java - 用另一个初始化一个类成员

Question

@Entity
@Table(name = "artist")
public class Artist implements java.io.Serializable{

    @Basic
    @Column(name = "is_active",nullable=false)
    private Boolean isActive = false;

    @OneToMany(mappedBy = "artist", cascade = {CascadeType.ALL}, fetch = FetchType.LAZY)
    private Set<Project> projects= new HashSet<Project>(); 
}

和

@Entity
@Table(name = "project")
public class Project implements java.io.Serializable{

     @ManyToOne(fetch = FetchType.LAZY)
     @JoinColumn(name = "artist_id")
     private Artist artist;

     @Basic
     @Column(name = "is_active",nullable=false)
     private Boolean isActive = false;
}

我可以像下面这样初始化isActive，其目的是 's flag 由's flag初始化ProjectProjectArtist

private Boolean isActive = ((getArtist()!=null)? getArtist().getIsActive(): false);

定义成员的顺序是否总是Project会导致isActive错误？

Answer 1

与该声明：

private Boolean isActive = ((getArtist()!=null)? getArtist().getIsActive(): false);

isActive 将始终为 false，因为 Artist 和 isActive 都将在 Project 的默认构造函数之前初始化。所以artist被初始化为null，然后isActive被初始化为false（因为getArtist()为null），然后Project的默认构造函数运行（但是构造函数什么都不做），所以isActive总是false。