Source code: org/apache/commons/jxpath/Function.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 * Extension function interface. Extension functions are grouped into
20 * {@link Functions Functions} objects, which are installed on
21 * JXPathContexts using the
22 * {@link JXPathContext#setFunctions JXPathContext.setFunctions()}
23 * call.
24 * <p>
25 * The Function interface can be implemented directly. However,
26 * most of the time JXPath's built-in implementations should suffice.
27 * See {@link ClassFunctions ClassFunctions} and
28 * {@link PackageFunctions PackageFunctions}.
29 *
30 * @author Dmitri Plotnikov
31 * @version $Revision: 1.7 $ $Date: 2004/02/29 14:17:42 $
32 */
33 public interface Function {
34
35 /**
36 * Computes the value of the function. Each implementation of Function
37 * is responsible for conversion of supplied parameters to the required
38 * argument types.
39 *
40 * @param context can be used to acquire the context in which the
41 * function is being evaluted.
42 */
43 Object invoke(ExpressionContext context, Object[] parameters);
44 }