1/*
2 * Copyright (C) 2017 The Android Open Source Project
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
18package android.provider;
19
20/**
21 * A builder that facilitates prohibiting its use after an instance was created with it.
22 *
23 * Suggested usage:
24 * call {@link #checkNotUsed} in each setter, and {@link #markUsed} in {@link #build}
25 *
26 * @param <T> Type of object being built
27 * @hide
28 */
29public abstract class OneTimeUseBuilder<T> {
30    private boolean used = false;
31
32    protected void markUsed() {
33        checkNotUsed();
34        used = true;
35    }
36
37    protected void checkNotUsed() {
38        if (used) {
39            throw new IllegalStateException(
40                    "This Builder should not be reused. Use a new Builder instance instead");
41        }
42    }
43
44    /**
45     * Builds the instance
46     *
47     * Once this method is called, this builder should no longer be used. Any subsequent calls to a
48     * setter or {@code build()} will throw an exception
49     */
50    public abstract T build();
51}
52