AstVisitor.java

biz/hammurapi/antlr/AstVisitor.java

Violations

Inspector	Message	Severity	Location
Java Inspector 048	Copyrights information should be present in each file.	1
Java Inspector 049	Use a Collection instead of arrays Object[]	2	41:9
Java Inspector 049	Use a Collection instead of arrays Object[]	2	42:9
Java Inspector 089	Constructor is not properly documented	2	51:9
Java Inspector 089	Undocumented method	2	83:9
Java Inspector 089	Undocumented method	2	105:9
Java Inspector 051	It is good practice to call in any case super() in a constructor.	3	51:9

Source code

1/*
2  * hgcommons 9
3 * Hammurapi Group Common Library
4 * Copyright (C) 2003  Hammurapi Group
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2 of the License, or (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with this library; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
19 *
20 * URL: http://www.hammurapi.biz/hammurapi-biz/ef/xmenu/hammurapi-group/products/products/hgcommons/index.html
21 * e-Mail: support@hammurapi.biz
22 */
23package biz.hammurapi.antlr;
24
25import java.lang.reflect.InvocationTargetException;
26import java.lang.reflect.Method;
27import java.lang.reflect.Modifier;
28
29import antlr.collections.AST;
30import biz.hammurapi.util.DispatchException;
31import biz.hammurapi.util.PoliteVisitor;
32
33
34/**
35 * Visits AST and dispatches invocations by
36 * node names.
37 * @author Pavel Vlasov
38 * @version $Revision: 1.2 $
39 */
40public class AstVisitor implements PoliteVisitor {
41	private Method[] visitMethods;
42	private Method[] leaveMethods;
43	
44	/**
45	 * @param tokenTypeNames - can be obtained from Parser.
46	 * @param visitPrefix - visit method name prefix. E.g. if prefix is <code>visit_</code>
47	 * then visit of AST with type name <code>LITERAL_throws</code> will be dispatched
48	 * to method <code>visit_LITERAL_throws</code> if such method is present.
49	 * @param leavePrefix - leave method name prefix.
50	 */
51	public AstVisitor(String[] tokenTypeNames, String visitPrefix, String leavePrefix) {		
52		Class thisClass=this.getClass();
53		for (int i=0, mc=thisClass.getMethods().length; i<mc; i++) {
54			Method m=thisClass.getMethods()[i];
55			if (!m.getName().equals(visitPrefix) 
56					&& Modifier.isPublic(m.getModifiers())
57					&& m.getName().startsWith(visitPrefix) 
58					&& m.getParameterTypes().length==1 
59					&& AST.class.isAssignableFrom(m.getParameterTypes()[0])
60					&& (boolean.class.equals(m.getReturnType()) || void.class.equals(m.getReturnType()))) {
61				for (int j=0; j<tokenTypeNames.length; j++) {
62					if (m.getName().substring(visitPrefix.length()).equals(tokenTypeNames[j])) {
63						visitMethods[j]=m;
64					}
65				}
66			}
67			
68			if (!m.getName().equals(leavePrefix) 
69					&& Modifier.isPublic(m.getModifiers())
70					&& m.getName().startsWith(leavePrefix) 
71					&& m.getParameterTypes().length==1 
72					&& AST.class.isAssignableFrom(m.getParameterTypes()[0])
73					&& void.class.equals(m.getReturnType())) {
74				for (int j=0; j<tokenTypeNames.length; j++) {
75					if (m.getName().substring(leavePrefix.length()).equals(tokenTypeNames[j])) {
76						leaveMethods[j]=m;
77					}
78				}
79			}									
80		}
81	}
82	
83	public boolean visit(Object target) {
84		if (target instanceof AST) {
85			Method m=visitMethods[((AST) target).getType()];
86			if (m==null) {
87				return true;
88			}
89			
90			try {
91				Object ret = m.invoke(this, new Object[] {target});
92				return ret instanceof Boolean ? ((Boolean) ret).booleanValue() : true;
93			} catch (IllegalArgumentException e) {
94				throw new DispatchException(e);
95			} catch (IllegalAccessException e) {
96				throw new DispatchException(e);
97			} catch (InvocationTargetException e) {
98				throw new DispatchException(e);
99			}
100		}
101		
102		return false;
103	}
104
105	public void leave(Object target) {
106		if (target instanceof AST) {
107			Method m=visitMethods[((AST) target).getType()];
108			if (m!=null) {
109				try {
110					m.invoke(this, new Object[] {target});
111				} catch (IllegalArgumentException e) {
112					throw new DispatchException(e);
113				} catch (IllegalAccessException e) {
114					throw new DispatchException(e);
115				} catch (InvocationTargetException e) {
116					throw new DispatchException(e);
117				}
118			}
119		}
120	}		
121}
122