/*
* Copyright 2010 Lincoln Baxter, III
*
* 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.ocpsoft.pretty.faces.el.resolver;
import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import javax.faces.webapp.FacesServlet;
import javax.servlet.ServletContext;
import org.apache.commons.digester.Digester;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.xml.sax.SAXException;
import com.ocpsoft.pretty.faces.spi.ELBeanNameResolver;
import com.ocpsoft.pretty.faces.util.EmptyEntityResolver;
/**
*
* <p>
* Implementation of {@link ELBeanNameResolver} handling beans configured via the
* standard XML configuration mechanism.
* </p>
*
* <p>
* This resolver handles beans specified in faces-config.xml files. The resolver
* will pick up the default configuration file <code>/WEB-INF/faces-config.xml</code>,
* all <code>/META-INF/faces-config.xml</code> found by the supplied {@link ClassLoader}
* and all files specified via the <code>javax.faces.CONFIG_FILES</code> init parameter.
* </p>
*
* @author Christian Kaltepoth
*
*/
public class FacesConfigBeanNameResolver implements ELBeanNameResolver
{
private final static Log log = LogFactory.getLog(FacesConfigBeanNameResolver.class);
/**
* Name of default <code>faces-config.xml</code> loaded via
* {@link ServletContext#getResource(String)}
*/
private final static String WEB_INF_FACES_CONFIG_XML = "/WEB-INF/faces-config.xml";
/**
* Name of <code>faces-config.xml</code> loaded via
* {@link ClassLoader#getResource(String)}
*/
private final static String META_INF_FACES_CONFIG_XML = "META-INF/faces-config.xml";
/**
* Lookup map: FQCN -> bean name
*/
private Map<String, String> beanNameMap = new HashMap<String, String>();
/**
* Initialization procedure. Reads all faces-config.xml files and registers
* the beans found.
*/
public boolean init(ServletContext servletContext, ClassLoader classLoader)
{
// list of beans found
List<FacesConfigEntry> facesConfigEntries = new ArrayList<FacesConfigEntry>();
// get the list of faces configuration files to process
Set<URL> facesConfigs = getFacesConfigFiles(servletContext, classLoader);
// process all configuration files
for (URL url : facesConfigs)
{
processFacesConfig(url, facesConfigEntries);
}
// Create bean name lookup map from all entries found
for (FacesConfigEntry entry : facesConfigEntries)
{
beanNameMap.put(entry.getBeanClass(), entry.getName());
}
// debug statement containing number of classes found
if (log.isDebugEnabled())
{
log.debug("Found " + beanNameMap.size() + " bean names in faces configuration.");
}
// we will always enable this resolver
return true;
}
/**
* Returns a set of faces-config.xml files. This set includes the default
* configuration file, all additional files mentioned via the
* <code>javax.faces.CONFIG_FILES</code> init parameter and all files found
* in META-INF folders.
*
* @param servletContext
* The ServletContext
* @param classLoader
* The classloader used to find files in META-INF directories
* @return A set of URLs
*/
private Set<URL> getFacesConfigFiles(ServletContext servletContext, ClassLoader classLoader)
{
// set of URLs to process
Set<URL> result = new HashSet<URL>();
try
{
// get default faces-config.xml
URL defaultFacesConfig = servletContext.getResource(WEB_INF_FACES_CONFIG_XML);
if (defaultFacesConfig != null)
{
result.add(defaultFacesConfig);
}
// get additional configuration files from init parameter
result.addAll(getConfigFilesFromInitParameter(servletContext));
// Find configuration files META-INF directories
try
{
Enumeration<URL> resources = classLoader.getResources(META_INF_FACES_CONFIG_XML);
while (resources.hasMoreElements())
{
result.add(resources.nextElement());
}
}
catch (IOException e)
{
log.error("Failed to load faces-config.xml files from META-INF directories", e);
}
}
catch (MalformedURLException e)
{
// should not happen, because URLs are hard-coded
throw new IllegalArgumentException(e);
}
return result;
}
/**
* Returns a collection of faces configuration files mentioned via the
* default <code>javax.faces.CONFIG_FILES</code> init parameter
*
* @param servletContext
* The ServletContext
* @return A collection of URLs (never null)
*/
private Collection<URL> getConfigFilesFromInitParameter(ServletContext servletContext)
{
// read init parameter
String initParam = servletContext.getInitParameter(FacesServlet.CONFIG_FILES_ATTR);
// empty? return empty set
if (initParam == null || initParam.trim().length() == 0)
{
return Collections.emptySet();
}
// split string at each comma
String[] files = initParam.split(",");
// the result
Set<URL> result = new HashSet<URL>();
// process each single file
for (String file : files)
{
// ignore empty entries
if (file.trim().length() == 0)
{
continue;
}
try
{
// try get URL for this file
URL url = servletContext.getResource(file.trim());
// add it to the result, if it exists
if (url != null)
{
result.add(url);
}
}
catch (MalformedURLException e)
{
// log on debug level, because the JSF implementation should
// handle such a case
log.debug("Invalid entry in javax.faces.CONFIG_FILES init parameter: " + file);
}
}
return result;
}
/**
* Process a single <code>faces-config.xml</code> file and add all beans
* found to the supplied list of {@link FacesConfigEntry} objects.
*
* @param url
* The faces-config.xml file
* @param facesConfigEntries
* list of entries to add the beans to
*/
private void processFacesConfig(URL url, List<FacesConfigEntry> facesConfigEntries)
{
// log name of current file
if (log.isTraceEnabled())
{
log.trace("Loading bean names from: " + url.toString());
}
// setup digester
Digester digester = new Digester();
/*
* We use the context class loader to resolve classes.
* This fixes ClassNotFoundExceptions on Geronimo.
*/
digester.setUseContextClassLoader(true);
// prevent downloading of DTDs
digester.setEntityResolver(new EmptyEntityResolver());
digester.setValidating(false);
digester.push(facesConfigEntries);
digester.addObjectCreate("faces-config/managed-bean", FacesConfigEntry.class);
digester.addCallMethod("faces-config/managed-bean/managed-bean-name", "setName", 0);
digester.addCallMethod("faces-config/managed-bean/managed-bean-class", "setBeanClass", 0);
digester.addSetNext("faces-config/managed-bean", "add");
// stream used to read faces-config.xml file
InputStream stream = null;
try
{
// open the file and let digester pares it
stream = url.openStream();
digester.parse(stream);
}
catch (IOException e)
{
// may be thrown when reading the file
log.error("Failed to parse: " + url.toString(), e);
}
catch (SAXException e)
{
// parsing errors
log.error("Failed to parse: " + url.toString(), e);
}
finally
{
// close stream
if (stream != null)
{
try
{
stream.close();
}
catch (IOException e)
{
// ignore IOExceptions on close
}
}
}
}
/*
* Implementation if interface method
*/
public String getBeanName(Class<?> clazz)
{
// first check bean name map containing faces-config.xml entries
String name = beanNameMap.get(clazz.getName());
if (name != null)
{
return name;
}
return null;
}
/**
* Private class to hold values of single "managed-bean" entries
*/
public static class FacesConfigEntry
{
private String name;
private String beanClass;
public String getName()
{
return name;
}
public void setName(String name)
{
this.name = name;
}
public String getBeanClass()
{
return beanClass;
}
public void setBeanClass(String beanClass)
{
this.beanClass = beanClass;
}
}
}