Add overloads with explicit class loader to FunctionUtils

.gitignore

@@ -18,4 +18,9 @@ target/
 
 # IntelliJ Idea project files
 .idea
-*.iml
+*.iml
+
+# Eclipse
+.project
+.classpath
+.settings/

core/src/main/java/com/schibsted/spt/data/jslt/FunctionUtils.java

@@ -31,7 +31,20 @@ static public Function wrapStaticMethod(String functionName,
                                           String className,
                                           String methodName)
     throws LinkageError, ExceptionInInitializerError, ClassNotFoundException {
-    Class klass = Class.forName(className);
+    return wrapStaticMethod(functionName, className, methodName, FunctionUtils.class.getClassLoader(), Thread.currentThread().getContextClassLoader());
+  }
+
+  /**
+   * Create a JSLT function from a static Java method. This will fail
+   * if the method is overloaded. The given class loaders will be tried
+   * in order to load the named class.
+   */
+  static public Function wrapStaticMethod(String functionName,
+                                          String className,
+                                          String methodName,
+                                          ClassLoader... classLoaders)
+    throws LinkageError, ExceptionInInitializerError, ClassNotFoundException {
+    Class klass = loadClass(className, classLoaders);
     Method[] methods = klass.getMethods();
     Method method = null;
     for (int ix = 0; ix < methods.length; ix++) {
@@ -58,8 +71,44 @@ static public Function wrapStaticMethod(String functionName,
                                           Class[] paramTypes)
     throws LinkageError, ExceptionInInitializerError, ClassNotFoundException,
            NoSuchMethodException {
-    Class klass = Class.forName(className);
+    return wrapStaticMethod(functionName, className, methodName, paramTypes, FunctionUtils.class.getClassLoader(), Thread.currentThread().getContextClassLoader());
+  }
+  /**
+   * Create a JSLT function from a static Java method. The given class
+   * loaders will be tried in order to load the named class.
+   * @param paramTypes Array of types used to match overloaded methods.
+   */
+  static public Function wrapStaticMethod(String functionName,
+                                          String className,
+                                          String methodName,
+                                          Class[] paramTypes,
+                                          ClassLoader... classLoaders)
+    throws LinkageError, ExceptionInInitializerError, ClassNotFoundException,
+           NoSuchMethodException {
+    Class klass = loadClass(className, classLoaders);
     Method method = klass.getMethod(methodName, paramTypes);
     return new FunctionWrapper(functionName, method);
   }
+
+  private static Class loadClass(String className, ClassLoader... classLoaders) throws LinkageError, ClassNotFoundException {
+    Class klass = null;
+    Throwable lastException = null;
+    for (ClassLoader classLoader : classLoaders) {
+      if (classLoader != null) {
+        try {
+          klass = Class.forName(className, true, classLoader);
+          lastException = null;
+          break;
+        } catch (LinkageError | ClassNotFoundException e) {
+          lastException = e;
+        }
+      }
+    }
+    if (lastException instanceof LinkageError) {
+       throw (LinkageError) lastException;
+    } else if (lastException instanceof ClassNotFoundException) {
+      throw (ClassNotFoundException) lastException;
+    }
+    return klass;
+  }
 }