[#5318] Add support for ALTER TABLE .. ADD (...) to add multiple objects to a table at once

jOOQ/src/main/java/org/jooq/AlterTableStep.java

@@ -229,6 +229,22 @@ public interface AlterTableStep {
     @Support
     AlterTableFinalStep add(Field<?> field);
 
+    /**
+     * Add an <code>ADD</code> clause with multiple columns or constraints to
+     * the <code>ALTER TABLE</code> statement.
+     */
+    // @Support({ H2, FIREBIRD, MARIADB, MYSQL, POSTGRES })
+    @Support({ H2 })
+    AlterTableFinalStep add(FieldOrConstraint... fields);
+
+    /**
+     * Add an <code>ADD</code> clause with multiple columns or constraints to
+     * the <code>ALTER TABLE</code> statement.
+     */
+    // @Support({ H2, FIREBIRD, MARIADB, MYSQL, POSTGRES })
+    @Support({ H2 })
+    AlterTableFinalStep add(Collection<? extends FieldOrConstraint> fields);
+
     /**
      * Add an <code>ADD COLUMN</code> clause to the <code>ALTER TABLE</code>
      * statement.

jOOQ/src/main/java/org/jooq/Constraint.java

@@ -42,6 +42,6 @@ package org.jooq;
  *
  * @author Lukas Eder
  */
-public interface Constraint extends QueryPart {
+public interface Constraint extends FieldOrConstraint {
 
 }

jOOQ/src/main/java/org/jooq/Field.java

@@ -79,7 +79,14 @@ import org.jooq.types.Interval;
  * @param <T> The field type
  * @author Lukas Eder
  */
-public interface Field<T> extends SelectField<T>, GroupField, OrderField<T>, FieldOrRow, Named {
+public interface Field<T>
+extends
+    SelectField<T>,
+    GroupField,
+    OrderField<T>,
+    FieldOrRow,
+    FieldOrConstraint,
+    Named {
 
     // ------------------------------------------------------------------------
     // API

jOOQ/src/main/java/org/jooq/FieldOrConstraint.java

@@ -0,0 +1,50 @@
+/*
+ * 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
+ *
+ *  http://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: http://www.jooq.org/licenses
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ */
+package org.jooq;
+
+/**
+ * A common base type for {@link Field} and {@link Constraint} where DSL API accepts
+ * both types alike.
+ * <p>
+ * This is useful for DDL statements.
+ *
+ * @author Lukas Eder
+ */
+public interface FieldOrConstraint extends QueryPart {
+
+}

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

@@ -144,6 +144,7 @@ import org.jooq.Context;
 import org.jooq.DSLContext;
 import org.jooq.DataType;
 import org.jooq.Field;
+import org.jooq.FieldOrConstraint;
 import org.jooq.Index;
 import org.jooq.Name;
 import org.jooq.Nullability;
@@ -192,6 +193,7 @@ final class AlterTableImpl extends AbstractQuery implements
     private Index                            renameIndexTo;
     private Constraint                       renameConstraint;
     private Constraint                       renameConstraintTo;
+    private QueryPartList<FieldOrConstraint> add;
     private Field<?>                         addColumn;
     private DataType<?>                      addColumnType;
     private Constraint                       addConstraint;
@@ -349,6 +351,17 @@ final class AlterTableImpl extends AbstractQuery implements
         return addColumn(field);
     }
 
+    @Override
+    public final AlterTableImpl add(FieldOrConstraint... fields) {
+        return add(Arrays.asList(fields));
+    }
+
+    @Override
+    public final AlterTableImpl add(Collection<? extends FieldOrConstraint> fields) {
+        add = new QueryPartList<FieldOrConstraint>(fields);
+        return this;
+    }
+
     @Override
     public final <T> AlterTableImpl add(Field<T> field, DataType<T> type) {
         return addColumn(field, type);
@@ -867,6 +880,41 @@ final class AlterTableImpl extends AbstractQuery implements
             ctx.data().remove(DATA_CONSTRAINT_REFERENCE);
             ctx.end(ALTER_TABLE_RENAME_CONSTRAINT);
         }
+        else if (add != null) {
+            boolean qualify = ctx.qualify();
+
+            ctx.start(ALTER_TABLE_ADD)
+               .visit(K_ADD)
+               .qualify(false)
+               .sql(" (");
+
+            boolean indent = add.size() > 1;
+
+            if (indent)
+                ctx.formatIndentStart()
+                   .formatNewLine();
+
+            for (int i = 0; i < add.size(); i++) {
+                if (i > 0)
+                    ctx.sql(',').formatSeparator();
+
+                FieldOrConstraint part = add.get(i);
+                ctx.visit(part);
+
+                if (part instanceof Field) {
+                    ctx.sql(' ');
+                    toSQLDDLTypeDeclarationForAddition(ctx, ((Field<?>) part).getDataType());
+                }
+            }
+
+            if (indent)
+                ctx.formatIndentEnd()
+                   .formatNewLine();
+
+            ctx.sql(')')
+               .qualify(qualify)
+               .end(ALTER_TABLE_ADD);
+        }
         else if (addColumn != null) {
             boolean qualify = ctx.qualify();