1 /*
2 * Copyright 2005-2008 The Kuali Foundation
3 *
4 *
5 * Licensed under the Educational Community License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at
8 *
9 * http://www.opensource.org/licenses/ecl2.php
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.kuali.rice.kew.rule.xmlrouting;
18
19 import javax.xml.xpath.XPath;
20 import javax.xml.xpath.XPathFactory;
21 import javax.xml.xpath.XPathFunctionResolver;
22
23 import org.kuali.rice.kew.api.WorkflowRuntimeException;
24 import org.w3c.dom.Node;
25
26
27 /**
28 * Provides utilities for obtaining XPath instances which are "good-to-go" with access to the Workflow
29 * namespace and custom XPath functions.
30 *
31 * @author Kuali Rice Team (rice.collab@kuali.org)
32 */
33 public class XPathHelper {
34
35 /**
36 * Creates a new XPath instance and initializes it with the WorkflowNamespaceContext and the
37 * WorkflowFunctionResolver.
38 */
39 public static XPath newXPath() {
40 XPath xPath = XPathFactory.newInstance().newXPath();
41 xPath.setNamespaceContext(new WorkflowNamespaceContext());
42 WorkflowFunctionResolver resolver = new WorkflowFunctionResolver();
43 xPath.setXPathFunctionResolver(resolver);
44 resolver.setXpath(xPath);
45 return xPath;
46 }
47
48 /**
49 * Creates a new XPath instances and initializes it with the WorkflowNamespaceContext and the
50 * WorkflowFunctionResolver. Also sets the root node on the WorkflowFunctionResolver to
51 * the given Node. This is required for some of the functions in the function resolver
52 * to perform properly.
53 */
54 public static XPath newXPath(Node rootNode) {
55 XPath xPath = newXPath();
56 WorkflowFunctionResolver resolver = extractFunctionResolver(xPath);
57 resolver.setRootNode(rootNode);
58 return xPath;
59 }
60
61 /**
62 * A utility to extract the WorkflowFunctionResolver from the given XPath instances. If the XPath instance
63 * does not contain a WorkflowFunctionResolver, then this method will throw a WorkflowRuntimeException.
64 *
65 * @throws WorkflowRuntimeException if the given XPath instance does not contain a WorklflowFunctionResolver
66 */
67 public static WorkflowFunctionResolver extractFunctionResolver(XPath xPath) {
68 XPathFunctionResolver resolver = xPath.getXPathFunctionResolver();
69 if (!hasWorkflowFunctionResolver(xPath)) {
70 throw new WorkflowRuntimeException("The XPathFunctionResolver on the given XPath instance is not an instance of WorkflowFunctionResolver, was: " + resolver);
71 }
72 return (WorkflowFunctionResolver)resolver;
73 }
74
75 /**
76 * Returns true if the given XPath instance has a WorkflowFunctionResolver, false otherwise.
77 */
78 public static boolean hasWorkflowFunctionResolver(XPath xPath) {
79 return xPath.getXPathFunctionResolver() instanceof WorkflowFunctionResolver;
80 }
81
82 }