servletflowexecutionmanager.java

来自「spring的WEB开发插件,支持多状态WEB开发」· Java 代码 · 共 105 行

/*
 * Copyright 2002-2005 the original author or authors.
 *
 * 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.springframework.webflow.execution.servlet;

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

import org.springframework.webflow.Event;
import org.springframework.webflow.Flow;
import org.springframework.webflow.ViewDescriptor;
import org.springframework.webflow.access.FlowLocator;
import org.springframework.webflow.execution.FlowExecutionListener;
import org.springframework.webflow.execution.FlowExecutionManager;

/**
 * Flow execution manager to manage flow executions using HTTP servlet
 * requests and the HTTP session.
 * 
 * @author Erwin Vervaet
 * @author Keith Donald
 */
public class ServletFlowExecutionManager extends FlowExecutionManager {

	/**
	 * Creates an HTTP-servlet based flow execution manager.
	 */
	public ServletFlowExecutionManager() {
		initDefaults();
	}

	/**
	 * Creates an HTTP-servlet based flow execution manager.
	 * @param flow the flow to manage
	 */
	public ServletFlowExecutionManager(Flow flow) {
		initDefaults();
		setFlow(flow);
	}

	/**
	 * Creates an HTTP-servlet based flow execution manager.
	 * @param flowLocator the locator to find flows to manage
	 */
	public ServletFlowExecutionManager(FlowLocator flowLocator) {
		initDefaults();
		setFlowLocator(flowLocator);
	}

	/**
	 * Set default properties for this manager.
	 */
	protected void initDefaults() {
		setStorage(new HttpSessionFlowExecutionStorage());
	}

	/**
	 * The main entry point into managed HTTP-based flow executions.
	 * @param request the current HTTP request
	 * @param response the current HTTP response
	 * @return the view descriptor of the model and view to render
	 * @throws Exception in case of errors
	 */
	public ViewDescriptor handle(HttpServletRequest request, HttpServletResponse response) throws Exception {
		return onEvent(createEvent(request, response));
	}

	/**
	 * The main entry point into managed HTTP-based flow executions.
	 * @param request the current HTTP request
	 * @param response the current HTTP response
	 * @param flowExecutionListener a listener interested in flow execution
	 *        lifecycle events that happen <i>while handling this request</i>
	 * @return the view descriptor of the model and view to render
	 * @throws Exception in case of errors
	 */
	public ViewDescriptor handle(HttpServletRequest request, HttpServletResponse response,
			FlowExecutionListener flowExecutionListener) throws Exception {
		return onEvent(createEvent(request, response), flowExecutionListener);
	}

	// subclassing hooks

	/**
	 * Create a flow event wrapping given request and response. Subclasses
	 * can override this, e.g. when they want to use special names for the
	 * request parameters.
	 */
	protected Event createEvent(HttpServletRequest request, HttpServletResponse response) {
		return new ServletEvent(request, response);
	}

}