/*
 * Copyright 2007 Yusuke Yamamoto
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package twitter4j.internal.json;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

import twitter4j.json.DataObjectFactory;

/**
 * provides public access to package private methods of
 * twitter4j.json.DataObjectFactory class.<br>
 * This class is not intended to be used by Twitter4J client.
 * 
 * @author Yusuke Yamamoto - yusuke at mac.com
 * @since Twitter4J 2.1.7
 */
public class DataObjectFactoryUtil {
	private static final Method CLEAR_THREAD_LOCAL_MAP;

	private static final Method REGISTER_JSON_OBJECT;
	static {
		final Method[] methods = DataObjectFactory.class.getDeclaredMethods();
		Method clearThreadLocalMap = null;
		Method registerJSONObject = null;
		for (final Method method : methods) {
			if (method.getName().equals("clearThreadLocalMap")) {
				clearThreadLocalMap = method;
				clearThreadLocalMap.setAccessible(true);
			} else if (method.getName().equals("registerJSONObject")) {
				registerJSONObject = method;
				registerJSONObject.setAccessible(true);
			}
		}
		if (null == clearThreadLocalMap || null == registerJSONObject) throw new AssertionError();
		CLEAR_THREAD_LOCAL_MAP = clearThreadLocalMap;
		REGISTER_JSON_OBJECT = registerJSONObject;
	}

	private DataObjectFactoryUtil() {
		throw new AssertionError("not intended to be instantiated.");
	}

	/**
	 * provides a public access to {DAOFactory#clearThreadLocalMap}
	 */
	public static void clearThreadLocalMap() {
		try {
			CLEAR_THREAD_LOCAL_MAP.invoke(null);
		} catch (final IllegalAccessException e) {
			throw new AssertionError(e);
		} catch (final InvocationTargetException e) {
			throw new AssertionError(e);
		}
	}

	/**
	 * provides a public access to {DAOFactory#registerJSONObject}
	 */
	@SuppressWarnings("unchecked")
	public static <T> T registerJSONObject(final T key, final Object json) {
		try {
			return (T) REGISTER_JSON_OBJECT.invoke(null, key, json);
		} catch (final IllegalAccessException e) {
			throw new AssertionError(e);
		} catch (final InvocationTargetException e) {
			throw new AssertionError(e);
		}
	}
}