1 /*
2 * Copyright 2007 the original author or authors.
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.springframework.xml.xpath;
18
19 import java.util.List;
20 import javax.xml.transform.Source;
21
22 import org.w3c.dom.Node;
23
24 /**
25 * Interface that specifies a basic set of XPath operations, implemented by various XPathTemplates. Contains numerous
26 * evaluation methods,
27 * <p/>
28 * The templates that implement this interface do not use precompiled XPath expressions. Consider using the {@link
29 * XPathExpressionFactory} or the {@link XPathExpressionFactoryBean} for optimal performance, but less flexibility.
30 *
31 * @author Arjen Poutsma
32 * @see Jaxp13XPathTemplate
33 * @see JaxenXPathTemplate
34 * @since 1.0.0
35 */
36 public interface XPathOperations {
37
38 /**
39 * Evaluates the given expression as a <code>boolean</code>. Returns the boolean evaluation of the expression, or
40 * <code>false</code> if it is invalid.
41 *
42 * @param expression the XPath expression
43 * @param context the context starting point
44 * @return the result of the evaluation
45 * @throws XPathException in case of XPath errors
46 * @see <a href="http://www.w3.org/TR/xpath#booleans">XPath specification</a>
47 */
48 boolean evaluateAsBoolean(String expression, Source context) throws XPathException;
49
50 /**
51 * Evaluates the given expression as a {@link Node}. Returns the evaluation of the expression, or <code>null</code>
52 * if it is invalid.
53 *
54 * @param expression the XPath expression
55 * @param context the context starting point
56 * @return the result of the evaluation
57 * @throws XPathException in case of XPath errors
58 * @see <a href="http://www.w3.org/TR/xpath#node-sets">XPath specification</a>
59 */
60 Node evaluateAsNode(String expression, Source context) throws XPathException;
61
62 /**
63 * Evaluates the given expression as a list of {@link Node} objects. Returns the evaluation of the expression, or an
64 * empty list if no results are found.
65 *
66 * @param expression the XPath expression
67 * @param context the context starting point
68 * @return the result of the evaluation
69 * @throws XPathException in case of XPath errors
70 * @see <a href="http://www.w3.org/TR/xpath#node-sets">XPath specification</a>
71 */
72 List evaluateAsNodeList(String expression, Source context) throws XPathException;
73
74 /**
75 * Evaluates the given expression as a <code>double</code>. Returns the evaluation of the expression, or {@link
76 * Double#NaN} if it is invalid.
77 *
78 * @param expression the XPath expression
79 * @param context the context starting point
80 * @return the result of the evaluation
81 * @throws XPathException in case of XPath errors
82 * @see <a href="http://www.w3.org/TR/xpath#numbers">XPath specification</a>
83 */
84 double evaluateAsDouble(String expression, Source context) throws XPathException;
85
86 /**
87 * Evaluates the given expression as a {@link String}. Returns the evaluation of the expression, or
88 * <code>null</code> if it is invalid.
89 *
90 * @param expression the XPath expression
91 * @param context the context starting point
92 * @return the result of the evaluation
93 * @throws XPathException in case of XPath errors
94 * @see <a href="http://www.w3.org/TR/xpath#strings">XPath specification</a>
95 */
96 String evaluateAsString(String expression, Source context) throws XPathException;
97
98 /**
99 * Evaluates the given expression, mapping a single {@link Node} result to a Java object via a {@link NodeMapper}.
100 *
101 * @param expression the XPath expression
102 * @param context the context starting point
103 * @param nodeMapper object that will map one object per node
104 * @return the single mapped object
105 * @throws XPathException in case of XPath errors
106 * @see <a href="http://www.w3.org/TR/xpath#node-sets">XPath specification</a>
107 */
108 Object evaluateAsObject(String expression, Source context, NodeMapper nodeMapper) throws XPathException;
109
110 /**
111 * Evaluates the given expression, mapping each result {@link Node} objects to a Java object via a {@link
112 * NodeMapper}.
113 *
114 * @param expression the XPath expression
115 * @param context the context starting point
116 * @param nodeMapper object that will map one object per node
117 * @return the result list, containing mapped objects
118 * @throws XPathException in case of XPath errors
119 * @see <a href="http://www.w3.org/TR/xpath#node-sets">XPath specification</a>
120 */
121 List evaluate(String expression, Source context, NodeMapper nodeMapper) throws XPathException;
122
123 /**
124 * Evaluates the given expression, handling the result {@link Node} objects on a per-node basis with a {@link
125 * NodeCallbackHandler}.
126 *
127 * @param expression the XPath expression
128 * @param context the context starting point
129 * @param callbackHandler object that will extract results, one row at a time
130 * @throws XPathException in case of XPath errors
131 * @see <a href="http://www.w3.org/TR/xpath#node-sets">XPath specification</a>
132 */
133 void evaluate(String expression, Source context, NodeCallbackHandler callbackHandler) throws XPathException;
134 }