77 lines
2.4 KiB
Java
Executable File
77 lines
2.4 KiB
Java
Executable File
package com.ankurm.hibernatedemo.proxy;
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import jakarta.persistence.Entity;
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import jakarta.persistence.FetchType;
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import jakarta.persistence.GeneratedValue;
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import jakarta.persistence.GenerationType;
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import jakarta.persistence.Id;
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import jakarta.persistence.JoinColumn;
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import jakarta.persistence.ManyToOne;
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import jakarta.persistence.NamedAttributeNode;
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import jakarta.persistence.NamedEntityGraph;
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import jakarta.persistence.OneToMany;
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import java.util.ArrayList;
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import java.util.List;
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/**
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* Backs docs/11-proxies-and-lazy-initialization.md (post 4870 rewrite). Two associations on purpose:
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*
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* <ul>
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* <li>{@code publisher} -- {@code @ManyToOne} with the JPA-default fetch type, EAGER.
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* Nothing in this class overrides it.</li>
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* <li>{@code reviews} -- {@code @OneToMany}, explicitly LAZY, and the only attribute named
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* in {@code Book.reviews-only}. This is the association the fetchgraph/loadgraph demo
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* turns on and off.</li>
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* </ul>
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*
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* <p>With a {@code jakarta.persistence.loadgraph} hint carrying {@code Book.reviews-only},
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* {@code reviews} gets join-fetched AND {@code publisher} still gets its default EAGER join --
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* loadgraph only promotes attributes, it never demotes ones the mapping already marks EAGER.
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* With a {@code jakarta.persistence.fetchgraph} hint carrying the same named graph,
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* {@code reviews} still gets join-fetched, but {@code publisher} is forced down to LAZY (a
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* proxy, no join) even though the mapping says EAGER -- fetchgraph treats the graph as the
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* complete fetch plan, not an addition to the mapping's own defaults.
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*/
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@Entity
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@NamedEntityGraph(name = "Book.reviews-only", attributeNodes = @NamedAttributeNode("reviews"))
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public class ProxyBook {
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@Id
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@GeneratedValue(strategy = GenerationType.IDENTITY)
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private Long id;
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private String title;
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@ManyToOne
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@JoinColumn(name = "publisher_id")
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private ProxyPublisher publisher;
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@OneToMany(mappedBy = "book", fetch = FetchType.LAZY)
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private List<ProxyReview> reviews = new ArrayList<>();
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protected ProxyBook() {
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// JPA
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}
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public ProxyBook(String title, ProxyPublisher publisher) {
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this.title = title;
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this.publisher = publisher;
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}
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public Long getId() {
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return id;
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}
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public String getTitle() {
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return title;
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}
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public ProxyPublisher getPublisher() {
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return publisher;
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}
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public List<ProxyReview> getReviews() {
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return reviews;
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}
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}
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