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POReturning a QueryDSL BooleanExpression that evaluates to true
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copied!<p>Say I have <code>CustomerQueryInfo</code> bean with the following properties:</p> <ul> <li>String firstName</li> <li>String lastName </li> <li>StatusEnum status</li> </ul> <p>I want to perform a "<strong>QueryDSL</strong>" search using this an object of this type that will return a list of customers <code>List<Customer></code>.</p> <p>If one of the fields of <code>CustomerQueryInfo</code> is <code>null</code>, I don't want to use it in the search. Thus a <code>CustomerQueryInfo</code> object with all three <strong>fields set to <code>null</code></strong> will return <strong>all customers</strong>.</p> <p>I am looking for best practices to perform such a search with QueryDSL.</p> <p>Is something like this OK:</p> <pre><code>private BooleanExpression isFirstNameLike(String firstName){ if(firstName==null) return true BooleanExpression somehow; return QCustomer.customer.firstName.like(firstName); } private BooleanExpression isStatutEq(StatusEnum status){ if(status==null) return true BooleanExpression somehow; return QCustomer.customer.status.eq(status); } </code></pre> <p>then:</p> <pre><code>return query.from(customer).where(isFirstNameLike(customerQueryInfo.getFirstName).and(isLastNameLike(customerQueryInfo.getLastName).and(isStatusEq(customerQueryInfo.getStatus))).list; </code></pre> <ol> <li>How do I return a <code>BooleanExpression</code> that evaluates to true?</li> <li>If the above approach is not advisable, then what is the recommended best practice?</li> </ol>

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