SupportedParameters.java

/**
 * Copyright 2010-2016 Ralph Schaer <ralphschaer@gmail.com>
 *
 * 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 ch.ralscha.extdirectspring.util;

import java.security.Principal;
import java.util.Locale;

import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import ch.ralscha.extdirectspring.bean.ExtDirectRequest;

/**
 * Enumeration of all supported parameter types.
 */
enum SupportedParameters {

	SERVLET_REQUEST(ServletRequest.class), SERVLET_RESPONSE(ServletResponse.class),
	SESSION(HttpSession.class), LOCALE(Locale.class), PRINCIPAL(Principal.class),
	EXT_DIRECT_REQUEST(ExtDirectRequest.class);

	private final Class<?> clazz;

	private SupportedParameters(Class<?> clazz) {
		this.clazz = clazz;
	}

	/**
	 * @return the enclosing class
	 */
	public Class<?> getSupportedClass() {
		return this.clazz;
	}

	/**
	 * Checks if the class is a supported parameter type.
	 *
	 * @param clazz
	 * @return true if is supported, else false
	 */
	public static boolean isSupported(Class<?> clazz) {
		if (clazz != null) {
			for (SupportedParameters supportedParameter : SupportedParameters.values()) {
				if (supportedParameter.clazz.isAssignableFrom(clazz)) {
					return true;
				}
			}
		}
		return false;
	}

	public static Object resolveParameter(Class<?> parameterType,
			HttpServletRequest request, HttpServletResponse response, Locale locale,
			ExtDirectRequest extDirectRequest) {

		if (SERVLET_REQUEST.getSupportedClass().isAssignableFrom(parameterType)) {
			return request;
		}
		else if (SERVLET_RESPONSE.getSupportedClass().isAssignableFrom(parameterType)) {
			return response;
		}
		else if (SESSION.getSupportedClass().isAssignableFrom(parameterType)) {
			return request.getSession();
		}
		else if (PRINCIPAL.getSupportedClass().isAssignableFrom(parameterType)) {
			return request.getUserPrincipal();
		}
		else if (LOCALE.getSupportedClass().equals(parameterType)) {
			return locale;
		}
		else if (EXT_DIRECT_REQUEST.getSupportedClass().equals(parameterType)) {
			return extDirectRequest;
		}

		return null;

	}

}