package org.apache.turbine.services.jsp;
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.
*/
import java.io.File;
import java.io.IOException;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletConfig;
import javax.servlet.http.HttpServletRequest;
import org.apache.commons.configuration.Configuration;
import org.apache.commons.lang.StringUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.turbine.Turbine;
import org.apache.turbine.services.InitializationException;
import org.apache.turbine.services.pull.ApplicationTool;
import org.apache.turbine.services.pull.tools.TemplateLink;
import org.apache.turbine.services.template.BaseTemplateEngineService;
import org.apache.turbine.util.RunData;
import org.apache.turbine.util.TurbineException;
/**
* This is a Service that can process JSP templates from within a Turbine
* screen.
*
* @author <a href="mailto:john.mcnally@clearink.com">John D. McNally</a>
* @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a>
* @author <a href="mailto:dlr@finemaltcoding.com">Daniel Rall</a>
* @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
*/
public class TurbineJspService
extends BaseTemplateEngineService
implements JspService
{
/** The base path[s] prepended to filenames given in arguments */
private String[] templatePaths;
/** The relative path[s] prepended to filenames */
private String[] relativeTemplatePaths;
/** The buffer size for the output stream. */
private int bufferSize;
/** Logging */
private static Log log = LogFactory.getLog(TurbineJspService.class);
/**
* Load all configured components and initialize them. This is
* a zero parameter variant which queries the Turbine Servlet
* for its config.
*
* @throws InitializationException Something went wrong in the init
* stage
*/
@Override
public void init()
throws InitializationException
{
try
{
initJsp();
registerConfiguration(JspService.JSP_EXTENSION);
setInit(true);
}
catch (Exception e)
{
throw new InitializationException(
"TurbineJspService failed to initialize", e);
}
}
/**
* Performs early initialization of this Turbine service.
*
* @param config The ServletConfiguration from Turbine
*
* @throws InitializationException Something went wrong when starting up.
* @deprecated use init() instead.
*/
@Deprecated
public void init(ServletConfig config)
throws InitializationException
{
init();
}
/**
* Adds some convenience objects to the request. For example an instance
* of TemplateLink which can be used to generate links to other templates.
*
* @param data the turbine rundata object
*/
public void addDefaultObjects(RunData data)
{
HttpServletRequest req = data.getRequest();
//
// This is a place where an Application Pull Tool is used
// in a regular Java Context. We have no Pull Service with the
// Jsp Paging stuff, but we can run our Application Tool by Hand:
//
ApplicationTool templateLink = new TemplateLink();
templateLink.init(data);
req.setAttribute(LINK, templateLink);
req.setAttribute(RUNDATA, data);
}
/**
* Returns the default buffer size of the JspService
*
* @return The default buffer size.
*/
public int getDefaultBufferSize()
{
return bufferSize;
}
/**
* executes the JSP given by templateName.
*
* @param data A RunData Object
* @param templateName the filename of the template.
* @throws TurbineException Any exception thrown while processing will be
* wrapped into a TurbineException and rethrown.
*/
public void handleRequest(RunData data, String templateName)
throws TurbineException
{
handleRequest(data, templateName, false);
}
/**
* executes the JSP given by templateName.
*
* @param data A RunData Object
* @param templateName the filename of the template.
* @param isForward whether to perform a forward or include.
* @throws TurbineException Any exception trown while processing will be
* wrapped into a TurbineException and rethrown.
*/
public void handleRequest(RunData data, String templateName, boolean isForward)
throws TurbineException
{
/** template name with relative path */
String relativeTemplateName = getRelativeTemplateName(templateName);
if (StringUtils.isEmpty(relativeTemplateName))
{
throw new TurbineException(
"Template " + templateName + " not found in template paths");
}
// get the RequestDispatcher for the JSP
RequestDispatcher dispatcher = data.getServletContext()
.getRequestDispatcher(relativeTemplateName);
try
{
if (isForward)
{
// forward the request to the JSP
dispatcher.forward(data.getRequest(), data.getResponse());
}
else
{
data.getResponse().getWriter().flush();
// include the JSP
dispatcher.include(data.getRequest(), data.getResponse());
}
}
catch (Exception e)
{
// as JSP service is in Alpha stage, let's try hard to send the
// error message to the browser, to speed up debugging
try
{
data.getResponse().getWriter().print("Error encountered processing a template: "
+ templateName);
e.printStackTrace(data.getResponse().getWriter());
}
catch (IOException ignored)
{
// ignore
}
// pass the exception to the caller according to the general
// contract for tamplating services in Turbine
throw new TurbineException(
"Error encountered processing a template: " + templateName, e);
}
}
/**
* This method sets up the template cache.
*/
private void initJsp()
throws Exception
{
Configuration config = getConfiguration();
// Set relative paths from config.
// Needed for javax.servlet.RequestDispatcher
relativeTemplatePaths = config.getStringArray(TEMPLATE_PATH_KEY);
// Use Turbine Servlet to translate the template paths.
templatePaths = new String [relativeTemplatePaths.length];
for (int i=0; i < relativeTemplatePaths.length; i++)
{
relativeTemplatePaths[i] = warnAbsolute(relativeTemplatePaths[i]);
templatePaths[i] = Turbine.getRealPath(relativeTemplatePaths[i]);
}
bufferSize = config.getInt(JspService.BUFFER_SIZE_KEY,
JspService.BUFFER_SIZE_DEFAULT);
}
/**
* Determine whether a given template is available on the
* configured template pathes.
*
* @param template The name of the requested Template
* @return True if the template is available.
*/
@Override
public boolean templateExists(String template)
{
for (int i = 0; i < templatePaths.length; i++)
{
if (templateExists(templatePaths[i], template))
{
return true;
}
}
return false;
}
/**
* Determine whether a given template exists on the supplied
* template path. This service ATM only supports file based
* templates so it simply checks for file existence.
*
* @param path The absolute (file system) template path
* @param template The name of the requested Template
* @return True if the template is available.
*/
private boolean templateExists(String path, String template)
{
return new File(path, template).exists();
}
/**
* Searchs for a template in the default.template path[s] and
* returns the template name with a relative path which is
* required by <a href="http://java.sun.com/products/servlet/2.3/javadoc/javax/servlet/ServletContext.html#getRequestDispatcher(java.lang.String)">
* javax.servlet.RequestDispatcher</a>
*
* @param template
* @return String
*/
public String getRelativeTemplateName(String template)
{
template = warnAbsolute(template);
// Find which template path the template is in
// We have a 1:1 match between relative and absolute
// pathes so we can use the index for translation.
for (int i = 0; i < templatePaths.length; i++)
{
if (templateExists(templatePaths[i], template))
{
return relativeTemplatePaths[i] + "/" + template;
}
}
return null;
}
/**
* Warn if a template name or path starts with "/".
*
* @param template The template to test
* @return The template name with a leading / stripped off
*/
private String warnAbsolute(String template)
{
if (template.startsWith("/"))
{
log.warn("Template " + template
+ " has a leading /, which is wrong!");
return template.substring(1);
}
return template;
}
}