[jOOQ/jOOQ#579] Add NamedCheckField

Like SimpleCheckQueryPart for SimpleQueryPart, a new NamedCheckField for NamedField contents has been added for cases like Coerce, which are wrappers for something that could be a NamedField.

jOOQ/src/main/java/org/jooq/impl/Coerce.java

@@ -58,6 +58,7 @@ extends
     AbstractField<T>
 implements
     AutoAlias<Field<T>>,
+    NamedCheckField<T>,
     QOM.Coerce<T>
 {
 
@@ -69,6 +70,11 @@ implements
         this.field = (AbstractField<?>) Tools.uncoerce(field);
     }
 
+    @Override
+    public final boolean hasName(Context<?> ctx) {
+        return Tools.hasName(ctx, field);
+    }
+
     @Override
     public final void accept(Context<?> ctx) {
         ctx.visit(field);

jOOQ/src/main/java/org/jooq/impl/ConditionAsField.java

@@ -69,6 +69,7 @@ final class ConditionAsField
 extends
     AbstractField<Boolean>
 implements
+    NamedCheckField<Boolean>,
     QOM.ConditionAsField
 {
 
@@ -142,6 +143,11 @@ implements
 
 
 
+    @Override
+    public final boolean hasName(Context<?> ctx) {
+        return Tools.hasName(ctx, condition);
+    }
+
     // -------------------------------------------------------------------------
     // XXX: Query Object Model
     // -------------------------------------------------------------------------

jOOQ/src/main/java/org/jooq/impl/FieldCondition.java

@@ -69,6 +69,7 @@ final class FieldCondition
 extends
     AbstractCondition
 implements
+    NamedCheckField<Boolean>,
     QOM.FieldCondition
 {
 
@@ -125,6 +126,11 @@ implements
 
 
 
+    @Override
+    public final boolean hasName(Context<?> ctx) {
+        return Tools.hasName(ctx, field);
+    }
+
     // -------------------------------------------------------------------------
     // XXX: Query Object Model
     // -------------------------------------------------------------------------

jOOQ/src/main/java/org/jooq/impl/FieldProxy.java

@@ -60,6 +60,7 @@ extends
 implements
     TableField<Record, T>,
     UProxy<Field<T>>,
+    NamedCheckField<T>,
     ScopeMappable
 {
 
@@ -96,6 +97,11 @@ implements
         this.position = position;
     }
 
+    @Override
+    public final boolean hasName(Context<?> ctx) {
+        return Tools.hasName(ctx, delegate);
+    }
+
     final int position() {
         return position;
     }

jOOQ/src/main/java/org/jooq/impl/NamedCheckField.java

@@ -0,0 +1,63 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *  https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * Other licenses:
+ * -----------------------------------------------------------------------------
+ * Commercial licenses for this work are available. These replace the above
+ * ASL 2.0 and offer limited warranties, support, maintenance, and commercial
+ * database integrations.
+ *
+ * For more information, please visit: https://www.jooq.org/legal/licensing
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ */
+package org.jooq.impl;
+
+import org.jooq.Context;
+import org.jooq.DataType;
+import org.jooq.Field;
+import org.jooq.TableField;
+
+/**
+ * A marker interface for fields that are capable of generating fields whose
+ * name is defined.
+ * <p>
+ * Unlike {@link NamedField}, which marks fields that have a name defined,
+ * unconditionally, this allows for checking whether a {@link Field} has {@link #hasName()}.
+ *
+ * @author Lukas Eder
+ */
+interface NamedCheckField<T> extends Field<T> {
+
+    /**
+     * Whether the field really has a name defined, e.g. a
+     * {@link Field#coerce(DataType)} expression on a {@link TableField}.
+     */
+    default boolean hasName(Context<?> ctx) {
+        return false;
+    }
+}

jOOQ/src/main/java/org/jooq/impl/SelectQueryImpl.java

@@ -210,6 +210,7 @@ import static org.jooq.impl.Tools.containsUnaliasedTable;
 import static org.jooq.impl.Tools.fieldArray;
 import static org.jooq.impl.Tools.hasAmbiguousNames;
 import static org.jooq.impl.Tools.hasAmbiguousNamesInTables;
+import static org.jooq.impl.Tools.hasName;
 import static org.jooq.impl.Tools.isEmpty;
 import static org.jooq.impl.Tools.isNotEmpty;
 import static org.jooq.impl.Tools.isWindow;

jOOQ/src/main/java/org/jooq/impl/Tools.java

@@ -3995,6 +3995,11 @@ final class Tools {
         return true;
     }
 
+    static final boolean hasName(Context<?> ctx, Field<?> field) {
+        return field instanceof NamedField
+            || field instanceof NamedCheckField && ((NamedCheckField<?>) field).hasName(ctx);
+    }
+
     static final boolean isRendersSeparator(QueryPart part) {
         return part instanceof SeparatedQueryPart && ((SeparatedQueryPart) part).rendersSeparator();
     }