將嵌套的HibernateSearch5謂詞轉換為HibernateSearch6-有解無憂

在將應用程式從 Hibernate Search 5 轉換為 6 的程序中。我已經閱讀了很多檔案，尤其是https://docs.jboss.org/hibernate/search/6.0/migration/html_single/#queries-reference on如何轉換 Query DSL，我在一個簡單的場景中理解它，但是如何將謂詞嵌套到其他嵌套謂詞中，然后在更大的查詢中將它們與其他謂詞結合起來？
在 Hibernate Search 5 中，我們將使用 queryBuilder.bool() 創建一個 BooleanJunction，然后您可以通過在 bool 上呼叫 createQuery 將其添加到另一個 BooleanJunction 中，并一遍又一遍地創建嵌套謂詞查詢。

我正在談論轉換的代碼型別示例：

    BooleanJunction vendorNameBool = queryBuilder.bool();
    BooleanJunction nameBool = queryBuilder.bool();
    
    nameBool.must(
        qb.keyword()
            .onField(CompanyName)
            .matching(nameToken1)
            .createQuery()
    );
    
    nameBool.must(
        qb.keyword()
            .onField(CompanyName)
            .matching(nameToken2)
            .createQuery()
    );

    vendorNameBool.should(nameBool.createQuery);
    
    // do vendorNameBool.should(...) for as many vendor Names that exist, then createQuery 
    probableVendorNamesQuery = vendorNameBool.createQuery();
    
    // creating a number of Queries from various bools and then combining them:
    Query taxIdOrVendorNameOrPhoneNumberQuery = qb.bool()
        .should(probableVendorNamesQuery)
        .should(taxIdQuery)
        .should(phoneNumberQuery)
        .createQuery();
        
    //and add to the final BooleanQuery along with other Query pieces
    
    Query idQuery = getIdQuery();
    Query fileIdQuery = getFileIdQuery();
    
    BooleanQuery.Builder theQuery = new BooleanQuery.Builder();
    theQuery.add(taxIdOrVendorNameOrPhoneNumberQuery, MUST);
    theQuery.add(fileIdQuery, MUST);    
    theQuery.add(idQuery, MUST_NOT);    
    
    BooleanQuery probableQuery = theQuery.build();
     
    // add some projections and execute query

大多數 HS6 代碼示例都是 lambda 形式。這里有一個部分提供了一個創建非lamba謂詞的簡單示例，將它們添加到串列中，但是，例如，您如何將該謂詞串列添加到外部should子句，然后添加該should子句，連同另一個應該從句，到外部“必須”從句等等等等？

uj5u.com熱心網友回復：

就個人而言，我只會使用 lambda 語法并嵌套第二個 lambda。改編遷移指南中的示例：

 MySearchParameters searchParameters = ...;
 SearchSession session = Search.session( entityManager );
 List<Book> hits = searchSession.search( Book.class )
         .where( f -> f.bool( b -> {
             b.must( f.matchAll() );
             if ( searchParameters.getSearchTerms() != null ) {
                 b.must( f.simpleQueryString().fields( "title", "description" )
                         .matching( searchParameters.getSearchTerms() )
                         .defaultOperator( BooleanOperator.AND ) );
             }
             // ...
             // BEGIN NEW CODE
             SomeComplexParameter complexParam = searchParameters.getSomeComplexParameter();
             if ( complexParam != null ) {
                 b.must( f.bool( b2 -> {
                     b2.should( f.match().field( "someField1" )
                         .matching( complexParam.getSomeField1() ) );
                     b2.should( f.match().field( "someField2" )
                         .matching( complexParam.getSomeField2() ) );
                 } ) );
             }
             // END NEW CODE
         } ) )
         .fetchHits( params.getPageIndex() * params.getPageSize(), params.getPageSize() );

如果您在編譯時知道子句的數量，您甚至不需要第二個 lambda：

 MySearchParameters searchParameters = ...;
 SearchSession session = Search.session( entityManager );
 List<Book> hits = searchSession.search( Book.class )
         .where( f -> f.bool( b -> {
             b.must( f.matchAll() );
             if ( searchParameters.getSearchTerms() != null ) {
                 b.must( f.simpleQueryString().fields( "title", "description" )
                         .matching( searchParameters.getSearchTerms() )
                         .defaultOperator( BooleanOperator.AND ) );
             }
             // ...
             // BEGIN NEW CODE
             SomeComplexParameter complexParam = searchParameters.getSomeComplexParameter();
             if ( complexParam != null ) {
                 b.must( f.bool()
                         .should( f.match().field( "someField1" )
                             .matching( complexParam.getSomeField1() ) )
                         .should( f.match().field( "someField2" )
                             .matching( complexParam.getSomeField2() ) ) );
             }
             // END NEW CODE
         } ) )
         .fetchHits( params.getPageIndex() * params.getPageSize(), params.getPageSize() );

如果您真的不想在頂層使用 lambdas（為什么？），您可以將 lambdas 用于嵌套謂詞，至少：

MySearchParameters searchParameters = ...;
SearchSession session = Search.session( entityManager );
SearchPredicateFactory pf = session.scope( Book.class ).predicate();
List<SearchPredicate> predicates = new ArrayList<>();

if ( searchParameters.getSearchTerms() != null ) {
    predicates.add( pf.simpleQueryString().fields( "title", "description" )
            .matching( searchParameters.getSearchTerms() )
            .defaultOperator( BooleanOperator.AND )
            .toPredicate() );
}

// ...

// BEGIN NEW CODE
SomeComplexParameter complexParam = searchParameters.getSomeComplexParameter();
if ( complexParam != null ) {
    predicates.add( pf.bool( b -> {
        b.should( pf.match().field( "someField1" )
            .matching( complexParam.getSomeField1() ) );
        b.should( pf.match().field( "someField2" )
            .matching( complexParam.getSomeField2() ) );
    } )
            .toPredicate() );
}
// END NEW CODE

List<Book> hits = searchSession.search( Book.class )
        .where( f -> f.bool( b -> {
            b.must( f.matchAll() );
            for ( SearchPredicate predicate : predicates ) {
                b.must( predicate );
            }
        } )

在這里，只要您事先知道謂詞的數量，就不需要 lambda：

MySearchParameters searchParameters = ...;
SearchSession session = Search.session( entityManager );
SearchPredicateFactory pf = session.scope( Book.class ).predicate();
List<SearchPredicate> predicates = new ArrayList<>();

if ( searchParameters.getSearchTerms() != null ) {
    predicates.add( pf.simpleQueryString().fields( "title", "description" )
            .matching( searchParameters.getSearchTerms() )
            .defaultOperator( BooleanOperator.AND )
            .toPredicate() );
}

// ...

// BEGIN NEW CODE
SomeComplexParameter complexParam = searchParameters.getSomeComplexParameter();
if ( complexParam != null ) {
    predicates.add( pf.bool()
            .should( pf.match().field( "someField1" )
                .matching( complexParam.getSomeField1() ) )
            .should( pf.match().field( "someField2" )
                 .matching( complexParam.getSomeField2() ) )
            .toPredicate() );
}
// END NEW CODE

List<Book> hits = searchSession.search( Book.class )
        .where( f -> f.bool( b -> {
            b.must( f.matchAll() );
            for ( SearchPredicate predicate : predicates ) {
                b.must( predicate );
            }
        } )
        .fetchHits( params.getPageIndex() * params.getPageSize(), params.getPageSize() );

最后，如果你真的想完全遠離 lambdas（但又是為什么？），你可以做這樣的事情。但是請注意，在BooleanPredicateClausesStepHibernate Search 的次要版本中，泛型型別引數可能會發生變化，因此升級時此代碼更有可能中斷。

MySearchParameters searchParameters = ...;
SearchSession session = Search.session( entityManager );
SearchPredicateFactory pf = session.scope( Book.class ).predicate();
BooleanPredicateClausesStep<?> boolStep = pf.bool();

boolStep.must( f.matchAll() );

if ( searchParameters.getSearchTerms() != null ) {
    boolStep.must( pf.simpleQueryString().fields( "title", "description" )
            .matching( searchParameters.getSearchTerms() )
            .defaultOperator( BooleanOperator.AND ) );
}

// ...

SomeComplexParameter complexParam = searchParameters.getSomeComplexParameter();
if ( complexParam != null ) {
    BooleanPredicateClausesStep<?> boolStep2 = pf.bool();
    boolStep2.should( f.match().field( "someField1" )
            .matching( complexParam.getSomeField1() ) );
    boolStep2.should( f.match().field( "someField2" )
            .matching( complexParam.getSomeField2() ) );
    boolStep.must( boolStep2 );
}

SearchPredicate boolPredicate = boolStep.toPredicate();

List<Book> hits = searchSession.search( Book.class )
        .where( boolPredicate )
        .fetchHits( params.getPageIndex() * params.getPageSize(), params.getPageSize() );

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