RequestInjection.java

/*
 * 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 org.gwtwidgets.server.spring;

import java.lang.reflect.Method;

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

import org.aopalliance.intercept.MethodInterceptor;
import org.aopalliance.intercept.MethodInvocation;

/**
 * Method interceptor that injects the current {@link HttpServletRequest} and
 * the current {@link HttpServletResponse} via reflection to a service. You must
 * specify the setter names via {@link #setRequestSetterName(String)} and
 * {@link #setResponseSetterName(String)} otherwise they will fail silently.
 * These setters can and must have only a single argument namely
 * {@link ServletRequest} and {@link ServletResponse} respectively.
 * 
 * @author George Georgovassilis, g.georgovassilis[at]gmail.com
 * 
 */
public class RequestInjection implements MethodInterceptor {

	protected String requestSetterName;

	protected String responseSetterName;

	private void setRequestOnTarget(HttpServletRequest request, HttpServletResponse response, Object target) throws Exception {
		if (requestSetterName != null)
			try {
				Method method = target.getClass().getMethod(requestSetterName, new Class[] { HttpServletRequest.class });
				method.invoke(target, new Object[] { request });
			} catch (NoSuchMethodException e) {
			}
		if (responseSetterName != null)
			try {
				Method method = target.getClass().getMethod(responseSetterName, new Class[] { HttpServletResponse.class });
				method.invoke(target, new Object[] { response });
			} catch (NoSuchMethodException e) {
			}
	}

	public Object invoke(MethodInvocation invocation) throws Throwable {
		Object target = invocation.getThis();
		setRequestOnTarget(ServletUtils.getRequest(), ServletUtils.getResponse(), target);
		return invocation.proceed();
	}

	/**
	 * Specify the name of the setter method that can be invoked to set the
	 * current request and response on the service. If the method does not exist
	 * on the service, it is silently discarded.
	 * 
	 * @param setterName name of setter field
	 */
	public void setRequestSetterName(String setterName) {
		this.requestSetterName = setterName;
	}

	/**
	 * Specify the name of the setter method that can be invoked to set the
	 * current response on the service. If the method does not exist on the
	 * service, it is silently discarded.
	 * 
	 * @param setterName Name of the response setter field
	 */
	public void setResponseSetterName(String setterName) {
		this.responseSetterName = setterName;
	}

}