01: /*
02: * Copyright 1999-2004 The Apache Software Foundation
03: *
04: * Licensed under the Apache License, Version 2.0 (the "License");
05: * you may not use this file except in compliance with the License.
06: * You may obtain a copy of the License at
07: *
08: * http://www.apache.org/licenses/LICENSE-2.0
09: *
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: }
|