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 * Variables provide access to a global set of values accessible via XPath. XPath can reference variables using the {@code "$varname"} syntax. To use a custom
24 * implementation of this interface, pass it to {@link JXPathContext#setVariables JXPathContext.setVariables()}
25 */
26 public interface Variables extends Serializable {
27
28 /**
29 * Defines a new variable with the specified value or modifies the value of an existing variable. May throw UnsupportedOperationException.
30 *
31 * @param name variable name
32 * @param value to declare
33 */
34 void declareVariable(String name, Object value);
35
36 /**
37 * Returns the value of the specified variable.
38 *
39 * @param name variable name
40 * @return Object value
41 * @throws IllegalArgumentException if there is no such variable.
42 */
43 Object getVariable(String name);
44
45 /**
46 * Returns true if the specified variable is declared.
47 *
48 * @param name variable name
49 * @return boolean
50 */
51 boolean isDeclaredVariable(String name);
52
53 /**
54 * Removes an existing variable. May throw UnsupportedOperationException.
55 *
56 * @param name is a variable name without the "$" sign
57 */
58 void undeclareVariable(String name);
59 }