1 /*
2 * Copyright 2002-2006 The Apache Software Foundation.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16 /* Generated By:JJTree: Do not edit this line. JJTParserState.java */
17
18 package org.apache.commons.jexl.parser;
19
20 import java.util.Stack;
21
22 class JJTParserState {
23 private final Stack nodes;
24
25 private final Stack marks;
26
27 private int sp; // number of nodes on stack
28
29 private int mk; // current mark
30
31 private boolean node_created;
32
33 JJTParserState() {
34 nodes = new Stack();
35 marks = new Stack();
36 sp = 0;
37 mk = 0;
38 }
39
40 /*
41 * Determines whether the current node was actually closed and pushed. This
42 * should only be called in the final user action of a node scope.
43 */
44 boolean nodeCreated() {
45 return node_created;
46 }
47
48 /*
49 * Call this to reinitialize the node stack. It is called automatically by
50 * the parser's ReInit() method.
51 */
52 void reset() {
53 nodes.removeAllElements();
54 marks.removeAllElements();
55 sp = 0;
56 mk = 0;
57 }
58
59 /*
60 * Returns the root node of the AST. It only makes sense to call this after
61 * a successful parse.
62 */
63 Node rootNode() {
64 return (Node) nodes.elementAt(0);
65 }
66
67 /* Pushes a node on to the stack. */
68 void pushNode(Node n) {
69 nodes.push(n);
70 ++sp;
71 }
72
73 /*
74 * Returns the node on the top of the stack, and remove it from the stack.
75 */
76 Node popNode() {
77 if (--sp < mk) {
78 mk = ((Integer) marks.pop()).intValue();
79 }
80 return (Node) nodes.pop();
81 }
82
83 /* Returns the node currently on the top of the stack. */
84 Node peekNode() {
85 return (Node) nodes.peek();
86 }
87
88 /*
89 * Returns the number of children on the stack in the current node scope.
90 */
91 int nodeArity() {
92 return sp - mk;
93 }
94
95 void clearNodeScope(Node n) {
96 while (sp > mk) {
97 popNode();
98 }
99 mk = ((Integer) marks.pop()).intValue();
100 }
101
102 void openNodeScope(Node n) {
103 marks.push(new Integer(mk));
104 mk = sp;
105 n.jjtOpen();
106 }
107
108 /*
109 * A definite node is constructed from a specified number of children. That
110 * number of nodes are popped from the stack and made the children of the
111 * definite node. Then the definite node is pushed on to the stack.
112 */
113 void closeNodeScope(Node n, int num) {
114 mk = ((Integer) marks.pop()).intValue();
115 while (num-- > 0) {
116 Node c = popNode();
117 c.jjtSetParent(n);
118 n.jjtAddChild(c, num);
119 }
120 n.jjtClose();
121 pushNode(n);
122 node_created = true;
123 }
124
125 /*
126 * A conditional node is constructed if its condition is true. All the nodes
127 * that have been pushed since the node was opened are made children of the
128 * the conditional node, which is then pushed on to the stack. If the
129 * condition is false the node is not constructed and they are left on the
130 * stack.
131 */
132 void closeNodeScope(Node n, boolean condition) {
133 if (condition) {
134 int a = nodeArity();
135 mk = ((Integer) marks.pop()).intValue();
136 while (a-- > 0) {
137 Node c = popNode();
138 c.jjtSetParent(n);
139 n.jjtAddChild(c, a);
140 }
141 n.jjtClose();
142 pushNode(n);
143 node_created = true;
144 } else {
145 mk = ((Integer) marks.pop()).intValue();
146 node_created = false;
147 }
148 }
149 }