001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017 package org.apache.commons.jexl2.parser;
018
019 import org.apache.commons.jexl2.DebugInfo;
020 import org.apache.commons.jexl2.JexlEngine;
021 import org.apache.commons.jexl2.JexlException;
022
023 /**
024 * The base class for parsing, manages the parameter/local variable frame.
025 * @author henri
026 */
027 public class JexlParser extends StringParser {
028 /**
029 * The map of named registers aka script parameters.
030 * Each parameter is associated to a register and is materialized as an offset in the registers array used
031 * during evaluation.
032 */
033 protected JexlEngine.Scope frame;
034
035 /**
036 * Sets the frame to use bythis parser.
037 * <p>
038 * This is used to allow parameters to be declared before parsing.
039 * </p>
040 * @param theFrame the register map
041 */
042 public void setFrame(JexlEngine.Scope theFrame) {
043 frame = theFrame;
044 }
045
046 /**
047 * Gets the frame used by this parser.
048 * <p>
049 * Since local variables create new named registers, it is important to regain access after
050 * parsing to known which / how-many registers are needed.
051 * </p>
052 * @return the named register map
053 */
054 public JexlEngine.Scope getFrame() {
055 return frame;
056 }
057
058
059 /**
060 * Checks whether an identifier is a local variable or argument, ie stored in a register.
061 * @param identifier the identifier
062 * @param image the identifier image
063 * @return the image
064 */
065 public String checkVariable(ASTIdentifier identifier, String image) {
066 if (frame != null) {
067 Integer register = frame.getRegister(image);
068 if (register != null) {
069 identifier.setRegister(register.intValue());
070 }
071 }
072 return image;
073 }
074
075 /**
076 * Declares a local variable.
077 * <p>
078 * This method creates an new entry in the named register map.
079 * </p>
080 * @param identifier the identifier used to declare
081 * @param image the variable name
082 */
083 public void declareVariable(ASTVar identifier, String image) {
084 if (frame == null) {
085 frame = new JexlEngine.Scope((String[])null);
086 }
087 Integer register = frame.declareVariable(image);
088 identifier.setRegister(register.intValue());
089 identifier.image = image;
090 }
091
092 /**
093 * Default implementation does nothing but is overriden by generated code.
094 * @param top whether the identifier is beginning an l/r value
095 * @throws ParseException subclasses may throw this
096 */
097 public void Identifier(boolean top) throws ParseException {
098 // Overriden by generated code
099 }
100
101 final public void Identifier() throws ParseException {
102 Identifier(false);
103 }
104
105 public Token getToken(int index) {
106 return null;
107 }
108
109 void jjtreeOpenNodeScope(JexlNode n) {
110 }
111
112 /**
113 * Ambiguous statement detector.
114 * @param n the node
115 * @throws ParseException
116 */
117 void jjtreeCloseNodeScope(JexlNode n) throws ParseException {
118 if (n instanceof ASTAmbiguous && n.jjtGetNumChildren() > 0) {
119 DebugInfo dbgInfo = null;
120 Token tok = this.getToken(0);
121 if (tok != null) {
122 dbgInfo = new DebugInfo(tok.image, tok.beginLine, tok.beginColumn);
123 } else {
124 dbgInfo = n.debugInfo();
125 }
126 throw new JexlException.Parsing(dbgInfo, "Ambiguous statement, missing ';' between expressions", null);
127 }
128 }
129 }