JstlSqlTLV


1   /*
2    * Copyright 1999-2004 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  
17  package org.apache.taglibs.standard.tlv;
18  
19  import java.util.Set  ;
20  import java.util.Stack  ;
21  
22  import javax.servlet.jsp.tagext.PageData  ;
23  import javax.servlet.jsp.tagext.ValidationMessage  ;
24  
25  import org.apache.taglibs.standard.resources.Resources;
26  import org.xml.sax.Attributes  ;
27  import org.xml.sax.helpers.DefaultHandler  ;
28  
29  /**
30   * <p>A SAX-based TagLibraryValidator for the JSTL SQL tag library.
31   * 
32   * @author Shawn Bayern
33   */
34  public class JstlSqlTLV extends JstlBaseTLV {
35  
36      //*********************************************************************
37      // Constants
38  
39      // tag names
40      private final String   SETDATASOURCE = "setDataSource";
41      private final String   QUERY = "query";
42      private final String   UPDATE = "update";
43      private final String   TRANSACTION = "transaction";
44      private final String   PARAM = "param";
45      private final String   DATEPARAM = "dateParam";
46  
47      private final String   JSP_TEXT = "jsp:text";
48  
49      // attribute names
50      private final String   SQL = "sql";
51      private final String   DATASOURCE = "dataSource";
52  
53  
54      //*********************************************************************
55      // set its type and delegate validation to super-class
56      public  ValidationMessage  [] validate(
57          String   prefix, String   uri, PageData   page) {
58      return super.validate( TYPE_SQL, prefix, uri, page );
59      }
60  
61  
62      //*********************************************************************
63      // Contract fulfillment
64  
65      protected DefaultHandler   getHandler() {
66      return new Handler  ();
67      }
68  
69  
70      //*********************************************************************
71      // SAX event handler
72  
73      /** The handler that provides the base of our implementation. */
74      private class Handler extends DefaultHandler   {
75  
76      // parser state
77      private int depth = 0;
78          private Stack   queryDepths = new Stack  ();
79          private Stack   updateDepths = new Stack  ();
80          private Stack   transactionDepths = new Stack  ();
81      private String   lastElementName = null;
82      private boolean bodyNecessary = false;
83      private boolean bodyIllegal = false;
84  
85      // process under the existing context (state), then modify it
86      public void startElement(
87              String   ns, String   ln, String   qn, Attributes   a) {
88  
89          // substitute our own parsed 'ln' if it's not provided
90          if (ln == null)
91          ln = getLocalPart(qn);
92  
93          // for simplicity, we can ignore <jsp:text> for our purposes
94          // (don't bother distinguishing between it and its characters)
95          if (qn.equals(JSP_TEXT))
96          return;
97  
98          // check body-related constraint
99          if (bodyIllegal)
100         fail(Resources.getMessage("TLV_ILLEGAL_BODY", lastElementName));
101 
102         // validate expression syntax if we need to
103         Set   expAtts;
104         if (qn.startsWith(prefix + ":")
105             && (expAtts = (Set  ) config.get(ln)) != null) {
106         for (int i = 0; i < a.getLength(); i++) {
107             String   attName = a.getLocalName(i);
108             if (expAtts.contains(attName)) {
109             String   vMsg =
110                 validateExpression(
111                 ln,
112                 attName,
113                 a.getValue(i));
114             if (vMsg != null)
115                 fail(vMsg);
116             }
117         }
118         }
119 
120             // validate attributes
121             if (qn.startsWith(prefix + ":") && !hasNoInvalidScope(a))
122                 fail(Resources.getMessage("TLV_INVALID_ATTRIBUTE",
123                     SCOPE, qn, a.getValue(SCOPE))); 
124         if (qn.startsWith(prefix + ":") && hasEmptyVar(a))
125         fail(Resources.getMessage("TLV_EMPTY_VAR", qn));
126         if (qn.startsWith(prefix + ":") && hasDanglingScope(a) &&
127                 !qn.startsWith(prefix + ":" + SETDATASOURCE))
128         fail(Resources.getMessage("TLV_DANGLING_SCOPE", qn));
129 
130         // now, modify state
131 
132             /*
133              * Make sure <sql:param> is nested inside <sql:query> or
134              * <sql:update>. Note that <sql:param> does not need to
135              * be a direct child of <sql:query> or <sql:update>.
136              * Otherwise, the following would not work:
137              *
138              *  <sql:query sql="..." var="...">
139              *   <c:forEach var="arg" items="...">
140              *    <sql:param value="${arg}"/>
141              *   </c:forEach>
142              *  </sql:query>
143              */
144             if ( (isSqlTag(ns, ln, PARAM) || isSqlTag(ns, ln, DATEPARAM)) 
145                 && (queryDepths.empty() && updateDepths.empty()) ) {
146                 fail(Resources.getMessage("SQL_PARAM_OUTSIDE_PARENT"));
147             }
148 
149             // If we're in a <query>, record relevant state
150             if (isSqlTag(ns, ln, QUERY)) {
151                 queryDepths.push(new Integer  (depth));
152             }
153             // If we're in a <update>, record relevant state
154             if (isSqlTag(ns, ln, UPDATE)) {
155                 updateDepths.push(new Integer  (depth));
156             }
157             // If we're in a <transaction>, record relevant state
158             if (isSqlTag(ns, ln, TRANSACTION)) {
159                 transactionDepths.push(new Integer  (depth));
160             }
161 
162         // set up a check against illegal attribute/body combinations
163         bodyIllegal = false;
164         bodyNecessary = false;
165 
166             if (isSqlTag(ns, ln, QUERY) || isSqlTag(ns, ln, UPDATE)) {
167                 if (!hasAttribute(a, SQL)) {
168                     bodyNecessary = true;
169                 }
170                 if (hasAttribute(a, DATASOURCE) && !transactionDepths.empty()) {
171                     fail(Resources.getMessage("ERROR_NESTED_DATASOURCE"));
172                 }
173             }
174 
175             if (isSqlTag(ns, ln, DATEPARAM)) {
176                 bodyIllegal = true;
177             }
178 
179         // record the most recent tag (for error reporting)
180         lastElementName = qn;
181         lastElementId = a.getValue("http://java.sun.com/JSP/Page", "id");
182 
183         // we're a new element, so increase depth
184         depth++;
185     }
186 
187     public void characters(char[] ch, int start, int length) {
188 
189         bodyNecessary = false;      // body is no longer necessary!
190 
191         // ignore strings that are just whitespace
192         String   s = new String  (ch, start, length).trim();
193         if (s.equals(""))
194         return;
195 
196         // check and update body-related constraints
197         if (bodyIllegal)
198         fail(Resources.getMessage("TLV_ILLEGAL_BODY", lastElementName));
199     }
200 
201     public void endElement(String   ns, String   ln, String   qn) {
202 
203         // consistently, we ignore JSP_TEXT
204         if (qn.equals(JSP_TEXT))
205         return;
206 
207         // handle body-related invariant
208         if (bodyNecessary)
209         fail(Resources.getMessage("TLV_MISSING_BODY",
210             lastElementName));
211         bodyIllegal = false;    // reset: we've left the tag
212 
213             // update <query>-related state
214             if (isSqlTag(ns, ln, QUERY)) {
215                 queryDepths.pop();
216             }
217             // update <update>-related state
218             if (isSqlTag(ns, ln, UPDATE)) {
219                 updateDepths.pop();
220             }
221             // update <update>-related state
222             if (isSqlTag(ns, ln, TRANSACTION)) {
223                 transactionDepths.pop();
224             }
225 
226         // update our depth
227         depth--;
228     }
229     }
230 }
231
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