com.github.tomschi.commons.springdatajpa.dbo.AbstractJpaDatabaseObject Maven / Gradle / Ivy
package com.github.tomschi.commons.springdatajpa.dbo;
import java.io.Serializable;
/**
* The abstract class {@link AbstractJpaDatabaseObject} can be used
* for database objects with a id also called primary key. This
* class overrides the {@link #equals(Object)} and {@link #hashCode()}
* method.
*
* @author Tomschi
* @since 0.1.0
*/
public abstract class AbstractJpaDatabaseObject implements JpaDatabaseObject {
private static final long serialVersionUID = 1L;
/**
* Indicates if this object is equals to another object.
* For checking this equality the id is used.
* Two objects are equal, if the given object is this
* object (this == obj) or the given object
* has the same class like this and both id's are equal.
* If id is null the the method only check
* if the given object is this object.
*
* @param obj The reference object with which to compare.
* @return True, if obj equals this, else false.
*/
@Override
public boolean equals(Object obj) {
if (getId() == null) return (this == obj);
return (this.getClass() == obj.getClass())
&& getId().equals(((JpaDatabaseObject) obj).getId());
}
/**
* Returns a hash code value for the object. The value
* is generated with the hashcode of the class name and
* the hashcode of the id. If the id is null
* {@link Object#hashCode()} is called.
*
* @return A hash code value for the object.
*/
@Override
public int hashCode() {
if (getId() == null) return super.hashCode();
return (this.getClass().getName().hashCode() * 13) + getId().hashCode();
}
}