/*
* JBoss, Home of Professional Open Source
* Copyright 2011, Red Hat, Inc., and individual contributors
* by the @authors tag. See the copyright.txt in the distribution for a
* full listing of individual contributors.
*
* 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.jboss.seam.faces.projectstage;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import javax.faces.application.ProjectStage;
import javax.servlet.ServletContext;
import org.jboss.solder.logging.Logger;
import org.jboss.solder.servlet.resource.WebResourceLocator;
/**
* Implementation of {@link ProjectStageDetector} that tries to read the project stage from the standard servlet context
* parameter. As a CDI extension cannot access the {@link ServletContext}, we try to use the context class loader to find
* web.xml and parse it manually.
*
* @author Christian Kaltepoth <christian@kaltepoth.de>
*
*/
public class WebXmlProjectStageDetector implements ProjectStageDetector {
private final Logger log = Logger.getLogger(WebXmlProjectStageDetector.class);
@Override
public int getPrecedence() {
return 75;
}
@Override
public ProjectStage getProjectStage() {
// try to get the name of the project stage
String projectStageName = getProjectStageFromLocators();
// lookup the correct enum for the value
if (projectStageName != null && projectStageName.length() > 0) {
for (ProjectStage stage : ProjectStage.values()) {
if (stage.name().equalsIgnoreCase(projectStageName)) {
return stage;
}
}
}
// no result
return null;
}
/**
* Tries to get the name of the project stage from web.xml. This method will use Solder's {@link WebResourceLocator} to find
* the location of web.xml.
*
* @return name of the project stage or <code>null</code>
*/
private String getProjectStageFromLocators() {
// try to locate web.xml
WebResourceLocator webResourceLocator = new WebResourceLocator();
URL webXmlLocation = webResourceLocator.getWebResourceUrl("/WEB-INF/web.xml");
// try to parse the web.xml if the locator returned a result
if (webXmlLocation != null) {
String projectStage = parseWebXml(webXmlLocation);
// accept the first result
if (projectStage != null) {
return projectStage;
}
}
// not result found
return null;
}
/**
* Tries to parse the project stage from the supplied web.xml location. The method will return <code>null</code> if the
* web.xml does not exist, cannot be opened, a parsing error occurred or if the web.xml doesn't contain a context parameter
* specifying the project stage.
*
* @param location URL of the web.xml
* @return project stage or <code>null</code>
*/
private String parseWebXml(URL location) {
if (log.isTraceEnabled()) {
log.trace("Processing possible web.xml location: " + location);
}
InputStream webXmlStream = null;
// try to open this guessed location of the web.xml
try {
webXmlStream = location.openStream();
} catch (IOException e) {
if (log.isDebugEnabled()) {
log.debug("Unable to open web.xml: " + e.getMessage());
}
}
if (webXmlStream != null) {
try {
// parse the input stream
WebXmlContextParameterParser parser = new WebXmlContextParameterParser();
parser.parse(webXmlStream);
// return the project stage if the parser found it
String projectStage = parser.getContextParameter(ProjectStage.PROJECT_STAGE_PARAM_NAME);
// did we find a project stage?
if (projectStage != null) {
if (log.isDebugEnabled()) {
log.debug("Found project stage in web.xml: " + projectStage);
}
return projectStage;
}
} catch (IOException e) {
if (log.isDebugEnabled()) {
log.debug("Parsing of web.xml failed: " + e.getMessage());
}
}
}
// no result
return null;
}
}