1 /*
2 Copyright (c) 2016 James Ahlborn
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
17 package com.healthmarketscience.jackcess.expr;
18
19 /**
20 * A Function provides an invokable handle to external functionality to an
21 * expression.
22 *
23 * @author James Ahlborn
24 */
25 public interface Function
26 {
27
28 /**
29 * @return the name of this function
30 */
31 public String getName();
32
33 /**
34 * Evaluates this function within the given context with the given
35 * parameters.
36 *
37 * @return the result of the function evaluation
38 */
39 public Value eval(EvalContext ctx, Value... params);
40
41 /**
42 * @return {@code true} if this function is a "pure" function, {@code false}
43 * otherwise. A pure function will always return the same result
44 * for a given set of parameters and has no side effects.
45 */
46 public boolean isPure();
47 }