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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 }