| 1 | package org.apache.velocity.runtime.visitor; |
| 2 | |
| 3 | /* |
| 4 | * Copyright 2001,2004 The Apache Software Foundation. |
| 5 | * |
| 6 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 7 | * you may not use this file except in compliance with the License. |
| 8 | * You may obtain a copy of the License at |
| 9 | * |
| 10 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 11 | * |
| 12 | * Unless required by applicable law or agreed to in writing, software |
| 13 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 14 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 15 | * See the License for the specific language governing permissions and |
| 16 | * limitations under the License. |
| 17 | */ |
| 18 | |
| 19 | import java.util.Map; |
| 20 | |
| 21 | import org.apache.velocity.runtime.parser.node.ASTReference; |
| 22 | |
| 23 | /** |
| 24 | * This class is a visitor used by the VM proxy to change the |
| 25 | * literal representation of a reference in a VM. The reason is |
| 26 | * to preserve the 'render literal if null' behavior w/o making |
| 27 | * the VMProxy stuff more complicated than it is already. |
| 28 | * |
| 29 | * @author <a href="mailto:geirm@optonline.net">Geir Magnusson Jr.</a> |
| 30 | * @version $Id: VMReferenceMungeVisitor.java,v 1.2.4.1 2004/03/03 23:23:03 geirm Exp $ |
| 31 | */ |
| 32 | public class VMReferenceMungeVisitor extends BaseVisitor |
| 33 | { |
| 34 | /** |
| 35 | * Map containing VM arg to instance-use reference |
| 36 | * Passed in with CTOR |
| 37 | */ |
| 38 | private Map argmap = null; |
| 39 | |
| 40 | /** |
| 41 | * CTOR - takes a map of args to reference |
| 42 | */ |
| 43 | public VMReferenceMungeVisitor( Map map ) |
| 44 | { |
| 45 | argmap = map; |
| 46 | } |
| 47 | |
| 48 | /** |
| 49 | * Visitor method - if the literal is right, will |
| 50 | * set the literal in the ASTReference node |
| 51 | * |
| 52 | * @param node ASTReference to work on |
| 53 | * @param data Object to pass down from caller |
| 54 | */ |
| 55 | public Object visit( ASTReference node, Object data) |
| 56 | { |
| 57 | /* |
| 58 | * see if there is an override value for this |
| 59 | * reference |
| 60 | */ |
| 61 | String override = (String) argmap.get( node.literal().substring(1) ); |
| 62 | |
| 63 | /* |
| 64 | * if so, set in the node |
| 65 | */ |
| 66 | if( override != null) |
| 67 | { |
| 68 | node.setLiteral( override ); |
| 69 | } |
| 70 | |
| 71 | /* |
| 72 | * feed the children... |
| 73 | */ |
| 74 | data = node.childrenAccept(this, data); |
| 75 | |
| 76 | return data; |
| 77 | } |
| 78 | } |
| 79 | |