1 /*--------------------------------------------------------------------------
2 * Copyright 2009 utgenome.org
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 // utgb-core Project
18 //
19 // Optional.java
20 // Since: May 27, 2010
21 //
22 // $URL$
23 // $Author$
24 //--------------------------------------
25 package org.utgenome.gwt.utgb.client.util;
26
27 /**
28 * variable holder that can distinguish defined/undefined states.
29 *
30 * @author leo
31 *
32 */
33 public class Optional<T> {
34
35 private boolean isDefined = false;
36 private T holder;
37
38 public Optional() {
39 }
40
41 public boolean isDefined() {
42 return isDefined;
43 }
44
45 public boolean isUndefined() {
46 return !isDefined;
47 }
48
49 public T get() {
50 return holder;
51 }
52
53 public void set(T value) {
54 this.holder = value;
55 this.isDefined = true;
56 }
57
58 public void reset() {
59 this.holder = null;
60 this.isDefined = false;
61 }
62
63 }