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/*
* Copyright 2006-2023 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.batch.core;
import java.io.Serializable;
import org.springframework.util.ClassUtils;
/**
* Batch Domain Entity class. Any class that should be uniquely identifiable from another
* should subclass from Entity. See Domain Driven Design, by Eric Evans, for more
* information on this pattern and the difference between Entities and Value Objects.
*
* @author Lucas Ward
* @author Dave Syer
* @author Mahmoud Ben Hassine
*
*/
@SuppressWarnings("serial")
public class Entity implements Serializable {
private Long id;
private volatile Integer version;
/**
* Default constructor for {@link Entity}.
*
* The ID defaults to zero.
*/
public Entity() {
super();
}
/**
* The constructor for the {@link Entity} where the ID is established.
* @param id The ID for the entity.
*/
public Entity(Long id) {
super();
// Commented out because StepExecutions are still created in a disconnected
// manner. The Repository should create them, then this can be uncommented.
// Assert.notNull(id, "Entity id must not be null.");
this.id = id;
}
/**
* @return The ID associated with the {@link Entity}.
*/
public Long getId() {
return id;
}
/**
* @param id The ID for the {@link Entity}.
*/
public void setId(Long id) {
this.id = id;
}
/**
* @return the version.
*/
public Integer getVersion() {
return version;
}
/**
* Public setter for the version. Needed only by repository methods.
* @param version The version to set.
*/
public void setVersion(Integer version) {
this.version = version;
}
/**
* Increment the version number.
*/
public void incrementVersion() {
if (version == null) {
version = 0;
}
else {
version = version + 1;
}
}
/**
* Creates a string representation of the {@code Entity}, including the {@code id},
* {@code version}, and class name.
*/
@Override
public String toString() {
return String.format("%s: id=%d, version=%d", ClassUtils.getShortName(getClass()), id, version);
}
/**
* Attempt to establish identity based on {@code id} if both exist. If either
* {@code id} does not exist, use {@code Object.equals()}.
*
* @see java.lang.Object#equals(java.lang.Object)
*/
@Override
public boolean equals(Object other) {
if (other == this) {
return true;
}
if (other == null) {
return false;
}
if (!(other instanceof Entity entity)) {
return false;
}
if (id == null || entity.getId() == null) {
return false;
}
return id.equals(entity.getId());
}
/**
* Use {@code id}, if it exists, to establish a hash code. Otherwise fall back to
* {@code Object.hashCode()}. It is based on the same information as {@code equals},
* so, if that changes, this will. Note that this follows the contract of
* {@code Object.hashCode()} but will cause problems for anyone adding an unsaved
* {@link Entity} to a {@code Set} because {@code Set.contains()} almost certainly
* returns false for the {@link Entity} after it is saved. Spring Batch does not store
* any of its entities in sets as a matter of course, so this is internally
* consistent. Clients should not be exposed to unsaved entities.
*
* @see java.lang.Object#hashCode()
*/
@Override
public int hashCode() {
if (id == null) {
return super.hashCode();
}
return 39 + 87 * id.hashCode();
}
}