| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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. |
| */ |
| package org.apache.openjpa.jdbc.sql; |
| |
| /** |
| * SQL UNION. |
| * |
| * @author Abe White |
| */ |
| public interface Union |
| extends SelectExecutor { |
| |
| /** |
| * Return the selects that make up this union. |
| */ |
| Select[] getSelects(); |
| |
| /** |
| * Get the union-level ordering, if any. |
| */ |
| String getOrdering(); |
| |
| /** |
| * Whether this is a true UNION, rather than a logical combination of |
| * independent selects. |
| */ |
| boolean isUnion(); |
| |
| /** |
| * Force the use of a series of standard selects rather than a true UNION. |
| */ |
| void abortUnion(); |
| |
| /** |
| * Select data using the given selector. |
| */ |
| void select(Selector selector); |
| |
| /** |
| * A callback used to create the selects in a SQL union. |
| */ |
| public interface Selector { |
| |
| /** |
| * Populate the <code>i</code>th select in the union. |
| */ |
| void select(Select sel, int i); |
| } |
| } |