/*
* Copyright (c) 2002-2012 Alibaba Group Holding Limited.
* All rights reserved.
*
* 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 com.alibaba.citrus.turbine.pipeline.valve;
import static com.alibaba.citrus.springext.util.SpringExtUtil.*;
import static com.alibaba.citrus.turbine.TurbineConstant.*;
import static com.alibaba.citrus.turbine.util.TurbineUtil.*;
import static com.alibaba.citrus.util.Assert.*;
import static com.alibaba.citrus.util.StringUtil.*;
import javax.servlet.http.HttpServletRequest;
import com.alibaba.citrus.service.mappingrule.MappingRuleService;
import com.alibaba.citrus.service.moduleloader.Module;
import com.alibaba.citrus.service.moduleloader.ModuleEvent;
import com.alibaba.citrus.service.moduleloader.ModuleLoaderException;
import com.alibaba.citrus.service.moduleloader.ModuleLoaderService;
import com.alibaba.citrus.service.moduleloader.ModuleNotFoundException;
import com.alibaba.citrus.service.moduleloader.ModuleReturningValue;
import com.alibaba.citrus.service.pipeline.PipelineContext;
import com.alibaba.citrus.service.pipeline.support.AbstractValve;
import com.alibaba.citrus.service.pipeline.support.AbstractValveDefinitionParser;
import com.alibaba.citrus.turbine.TurbineRunData;
import com.alibaba.citrus.util.StringUtil;
import com.alibaba.citrus.util.internal.ScreenEventUtil;
import com.alibaba.citrus.webx.WebxException;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.support.BeanDefinitionBuilder;
import org.springframework.beans.factory.xml.ParserContext;
import org.w3c.dom.Element;
/**
* 执行screen。
*
* @author Michael Zhou
*/
public class PerformScreenValve extends AbstractValve {
static final String DEFAULT_RESULT_NAME = "screenResult";
@Autowired
private ModuleLoaderService moduleLoaderService;
@Autowired
private HttpServletRequest request;
@Autowired
private MappingRuleService mappingRuleService;
private String resultName;
public MappingRuleService getMappingRuleService() {
return mappingRuleService;
}
public String getResultName() {
return resultName == null ? DEFAULT_RESULT_NAME : resultName;
}
public void setResultName(String resultName) {
this.resultName = trimToNull(resultName);
}
public void invoke(PipelineContext pipelineContext) throws Exception {
TurbineRunData rundata = getTurbineRunData(request);
// 检查重定向标志，如果是重定向，则不需要将页面输出。
if (!rundata.isRedirected()) {
setContentType(rundata);
Object result = null;
try {
result = performScreenModule(rundata);
} finally {
pipelineContext.setAttribute(getResultName(), result);
}
}
pipelineContext.invokeNext();
}
/** 设置content type。 */
protected void setContentType(TurbineRunData rundata) {
// 设置content type，不需要设置charset，因为SetLocaleRequestContext已经设置了charset。
// 避免覆盖别人设置的contentType。
if (StringUtil.isEmpty(rundata.getResponse().getContentType())) {
rundata.getResponse().setContentType("text/html");
}
}
/** 执行screen模块。 */
protected Object performScreenModule(TurbineRunData rundata) {
ModuleFinder finder = new ModuleFinder(rundata.getTarget());
// 如果设置了template，则默认打开layout
rundata.setLayoutEnabled(true);
try {
Module module = finder.getScreenModule();
// 当指定了templateName时，可以没有的screen module，而单单渲染模板。
// 这样就实现了page-driven，即先写模板，必要时再写一个module class与之对应。
if (module != null) {
// 将event传入screen。
ScreenEventUtil.setEventName(rundata.getRequest(), finder.event);
try {
if (module instanceof ModuleReturningValue) {
return ((ModuleReturningValue) module).executeAndReturn();
} else {
module.execute();
}
} finally {
ScreenEventUtil.setEventName(rundata.getRequest(), null);
}
} else {
if (isScreenModuleRequired()) {
throw new ModuleNotFoundException("Could not find screen module: " + finder.moduleName);
}
}
} catch (ModuleLoaderException e) {
throw new WebxException("Failed to load screen module: " + finder.moduleName, e);
} catch (Exception e) {
throw new WebxException("Failed to execute screen: " + finder.moduleName, e);
}
return null;
}
private class ModuleFinder {
private final String target;
private String moduleName;
private String eventModuleName;
private String event;
public ModuleFinder(String target) {
this.target = assertNotNull(target, "Target was not specified");
}
public Module getScreenModule() throws ModuleLoaderException {
// 从target中取得screen module名称
moduleName = getModuleName(target);
Module module = moduleLoaderService.getModuleQuiet(SCREEN_MODULE, moduleName);
if (module != null) {
return module;
}
if (parseEvent()) {
module = moduleLoaderService.getModuleQuiet(SCREEN_MODULE, eventModuleName);
if (module instanceof ModuleEvent) {
return module;
}
}
return null;
}
/** 尝试将target解释成moduleName/eventName。如果target=/xxx/yyy.ext，则moduleName=/Xxx，eventName=yyy。 */
private boolean parseEvent() {
int slashIndex = target.lastIndexOf("/");
int dotIndex = target.lastIndexOf(".");
if (slashIndex > 0) {
event = target.substring(slashIndex + 1, dotIndex > slashIndex ? dotIndex : target.length());
eventModuleName = getModuleName(target.substring(0, slashIndex));
return true;
}
return false;
}
}
/** 如果返回<code>true</code>，那么当模块找不到时，会抛异常。子类可以覆盖此方法，以改变行为。 */
protected boolean isScreenModuleRequired() {
return true;
}
/** 根据target取得screen模块名。子类可以修改映射规则。 */
protected String getModuleName(String target) {
return mappingRuleService.getMappedName(SCREEN_MODULE_NO_TEMPLATE, target);
}
public static class DefinitionParser extends AbstractValveDefinitionParser<PerformScreenValve> {
@Override
protected void doParse(Element element, ParserContext parserContext, BeanDefinitionBuilder builder) {
attributesToProperties(element, builder, "resultName");
}
}
}