Madan Jampani | bff6d8f | 2015-03-31 16:53:47 -0700 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2015 Open Networking Laboratory |
| 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 | package org.onosproject.store.consistent.impl; |
| 17 | |
| 18 | /** |
| 19 | * Result of a database update operation. |
| 20 | * |
| 21 | * @param <V> return value type |
| 22 | */ |
| 23 | public final class Result<V> { |
| 24 | |
| 25 | public enum Status { |
| 26 | /** |
| 27 | * Indicates a successful update. |
| 28 | */ |
| 29 | OK, |
| 30 | |
| 31 | /** |
| 32 | * Indicates a failure due to underlying state being locked by another transaction. |
| 33 | */ |
| 34 | LOCKED |
| 35 | } |
| 36 | |
| 37 | private final Status status; |
| 38 | private final V value; |
| 39 | |
| 40 | /** |
| 41 | * Creates a new Result instance with the specified value with status set to Status.OK. |
| 42 | * |
| 43 | * @param <V> result value type |
| 44 | * @param value result value |
| 45 | * @return Result instance |
| 46 | */ |
| 47 | public static <V> Result<V> ok(V value) { |
| 48 | return new Result<>(value, Status.OK); |
| 49 | } |
| 50 | |
| 51 | /** |
| 52 | * Creates a new Result instance with status set to Status.LOCKED. |
| 53 | * |
| 54 | * @param <V> result value type |
| 55 | * @return Result instance |
| 56 | */ |
| 57 | public static <V> Result<V> locked() { |
| 58 | return new Result<>(null, Status.LOCKED); |
| 59 | } |
| 60 | |
| 61 | private Result(V value, Status status) { |
| 62 | this.value = value; |
| 63 | this.status = status; |
| 64 | } |
| 65 | |
| 66 | /** |
| 67 | * Returns true if this result indicates a successful execution i.e status is Status.OK. |
| 68 | * |
| 69 | * @return true if successful, false otherwise |
| 70 | */ |
| 71 | public boolean success() { |
| 72 | return status == Status.OK; |
| 73 | } |
| 74 | |
| 75 | /** |
| 76 | * Returns the status of database update operation. |
| 77 | * @return database update status |
| 78 | */ |
| 79 | public Status status() { |
| 80 | return status; |
| 81 | } |
| 82 | |
| 83 | /** |
| 84 | * Returns the return value for the update. |
| 85 | * @return value returned by database update. If the status is another |
| 86 | * other than Status.OK, this returns a null |
| 87 | */ |
| 88 | public V value() { |
| 89 | return value; |
| 90 | } |
| 91 | } |