How to use

getClassLoader

method

in

org.jfree.util.ObjectUtilities

/**
 * Returns the resource specified by the <strong>absolute</strong> name.
 *
 * @param name the name of the resource
 * @param c    the source class
 * @return the url of the resource or null, if not found.
 */
public static URL getResource(final String name, final Class c) {
  final ClassLoader cl = getClassLoader(c);
  if (cl == null) {
    return null;
  }
  return cl.getResource(name);
}

/**
 * Returns the resource specified by the <strong>absolute</strong> name.
 *
 * @param name the name of the resource
 * @param c    the source class
 * @return the url of the resource or null, if not found.
 */
public static URL getResource(final String name, final Class c) {
  final ClassLoader cl = getClassLoader(c);
  if (cl == null) {
    return null;
  }
  return cl.getResource(name);
}

/**
 * Returns the resource specified by the <strong>absolute</strong> name.
 *
 * @param name the name of the resource
 * @param c    the source class
 * @return the url of the resource or null, if not found.
 */
public static URL getResource(final String name, final Class c) {
  final ClassLoader cl = getClassLoader(c);
  if (cl == null) {
    return null;
  }
  return cl.getResource(name);
}

/**
 * Tries to load a class to indirectly check for the existence
 * of a certain library.
 *
 * @param name the name of the library class.
 * @param context the context class to get a classloader from.
 * @return true, if the class could be loaded, false otherwise.
 */
protected static boolean isClassLoadable(final String name, final Class context)
{
 try
 {
  ObjectUtilities.getClassLoader(context).loadClass(name);
  return true;
 }
 catch (Exception e)
 {
  return false;
 }
}

/**
 * Tries to load a class to indirectly check for the existence
 * of a certain library.
 *
 * @param name the name of the library class.
 * @param context the context class to get a classloader from.
 * @return true, if the class could be loaded, false otherwise.
 */
protected static boolean isClassLoadable(final String name, final Class context)
{
 try
 {
  ObjectUtilities.getClassLoader(context).loadClass(name);
  return true;
 }
 catch (Exception e)
 {
  return false;
 }
}

/**
 * Tries to load a class to indirectly check for the existence
 * of a certain library.
 *
 * @param name the name of the library class.
 * @param context the context class to get a classloader from.
 * @return true, if the class could be loaded, false otherwise.
 */
protected static boolean isClassLoadable(final String name, final Class context)
{
 try
 {
  ObjectUtilities.getClassLoader(context).loadClass(name);
  return true;
 }
 catch (Exception e)
 {
  return false;
 }
}

/**
 * Tries to create a new instance of the given class. This is a short cut
 * for the common bean instantiation code.
 *
 * @param className the class name as String, never null.
 * @param source    the source class, from where to get the classloader.
 * @return the instantiated object or null, if an error occured.
 */
public static Object loadAndInstantiate(final String className,
                    final Class source) {
  try {
    final ClassLoader loader = getClassLoader(source);
    final Class c = loader.loadClass(className);
    return c.newInstance();
  }
  catch (Exception e) {
    return null;
  }
}

/**
 * Tries to create a new instance of the given class. This is a short cut
 * for the common bean instantiation code.
 *
 * @param className the class name as String, never null.
 * @param source    the source class, from where to get the classloader.
 * @return the instantiated object or null, if an error occured.
 */
public static Object loadAndInstantiate(final String className,
                    final Class source) {
  try {
    final ClassLoader loader = getClassLoader(source);
    final Class c = loader.loadClass(className);
    return c.newInstance();
  }
  catch (Exception e) {
    return null;
  }
}

/**
 * Tries to create a new instance of the given class. This is a short cut
 * for the common bean instantiation code.
 *
 * @param className the class name as String, never null.
 * @param source    the source class, from where to get the classloader.
 * @return the instantiated object or null, if an error occured.
 */
public static Object loadAndInstantiate(final String className,
                    final Class source) {
  try {
    final ClassLoader loader = getClassLoader(source);
    final Class c = loader.loadClass(className);
    return c.newInstance();
  }
  catch (Exception e) {
    return null;
  }
}

/**
 * Creates an object based on this object description.
 *
 * @return The object.
 */
public Object createObject() {
  try {
    final String o = (String) getParameter("class");
    return ObjectUtilities.getClassLoader(getClass()).loadClass(o).newInstance();
  }
  catch (Exception e) {
    return null;
  }
}

protected Library loadLibrary(final String classname) {
  if (classname == null) {
    return null;
  }
  try {
    final Class c = ObjectUtilities.getClassLoader(
        getClass()).loadClass(classname);
    try {
      final Method m = c.getMethod("getInstance", (Class[]) null);
      return (Library) m.invoke(null, (Object[]) null);
    }
    catch(Exception e) {
      // ok, fall back ...
    }
    return (Library) c.newInstance();
  }
  catch (Exception e) {
    // ok, this library has no 'getInstance()' method. Check the
    // default constructor ...
    return null;
  }
}

/**
 * Returns the resource specified by the <strong>relative</strong> name.
 *
 * @param name the name of the resource relative to the given class
 * @param c    the source class
 * @return the url of the resource or null, if not found.
 */
public static URL getResourceRelative(final String name, final Class c) {
  final ClassLoader cl = getClassLoader(c);
  final String cname = convertName(name, c);
  if (cl == null) {
    return null;
  }
  return cl.getResource(cname);
}

/**
 * Returns the resource specified by the <strong>relative</strong> name.
 *
 * @param name the name of the resource relative to the given class
 * @param c    the source class
 * @return the url of the resource or null, if not found.
 */
public static URL getResourceRelative(final String name, final Class c) {
  final ClassLoader cl = getClassLoader(c);
  final String cname = convertName(name, c);
  if (cl == null) {
    return null;
  }
  return cl.getResource(cname);
}

/**
 * Returns the resource specified by the <strong>relative</strong> name.
 *
 * @param name the name of the resource relative to the given class
 * @param c    the source class
 * @return the url of the resource or null, if not found.
 */
public static URL getResourceRelative(final String name, final Class c) {
  final ClassLoader cl = getClassLoader(c);
  final String cname = convertName(name, c);
  if (cl == null) {
    return null;
  }
  return cl.getResource(cname);
}

/**
 * Loads the specified booter implementation.
 *
 * @param classname  the class name.
 *
 * @return The boot class.
 */
protected AbstractBoot loadBooter(final String classname) {
  if (classname == null) {
    return null;
  }
  try {
    final Class c = ObjectUtilities.getClassLoader(
        getClass()).loadClass(classname);
    final Method m = c.getMethod("getInstance", (Class[]) null);
    return (AbstractBoot) m.invoke(null, (Object[]) null);
  }
  catch (Exception e) {
    Log.info ("Unable to boot dependent class: " + classname);
    return null;
  }
}

/**
 * Loads the specified booter implementation.
 *
 * @param classname  the class name.
 *
 * @return The boot class.
 */
protected AbstractBoot loadBooter(final String classname) {
  if (classname == null) {
    return null;
  }
  try {
    final Class c = ObjectUtilities.getClassLoader(
        getClass()).loadClass(classname);
    final Method m = c.getMethod("getInstance", (Class[]) null);
    return (AbstractBoot) m.invoke(null, (Object[]) null);
  }
  catch (Exception e) {
    Log.info ("Unable to boot dependent class: " + classname);
    return null;
  }
}

/**
 * Loads the specified booter implementation.
 *
 * @param classname  the class name.
 *
 * @return The boot class.
 */
protected AbstractBoot loadBooter(final String classname) {
  if (classname == null) {
    return null;
  }
  try {
    final Class c = ObjectUtilities.getClassLoader(
        getClass()).loadClass(classname);
    final Method m = c.getMethod("getInstance", (Class[]) null);
    return (AbstractBoot) m.invoke(null, (Object[]) null);
  }
  catch (Exception e) {
    Log.info ("Unable to boot dependent class: " + classname);
    return null;
  }
}

/**
 * Loads a class by its fully qualified name.
 * 
 * @param name  the class name.
 * 
 * @return The class (or <code>null</code> if there was a problem loading the class).
 */
protected Class loadClass(final String name) {
  try {
    return ObjectUtilities.getClassLoader(JavaSourceCollector.class).loadClass(name);
  }
  catch (Exception e) {
    Log.warn (new Log.SimpleMessage("Do not process: Failed to load class:", name));
    return null;
  }
}

/**
 * Loads the given class, and ignores all exceptions which may occur
 * during the loading. If the class was invalid, null is returned instead.
 *
 * @param className the name of the class to be loaded.
 * @return the class or null.
 * 
 * @throws XMLWriterException if there is a writer exception.
 */
protected XmlWriteHandler loadHandlerClass(final String className)
  throws XMLWriterException {
  if (className == null) {
    throw new XMLWriterException("LoadHanderClass: Class name not defined");
  }
  try {
    final Class c = ObjectUtilities.getClassLoader(getClass()).loadClass(className);
    return (XmlWriteHandler) c.newInstance();
  }
  catch (Exception e) {
    // ignore buggy classes for now ..
    throw new XMLWriterException("LoadHanderClass: Unable to instantiate " + className, e);
  }
}
 

/**
 * Loads the given class, and ignores all exceptions which may occur
 * during the loading. If the class was invalid, null is returned instead.
 *
 * @param className the name of the class to be loaded.
 * @return the class or null.
 * @throws XmlReaderException if there is a reader error.
 */
protected Class loadClass(final String className)
  throws XmlReaderException {
  if (className == null) {
    throw new XmlReaderException("LoadHanderClass: Class name not defined");
  }
  try {
    final Class c = ObjectUtilities.getClassLoader(getClass()).loadClass(className);
    return c;
  }
  catch (Exception e) {
    // ignore buggy classes for now ..
    throw new XmlReaderException("LoadHanderClass: Unable to load " + className, e);
  }
}