velocimacrofactory.java

velocity 的脚本语言的全部代码集合

        synchronized( this ) 
        {
            vmManager.addVM( name, macroBody, argArray, sourceTemplate );
        }

        /*
         *  if we are to blather, blather...
         */
        if ( blather)
        {
            String s = "#" +  argArray[0];
            s += "(";
        
            for( int i=1; i < argArray.length; i++)
            {
                s += " ";
                s += argArray[i];
            }

            s += " ) : source = ";
            s += sourceTemplate;
            
           logVMMessageInfo( "Velocimacro : added new VM : " + s );
        }

        return true;
    }

    /**
     *  determines if a given macro/namespace (name, source) combo is allowed
     *  to be added
     *
     *  @param name Name of VM to add
     *  @param sourceTemplate Source template that contains the defintion of the VM
     *  @return true if it is allowed to be added, false otherwise
     */
    private boolean canAddVelocimacro( String name, String sourceTemplate)
    {
        /*
         *  short circuit and do it if autoloader is on, and the
         *  template is one of the library templates
         */
        
        if ( getAutoload() )
        {
            /*
             *  see if this is a library template
             */

            for( int i = 0; i < macroLibVec.size(); i++)
            {
                String lib = (String) macroLibVec.elementAt(i);

                if (lib.equals( sourceTemplate ) )
                {
                    return true;
                }
            }
        }

           
        /*
         * maybe the rules should be in manager?  I dunno. It's to manage 
         * the namespace issues first, are we allowed to add VMs at all? 
         * This trumps all.
         */
        if (!addNewAllowed)
        {
            logVMMessageWarn("Velocimacro : VM addition rejected : " + name + 
                " : inline VMs not allowed."  );
            
            return false;
        }

        /*
         *  are they local in scope?  Then it is ok to add.
         */
        if (!templateLocal)
        {
            /* 
             * otherwise, if we have it already in global namespace, and they can't replace
             * since local templates are not allowed, the global namespace is implied.
             *  remember, we don't know anything about namespace managment here, so lets
             *  note do anything fancy like trying to give it the global namespace here
             *
             *  so if we have it, and we aren't allowed to replace, bail
             */
            if ( isVelocimacro( name, sourceTemplate ) && !replaceAllowed )
            {
                logVMMessageWarn("Velocimacro : VM addition rejected : "
                    + name + " : inline not allowed to replace existing VM"  );
                return false;
            }
        }
        
        return true;
    }

    /**
     *  localization of the logging logic
     */
    private void logVMMessageInfo( String s )
    {
        if (blather)
            rsvc.info( s );
    }

    /**
     *  localization of the logging logic
     */
    private void logVMMessageWarn( String s )
    {
        if (blather)
            rsvc.warn( s );
    }
      
    /**
     *  Tells the world if a given directive string is a Velocimacro
     */
    public boolean isVelocimacro( String vm , String sourceTemplate )
    {
        synchronized(this)
        {
            /*
             * first we check the locals to see if we have 
             * a local definition for this template
             */
            if (vmManager.get( vm, sourceTemplate ) != null)
                return true;
        }
        return false;
    }

    /**
     *  actual factory : creates a Directive that will
     *  behave correctly wrt getting the framework to 
     *  dig out the correct # of args
     */
    public Directive getVelocimacro( String vmName, String sourceTemplate )
    {
        VelocimacroProxy vp = null;

        synchronized( this ) 
        {
            /*
             *  don't ask - do
             */

            vp = vmManager.get( vmName, sourceTemplate);

            /*
             *  if this exists, and autoload is on, we need to check
             *  where this VM came from
             */

            if ( vp != null && getAutoload() ) 
            {    
                /*
                 *  see if this VM came from a library.  Need to pass sourceTemplate
                 *  in the event namespaces are set, as it could be masked by local
                 */
                
                String lib = vmManager.getLibraryName( vmName, sourceTemplate );

                if (lib != null)
                {
                    try 
                    {
                        /*
                         *  get the template from our map
                         */

                        Twonk tw = (Twonk) libModMap.get( lib );
                        
                        if ( tw != null)
                        {
                            Template template = tw.template;
                            
                            /*
                             *  now, compare the last modified time of the resource
                             *  with the last modified time of the template
                             *  if the file has changed, then reload. Otherwise, we should
                             *  be ok.
                             */

                            long tt = tw.modificationTime;
                            long ft = template.getResourceLoader().getLastModified( template );

                            if ( ft > tt )
                            {
                                logVMMessageInfo("Velocimacro : autoload reload for VMs from " +
                                                 "VM library template : " + lib  );
             
                                /*
                                 *  when there are VMs in a library that invoke each other,
                                 *  there are calls into getVelocimacro() from the init() 
                                 *  process of the VM directive.  To stop the infinite loop
                                 *  we save the current time reported by the resource loader
                                 *  and then be honest when the reload is complete
                                 */
                                 
                                tw.modificationTime = ft;
                                                                       
                                template = rsvc.getTemplate( lib );
 
                                /*
                                 * and now we be honest
                                 */

                                tw.template = template;
                                tw.modificationTime = template.getLastModified();

                                /*
                                 *  note that we don't need to put this twonk back 
                                 *  into the map, as we can just use the same reference
                                 *  and this block is synchronized
                                 */                                  
                             }
                         } 
                    }
                    catch (Exception e)
                    {
                        logVMMessageInfo("Velocimacro : error using  VM " +
                                         "library template " + lib + " : " + e );
                    }

                    /*
                     *  and get again
                     */

                    vp = vmManager.get( vmName, sourceTemplate);
                }
            }
        }
        
        return vp;
    }

    /**
     *  tells the vmManager to dump the specified namespace
     */
    public boolean dumpVMNamespace( String namespace )
    {
        return vmManager.dumpNamespace( namespace );
    }

    /**
     *  sets permission to have VMs local in scope to their declaring template
     *  note that this is really taken care of in the VMManager class, but
     *  we need it here for gating purposes in addVM
     *  eventually, I will slide this all into the manager, maybe.
     */   
    private void setTemplateLocalInline( boolean b )
    {
        templateLocal = b;
    }

    private boolean getTemplateLocalInline()
    {
        return templateLocal;
    }

    /**
     *   sets the permission to add new macros
     */
    private boolean setAddMacroPermission( boolean arg )
    {
        boolean b = addNewAllowed;
        
        addNewAllowed = arg;
        return b;
    }

    /**
     *    sets the permission for allowing addMacro() calls to 
     *    replace existing VM's
     */
    private boolean setReplacementPermission( boolean arg )
    {
        boolean b = replaceAllowed;
        replaceAllowed = arg;
        return b;
    }

    /**
     *  set output message mode 
     */
    private void setBlather( boolean b )
    {
        blather = b;
    }

    /**
     * get output message mode
     */
    private boolean getBlather()
    {
        return blather;
    }

    /**
     *  set the switch for automatic reloading of
     *  global library-based VMs
     */
    private void setAutoload( boolean b)
    {
        autoReloadLibrary = b;
    }
    
    /**
     *  get the switch for automatic reloading of
     *  global library-based VMs
     */
    private boolean getAutoload()
    {
        return autoReloadLibrary;
    }

    /**
     * small continer class to hold the duple
     * of a template and modification time.
     * We keep the modification time so we can 
     * 'override' it on a reload to prevent
     * recursive reload due to inter-calling
     * VMs in a library
     */
    private class Twonk
    {
        public Template template;
        public long modificationTime;
    }
}