1 package net.sourceforge.pmd.lang.vm.ast;
2
3 /*
4 * Licensed to the Apache Software Foundation (ASF) under one
5 * or more contributor license agreements. See the NOTICE file
6 * distributed with this work for additional information
7 * regarding copyright ownership. The ASF licenses this file
8 * to you under the Apache License, Version 2.0 (the
9 * "License"); you may not use this file except in compliance
10 * with the License. You may obtain a copy of the License at
11 *
12 * http://www.apache.org/licenses/LICENSE-2.0
13 *
14 * Unless required by applicable law or agreed to in writing,
15 * software distributed under the License is distributed on an
16 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17 * KIND, either express or implied. See the License for the
18 * specific language governing permissions and limitations
19 * under the License.
20 */
21
22 /**
23 * This class is responsible for handling the references in VTL ($foo).
24 *
25 * Please look at the Parser.jjt file which is what controls the generation of this class.
26 *
27 * @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a>
28 * @author <a href="mailto:geirm@optonline.net">Geir Magnusson Jr.</a>
29 * @author <a href="mailto:Christoph.Reck@dlr.de">Christoph Reck</a>
30 * @author <a href="mailto:kjohnson@transparent.com>Kent Johnson</a>
31 * @version $Id: ASTReference.java 806597 2009-08-21 15:21:44Z nbubna $
32 */
33 public class ASTReference extends AbstractVmNode {
34 private String rootString;
35
36 private String literal = null;
37
38 /**
39 * Indicates if we are running in strict reference mode.
40 */
41 public boolean strictRef = false;
42
43 /**
44 * Indicates if toString() should be called during condition evaluation just to ensure it does not return null.
45 * Check is unnecessary if all toString() implementations are known to have non-null return values. Disabling the
46 * check will give a performance improval since toString() may be a complex operation on large objects.
47 */
48 public boolean toStringNullCheck = true;
49
50 /**
51 * @param id
52 */
53 public ASTReference(final int id) {
54 super(id);
55 }
56
57 /**
58 * @param p
59 * @param id
60 */
61 public ASTReference(final VmParser p, final int id) {
62 super(p, id);
63 }
64
65 /**
66 * @see org.apache.velocity.runtime.parser.node.SimpleNode#jjtAccept(org.apache.velocity.runtime.parser.node.VmParserVisitor,
67 * java.lang.Object)
68 */
69 @Override
70 public Object jjtAccept(final VmParserVisitor visitor, final Object data) {
71 return visitor.visit(this, data);
72 }
73
74 /**
75 * Returns the 'root string', the reference key
76 *
77 * @return the root string.
78 */
79 public String getRootString() {
80 return rootString;
81 }
82
83 /**
84 * Routine to allow the literal representation to be externally overridden. Used now in the VM system to override a
85 * reference in a VM tree with the literal of the calling arg to make it work nicely when calling arg is null. It
86 * seems a bit much, but does keep things consistant.
87 *
88 * Note, you can only set the literal once...
89 *
90 * @param literal String to render to when null
91 */
92 public void setLiteral(final String literal) {
93 /*
94 * do only once
95 */
96
97 if (this.literal == null)
98 this.literal = literal;
99 }
100
101 /**
102 * Override of the SimpleNode method literal() Returns the literal representation of the node. Should be something
103 * like $<token>.
104 *
105 * @return A literal string.
106 */
107 @Override
108 public String literal() {
109 if (literal != null)
110 return literal;
111
112 // this value could be cached in this.literal but it increases memory usage
113 return super.literal();
114 }
115 }