org.apache.commons.jexl.parser.JJTParserState Maven / Gradle / Ivy
/*
* 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.
*/
/* Generated By:JJTree: Do not edit this line. JJTParserState.java */
package org.apache.commons.jexl.parser;
import java.util.Stack;
class JJTParserState {
private final Stack nodes;
private final Stack marks;
private int sp; // number of nodes on stack
private int mk; // current mark
private boolean node_created;
JJTParserState() {
nodes = new Stack();
marks = new Stack();
sp = 0;
mk = 0;
}
/*
* Determines whether the current node was actually closed and pushed. This
* should only be called in the final user action of a node scope.
*/
boolean nodeCreated() {
return node_created;
}
/*
* Call this to reinitialize the node stack. It is called automatically by
* the parser's ReInit() method.
*/
void reset() {
nodes.removeAllElements();
marks.removeAllElements();
sp = 0;
mk = 0;
}
/*
* Returns the root node of the AST. It only makes sense to call this after
* a successful parse.
*/
Node rootNode() {
return (Node) nodes.elementAt(0);
}
/* Pushes a node on to the stack. */
void pushNode(Node n) {
nodes.push(n);
++sp;
}
/*
* Returns the node on the top of the stack, and remove it from the stack.
*/
Node popNode() {
if (--sp < mk) {
mk = ((Integer) marks.pop()).intValue();
}
return (Node) nodes.pop();
}
/* Returns the node currently on the top of the stack. */
Node peekNode() {
return (Node) nodes.peek();
}
/*
* Returns the number of children on the stack in the current node scope.
*/
int nodeArity() {
return sp - mk;
}
void clearNodeScope(Node n) {
while (sp > mk) {
popNode();
}
mk = ((Integer) marks.pop()).intValue();
}
void openNodeScope(Node n) {
marks.push(new Integer(mk));
mk = sp;
n.jjtOpen();
}
/*
* A definite node is constructed from a specified number of children. That
* number of nodes are popped from the stack and made the children of the
* definite node. Then the definite node is pushed on to the stack.
*/
void closeNodeScope(Node n, int num) {
mk = ((Integer) marks.pop()).intValue();
while (num-- > 0) {
Node c = popNode();
c.jjtSetParent(n);
n.jjtAddChild(c, num);
}
n.jjtClose();
pushNode(n);
node_created = true;
}
/*
* A conditional node is constructed if its condition is true. All the nodes
* that have been pushed since the node was opened are made children of the
* the conditional node, which is then pushed on to the stack. If the
* condition is false the node is not constructed and they are left on the
* stack.
*/
void closeNodeScope(Node n, boolean condition) {
if (condition) {
int a = nodeArity();
mk = ((Integer) marks.pop()).intValue();
while (a-- > 0) {
Node c = popNode();
c.jjtSetParent(n);
n.jjtAddChild(c, a);
}
n.jjtClose();
pushNode(n);
node_created = true;
} else {
mk = ((Integer) marks.pop()).intValue();
node_created = false;
}
}
}