1 package org.apache.torque.util.functions;
2
3 /*
4 * Licensed to the Apache Software Foundation (ASF) under one
5 * or more contributor license agreements. See the NOTICE file
6 * distributed with this work for additional information
7 * regarding copyright ownership. The ASF licenses this file
8 * to you under the Apache License, Version 2.0 (the
9 * "License"); you may not use this file except in compliance
10 * with the License. You may obtain a copy of the License at
11 *
12 * http://www.apache.org/licenses/LICENSE-2.0
13 *
14 * Unless required by applicable law or agreed to in writing,
15 * software distributed under the License is distributed on an
16 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17 * KIND, either express or implied. See the License for the
18 * specific language governing permissions and limitations
19 * under the License.
20 */
21
22 import org.apache.torque.Column;
23
24 /**
25 * Define the basic methods that classes that support SQL Functions
26 * need to implement for Classes that use them. This is intended to
27 * allow code to be written before functions are fully integrated
28 * with the DBAdaptors. As well as allowing for functions to
29 * expand as needed.
30 *
31 * @author <a href="mailto:greg.monroe@dukece.com">Greg Monroe</a>
32 * @version $Id: SQLFunction.java 1388656 2012-09-21 19:59:16Z tfischer $
33 */
34 public interface SQLFunction extends Column
35 {
36 /**
37 * Returns the function parameters at index i.
38 * Should be null if parameter does not exist.
39 *
40 * @param i The 0 based parameter to get.
41 * @return The parameter. Null if one does not exist.
42 */
43 Object getArgument(int i);
44
45 /**
46 * Returns the column to which this function is applied.
47 *
48 * @return the column, not null.
49 *
50 * @throws IllegalStateException if the column cannot be determined.
51 */
52 Column getColumn();
53
54 /**
55 * Return all the parameters as an object array. This allow for
56 * processing of the parameters in their original format rather
57 * than just in String format. E.g. a parameter might be specified
58 * as a Date object, or a Column object.
59 *
60 * @return Should return a valid Object array and not null. E.g.
61 * implementors should return new Object[0] if there are no parameters.
62 */
63 Object[] getArguments();
64
65 /**
66 * Sets the function specific arguments. Note, this should generally
67 * only be called by FunctionFactory.
68 *
69 * @param args The function specific arguments.
70 */
71 void setArguments(Object[] args);
72 }