1 /*
2 * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package com.sun.org.apache.xpath.internal.jaxp;
27
28 import com.sun.org.apache.xalan.internal.res.XSLMessages;
29 import com.sun.org.apache.xalan.internal.utils.FactoryImpl;
30 import com.sun.org.apache.xalan.internal.utils.FeatureManager;
31 import com.sun.org.apache.xml.internal.dtm.DTM;
32 import com.sun.org.apache.xpath.internal.objects.XObject;
33 import com.sun.org.apache.xpath.internal.res.XPATHErrorResources;
34 import java.io.IOException;
35 import javax.xml.namespace.QName;
36 import javax.xml.parsers.DocumentBuilderFactory;
37 import javax.xml.parsers.ParserConfigurationException;
38 import javax.xml.transform.TransformerException;
39 import javax.xml.xpath.XPathConstants;
40 import javax.xml.xpath.XPathEvaluationResult;
41 import javax.xml.xpath.XPathExpressionException;
42 import javax.xml.xpath.XPathFunctionResolver;
43 import javax.xml.xpath.XPathNodes;
44 import javax.xml.xpath.XPathVariableResolver;
45 import org.w3c.dom.Document;
46 import org.w3c.dom.Node;
47 import org.w3c.dom.traversal.NodeIterator;
48 import org.xml.sax.InputSource;
49 import org.xml.sax.SAXException;
50
51 /**
52 * This class contains several utility methods used by XPathImpl and
53 * XPathExpressionImpl
54 */
55 class XPathImplUtil {
56 XPathFunctionResolver functionResolver;
57 XPathVariableResolver variableResolver;
58 JAXPPrefixResolver prefixResolver;
59 boolean useServiceMechanism = true;
60 // By default Extension Functions are allowed in XPath Expressions. If
61 // Secure Processing Feature is set on XPathFactory then the invocation of
62 // extensions function need to throw XPathFunctionException
63 boolean featureSecureProcessing = false;
64 FeatureManager featureManager;
65
66 /**
67 * Evaluate an XPath context using the internal XPath engine
68 * @param contextItem The XPath context
69 * @param xpath The internal XPath engine
70 * @return an XObject
71 * @throws javax.xml.transform.TransformerException If the expression cannot be evaluated.
72 */
73 XObject eval(Object contextItem, com.sun.org.apache.xpath.internal.XPath xpath)
74 throws javax.xml.transform.TransformerException {
75 com.sun.org.apache.xpath.internal.XPathContext xpathSupport;
76 if (functionResolver != null) {
77 JAXPExtensionsProvider jep = new JAXPExtensionsProvider(
78 functionResolver, featureSecureProcessing, featureManager);
79 xpathSupport = new com.sun.org.apache.xpath.internal.XPathContext(jep);
80 } else {
81 xpathSupport = new com.sun.org.apache.xpath.internal.XPathContext();
82 }
83
84 xpathSupport.setVarStack(new JAXPVariableStack(variableResolver));
85 XObject xobj;
86
87 Node contextNode = (Node)contextItem;
88 // We always need to have a ContextNode with Xalan XPath implementation
89 // To allow simple expression evaluation like 1+1 we are setting
90 // dummy Document as Context Node
91 if (contextNode == null) {
92 xobj = xpath.execute(xpathSupport, DTM.NULL, prefixResolver);
93 } else {
94 xobj = xpath.execute(xpathSupport, contextNode, prefixResolver);
95 }
96
97 return xobj;
98 }
99
100 /**
101 * Parse the input source and return a Document.
102 * @param source The {@code InputSource} of the document
103 * @return a DOM Document
104 * @throws XPathExpressionException if there is an error parsing the source.
105 */
106 Document getDocument(InputSource source)
107 throws XPathExpressionException {
108 requireNonNull(source, "Source");
109 try {
110 // we'd really like to cache those DocumentBuilders, but we can't because:
111 // 1. thread safety. parsers are not thread-safe, so at least
112 // we need one instance per a thread.
113 // 2. parsers are non-reentrant, so now we are looking at having a
114 // pool of parsers.
115 // 3. then the class loading issue. The look-up procedure of
116 // DocumentBuilderFactory.newInstance() depends on context class loader
117 // and system properties, which may change during the execution of JVM.
118 //
119 // so we really have to create a fresh DocumentBuilder every time we need one
120 // - KK
121 DocumentBuilderFactory dbf = FactoryImpl.getDOMFactory(useServiceMechanism);
122 dbf.setNamespaceAware(true);
123 dbf.setValidating(false);
124 return dbf.newDocumentBuilder().parse(source);
125 } catch (ParserConfigurationException | SAXException | IOException e) {
126 throw new XPathExpressionException (e);
127 }
128 }
129
130 /**
131 * Get result depending on the QName type defined in XPathConstants
132 * @param resultObject the result of an evaluation
133 * @param returnType the return type
134 * @return result per the return type
135 * @throws TransformerException if the result can not be converted to
136 * the specified return type.
137 */
138 Object getResultAsType(XObject resultObject, QName returnType)
139 throws TransformerException {
140 // XPathConstants.STRING
141 if (returnType.equals(XPathConstants.STRING)) {
142 return resultObject.str();
143 }
144 // XPathConstants.NUMBER
145 if (returnType.equals(XPathConstants.NUMBER)) {
146 return resultObject.num();
147 }
148 // XPathConstants.BOOLEAN
149 if (returnType.equals(XPathConstants.BOOLEAN)) {
150 return resultObject.bool();
151 }
152 // XPathConstants.NODESET ---ORdered, UNOrdered???
153 if (returnType.equals(XPathConstants.NODESET)) {
154 return resultObject.nodelist();
155 }
156 // XPathConstants.NODE
157 if (returnType.equals(XPathConstants.NODE)) {
158 NodeIterator ni = resultObject.nodeset();
159 //Return the first node, or null
160 return ni.nextNode();
161 }
162 // If isSupported check is already done then the execution path
163 // shouldn't come here. Being defensive
164 String fmsg = XSLMessages.createXPATHMessage(
165 XPATHErrorResources.ER_UNSUPPORTED_RETURN_TYPE,
166 new Object[] { returnType.toString()});
167 throw new IllegalArgumentException (fmsg);
168 }
169
170 /**
171 * Get result depending on the class type defined in XPathExpressionResult
172 * @param resultObject the result of an evaluation
173 * @return XPathExpressionResult
174 * @throws TransformerException if there is an error converting the result
175 * to the specified type. It's unlikely to happen. This is mostly needed
176 * by the internal XPath engine.
177 */
178 XPathEvaluationResult<?> getXPathResult(XObject resultObject)
179 throws TransformerException {
180 int resultType = resultObject.getType();
181
182 switch (resultType) {
183 case XObject.CLASS_BOOLEAN :
184 return new XPathResultImpl<>(resultObject, Boolean.class);
185 case XObject.CLASS_NUMBER :
186 return new XPathResultImpl<>(resultObject, Double.class);
187 case XObject.CLASS_STRING :
188 return new XPathResultImpl<>(resultObject, String.class);
189 case XObject.CLASS_NODESET :
190 return new XPathResultImpl<>(resultObject, XPathNodes.class);
191 case XObject.CLASS_RTREEFRAG : //NODE
192 return new XPathResultImpl<>(resultObject, Node.class);
193 }
194
195 return null;
196 }
197
198 /**
199 * Check whether or not the specified type is supported
200 * @param <T> The class type
201 * @param type The type to be checked
202 * @throws IllegalArgumentException if the type is not supported
203 */
204 <T> void isSupportedClassType(Class<T> type) {
205 requireNonNull(type, "The class type");
206 if (type.isAssignableFrom(Boolean.class) ||
207 Number.class.isAssignableFrom(type) ||
208 type.isAssignableFrom(String.class) ||
209 type.isAssignableFrom(XPathNodes.class) ||
210 type.isAssignableFrom(Node.class) ||
211 type.isAssignableFrom(XPathEvaluationResult.class)) {
212 return;
213 }
214 String fmsg = XSLMessages.createXPATHMessage(
215 XPATHErrorResources.ER_UNSUPPORTED_RETURN_TYPE,
216 new Object[] { type.toString() });
217 throw new IllegalArgumentException (fmsg);
218 }
219
220 /**
221 * Check if the requested returnType is supported.
222 * @param returnType the return type
223 * @throws IllegalArgumentException if the return type is not supported
224 */
225 void isSupported(QName returnType) {
226 requireNonNull(returnType, "returnType");
227 if (returnType.equals(XPathConstants.STRING) ||
228 returnType.equals(XPathConstants.NUMBER) ||
229 returnType.equals(XPathConstants.BOOLEAN) ||
230 returnType.equals(XPathConstants.NODE) ||
231 returnType.equals(XPathConstants.NODESET)) {
232 return;
233 }
234 String fmsg = XSLMessages.createXPATHMessage(
235 XPATHErrorResources.ER_UNSUPPORTED_RETURN_TYPE,
236 new Object[] { returnType.toString() });
237 throw new IllegalArgumentException (fmsg);
238 }
239
240 /**
241 * Checks that the specified parameter is not {@code null}.
242 *
243 * @param <T> the type of the reference
244 * @param param the parameter to check for nullity
245 * @param paramName the parameter name
246 * @throws NullPointerException if {@code param} is {@code null}
247 */
248 <T> void requireNonNull(T param, String paramName) {
249 if (param == null) {
250 String fmsg = XSLMessages.createXPATHMessage(
251 XPATHErrorResources.ER_ARG_CANNOT_BE_NULL,
252 new Object[] {paramName});
253 throw new NullPointerException (fmsg);
254 }
255 }
256 }