Spring Framework example source code file (PortletContentGenerator.java)

This example Spring Framework source code file (PortletContentGenerator.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Spring Framework tags/keywords

portletapplicationobjectsupport, portletcontentgenerator, portletexception, portletexception, portletresponse, portletsessionrequiredexception, portletsessionrequiredexception, pre-existing, renderrequest, renderrequest, renderresponse, renderresponse

The Spring Framework PortletContentGenerator.java source code

/*
 * Copyright 2002-2007 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.web.portlet.handler;

import javax.portlet.PortletException;
import javax.portlet.PortletRequest;
import javax.portlet.PortletResponse;
import javax.portlet.RenderRequest;
import javax.portlet.RenderResponse;

import org.springframework.web.portlet.context.PortletApplicationObjectSupport;

/**
 * Convenient superclass for any kind of web content generator,
 * like {@link org.springframework.web.portlet.mvc.AbstractController}.
 * Can also be used for custom handlers that have their own
 * {@link org.springframework.web.portlet.HandlerAdapter}.
 *
 * <p>Supports portlet cache control options.
 *
 * @author Juergen Hoeller
 * @author John A. Lewis
 * @since 2.0
 * @see #setCacheSeconds
 * @see #setRequireSession
 */
public abstract class PortletContentGenerator extends PortletApplicationObjectSupport {

	private boolean requireSession = false;

	private int cacheSeconds = -1;


	/**
	 * Set whether a session should be required to handle requests.
	 */
	public final void setRequireSession(boolean requireSession) {
		this.requireSession = requireSession;
	}

	/**
	 * Return whether a session is required to handle requests.
	 */
	public final boolean isRequireSession() {
		return this.requireSession;
	}

	/**
	 * Cache content for the given number of seconds. Default is -1,
	 * indicating no override of portlet content caching.
	 * <p>Only if this is set to 0 (no cache) or a positive value (cache for
	 * this many seconds) will this class override the portlet settings.
	 * <p>The cache setting can be overwritten by subclasses, before content is generated.
	 */
	public final void setCacheSeconds(int seconds) {
		this.cacheSeconds = seconds;
	}

	/**
	 * Return the number of seconds that content is cached.
	 */
	public final int getCacheSeconds() {
		return this.cacheSeconds;
	}


	/**
	 * Check and prepare the given request and response according to the settings
	 * of this generator. Checks for a required session, and applies the number of
	 * cache seconds configured for this generator (if it is a render request/response).
	 * @param request current portlet request
	 * @param response current portlet response
	 * @throws PortletException if the request cannot be handled because a check failed
	 */
	protected final void check(PortletRequest request, PortletResponse response) throws PortletException {
		if (this.requireSession) {
			if (request.getPortletSession(false) == null) {
				throw new PortletSessionRequiredException("Pre-existing session required but none found");
			}
		}
	}

	/**
	 * Check and prepare the given request and response according to the settings
	 * of this generator. Checks for a required session, and applies the number of 
	 * cache seconds configured for this generator (if it is a render request/response).
	 * @param request current portlet request
	 * @param response current portlet response
	 * @throws PortletException if the request cannot be handled because a check failed
	 */
	protected final void checkAndPrepare(RenderRequest request, RenderResponse response)
			throws PortletException {

		checkAndPrepare(request, response, this.cacheSeconds);
	}

	/**
	 * Check and prepare the given request and response according to the settings
	 * of this generator. Checks for a required session, and applies the given 
	 * number of cache seconds (if it is a render request/response).
	 * @param request current portlet request
	 * @param response current portlet response
	 * @param cacheSeconds positive number of seconds into the future that the
	 * response should be cacheable for, 0 to prevent caching
	 * @throws PortletException if the request cannot be handled because a check failed
	 */
	protected final void checkAndPrepare(
			RenderRequest request, RenderResponse response, int cacheSeconds)
			throws PortletException {

		check(request, response);
		applyCacheSeconds(response, cacheSeconds);
	}

	/**
	 * Prevent the render response from being cached.
	 */
	protected final void preventCaching(RenderResponse response) {
		cacheForSeconds(response, 0);
	}

	/**
	 * Set portlet response to allow caching for the given number of seconds.
	 * @param response current portlet render response
	 * @param seconds number of seconds into the future that the response
	 * should be cacheable for
	 */
	protected final void cacheForSeconds(RenderResponse response, int seconds) {
		response.setProperty(RenderResponse.EXPIRATION_CACHE, Integer.toString(seconds));
	}

	/**
	 * Apply the given cache seconds to the render response
	 * @param response current portlet render response
	 * @param seconds positive number of seconds into the future that the
	 * response should be cacheable for, 0 to prevent caching
	 */
	protected final void applyCacheSeconds(RenderResponse response, int seconds) {
		if (seconds > 0) {
			cacheForSeconds(response, seconds);
		}
		else if (seconds == 0) {
			preventCaching(response);
		}
		// Leave caching to the portlet configuration otherwise.
	}

}