HHH-17355 Support double-pipe operator for array concatenation

hibernate · Nov 6, 2023 · 5b69d75 · 5b69d75
1 parent c257be6
commit 5b69d75
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diff --git a/documentation/src/main/asciidoc/userguide/chapters/query/hql/QueryLanguage.adoc b/documentation/src/main/asciidoc/userguide/chapters/query/hql/QueryLanguage.adoc
@@ -1173,7 +1173,7 @@ include::{array-example-dir-hql}/ArrayLengthTest.java[tags=hql-array-length-exam
 ====
 
 [[hql-array-concat-functions]]
-===== `array_concat()`
+===== `array_concat()` or `||`
 
 Concatenates arrays with each other in order. Returns `null` if one of the arguments is `null`.
 
@@ -1185,6 +1185,26 @@ include::{array-example-dir-hql}/ArrayConcatTest.java[tags=hql-array-concat-exam
 ----
 ====
 
+Arrays can also be concatenated with the `||` (double-pipe) operator.
+
+[[hql-array-concat-pipe-example]]
+====
+[source, JAVA, indent=0]
+----
+include::{array-example-dir-hql}/ArrayConcatTest.java[tags=hql-array-concat-pipe-example]
+----
+====
+
+In addition, the `||` (double-pipe) operator also support concatenating single elements to arrays.
+
+[[hql-array-concat-pipe-element-example]]
+====
+[source, JAVA, indent=0]
+----
+include::{array-example-dir-hql}/ArrayConcatTest.java[tags=hql-array-concat-pipe-element-example]
+----
+====
+
 [[hql-array-prepend-functions]]
 ===== `array_prepend()`
 

diff --git a/hibernate-core/src/main/java/org/hibernate/query/hql/internal/SemanticQueryBuilder.java b/hibernate-core/src/main/java/org/hibernate/query/hql/internal/SemanticQueryBuilder.java
@@ -211,6 +211,7 @@
 import org.hibernate.sql.ast.SqlAstNodeRenderingMode;
 import org.hibernate.sql.ast.tree.cte.CteMaterialization;
 import org.hibernate.sql.ast.tree.cte.CteSearchClauseKind;
+import org.hibernate.type.BasicPluralType;
 import org.hibernate.type.BasicType;
 import org.hibernate.type.descriptor.java.JavaType;
 import org.hibernate.type.descriptor.java.PrimitiveByteArrayJavaType;
@@ -2858,14 +2859,53 @@ public SqmExpression<?> visitConcatenationExpression(HqlParser.ConcatenationExpr
 		if ( ctx.getChildCount() != 3 ) {
 			throw new SyntaxException( "Expecting two operands to the '||' operator" );
 		}
-		return getFunctionDescriptor( "concat" ).generateSqmExpression(
-				asList(
-						(SqmExpression<?>) ctx.expression( 0 ).accept( this ),
-						(SqmExpression<?>) ctx.expression( 1 ).accept( this )
-				),
-				null,
-				creationContext.getQueryEngine()
-		);
+		final SqmExpression<?> lhs = (SqmExpression<?>) ctx.expression( 0 ).accept( this );
+		final SqmExpression<?> rhs = (SqmExpression<?>) ctx.expression( 1 ).accept( this );
+		final SqmExpressible<?> lhsExpressible = lhs.getExpressible();
+		final SqmExpressible<?> rhsExpressible = rhs.getExpressible();
+		if ( lhsExpressible != null && lhsExpressible.getSqmType() instanceof BasicPluralType<?, ?> ) {
+			if ( rhsExpressible == null || rhsExpressible.getSqmType() instanceof BasicPluralType<?, ?> ) {
+				// Both sides are array, so use array_concat
+				return getFunctionDescriptor( "array_concat" ).generateSqmExpression(
+						asList( lhs, rhs ),
+						null,
+						creationContext.getQueryEngine()
+				);
+			}
+			else {
+				// The RHS seems to be of the element type, so use array_append
+				return getFunctionDescriptor( "array_append" ).generateSqmExpression(
+						asList( lhs, rhs ),
+						null,
+						creationContext.getQueryEngine()
+				);
+			}
+		}
+		else if ( rhsExpressible != null && rhsExpressible.getSqmType() instanceof BasicPluralType<?, ?> ) {
+			if ( lhsExpressible == null ) {
+				// The RHS is an array and the LHS doesn't have a clear type, so use array_concat
+				return getFunctionDescriptor( "array_concat" ).generateSqmExpression(
+						asList( lhs, rhs ),
+						null,
+						creationContext.getQueryEngine()
+				);
+			}
+			else {
+				// The LHS seems to be of the element type, so use array_prepend
+				return getFunctionDescriptor( "array_prepend" ).generateSqmExpression(
+						asList( lhs, rhs ),
+						null,
+						creationContext.getQueryEngine()
+				);
+			}
+		}
+		else {
+			return getFunctionDescriptor( "concat" ).generateSqmExpression(
+					asList( lhs, rhs ),
+					null,
+					creationContext.getQueryEngine()
+			);
+		}
 	}
 
 	@Override

diff --git a/hibernate-core/src/test/java/org/hibernate/orm/test/function/array/ArrayConcatTest.java b/hibernate-core/src/test/java/org/hibernate/orm/test/function/array/ArrayConcatTest.java
@@ -87,4 +87,88 @@ public void testConcatPrepend(SessionFactoryScope scope) {
 		} );
 	}
 
+	@Test
+	public void testConcatPipe(SessionFactoryScope scope) {
+		scope.inSession( em -> {
+			//tag::hql-array-concat-pipe-example[]
+			List<Tuple> results = em.createQuery( "select e.id, e.theArray || array('xyz') from EntityWithArrays e order by e.id", Tuple.class )
+					.getResultList();
+			//end::hql-array-concat-pipe-example[]
+			assertEquals( 3, results.size() );
+			assertEquals( 1L, results.get( 0 ).get( 0 ) );
+			assertArrayEquals( new String[]{ "xyz" }, results.get( 0 ).get( 1, String[].class ) );
+			assertEquals( 2L, results.get( 1 ).get( 0 ) );
+			assertArrayEquals( new String[]{ "abc", null, "def", "xyz" }, results.get( 1 ).get( 1, String[].class ) );
+			assertEquals( 3L, results.get( 2 ).get( 0 ) );
+			assertNull( results.get( 2 ).get( 1, String[].class ) );
+		} );
+	}
+
+	@Test
+	public void testConcatPipeTwoArrayPaths(SessionFactoryScope scope) {
+		scope.inSession( em -> {
+			em.createQuery( "select e.id, e.theArray || e.theArray from EntityWithArrays e order by e.id" ).getResultList();
+		} );
+	}
+
+	@Test
+	public void testConcatPipeAppendLiteral(SessionFactoryScope scope) {
+		scope.inSession( em -> {
+			//tag::hql-array-concat-pipe-element-example[]
+			em.createQuery( "select e.id, e.theArray || 'last' from EntityWithArrays e order by e.id" ).getResultList();
+			//end::hql-array-concat-pipe-element-example[]
+		} );
+	}
+
+	@Test
+	public void testConcatPipePrependLiteral(SessionFactoryScope scope) {
+		scope.inSession( em -> {
+			em.createQuery( "select e.id, 'first' || e.theArray from EntityWithArrays e order by e.id" ).getResultList();
+		} );
+	}
+
+	@Test
+	public void testConcatPipeAppendNull(SessionFactoryScope scope) {
+		scope.inSession( em -> {
+			em.createQuery( "select e.id, e.theArray || null from EntityWithArrays e order by e.id" ).getResultList();
+		} );
+	}
+
+	@Test
+	public void testConcatPipePrependNull(SessionFactoryScope scope) {
+		scope.inSession( em -> {
+			em.createQuery( "select e.id, null || e.theArray from EntityWithArrays e order by e.id" ).getResultList();
+		} );
+	}
+
+	@Test
+	public void testConcatPipeAppendParameter(SessionFactoryScope scope) {
+		scope.inSession( em -> {
+			em.createQuery( "select e.id, e.theArray || :p from EntityWithArrays e order by e.id" )
+					.setParameter( "p", null )
+					.getResultList();
+			em.createQuery( "select e.id, e.theArray || :p from EntityWithArrays e order by e.id" )
+					.setParameter( "p", "last" )
+					.getResultList();
+			em.createQuery( "select e.id, e.theArray || :p from EntityWithArrays e order by e.id" )
+					.setParameter( "p", new String[]{ "last" } )
+					.getResultList();
+		} );
+	}
+
+	@Test
+	public void testConcatPipePrependParameter(SessionFactoryScope scope) {
+		scope.inSession( em -> {
+			em.createQuery( "select e.id, :p || e.theArray from EntityWithArrays e order by e.id" )
+					.setParameter( "p", null )
+					.getResultList();
+			em.createQuery( "select e.id, :p || e.theArray from EntityWithArrays e order by e.id" )
+					.setParameter( "p", "first" )
+					.getResultList();
+			em.createQuery( "select e.id, :p || e.theArray from EntityWithArrays e order by e.id" )
+					.setParameter( "p", new String[]{ "first" } )
+					.getResultList();
+		} );
+	}
+
 }