org.mybatis.dynamic.sql.select.SelectDSLCompleter Maven / Gradle / Ivy
/**
* Copyright 2016-2019 the original author or authors.
*
* 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.
*/
package org.mybatis.dynamic.sql.select;
import java.util.function.Function;
import org.mybatis.dynamic.sql.SortSpecification;
import org.mybatis.dynamic.sql.util.Buildable;
import org.mybatis.dynamic.sql.util.mybatis3.MyBatis3Utils;
/**
* Represents a function that can be used to create a general select method. When using this function,
* you can create a method that does not require a user to call the build() and render() methods - making
* client code look a bit cleaner.
*
* This function is intended to by used in conjunction with utility methods like the select methods in
* {@link MyBatis3Utils}.
*
*
For example, you can create mapper interface methods like this:
*
*
* @SelectProvider(type=SqlProviderAdapter.class, method="select")
* List<PersonRecord> selectMany(SelectStatementProvider selectStatement);
*
* BasicColumn[] selectList =
* BasicColumn.columnList(id, firstName, lastName, birthDate, employed, occupation, addressId);
*
* default List<PersonRecord> select(SelectDSLCompleter completer) {
* return MyBatis3Utils.select(this::selectMany, selectList, person, completer);
* }
*
*
* And then call the simplified default method like this:
*
*
* List<PersonRecord> rows = mapper.select(c ->
* c.where(occupation, isNull()));
*
*
* You can implement a "select all" with the following code:
*
*
* List<PersonRecord> rows = mapper.select(c -> c);
*
*
* Or
*
*
* List<PersonRecord> rows = mapper.select(SelectDSLCompleter.allRows());
*
*
* There is also a utility method to support selecting all rows in a specified order:
*
*
* List<PersonRecord> rows = mapper.select(SelectDSLCompleter.allRowsOrderedBy(lastName, firstName));
*
*
* @author Jeff Butler
*/
@FunctionalInterface
public interface SelectDSLCompleter extends
Function, Buildable> {
/**
* Returns a completer that can be used to select every row in a table.
*
* @return the completer that will select every row in a table
*/
static SelectDSLCompleter allRows() {
return c -> c;
}
/**
* Returns a completer that can be used to select every row in a table with specified order.
*
* @param columns list of sort specifications for an order by clause
* @return the completer that will select every row in a table with specified order
*/
static SelectDSLCompleter allRowsOrderedBy(SortSpecification...columns) {
return c -> c.orderBy(columns);
}
}