pluginmanager.java

jspwiki source code,jspwiki source code

            while( resources.hasMoreElements() )
            {
                URL resource = (URL) resources.nextElement();

                try
                {
                    log.debug( "Processing XML: " + resource );

                    Document doc = builder.build( resource );

                    List plugins = XPath.selectNodes( doc, "/modules/plugin");

                    for( Iterator i = plugins.iterator(); i.hasNext(); )
                    {
                        Element pluginEl = (Element) i.next();

                        String className = pluginEl.getAttributeValue("class");

                        WikiPluginInfo pluginInfo = WikiPluginInfo.newInstance( className, pluginEl );

                        if( pluginInfo != null )
                        {
                            registerPlugin( pluginInfo );
                        }
                    }
                }
                catch( java.io.IOException e )
                {
                    log.error( "Couldn't load " + PLUGIN_RESOURCE_LOCATION + " resources: " + resource, e );
                }
                catch( JDOMException e )
                {
                    log.error( "Error parsing XML for plugin: "+PLUGIN_RESOURCE_LOCATION );
                }
            }
        }
        catch( java.io.IOException e )
        {
            log.error( "Couldn't load all " + PLUGIN_RESOURCE_LOCATION + " resources", e );
        }
    }

    /**
     *  Contains information about a bunch of plugins.
     *
     *  @author Kees Kuip
     *  @author Janne Jalkanen
     *
     *  @since
     */
    // FIXME: This class needs a better interface to return all sorts of possible
    //        information from the plugin XML.  In fact, it probably should have
    //        some sort of a superclass system.
    public static final class WikiPluginInfo
        extends WikiModuleInfo
    {
        private String m_className;
        private String m_alias;
        private Class  m_clazz;

        private boolean m_initialized = false;

        /**
         *  Creates a new plugin info object which can be used to access a plugin.
         *
         *  @param className Either a fully qualified class name, or a "short" name which is then
         *                   checked against the internal list of plugin packages.
         *  @param el A JDOM Element containing the information about this class.
         *  @return A WikiPluginInfo object.
         */
        protected static WikiPluginInfo newInstance( String className, Element el )
        {
            if( className == null || className.length() == 0 ) return null;
            WikiPluginInfo info = new WikiPluginInfo( className );

            info.initializeFromXML( el );
            return info;
        }
        /**
         *  Initializes a plugin, if it has not yet been initialized.
         *
         *  @param engine The WikiEngine
         */
        protected void initializePlugin( WikiEngine engine )
        {
            if( !m_initialized )
            {
                // This makes sure we only try once per class, even if init fails.
                m_initialized = true;

                try
                {
                    WikiPlugin p = newPluginInstance();
                    if( p instanceof InitializablePlugin )
                    {
                        ((InitializablePlugin)p).initialize( engine );
                    }
                }
                catch( Exception e )
                {
                    log.info( "Cannot initialize plugin "+m_className, e );
                }
            }
        }

        /**
         *  {@inheritDoc}
         */
        @Override
        protected void initializeFromXML( Element el )
        {
            super.initializeFromXML( el );
            m_alias = el.getChildText("alias");
        }

        /**
         *  Create a new WikiPluginInfo based on the Class information.
         *  
         *  @param clazz The class to check
         *  @return A WikiPluginInfo instance
         */
        protected static WikiPluginInfo newInstance( Class clazz )
        {
            WikiPluginInfo info = new WikiPluginInfo( clazz.getName() );

            return info;
        }

        private WikiPluginInfo( String className )
        {
            super(className);
            setClassName( className );
        }

        private void setClassName( String fullClassName )
        {
            m_name = ClassUtils.getShortClassName( fullClassName );
            m_className = fullClassName;
        }

        /**
         *  Returns the full class name of this object.
         *  @return The full class name of the object.
         */
        public String getClassName()
        {
            return m_className;
        }

        /**
         *  Returns the alias name for this object.
         *  @return An alias name for the plugin.
         */
        public String getAlias()
        {
            return m_alias;
        }

        /**
         *  Creates a new plugin instance.
         *
         *  @return A new plugin.
         *  @throws ClassNotFoundException If the class declared was not found.
         *  @throws InstantiationException If the class cannot be instantiated-
         *  @throws IllegalAccessException If the class cannot be accessed.
         */
        public WikiPlugin newPluginInstance()
            throws ClassNotFoundException,
                   InstantiationException,
                   IllegalAccessException
        {
            if( m_clazz == null )
            {
                m_clazz = Class.forName(m_className);
            }

            return (WikiPlugin) m_clazz.newInstance();
        }

        /**
         *  Returns a text for IncludeResources.
         *
         *  @param type Either "script" or "stylesheet"
         *  @return Text, or an empty string, if there is nothing to be included.
         */
        public String getIncludeText(String type)
        {
            try
            {
                if( type.equals("script") )
                {
                    return getScriptText();
                }
                else if( type.equals("stylesheet") )
                {
                    return getStylesheetText();
                }
            }
            catch( Exception ex )
            {
                // We want to fail gracefully here
                return ex.getMessage();
            }

            return null;
        }

        private String getScriptText()
            throws IOException
        {
            if( m_scriptText != null )
            {
                return m_scriptText;
            }

            if( m_scriptLocation == null )
            {
                return "";
            }

            try
            {
                m_scriptText = getTextResource(m_scriptLocation);
            }
            catch( IOException ex )
            {
                // Only throw this exception once!
                m_scriptText = "";
                throw ex;
            }

            return m_scriptText;
        }

        private String getStylesheetText()
            throws IOException
        {
            if( m_stylesheetText != null )
            {
                return m_stylesheetText;
            }

            if( m_stylesheetLocation == null )
            {
                return "";
            }

            try
            {
                m_stylesheetText = getTextResource(m_stylesheetLocation);
            }
            catch( IOException ex )
            {
                // Only throw this exception once!
                m_stylesheetText = "";
                throw ex;
            }

            return m_stylesheetText;
        }

        /**
         *  Returns a string suitable for debugging.  Don't assume that the format
         *  would stay the same.
         *  
         *  @return Something human-readable
         */
        public String toString()
        {
            return "Plugin :[name=" + m_name + "][className=" + m_className + "]";
        }
    } // WikiPluginClass

    /**
     *  {@inheritDoc}
     */
    public Collection modules()
    {
        TreeSet<WikiModuleInfo> ls = new TreeSet<WikiModuleInfo>();
        
        for( Iterator i = m_pluginClassMap.values().iterator(); i.hasNext(); )
        {
            WikiModuleInfo wmi = (WikiModuleInfo)i.next();
            
            if( !ls.contains(wmi) ) ls.add(wmi);
        }
        
        return ls;
    }

    /**
     *  Executes parse stage, unless plugins are disabled.
     *  
     *  @param content The content item.
     *  @param context A WikiContext
     *  @throws PluginException If something goes wrong.
     */
    // FIXME: This method needs to be reintegrated with execute() above, since they
    //        share plenty of code.
    public void executeParse(PluginContent content, WikiContext context)
        throws PluginException
    {
        if( !m_pluginsEnabled )
            return;

        ResourceBundle rb = context.getBundle(WikiPlugin.CORE_PLUGINS_RESOURCEBUNDLE);
        Object[] args = { content.getPluginName() };
        Map params = content.getParameters();
        try
        {
            WikiPlugin plugin;

            WikiPluginInfo pluginInfo = m_pluginClassMap.get( content.getPluginName() );

            if(pluginInfo == null)
            {
                pluginInfo = WikiPluginInfo.newInstance(findPluginClass( content.getPluginName() ));
                registerPlugin(pluginInfo);
            }

            if( !checkCompatibility(pluginInfo) )
            {
                String msg = "Plugin '"+pluginInfo.getName()+"' not compatible with this version of JSPWiki";
                log.info(msg);
                return;
            }

            plugin = pluginInfo.newPluginInstance();

            if( plugin instanceof ParserStagePlugin )
            {
                ((ParserStagePlugin)plugin).executeParser( content, context, params );
            }
        }
        catch( InstantiationException e )
        {
            throw new PluginException( MessageFormat.format( rb.getString( "plugin.error.cannotinstantiate" ), args), e );
        }
        catch( IllegalAccessException e )
        {
            throw new PluginException( MessageFormat.format( rb.getString( "plugin.error.notallowed" ), args), e );
        }
        catch( ClassNotFoundException e )
        {
            throw new PluginException( MessageFormat.format( rb.getString( "plugin.error.couldnotfind" ), args) );
        }
        catch( ClassCastException e )
        {
            throw new PluginException( MessageFormat.format( rb.getString( "plugin.error.notawikiplugin" ), args), e );
        }
        catch( Exception e )
        {
            throw new PluginException( MessageFormat.format( rb.getString( "plugin.error.instantationfailed" ), args), e );
        }
    }
}