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 /**
21 * Extension function interface. Extension functions are grouped into {@link Functions Functions} objects, which are installed on JXPathContexts using the
22 * {@link JXPathContext#setFunctions JXPathContext.setFunctions()} call.
23 * <p>
24 * The Function interface can be implemented directly. However, most of the time JXPath's built-in implementations should suffice. See {@link ClassFunctions
25 * ClassFunctions} and {@link PackageFunctions PackageFunctions}.
26 */
27 public interface Function {
28
29 /**
30 * Computes the value of the function. Each implementation of Function is responsible for conversion of supplied parameters to the required argument types.
31 *
32 * @param context can be used to acquire the context in which the function is being evaluted.
33 * @param parameters function arguments
34 * @return Object result
35 */
36 Object invoke(ExpressionContext context, Object[] parameters);
37 }