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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  
18  package org.apache.commons.jxpath;
19  
20  import java.io.Serializable;
21  
22  /**
23   * Pointers represent locations of objects and their properties in Java object graphs. JXPathContext has methods
24   * ({@link JXPathContext#getPointer(java.lang.String) getPointer()} and ({@link JXPathContext#iteratePointers(java.lang.String) iteratePointers()}, which, given
25   * an XPath, produce Pointers for the objects or properties described the path. For example, {@code ctx.getPointer
26   * ("foo/bar")} will produce a Pointer that can get and set the property "bar" of the object which is the value of the property "foo" of the root object. The
27   * value of {@code ctx.getPointer("aMap/aKey[3]")} will be a pointer to the 3'rd element of the array, which is the value for the key "aKey" of the map, which
28   * is the value of the property "aMap" of the root object.
29   */
30  public interface Pointer extends Cloneable, Comparable, Serializable {
31  
32      /**
33       * Returns a string that is a proper "canonical" XPath that corresponds to this pointer. Consider this example:
34       * <p>
35       * {@code Pointer  ptr = ctx.getPointer("//employees[firstName = 'John']")
36       * }
37       * </p>
38       * <p>
39       * The value of {@code ptr.asPath()} will look something like {@code "/departments[2]/employees[3]"}, so, basically, it represents the concrete location(s)
40       * of the result of a search performed by JXPath. If an object in the pointer's path is a Dynamic Property object (like a Map), the asPath method generates
41       * an XPath that looks like this: {@code "
42       * /departments[@name = 'HR']/employees[3]"}.
43       *
44       * @return String path
45       */
46      String asPath();
47  
48      /**
49       * Pointers are cloneable.
50       *
51       * @return cloned Object
52       */
53      Object clone();
54  
55      /**
56       * Returns the raw value of the object, property or collection element this pointer represents. Never converts the object to a canonical type: returns it as
57       * is.
58       * <p>
59       * For example, for an XML element, getNode() will return the element itself rather than the text it contains.
60       * </p>
61       *
62       * @return Object node
63       */
64      Object getNode();
65  
66      /**
67       * Returns the node this pointer is based on.
68       *
69       * @return Object
70       */
71      Object getRootNode();
72  
73      /**
74       * Returns the value of the object, property or collection element this pointer represents. May convert the value to one of the canonical InfoSet types:
75       * String, Number, Boolean, Set.
76       * <p>
77       * For example, in the case of an XML element, getValue() will return the text contained by the element rather than the element itself.
78       * </p>
79       *
80       * @return Object value
81       */
82      Object getValue();
83  
84      /**
85       * Modifies the value of the object, property or collection element this pointer represents.
86       *
87       * @param value value to set
88       */
89      void setValue(Object value);
90  }