+ *
+ * Sonar is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * Sonar is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with Sonar; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02
+ */
+package org.sonar.batch.bootstrapper;
+
+import org.junit.Test;
+
+import static org.hamcrest.Matchers.is;
+import static org.junit.Assert.assertThat;
+
+public class BootstrapClassLoaderTest {
+
+  @Test
+  public void shouldRestrictLoadingFromParent() throws Exception {
+    BootstrapClassLoader classLoader = new BootstrapClassLoader(getClass().getClassLoader(), "org.sonar.ant");
+    assertThat(classLoader.canLoadFromParent("org.sonar.ant.Launcher"), is(true));
+    assertThat(classLoader.canLoadFromParent("org.objectweb.asm.ClassVisitor"), is(false));
+  }
+
+}
diff --git a/sonar-batch-bootstrapper/src/test/java/org/sonar/batch/bootstrapper/BatchDownloaderTest.java b/sonar-batch-bootstrapper/src/test/java/org/sonar/batch/bootstrapper/BootstrapperTest.java
index 1822a53f014..945940a4873 100644
--- a/sonar-batch-bootstrapper/src/test/java/org/sonar/batch/bootstrapper/BatchDownloaderTest.java
+++ b/sonar-batch-bootstrapper/src/test/java/org/sonar/batch/bootstrapper/BootstrapperTest.java
@@ -21,28 +21,29 @@ package org.sonar.batch.bootstrapper;
 
 import org.junit.Test;
 
+import java.io.File;
 import java.io.IOException;
 
 import static org.hamcrest.Matchers.is;
 import static org.junit.Assert.assertThat;
 
-public class BatchDownloaderTest {
+public class BootstrapperTest {
 
   @Test
   public void shouldRemoveLastUrlSlash() {
-    BatchDownloader bootstrapper = new BatchDownloader("http://test/");
+    Bootstrapper bootstrapper = new Bootstrapper("http://test/", new File("target"));
     assertThat(bootstrapper.getServerUrl(), is("http://test"));
   }
 
   @Test(expected = Exception.class)
   public void shouldFailIfCanNotConnectServer() {
-    BatchDownloader bootstrapper = new BatchDownloader("http://unknown.foo");
+    Bootstrapper bootstrapper = new Bootstrapper("http://unknown.foo", new File("target"));
     bootstrapper.getServerVersion();
   }
 
   @Test
   public void shouldReturnValidVersion() {
-    BatchDownloader bootstrapper = new BatchDownloader("http://test") {
+    Bootstrapper bootstrapper = new Bootstrapper("http://test", new File("target")) {
       @Override
       String remoteContent(String path) throws IOException {
         return "2.6";