RemoteExceptionUtil.java

package co.codewizards.cloudstore.core.dto;

import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;

public final class RemoteExceptionUtil {

	private RemoteExceptionUtil() { }

	public static void throwOriginalExceptionIfPossible(final Error error) {
		Class<?> clazz;
		try {
			clazz = Class.forName(error.getClassName());
		} catch (final ClassNotFoundException e) {
			return;
		}
		if (!Throwable.class.isAssignableFrom(clazz))
			return;

		@SuppressWarnings("unchecked")
		final Class<? extends Throwable> clasz = (Class<? extends Throwable>) clazz;

		final RemoteException cause = new RemoteException(error);

		Throwable throwable = null;

		// trying XyzException(String message, Throwable cause)
		if (throwable == null)
			throwable = getObjectOrNull(clasz, new Class<?>[] { String.class, Throwable.class }, error.getMessage(), cause);

		// trying XyzException(String message)
		if (throwable == null)
			throwable = getObjectOrNull(clasz, new Class<?>[] { String.class }, error.getMessage());

		// trying XyzException(Throwable cause)
		if (throwable == null)
			throwable = getObjectOrNull(clasz, new Class<?>[] { Throwable.class }, cause);

		// trying XyzException()
		if (throwable == null)
			throwable = getObjectOrNull(clasz, null);

		if (throwable != null) {
			try {
				throwable.initCause(cause);
			} catch (final Exception x) {
				// This happens, if either the cause was already set in an appropriate constructor (see above)
				// or the concrete Throwable does not support it. If we were unable to set the cause we want,
				// we better use a RemoteException and not the original one.
				if (throwable.getCause() != cause)
					return;
			}
			if (throwable instanceof RuntimeException)
				throw (RuntimeException) throwable;

			if (throwable instanceof java.lang.Error)
				throw (java.lang.Error) throwable;

			throw new RuntimeException(throwable);
		}
	}

	private static <T> T getObjectOrNull(final Class<T> clazz, Class<?>[] argumentTypes, final Object ... arguments) {
		T result = null;
		if (argumentTypes == null)
			argumentTypes = new Class<?> [0];

		if (argumentTypes.length == 0) {
			try {
				result = clazz.newInstance();
			} catch (final InstantiationException e) {
				return null;
			} catch (final IllegalAccessException e) {
				return null;
			}
		}

		if (result == null) {
			Constructor<T> constructor;
			try {
				constructor = clazz.getConstructor(argumentTypes);
			} catch (final NoSuchMethodException e) {
				return null;
			} catch (final SecurityException e) {
				return null;
			}

			try {
				result = constructor.newInstance(arguments);
			} catch (final InstantiationException e) {
				return null;
			} catch (final IllegalAccessException e) {
				return null;
			} catch (final IllegalArgumentException e) {
				return null;
			} catch (final InvocationTargetException e) {
				return null;
			}
		}

		return result;
	}
}