1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
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.apache.commons.jxpath;
18
19 import java.io.Serializable;
20
21 /**
22 * Pointers represent locations of objects and their properties
23 * in Java object graphs. JXPathContext has methods
24 * ({@link JXPathContext#getPointer(java.lang.String) getPointer()}
25 * and ({@link JXPathContext#iteratePointers(java.lang.String)
26 * iteratePointers()}, which, given an XPath, produce Pointers for the objects
27 * or properties described the the path. For example, <code>ctx.getPointer
28 * ("foo/bar")</code> will produce a Pointer that can get and set the property
29 * "bar" of the object which is the value of the property "foo" of the root
30 * object. The value of <code>ctx.getPointer("aMap/aKey[3]")</code> will be a
31 * pointer to the 3'rd element of the array, which is the value for the key
32 * "aKey" of the map, which is the value of the property "aMap" of the root
33 * object.
34 *
35 * @author Dmitri Plotnikov
36 * @version $Revision: 652845 $ $Date: 2008-05-02 19:46:46 +0200 (Fr, 02 Mai 2008) $
37 */
38 public interface Pointer extends Cloneable, Comparable, Serializable {
39
40 /**
41 * Returns the value of the object, property or collection element
42 * this pointer represents. May convert the value to one of the
43 * canonical InfoSet types: String, Number, Boolean, Set.
44 *
45 * For example, in the case of an XML element, getValue() will
46 * return the text contained by the element rather than
47 * the element itself.
48 * @return Object value
49 */
50 Object getValue();
51
52 /**
53 * Returns the raw value of the object, property or collection element
54 * this pointer represents. Never converts the object to a
55 * canonical type: returns it as is.
56 *
57 * For example, for an XML element, getNode() will
58 * return the element itself rather than the text it contains.
59 * @return Object node
60 */
61 Object getNode();
62
63 /**
64 * Modifies the value of the object, property or collection element
65 * this pointer represents.
66 * @param value value to set
67 */
68 void setValue(Object value);
69
70 /**
71 * Returns the node this pointer is based on.
72 * @return Object
73 */
74 Object getRootNode();
75
76 /**
77 * Returns a string that is a proper "canonical" XPath that corresponds to
78 * this pointer. Consider this example:
79 * <p><code>Pointer ptr = ctx.getPointer("//employees[firstName = 'John']")
80 * </code>
81 * <p>The value of <code>ptr.asPath()</code> will look something like
82 * <code>"/departments[2]/employees[3]"</code>, so, basically, it represents
83 * the concrete location(s) of the result of a search performed by JXPath.
84 * If an object in the pointer's path is a Dynamic Property object (like a
85 * Map), the asPath method generates an XPath that looks like this: <code>"
86 * /departments[@name = 'HR']/employees[3]"</code>.
87 * @return String path
88 */
89 String asPath();
90
91 /**
92 * Pointers are cloneable.
93 * @return cloned Object
94 */
95 Object clone();
96 }