| 1 | /* |
| 2 | * Copyright 2006-2013 the original author or authors. |
| 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 org.springframework.batch.core; |
| 18 | |
| 19 | import java.io.Serializable; |
| 20 | |
| 21 | import org.springframework.util.ClassUtils; |
| 22 | |
| 23 | /** |
| 24 | * Batch Domain Entity class. Any class that should be uniquely identifiable |
| 25 | * from another should subclass from Entity. More information on this pattern |
| 26 | * and the difference between Entities and Value Objects can be found in Domain |
| 27 | * Driven Design by Eric Evans. |
| 28 | * |
| 29 | * @author Lucas Ward |
| 30 | * @author Dave Syer |
| 31 | * |
| 32 | */ |
| 33 | @SuppressWarnings("serial") |
| 34 | public class Entity implements Serializable { |
| 35 | |
| 36 | private Long id; |
| 37 | |
| 38 | private volatile Integer version; |
| 39 | |
| 40 | public Entity() { |
| 41 | super(); |
| 42 | } |
| 43 | |
| 44 | public Entity(Long id) { |
| 45 | super(); |
| 46 | |
| 47 | //Commented out because StepExecutions are still created in a disconnected |
| 48 | //manner. The Repository should create them, then this can be uncommented. |
| 49 | //Assert.notNull(id, "Entity id must not be null."); |
| 50 | this.id = id; |
| 51 | } |
| 52 | |
| 53 | public Long getId() { |
| 54 | return id; |
| 55 | } |
| 56 | |
| 57 | public void setId(Long id) { |
| 58 | this.id = id; |
| 59 | } |
| 60 | |
| 61 | /** |
| 62 | * @return the version |
| 63 | */ |
| 64 | public Integer getVersion() { |
| 65 | return version; |
| 66 | } |
| 67 | |
| 68 | /** |
| 69 | * Public setter for the version needed only by repository methods. |
| 70 | * @param version the version to set |
| 71 | */ |
| 72 | public void setVersion(Integer version) { |
| 73 | this.version = version; |
| 74 | } |
| 75 | |
| 76 | /** |
| 77 | * Increment the version number |
| 78 | */ |
| 79 | public void incrementVersion() { |
| 80 | if (version == null) { |
| 81 | version = 0; |
| 82 | } else { |
| 83 | version = version + 1; |
| 84 | } |
| 85 | } |
| 86 | |
| 87 | @Override |
| 88 | public String toString() { |
| 89 | return String.format("%s: id=%d, version=%d", ClassUtils.getShortName(getClass()), id, version); |
| 90 | } |
| 91 | |
| 92 | /** |
| 93 | * Attempt to establish identity based on id if both exist. If either id |
| 94 | * does not exist use Object.equals(). |
| 95 | * |
| 96 | * @see java.lang.Object#equals(java.lang.Object) |
| 97 | */ |
| 98 | @Override |
| 99 | public boolean equals(Object other) { |
| 100 | if (other == this) { |
| 101 | return true; |
| 102 | } |
| 103 | if (other == null) { |
| 104 | return false; |
| 105 | } |
| 106 | if (!(other instanceof Entity)) { |
| 107 | return false; |
| 108 | } |
| 109 | Entity entity = (Entity) other; |
| 110 | if (id == null || entity.getId() == null) { |
| 111 | return false; |
| 112 | } |
| 113 | return id.equals(entity.getId()); |
| 114 | } |
| 115 | |
| 116 | /** |
| 117 | * Use ID if it exists to establish hash code, otherwise fall back to |
| 118 | * Object.hashCode(). Based on the same information as equals, so if that |
| 119 | * changes, this will. N.B. this follows the contract of Object.hashCode(), |
| 120 | * but will cause problems for anyone adding an unsaved {@link Entity} to a |
| 121 | * Set because Set.contains() will almost certainly return false for the |
| 122 | * {@link Entity} after it is saved. Spring Batch does not store any of its |
| 123 | * entities in Sets as a matter of course, so internally this is consistent. |
| 124 | * Clients should not be exposed to unsaved entities. |
| 125 | * |
| 126 | * @see java.lang.Object#hashCode() |
| 127 | */ |
| 128 | @Override |
| 129 | public int hashCode() { |
| 130 | if (id == null) { |
| 131 | return super.hashCode(); |
| 132 | } |
| 133 | return 39 + 87 * id.hashCode(); |
| 134 | } |
| 135 | |
| 136 | } |