two utilities added

jodd-core/src/main/java/jodd/util/ClassUtil.java

@@ -27,6 +27,8 @@
 
 import jodd.util.cl.ClassLoaderStrategy;
 
+import java.io.File;
+import java.io.IOException;
 import java.lang.annotation.Annotation;
 import java.lang.reflect.AccessibleObject;
 import java.lang.reflect.Array;
@@ -41,6 +43,7 @@
 import java.lang.reflect.Type;
 import java.lang.reflect.TypeVariable;
 import java.lang.reflect.WildcardType;
+import java.net.URL;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
@@ -50,6 +53,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import java.util.jar.JarFile;
 
 /**
  * Class utilities.
@@ -1250,4 +1254,67 @@ public static Class findEnum(Class target) {
 		return null;
 	}
 
+
+	// ---------------------------------------------------------------- misc
+
+	/**
+	 * Returns the class of the immediate subclass of the given parent class for
+	 * the given object instance; or null if such immediate subclass cannot be
+	 * uniquely identified for the given object instance.
+	 */
+	public static Class<?> childClassOf(Class<?> parentClass, Object instance) {
+
+		if (instance == null || instance == Object.class) {
+			return null;
+		}
+
+		if (parentClass != null) {
+			if (parentClass.isInterface()) {
+				return null;
+			}
+		}
+
+		Class<?> childClass = instance.getClass();
+		while (true) {
+			Class<?> parent = childClass.getSuperclass();
+			if (parent == parentClass) {
+				return childClass;
+			}
+			if (parent == null) {
+				return null;
+			}
+			childClass = parent;
+		}
+	}
+
+	/**
+	 * Returns the jar file from which the given class is loaded; or null
+	 * if no such jar file can be located.
+	 */
+	public static JarFile jarFileOf(Class<?> klass) {
+		URL url = klass.getResource(
+			"/" + klass.getName().replace('.', '/') + ".class");
+
+		if (url == null) {
+			return null;
+		}
+
+		String s = url.getFile();
+		int beginIndex = s.indexOf("file:") + "file:".length();
+		int endIndex = s.indexOf(".jar!");
+		if (endIndex == -1) {
+			return null;
+		}
+
+		endIndex += ".jar".length();
+		String f = s.substring(beginIndex, endIndex);
+		File file = new File(f);
+
+		try {
+			return file.exists() ? new JarFile(file) : null;
+		} catch (IOException e) {
+			throw new IllegalStateException(e);
+		}
+	}
+
 }