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POHow to query properties of an @Entity attribute mapped using EclipseLink @ReadTransformer and @WriteTransformer?
 

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  1. POHow to query properties of an @Entity attribute mapped using EclipseLink @ReadTransformer and @WriteTransformer?
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    <p>I am using EclipseLink 2.4.2.</p> <p>I have an @Entity with an attribute of type Money, which is a final class from an external library. Instances of Money are immutable and must be persisted as two columns, one for amount and one for currency.</p> <p>I am using a @ReadTransformer and two @WriteTransformers to do this:</p> <pre><code>@Transformation(fetch = FetchType.EAGER, optional = false) @ReadTransformer(transformerClass = MoneyReadTransformer.class) @WriteTransformers({ @WriteTransformer( transformerClass = MoneyCurrencyWriteTransformer.class, column = @Column(name = "SAVINGS_CURRENCY", nullable = false)), @WriteTransformer( transformerClass = MoneyAmountWriteTransformer.class, column = @Column(name = "SAVINGS_BALANCE", nullable = false)) }) private Money savings; </code></pre> <p>This works well; I can load and save the entity with no problem.</p> <p>The problem comes when I try to perform a JPQL query for entities based on attributes of the embedded Money instance:</p> <pre><code>SELECT t FROM Thing t WHERE t.savings.amount &gt; 0; </code></pre> <p>This returns:</p> <pre><code>org.eclipse.persistence.exceptions.JPQLException: Exception Description: Problem compiling [SELECT t FROM Thing t WHERE t.savings.amount &gt; 0]. [29, 45] The state field path 't.savings.amount' cannot be resolved to a valid type. </code></pre> <p>This kind of thing worked in Hibernate just fine (with UserTypes and a @Type annotation).</p> <p>I also noted the following messages on startup:</p> <pre><code>[EL Config]: metadata: 2013-04-28 15:30:04.276--Thread(Thread[main,5,main])--The default table generator could not locate or convert a java type (null) into a database type for database field (THING.SAVINGS_CURRENCY). The generator uses java.lang.String as default java type for the field. [EL Config]: metadata: 2013-04-28 15:30:04.276--Thread(Thread[main,5,main])--The default table generator could not locate or convert a java type (null) into a database type for database field (THING.SAVINGS_BALANCE). The generator uses java.lang.String as default java type for the field. </code></pre> <p>These messages go away if I define a columnDefinition on the @Column attribute for each @WriteTransformer. </p> <p>What might the problem be? My suspicion is that something's not right with the transformers, maybe I'm not setting a type hint somewhere - but it's non-obvious and examples are few and far between.</p>
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    1. USGabriel Bauman
    1. USGabriel Bauman
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      1. POHow to query properties of an @Entity attribute mapped using EclipseLink @ReadTransformer and @WriteTransformer?
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