SONAR-1861: Allow to access files stored in "extensions/rules/" during batch execution

3 files changed, 70 insertions, 2 deletions

diff --git a/sonar-core/src/main/java/org/sonar/core/classloaders/ClassLoadersCollection.java b/sonar-core/src/main/java/org/sonar/core/classloaders/ClassLoadersCollection.java
index d929dc535e9..852649a49c6 100644
--- a/sonar-core/src/main/java/org/sonar/core/classloaders/ClassLoadersCollection.java
+++ b/sonar-core/src/main/java/org/sonar/core/classloaders/ClassLoadersCollection.java
@@ -22,6 +22,14 @@ import java.util.Collection;
  * for all other plugins even if they located in dependent library.
  * </p>
  * 
+ * <h4>Search order for {@link ClassRealm} :</h4>
+ * <ul>
+ * <li>parent class loader (passed via the constructor) if there is one</li>
+ * <li>imports</li>
+ * <li>realm's constituents</li>
+ * <li>parent realm</li>
+ * </ul>
+ * 
  * @since 2.4
  */
 public class ClassLoadersCollection {
@@ -46,12 +54,13 @@ public class ClassLoadersCollection {
    */
   public ClassLoader createClassLoader(String key, Collection<URL> urls, boolean childFirst) {
     try {
+      ClassLoader resourcesClassLoader = new ResourcesClassLoader(urls, baseClassLoader);
       final ClassRealm realm;
       if (childFirst) {
-        ClassRealm parentRealm = world.newRealm(key + "-parent", baseClassLoader);
+        ClassRealm parentRealm = world.newRealm(key + "-parent", resourcesClassLoader);
         realm = parentRealm.createChildRealm(key);
       } else {
-        realm = world.newRealm(key, baseClassLoader);
+        realm = world.newRealm(key, resourcesClassLoader);
       }
       for (URL constituent : urls) {
         realm.addConstituent(constituent);
diff --git a/sonar-core/src/main/java/org/sonar/core/classloaders/ResourcesClassLoader.java b/sonar-core/src/main/java/org/sonar/core/classloaders/ResourcesClassLoader.java
new file mode 100644
index 00000000000..e2298f42602
--- /dev/null
+++ b/sonar-core/src/main/java/org/sonar/core/classloaders/ResourcesClassLoader.java
@@ -0,0 +1,39 @@
+package org.sonar.core.classloaders;
+
+import org.apache.commons.lang.StringUtils;
+
+import com.google.common.collect.Lists;
+
+import java.net.URL;
+import java.net.URLClassLoader;
+import java.util.Collection;
+import java.util.List;
+
+/**
+ * This class loader is used to load resources from a list of URLs - see SONAR-1861.
+ */
+public class ResourcesClassLoader extends URLClassLoader {
+  private Collection<URL> urls;
+
+  public ResourcesClassLoader(Collection<URL> urls, ClassLoader parent) {
+    super(new URL[] {}, parent);
+    List<URL> filtered = Lists.newArrayList();
+    for (URL url : urls) {
+      String path = url.getPath();
+      if ( !StringUtils.endsWith(path, ".jar") && !StringUtils.endsWith(path, "/")) {
+        filtered.add(url);
+      }
+    }
+    this.urls = filtered;
+  }
+
+  @Override
+  public URL findResource(String name) {
+    for (URL url : urls) {
+      if (StringUtils.endsWith(url.getPath(), name)) {
+        return url;
+      }
+    }
+    return null;
+  }
+}
diff --git a/sonar-core/src/test/java/org/sonar/core/classloaders/ResourcesClassLoaderTest.java b/sonar-core/src/test/java/org/sonar/core/classloaders/ResourcesClassLoaderTest.java
new file mode 100644
index 00000000000..ad9fe8375d6
--- /dev/null
+++ b/sonar-core/src/test/java/org/sonar/core/classloaders/ResourcesClassLoaderTest.java
@@ -0,0 +1,20 @@
+package org.sonar.core.classloaders;
+
+import org.junit.Test;
+
+import java.net.URL;
+import java.util.Arrays;
+import java.util.List;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.notNullValue;
+
+public class ResourcesClassLoaderTest {
+
+  @Test
+  public void test() throws Exception {
+    List<URL> urls = Arrays.asList(new URL("http://localhost:9000/deploy/plugins/checkstyle/extension.xml"));
+    ResourcesClassLoader classLoader = new ResourcesClassLoader(urls, null);
+    assertThat(classLoader.findResource("extension.xml"), notNullValue());
+  }
+}