velocimacrofactory.java

velocity 的脚本语言的全部代码集合

package org.apache.velocity.runtime;

/*
 * Copyright 2000-2001,2004 The Apache Software Foundation.
 * 
 * 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.
 */

import org.apache.velocity.Template;
import org.apache.velocity.runtime.directive.Directive;
import org.apache.velocity.runtime.directive.VelocimacroProxy;

import java.util.Vector;
import java.util.Map;
import java.util.HashMap;

/**
 *  VelocimacroFactory.java
 *
 *   manages the set of VMs in a running Velocity engine.
 *
 * @author <a href="mailto:[e-mail]">Geir Magnusson Jr.</a>
 * @version $Id: VelocimacroFactory.java,v 1.17.4.1 2004/03/03 23:22:55 geirm Exp $ 
 */
public class VelocimacroFactory
{
    /**
     *  runtime services for this instance
     */
    private RuntimeServices rsvc = null;

    /**
     *  VMManager : deal with namespace management
     *  and actually keeps all the VM definitions
     */
    private VelocimacroManager vmManager = null;

    /**
     *  determines if replacement of global VMs are allowed
     *  controlled by  VM_PERM_ALLOW_INLINE_REPLACE_GLOBAL
     */
    private boolean replaceAllowed = false;

    /**
     *  controls if new VMs can be added.  Set by
     *  VM_PERM_ALLOW_INLINE  Note the assumption that only
     *  through inline defs can this happen.
     *  additions through autoloaded VMs is allowed
     */
    private boolean addNewAllowed = true;

    /**
     *  sets if template-local namespace in used
     */
    private boolean templateLocal = false;

    /**
     *  controls log output
     */
    private boolean blather = false;

    /**
     *  determines if the libraries are auto-loaded
     *  when they change
     */
    private boolean autoReloadLibrary = false;

    /**
     *  vector of the library names
     */
    private Vector macroLibVec = null;

    /**
     *  map of the library Template objects
     *  used for reload determination
     */
    private Map libModMap;

    /**
     *  CTOR : requires a runtime services from now
     *  on
     */
    public VelocimacroFactory( RuntimeServices rs )
    {
        this.rsvc = rs;

        /*
         *  we always access in a synchronized(), so we 
         *  can use an unsynchronized hashmap
         */
        libModMap = new HashMap();
        vmManager = new VelocimacroManager( rsvc );
    }

    /**
     *  initialize the factory - setup all permissions
     *  load all global libraries.
     */
    public void initVelocimacro()
    {
        /*
         *  maybe I'm just paranoid...
         */
        synchronized( this )
        {
            /*
             *   allow replacements while we add the libraries, if exist
             */
            setReplacementPermission( true );
            setBlather( true );

            logVMMessageInfo("Velocimacro : initialization starting.");
 
            /*
             *  add all library macros to the global namespace
             */
            
            vmManager.setNamespaceUsage( false );
        
            /*
             *  now, if there is a global or local libraries specified, use them.
             *  All we have to do is get the template. The template will be parsed;
             *  VM's  are added during the parse phase
             */

             Object libfiles = rsvc.getProperty( RuntimeConstants.VM_LIBRARY );
           
             if( libfiles != null)
             {         
                 if (libfiles instanceof Vector)
                 {
                     macroLibVec = (Vector) libfiles;
                 }
                 else if (libfiles instanceof String)
                 { 
                     macroLibVec = new Vector();
                     macroLibVec.addElement( libfiles );
                 }
                 
                 for( int i = 0; i < macroLibVec.size(); i++)
                 {
                     String lib = (String) macroLibVec.elementAt(i);
                 
                     /*
                      * only if it's a non-empty string do we bother
                      */

                     if (lib != null && !lib.equals(""))
                     {
                         /*
                          *  let the VMManager know that the following is coming
                          *  from libraries - need to know for auto-load
                          */

                         vmManager.setRegisterFromLib( true );

                         logVMMessageInfo("Velocimacro : adding VMs from " +
                             "VM library template : " + lib  );

                         try 
                         {
                             Template template = rsvc.getTemplate( lib );

                             /*
                              *  save the template.  This depends on the assumption
                              *  that the Template object won't change - currently
                              *  this is how the Resource manager works
                              */

                             Twonk twonk = new Twonk();
                             twonk.template = template;
                             twonk.modificationTime = template.getLastModified();
                             libModMap.put( lib, twonk );                         
                         } 
                         catch (Exception e)
                         {
                             logVMMessageInfo("Velocimacro : error using  VM " +
                                              "library template " + lib + " : " + e );
                         }

                         logVMMessageInfo("Velocimacro :  VM library template " +
                                 "macro registration complete." );
            
                         vmManager.setRegisterFromLib( false );
                     }
                 }
             }

            /*
             *   now, the permissions
             */
            
            /*
             *  allowinline : anything after this will be an inline macro, I think
             *  there is the question if a #include is an inline, and I think so
             *
             *  default = true
             */
            setAddMacroPermission( true );
                        
            if ( !rsvc.getBoolean(  RuntimeConstants.VM_PERM_ALLOW_INLINE, true) )
            {
                setAddMacroPermission( false );
                
                logVMMessageInfo("Velocimacro : allowInline = false : VMs can not " +
                    "be defined inline in templates");
            }
            else
            {
                logVMMessageInfo("Velocimacro : allowInline = true : VMs can be " +
                    "defined inline in templates");
            }

            /*
             *  allowInlineToReplaceGlobal : allows an inline VM , if allowed at all,
             *  to replace an existing global VM
             *
             *  default = false
             */
            setReplacementPermission( false );
            
            if ( rsvc.getBoolean(  
                 RuntimeConstants.VM_PERM_ALLOW_INLINE_REPLACE_GLOBAL, false) )
            {
                setReplacementPermission( true );
                
                logVMMessageInfo("Velocimacro : allowInlineToOverride = true : VMs " +
                    "defined inline may replace previous VM definitions");
            }
            else
            {
                logVMMessageInfo("Velocimacro : allowInlineToOverride = false : VMs " +
                    "defined inline may NOT replace previous VM definitions");
            }

            /*
             * now turn on namespace handling as far as permissions allow in the 
             * manager, and also set it here for gating purposes
             */
            vmManager.setNamespaceUsage( true );

            /*
             *  template-local inline VM mode : default is off
             */
            setTemplateLocalInline( rsvc.getBoolean(
                RuntimeConstants.VM_PERM_INLINE_LOCAL, false) );
        
            if ( getTemplateLocalInline() )
            {
                logVMMessageInfo("Velocimacro : allowInlineLocal = true : VMs " +
                    "defined inline will be local to their defining template only.");
            }
            else
            {
                logVMMessageInfo("Velocimacro : allowInlineLocal = false : VMs " +
                    "defined inline will be  global in scope if allowed.");
            }
 
            vmManager.setTemplateLocalInlineVM( getTemplateLocalInline() );

            /*
             *  general message switch.  default is on
             */
            setBlather( rsvc.getBoolean( RuntimeConstants.VM_MESSAGES_ON, true ));
        
            if (getBlather())
            {
                logVMMessageInfo("Velocimacro : messages on  : VM system " +
                    "will output logging messages");
            }
            else
            {
                logVMMessageInfo("Velocimacro : messages off : VM system will be quiet");
            }

            /*
             *  autoload VM libraries
             */
            setAutoload( rsvc.getBoolean( RuntimeConstants.VM_LIBRARY_AUTORELOAD, false ));
        
            if (getAutoload())
            {
                logVMMessageInfo("Velocimacro : autoload on  : VM system " +
                                 "will automatically reload global library macros");
            }
            else
            {
                logVMMessageInfo("Velocimacro : autoload off  : VM system " +
                                 "will not automatically reload global library macros");
            }

            rsvc.info("Velocimacro : initialization complete.");
        }
    
        return;
    }

    /**
     *  adds a macro to the factory. 
     */
    public boolean addVelocimacro( String name, String macroBody,  
    	String argArray[], String sourceTemplate )
    {
        /*
         * maybe we should throw an exception, maybe just tell 
         * the caller like this...
         * 
         * I hate this : maybe exceptions are in order here...
         */
        if ( name == null ||   macroBody == null || argArray == null || 
        	sourceTemplate == null )
        {
            logVMMessageWarn("Velocimacro : VM addition rejected : " +
                "programmer error : arg null"  );
            
            return false;
        }
        
        /*
         *  see if the current ruleset allows this addition
         */

        if (!canAddVelocimacro( name, sourceTemplate ))
        {
            return false;
        }

        /*
         *  seems like all is good.  Lets do it.
         */