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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 }