#919 - io.ebean package initial

src/main/java/io/ebeaninternal/api/ClassUtil.java

@@ -0,0 +1,65 @@
+package io.ebeaninternal.api;
+
+
+/**
+ * Helper to find classes taking into account the context class loader.
+ */
+public class ClassUtil {
+
+  /**
+   * Return a new instance of the class using the default constructor.
+   */
+  public static Object newInstance(String className) {
+
+    try {
+      Class<?> cls = forName(className);
+      return cls.newInstance();
+    } catch (Exception e) {
+      String msg = "Error constructing " + className;
+      throw new IllegalArgumentException(msg, e);
+    }
+  }
+
+  /**
+   * Load a class taking into account a context class loader (if present).
+   */
+  public static Class<?> forName(String name) throws ClassNotFoundException {
+    return new ClassLoadContext().forName(name);
+  }
+
+
+  /**
+   * Helper to wrap the context and caller classLoaders (to use/try both).
+   */
+  static class ClassLoadContext {
+
+    private final ClassLoader contextLoader;
+
+    private final ClassLoader callerLoader;
+
+    ClassLoadContext() {
+      this.callerLoader = ClassUtil.class.getClassLoader();
+      this.contextLoader = contextLoader();
+    }
+
+    ClassLoader contextLoader() {
+      ClassLoader loader = Thread.currentThread().getContextClassLoader();
+      return (loader != null) ? loader : callerLoader;
+    }
+
+    public Class<?> forName(String name) throws ClassNotFoundException {
+
+      try {
+        return Class.forName(name, true, contextLoader);
+      } catch (ClassNotFoundException e) {
+        if (callerLoader == contextLoader) {
+          throw e;
+        } else {
+          return Class.forName(name, true, callerLoader);
+        }
+      }
+    }
+
+  }
+}
+