/*
* The Apache Software License, Version 1.1
*
* Copyright (c) 2003 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution, if
* any, must include the following acknowlegement:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowlegement may appear in the software itself,
* if and wherever such third-party acknowlegements normally appear.
*
* 4. The names "The Jakarta Project", "Velocity", and "Apache Software
* Foundation" must not be used to endorse or promote products derived
* from this software without prior written permission. For written
* permission, please contact apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache"
* nor may "Apache" appear in their names without prior written
* permission of the Apache Group.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*/
package org.apache.velocity.tools.view.servlet;
import java.io.IOException;
import java.io.FileNotFoundException;
import java.io.InputStream;
import java.util.List;
import java.util.Iterator;
import java.util.HashMap;
import java.util.Map;
import java.util.ArrayList;
import javax.servlet.http.HttpSession;
import javax.servlet.ServletContext;
import org.dom4j.Element;
import org.dom4j.Node;
import org.apache.velocity.app.Velocity;
import org.apache.velocity.tools.view.DataInfo;
import org.apache.velocity.tools.view.ToolInfo;
import org.apache.velocity.tools.view.XMLToolboxManager;
import org.apache.velocity.tools.view.context.ToolboxContext;
import org.apache.velocity.tools.view.context.ViewContext;
/**
* <p>A toolbox manager for the servlet environment.</p>
*
* <p>A toolbox manager is responsible for automatically filling the Velocity
* context with a set of view tools. This class provides the following
* features:</p>
* <ul>
* <li>configurable through an XML-based configuration file</li>
* <li>assembles a set of view tools (the toolbox) on request</li>
* <li>handles different tool scopes (request, session, application)</li>
* <li>supports any class with a public constructor without parameters
* to be used as a view tool</li>
* <li>supports adding primitive data values to the context(String,Number,Boolean)</li>
* </ul>
*
*
* <p><strong>Configuration</strong></p>
* <p>The toolbox manager is configured through an XML-based configuration
* file. The configuration file is passed to the {@link #load(java.io.InputStream input)}
* method. The required format is shown in the following example:</p>
* <pre>
* <?xml version="1.0"?>
*
* <toolbox>
* <tool>
* <key>toolLoader</key>
* <scope>application</scope>
* <class>org.apache.velocity.tools.tools.ToolLoader</class>
* </tool>
* <tool>
* <key>math</key>
* <scope>application</scope>
* <class>org.apache.velocity.tools.tools.MathTool</class>
* </tool>
* <data type="number">
* <key>luckynumber</key>
* <value>1.37</class>
* </data>
* <data type="string">
* <key>greeting</key>
* <value>Hello World!</class>
* </data>
* </toolbox>
* </pre>
* <p>The recommended location for the configuration file is the WEB-INF directory of the
* web application.</p>
*
* @author <a href="mailto:sidler@teamup.com">Gabriel Sidler</a>
* @author <a href="mailto:nathan@esha.com">Nathan Bubna</a>
* @author <a href="mailto:geirm@apache.org">Geir Magnusson Jr.</a>
*
* @version $Id: ServletToolboxManager.java,v 1.4 2003/05/28 00:17:16 nbubna Exp $
*
*/
public class ServletToolboxManager extends XMLToolboxManager
{
// --------------------------------------------------- Properties ---------
public static final String ELEMENT_SCOPE = "scope";
public static final String ELEMENT_CREATE_SESSION = "create-session";
public static final String VALUE_YES = "yes";
public static final String VALUE_NO = "no";
public static final String SESSION_TOOLS_KEY = "org.apache.velocity.tools.view.tools.ServletToolboxManager.SessionTools";
private ServletContext servletContext;
private Map appTools;
private ArrayList sessionToolInfo;
private ArrayList requestToolInfo;
private boolean createSession;
private static HashMap managersMap = new HashMap();
// --------------------------------------------------- Constructor --------
/**
* Use getInstance(ServletContext,String) instead
* to ensure there is exactly one ServletToolboxManager
* per xml toolbox configuration file.
*/
private ServletToolboxManager(ServletContext servletContext)
{
this.servletContext = servletContext;
appTools = new HashMap();
sessionToolInfo = new ArrayList();
requestToolInfo = new ArrayList();
createSession = true;
}
/**
* ServletToolboxManager factory method.
* This method will ensure there is exactly one ServletToolboxManager
* per xml toolbox configuration file.
*/
public static synchronized ServletToolboxManager getInstance(ServletContext servletContext,
String toolboxFile)
{
// little fix up
if (!toolboxFile.startsWith("/"))
{
toolboxFile = "/" + toolboxFile;
}
// get config file pathname
String pathname = servletContext.getRealPath(toolboxFile);
// check if a previous instance exists
ServletToolboxManager toolboxManager =
(ServletToolboxManager)managersMap.get(pathname);
if (toolboxManager == null)
{
// if not, build one
InputStream is = null;
try
{
// get the bits
is = servletContext.getResourceAsStream(toolboxFile);
if (is != null)
{
Velocity.info("Using toolbox configuration file '" + toolboxFile +"'");
toolboxManager = new ServletToolboxManager(servletContext);
toolboxManager.load(is);
// remember it
managersMap.put(pathname, toolboxManager);
Velocity.info("Toolbox setup complete.");
}
}
catch(Exception e)
{
Velocity.error("Problem loading toolbox '" + toolboxFile +"' : " + e);
// if this happens, it probably deserves
// to have the stack trace logged
java.io.StringWriter sw = new java.io.StringWriter();
e.printStackTrace(new java.io.PrintWriter(sw));
Velocity.error(sw.toString());
}
finally
{
try
{
if (is != null)
{
is.close();
}
}
catch(Exception ee) {}
}
}
return toolboxManager;
}
// --------------------------------------------------- Methods ------------
/**
* <p>Sets whether or not to create a new session when none exists for the
* current request and session-scoped tools have been defined for this
* toolbox.</p>
*
* <p>If true, then a call to {@link #getToolboxContext(Object)} will
* create a new session if none currently exists for this request and
* the toolbox has one or more session-scoped tools designed.</p>
*
* <p>If false, then a call to getToolboxContext(Object) will never
* create a new session for the current request.
* This effectively means that no session-scoped tools will be added to
* the ToolboxContext for a request that does not have a session object.
* </p>
*
* The default value is true.
*/
public void setCreateSession(boolean b)
{
createSession = b;
}
/**
* Overrides XMLToolboxManager
*/
protected void log(String s)
{
Velocity.info("ServletToolboxManager: " + s);
}
/**
* Overrides XMLToolboxManager to handle the create-session element.
*/
protected boolean readElement(Element e) throws Exception
{
String name = e.getName();
ToolInfo info = null;
if (name.equalsIgnoreCase(ELEMENT_TOOL))
{
info = readToolInfo(e);
}
else if (name.equalsIgnoreCase(ELEMENT_DATA))
{
info = readDataInfo(e);
}
else if (name.equalsIgnoreCase(ELEMENT_CREATE_SESSION))
{
readCreateSession(e);
return true;
}
else
{
log("Unreadable element: "+name);
return false;
}
addTool(info);
log("Added "+info.getClassname()+" as "+info.getKey());
return true;
}
/**
* Reads the value for create-session.
*
* @see #setCreateSession(boolean)
*/
protected boolean readCreateSession(Element e) throws Exception
{
String csValue = e.getText();
if (VALUE_YES.equalsIgnoreCase(csValue))
{
setCreateSession(true);
}
else if (VALUE_NO.equalsIgnoreCase(csValue))
{
setCreateSession(false);
}
else
{
log("Unknown value for create-session. Valid options are 'yes' or 'no'.");
return false;
}
log("create-session is set to "+createSession);
return true;
}
/**
* Overrides XMLToolboxManager to read a {@link ServletToolInfo}
* instead of a {@link org.apache.velocity.tools.view.ViewToolInfo}.
*/
protected ToolInfo readToolInfo(Element e) throws Exception
{
Node n = e.selectSingleNode(ELEMENT_KEY);
String key = n.getText();
n = e.selectSingleNode(ELEMENT_CLASS);
String classname = n.getText();
String scope = ServletToolInfo.REQUEST_SCOPE;
n = e.selectSingleNode(ELEMENT_SCOPE);
if (n != null)
{
scope = n.getText();
}
return new ServletToolInfo(key, classname, scope);
}
/**
* Overrides XMLToolboxManager to separate tools by scope.
* For this to work, we obviously override getToolboxContext(Object) as well.
*/
public void addTool(ToolInfo info)
{
if (info instanceof DataInfo)
{
//add static data to the appTools map
appTools.put(info.getKey(), info.getInstance(null));
}
else if (info instanceof ServletToolInfo)
{
ServletToolInfo stInfo = (ServletToolInfo)info;
if (stInfo.getScope().equalsIgnoreCase(ServletToolInfo.REQUEST_SCOPE))
{
requestToolInfo.add(stInfo);
}
else if (stInfo.getScope().equalsIgnoreCase(ServletToolInfo.SESSION_SCOPE))
{
sessionToolInfo.add(stInfo);
}
else if (stInfo.getScope().equalsIgnoreCase(ServletToolInfo.APPLICATION_SCOPE))
{
//add application scoped tools to appTools and
//initialize them with the ServletContext
appTools.put(stInfo.getKey(), stInfo.getInstance(servletContext));
}
else
{
log("Unknown scope: "+stInfo.getScope()+" "+stInfo.getKey()+" will be request scoped.");
requestToolInfo.add(stInfo);
}
}
else
{
//default is request scope
requestToolInfo.add(info);
}
}
/**
* Overrides XMLToolboxManager to handle the separate
* scopes.
*
* Application scope tools were initialized when the toolbox was loaded.
* Session scope tools are initialized once per session and stored in a
* map in the session attributes.
* Request scope tools are initialized on every request.
*
* @param initData the {@link ViewContext} for the current servlet request
*/
public ToolboxContext getToolboxContext(Object initData)
{
//we know the initData is a ViewContext
ViewContext ctx = (ViewContext)initData;
//create the toolbox map with the application tools in it
Map toolbox = new HashMap(appTools);
if (!sessionToolInfo.isEmpty())
{
HttpSession session = ctx.getRequest().getSession(createSession);
if (session != null) {
//synchronize session tool initialization to avoid potential
//conflicts from multiple simultaneous requests in the same session
synchronized(session)
{
//get the initialized session tools
Map stmap = (Map)session.getAttribute(SESSION_TOOLS_KEY);
//if session tools aren't initialized,
//do so and store them in the session
if (stmap == null)
{
stmap = new HashMap(sessionToolInfo.size());
Iterator i = sessionToolInfo.iterator();
while(i.hasNext())
{
ToolInfo info = (ToolInfo)i.next();
stmap.put(info.getKey(), info.getInstance(ctx));
}
session.setAttribute(SESSION_TOOLS_KEY, stmap);
}
//add the initialized session tools to the toolbox
toolbox.putAll(stmap);
}
}
}
//add and initialize request tools
Iterator i = requestToolInfo.iterator();
while(i.hasNext())
{
ToolInfo info = (ToolInfo)i.next();
toolbox.put(info.getKey(), info.getInstance(ctx));
}
return new ToolboxContext(toolbox);
}
}