Source code: org/apache/commons/jxpath/Variables.java
1 /*
2 * Copyright 1999-2004 The Apache Software Foundation
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 package org.apache.commons.jxpath;
17
18 /**
19 * Variables provide access to a global set of values accessible via XPath.
20 * XPath can reference variables using the <code>"$varname"</code> syntax.
21 * To use a custom implementation of this interface, pass it to
22 * {@link JXPathContext#setVariables JXPathContext.setVariables()}
23 *
24 * @author Dmitri Plotnikov
25 * @version $Revision: 1.6 $ $Date: 2004/02/29 14:17:42 $
26 */
27 public interface Variables {
28
29 /**
30 * Returns true if the specified variable is declared.
31 */
32 boolean isDeclaredVariable(String varName);
33
34 /**
35 * Returns the value of the specified variable.
36 * Throws IllegalArgumentException if there is no such variable.
37 */
38 Object getVariable(String varName);
39
40 /**
41 * Defines a new variable with the specified value or modifies
42 * the value of an existing variable.
43 * May throw UnsupportedOperationException.
44 */
45 void declareVariable(String varName, Object value);
46
47 /**
48 * Removes an existing variable. May throw UnsupportedOperationException.
49 *
50 * @param varName is a variable name without the "$" sign
51 */
52 void undeclareVariable(String varName);
53 }