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POJPA Criteria API - How to add JOIN clause (as general sentence as possible)
 

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  1. POJPA Criteria API - How to add JOIN clause (as general sentence as possible)
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    <p>I am trying to construct queries dynamically, and my next target is add JOIN clauses (I don't know how can I use the API).</p> <p>By now, for example, this code work for me :</p> <pre><code>... Class baseClass; ... CriteriaBuilder cb = JpaHandle.get().getCriteriaBuilder(); CriteriaQuery cq = cb.createQuery(this.baseClass); Root entity_ = cq.from(this.baseClass); Predicate restrictions = null; ... restrictions = cb.conjunction(); restrictions = cb.and(restrictions, entity_.get("id").in(this.listId)); ... cq.where(restrictions); ... Query qry = JpaHandle.get().createQuery(cq); </code></pre> <p>(Note : JpaHandle is from wicket-JPA implementation)</p> <p><strong>My desire is add JOIN clause (as generical as possible)!</strong> </p> <p>I have the particular annotations in the classes (this.baseClass) </p> <p>For example : </p> <pre><code>@ManyToOne(fetch = FetchType.LAZY) @JoinColumn(name = "assay_id", nullable = false) </code></pre> <p>So,Is there a way to something like this in standard JPA ? (Note : this don't compile)</p> <p><strong>Here a practical fail aproaches :</strong> </p> <pre><code>... Join&lt;Experiment,Assay&gt; experimentAssays = entity_.join( entity_.get("assay_id") ); </code></pre> <p>Or like that : </p> <pre><code>... CriteriaQuery&lt;Customer&gt; q = cb.createQuery(Customer.class); Root&lt;Customer&gt; c = q.from(Customer.class); SetJoin&lt;Customer, PurchaseOrder&gt; o = c.join(Customer_.orders); </code></pre> <p>For me, if it could be more generical as possible it will be great... : </p> <pre><code>... Join joinClause = entity_join(entity_.get("assay_id"), entity2_.get("id")); </code></pre> <p>Of course, I have the particular annotations in the classes (this.baseClass) </p> <p>Thank you for your time. I'll appreciate all kind of comments!</p>
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    1. USPascal Thivent
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    1. COCould you provide your annotated domain class or some other example class?
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      1. POJPA Criteria API - How to add JOIN clause (as general sentence as possible)
      1. USTimo Westkämper
 

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