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package org.apache.velocity.runtime;

/*
 * 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.util.Collections;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import org.apache.velocity.runtime.directive.VelocimacroProxy;
import org.apache.velocity.runtime.parser.node.Node;
import org.apache.velocity.runtime.parser.node.SimpleNode;
import org.apache.velocity.util.MapFactory;

/**
 * Manages VMs in namespaces.  Currently, two namespace modes are
 * supported:
 *
 * 
    *
  • flat - all allowable VMs are in the global namespace
  • *
  • local - inline VMs are added to it's own template namespace
  • *
* * Thanks to Jose Alberto Fernandez * for some ideas incorporated here. * * @author Geir Magnusson Jr. * @author Jose Alberto Fernandez * @version $Id: VelocimacroManager.java 698376 2008-09-23 22:15:49Z nbubna $ */ public class VelocimacroManager { private static String GLOBAL_NAMESPACE = ""; private boolean registerFromLib = false; /** Hash of namespace hashes. */ private final Map namespaceHash = MapFactory.create(17, 0.5f, 20, false); /** reference to global namespace hash */ private final Map globalNamespace; /** set of names of library tempates/namespaces */ private final Set libraries = Collections.synchronizedSet(new HashSet()); /* * big switch for namespaces. If true, then properties control * usage. If false, no. */ private boolean namespacesOn = true; private boolean inlineLocalMode = false; private boolean inlineReplacesGlobal = false; /** * Adds the global namespace to the hash. */ VelocimacroManager(RuntimeServices rsvc) { /* * add the global namespace to the namespace hash. We always have that. */ globalNamespace = addNamespace(GLOBAL_NAMESPACE); } /** * Adds a VM definition to the cache. * * Called by VelocimacroFactory.addVelociMacro (after parsing and discovery in Macro directive) * * @param vmName Name of the new VelociMacro. * @param macroBody String representation of the macro body. * @param argArray Array of macro parameters, first parameter is the macro name. * @param namespace The namespace/template from which this macro has been loaded. * @return Whether everything went okay. */ public boolean addVM(final String vmName, final Node macroBody, final String argArray[], final String namespace, boolean canReplaceGlobalMacro) { if (macroBody == null) { // happens only if someone uses this class without the Macro directive // and provides a null value as an argument throw new RuntimeException("Null AST for "+vmName+" in "+namespace); } MacroEntry me = new MacroEntry(vmName, macroBody, argArray, namespace); me.setFromLibrary(registerFromLib); /* * the client (VMFactory) will signal to us via * registerFromLib that we are in startup mode registering * new VMs from libraries. Therefore, we want to * addto the library map for subsequent auto reloads */ boolean isLib = true; MacroEntry exist = (MacroEntry) globalNamespace.get(vmName); if (registerFromLib) { libraries.add(namespace); } else { /* * now, we first want to check to see if this namespace (template) * is actually a library - if so, we need to use the global namespace * we don't have to do this when registering, as namespaces should * be shut off. If not, the default value is true, so we still go * global */ isLib = libraries.contains(namespace); } if ( !isLib && usingNamespaces(namespace) ) { /* * first, do we have a namespace hash already for this namespace? * if not, add it to the namespaces, and add the VM */ Map local = getNamespace(namespace, true); local.put(vmName, me); return true; } else { /* * otherwise, add to global template. First, check if we * already have it to preserve some of the autoload information */ if (exist != null) { me.setFromLibrary(exist.getFromLibrary()); } /* * now add it */ globalNamespace.put(vmName, me); return true; } } /** * Gets a VelocimacroProxy object by the name / source template duple. * * @param vmName Name of the VelocityMacro to look up. * @param namespace Namespace in which to look up the macro. * @return A proxy representing the Macro. */ public VelocimacroProxy get(final String vmName, final String namespace) { return(get(vmName, namespace, null)); } /** * Gets a VelocimacroProxy object by the name / source template duple. * * @param vmName Name of the VelocityMacro to look up. * @param namespace Namespace in which to look up the macro. * @param renderingTemplate Name of the template we are currently rendering. * @return A proxy representing the Macro. * @since 1.6 */ public VelocimacroProxy get(final String vmName, final String namespace, final String renderingTemplate) { if( inlineReplacesGlobal && renderingTemplate != null ) { /* * if VM_PERM_ALLOW_INLINE_REPLACE_GLOBAL is true (local macros can * override global macros) and we know which template we are rendering at the * moment, check if local namespace contains a macro we are looking for * if so, return it instead of the global one */ Map local = getNamespace(renderingTemplate, false); if (local != null) { MacroEntry me = (MacroEntry) local.get(vmName); if (me != null) { return me.getProxy(namespace); } } } if (usingNamespaces(namespace)) { Map local = getNamespace(namespace, false); /* * if we have macros defined for this template */ if (local != null) { MacroEntry me = (MacroEntry) local.get(vmName); if (me != null) { return me.getProxy(namespace); } } } /* * if we didn't return from there, we need to simply see * if it's in the global namespace */ MacroEntry me = (MacroEntry) globalNamespace.get(vmName); if (me != null) { return me.getProxy(namespace); } return null; } /** * Removes the VMs and the namespace from the manager. * Used when a template is reloaded to avoid * losing memory. * * @param namespace namespace to dump * @return boolean representing success */ public boolean dumpNamespace(final String namespace) { synchronized(this) { if (usingNamespaces(namespace)) { Map h = (Map) namespaceHash.remove(namespace); if (h == null) { return false; } h.clear(); return true; } return false; } } /** * public switch to let external user of manager to control namespace * usage indep of properties. That way, for example, at startup the * library files are loaded into global namespace * * @param namespaceOn True if namespaces should be used. */ public void setNamespaceUsage(final boolean namespaceOn) { this.namespacesOn = namespaceOn; } /** * Should macros registered from Libraries be marked special? * @param registerFromLib True if macros from Libs should be marked. */ public void setRegisterFromLib(final boolean registerFromLib) { this.registerFromLib = registerFromLib; } /** * Should macros from the same template be inlined? * * @param inlineLocalMode True if macros should be inlined on the same template. */ public void setTemplateLocalInlineVM(final boolean inlineLocalMode) { this.inlineLocalMode = inlineLocalMode; } /** * returns the hash for the specified namespace, and if it doesn't exist * will create a new one and add it to the namespaces * * @param namespace name of the namespace :) * @param addIfNew flag to add a new namespace if it doesn't exist * @return namespace Map of VMs or null if doesn't exist */ private Map getNamespace(final String namespace, final boolean addIfNew) { Map h = (Map) namespaceHash.get(namespace); if (h == null && addIfNew) { h = addNamespace(namespace); } return h; } /** * adds a namespace to the namespaces * * @param namespace name of namespace to add * @return Hash added to namespaces, ready for use */ private Map addNamespace(final String namespace) { Map h = MapFactory.create(17, 0.5f, 20, false); Object oh; if ((oh = namespaceHash.put(namespace, h)) != null) { /* * There was already an entry on the table, restore it! * This condition should never occur, given the code * and the fact that this method is private. * But just in case, this way of testing for it is much * more efficient than testing before hand using get(). */ namespaceHash.put(namespace, oh); /* * Should't we be returning the old entry (oh)? * The previous code was just returning null in this case. */ return null; } return h; } /** * determines if currently using namespaces. * * @param namespace currently ignored * @return true if using namespaces, false if not */ private boolean usingNamespaces(final String namespace) { /* * if the big switch turns of namespaces, then ignore the rules */ if (!namespacesOn) { return false; } /* * currently, we only support the local template namespace idea */ if (inlineLocalMode) { return true; } return false; } /** * Return the library name for a given macro. * @param vmName Name of the Macro to look up. * @param namespace Namespace to look the macro up. * @return The name of the library which registered this macro in a namespace. */ public String getLibraryName(final String vmName, final String namespace) { if (usingNamespaces(namespace)) { Map local = getNamespace(namespace, false); /* * if we have this macro defined in this namespace, then * it is masking the global, library-based one, so * just return null */ if ( local != null) { MacroEntry me = (MacroEntry) local.get(vmName); if (me != null) { return null; } } } /* * if we didn't return from there, we need to simply see * if it's in the global namespace */ MacroEntry me = (MacroEntry) globalNamespace.get(vmName); if (me != null) { return me.getSourceTemplate(); } return null; } /** * @since 1.6 */ public void setInlineReplacesGlobal(boolean is) { inlineReplacesGlobal = is; } /** * wrapper class for holding VM information */ private static class MacroEntry { private final String vmName; private final String[] argArray; private final String sourceTemplate; private SimpleNode nodeTree = null; private boolean fromLibrary = false; private VelocimacroProxy vp; private MacroEntry(final String vmName, final Node macro, final String argArray[], final String sourceTemplate) { this.vmName = vmName; this.argArray = argArray; this.nodeTree = (SimpleNode)macro; this.sourceTemplate = sourceTemplate; vp = new VelocimacroProxy(); vp.setName(this.vmName); vp.setArgArray(this.argArray); vp.setNodeTree(this.nodeTree); } /** * Has the macro been registered from a library. * @param fromLibrary True if the macro was registered from a Library. */ public void setFromLibrary(final boolean fromLibrary) { this.fromLibrary = fromLibrary; } /** * Returns true if the macro was registered from a library. * @return True if the macro was registered from a library. */ public boolean getFromLibrary() { return fromLibrary; } /** * Returns the node tree for this macro. * @return The node tree for this macro. */ public SimpleNode getNodeTree() { return nodeTree; } /** * Returns the source template name for this macro. * @return The source template name for this macro. */ public String getSourceTemplate() { return sourceTemplate; } VelocimacroProxy getProxy(final String namespace) { /* * FIXME: namespace data is omitted, this probably * breaks some error reporting? */ return vp; } } }




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