/*
* Copyright 2014 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.js.ajax.tiles3;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.tiles.Attribute;
import org.apache.tiles.AttributeContext;
import org.apache.tiles.Definition;
import org.apache.tiles.access.TilesAccess;
import org.apache.tiles.impl.BasicTilesContainer;
import org.apache.tiles.request.ApplicationContext;
import org.apache.tiles.request.Request;
import org.apache.tiles.request.servlet.ServletRequest;
import org.springframework.js.ajax.AjaxHandler;
import org.springframework.js.ajax.SpringJavascriptAjaxHandler;
import org.springframework.util.Assert;
import org.springframework.util.StringUtils;
import org.springframework.web.servlet.support.JstlUtils;
import org.springframework.web.servlet.support.RequestContext;
import org.springframework.web.servlet.view.tiles3.TilesView;
/**
* Tiles 3 view implementation that is able to handle partial rendering for Spring
* Javascript Ajax requests.
*
* <p>This implementation uses the {@link SpringJavascriptAjaxHandler} by default
* to determine whether the current request is an Ajax request. On an Ajax request,
* a "fragments" parameter will be extracted from the request in order to
* determine which attributes to render from the current tiles view.
*
* @author Rossen Stoyanchev
* @since 2.4
*/
public class AjaxTilesView extends TilesView {
private static final String FRAGMENTS_PARAM = "fragments";
private AjaxHandler ajaxHandler = new SpringJavascriptAjaxHandler();
public AjaxHandler getAjaxHandler() {
return this.ajaxHandler;
}
public void setAjaxHandler(AjaxHandler ajaxHandler) {
this.ajaxHandler = ajaxHandler;
}
protected void renderMergedOutputModel(Map<String, Object> model, HttpServletRequest request,
HttpServletResponse response) throws Exception {
ServletContext servletContext = getServletContext();
if (ajaxHandler.isAjaxRequest(request, response)) {
String[] fragmentsToRender = getRenderFragments(model, request, response);
if (fragmentsToRender.length == 0) {
logger.warn("An Ajax request was detected, but no fragments were specified to be re-rendered. "
+ "Falling back to full page render. This can cause unpredictable results when processing "
+ "the ajax response on the client.");
super.renderMergedOutputModel(model, request, response);
return;
}
Request tilesRequest = createTilesRequest(request, response);
ApplicationContext tilesAppContext = tilesRequest.getApplicationContext();
BasicTilesContainer container = (BasicTilesContainer) TilesAccess.getContainer(tilesAppContext);
if (container == null) {
throw new ServletException("Tiles container is not initialized. "
+ "Have you added a TilesConfigurer to your web application context?");
}
exposeModelAsRequestAttributes(model, request);
JstlUtils.exposeLocalizationContext(new RequestContext(request, servletContext));
Definition compositeDefinition = container.getDefinitionsFactory().getDefinition(getUrl(), tilesRequest);
Map<String, Attribute> flattenedAttributeMap = new HashMap<String, Attribute>();
flattenAttributeMap(container, tilesRequest, flattenedAttributeMap, compositeDefinition);
addRuntimeAttributes(container, tilesRequest, flattenedAttributeMap);
if (fragmentsToRender.length > 1) {
tilesRequest.getContext("request").put(ServletRequest.FORCE_INCLUDE_ATTRIBUTE_NAME, true);
}
for (String element : fragmentsToRender) {
Attribute attributeToRender = flattenedAttributeMap.get(element);
if (attributeToRender == null) {
throw new ServletException("No tiles attribute with a name of '" + element
+ "' could be found for the current view: " + this);
}
container.startContext(tilesRequest).inheritCascadedAttributes(compositeDefinition);
container.render(attributeToRender, tilesRequest);
container.endContext(tilesRequest);
}
} else {
super.renderMergedOutputModel(model, request, response);
}
}
protected String[] getRenderFragments(Map<String, Object> model, HttpServletRequest request,
HttpServletResponse response) {
String attrName = request.getParameter(FRAGMENTS_PARAM);
String[] renderFragments = StringUtils.commaDelimitedListToStringArray(attrName);
return StringUtils.trimArrayElements(renderFragments);
}
/**
* Iterate over all attributes in the given Tiles definition. Every attribute
* value that represents a template (i.e. start with "/") or is a nested
* definition is added to a Map. The method class itself recursively to traverse
* nested definitions.
*
* @param container the TilesContainer
* @param tilesRequest the Tiles Request
* @param resultMap the output Map where attributes of interest are added to.
* @param definition the definition to search for attributes of interest.
*/
protected void flattenAttributeMap(BasicTilesContainer container, Request tilesRequest,
Map<String, Attribute> resultMap, Definition definition) {
Set<String> attributeNames = new HashSet<String>();
if (definition.getLocalAttributeNames() != null) {
attributeNames.addAll(definition.getLocalAttributeNames());
}
if (definition.getCascadedAttributeNames() != null) {
attributeNames.addAll(definition.getCascadedAttributeNames());
}
for (String attributeName : attributeNames) {
Attribute attribute = definition.getAttribute(attributeName);
if (attribute.getValue() == null || !(attribute.getValue() instanceof String)) {
continue;
}
String value = attribute.getValue().toString();
if (value.startsWith("/")) {
resultMap.put(attributeName, attribute);
} else if (container.isValidDefinition(value, tilesRequest)) {
resultMap.put(attributeName, attribute);
Definition nestedDefinition = container.getDefinitionsFactory().getDefinition(value, tilesRequest);
Assert.isTrue(nestedDefinition != definition, "Circular nested definition: " + value);
flattenAttributeMap(container, tilesRequest, resultMap, nestedDefinition);
}
}
}
/**
* Iterate over dynamically added Tiles attributes (see "Runtime Composition"
* in the Tiles documentation) and add them to the output Map passed as input.
*
* @param container the Tiles container
* @param tilesRequest the Tiles request
* @param resultMap the output Map where attributes of interest are added to.
*/
protected void addRuntimeAttributes(BasicTilesContainer container,
Request tilesRequest, Map<String, Attribute> resultMap) {
AttributeContext attributeContext = container.getAttributeContext(tilesRequest);
Set<String> attributeNames = new HashSet<String>();
if (attributeContext.getLocalAttributeNames() != null) {
attributeNames.addAll(attributeContext.getLocalAttributeNames());
}
if (attributeContext.getCascadedAttributeNames() != null) {
attributeNames.addAll(attributeContext.getCascadedAttributeNames());
}
for (String name : attributeNames) {
Attribute attr = attributeContext.getAttribute(name);
resultMap.put(name, attr);
}
}
}