/**
*
* Copyright (c) 2006-2017, Speedment, Inc. All Rights Reserved.
*
* 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 com.speedment.runtime.core.db;
import com.speedment.runtime.core.db.metadata.ColumnMetaData;
import com.speedment.runtime.core.internal.db.JavaTypeMapImpl;
import java.util.Map;
import java.util.Optional;
/**
* A convenience class for mapping between column types using a database
* specific rule set.
*
* @author Emil Forslund
* @since 3.0.0
*/
public interface JavaTypeMap {
/**
* A rule that helps defining how the metadata for a column
* should apply to the java mapping.
*/
@FunctionalInterface
interface Rule {
/**
* Returns the java type that should be used to represent the
* column with the specified metadata. A map of existing type
* mappings is also supplied since some implementations might
* need this.
* <p>
* If this rule does not apply to the specified column, an empty
* {@code Optional} is returned. The rule engine will continue
* to look at rules until one that returns something other than
* empty is found. If no valid rule can be found, the standard
* mapping is used.
* <p>
* The supplied map is read-only.
*
* @param sqlTypeMapping read-only map of existing mappings
* @param metadata metadata about the particular column
* @return the mapped type to be used or empty
*/
Optional<Class<?>> findJdbcType(Map<String, Class<?>> sqlTypeMapping, ColumnMetaData metadata);
}
/**
* Adds the specified rule to the rule engine.
*
* @param rule the rule to add
*/
void addRule(Rule rule);
/**
* Looks through all the rules that has been installed into this
* rule engine to try and find one that returns something other
* than an empty {@code Optional}. If none is found, the default
* mapping is returned.
*
* @param sqlTypeMapping read-only map of existing mappings
* @param metadata metadata about the particular column
* @return the mapped type to be used
*/
Class<?> findJdbcType(Map<String, Class<?>> sqlTypeMapping, ColumnMetaData metadata);
/**
* Adds a new mapping to this type map. If a previous mapping with
* the same key exists, it will be overwritten.
* <p>
* A read-only view of the map with installed mappings will be
* available to the rules upon execution.
*
* @param key the key for the particular mapping
* @param clazz the mapped type
*/
void put(String key, Class<?> clazz);
/**
* Returns the mapped type for the particular key.
*
* @param key the key to look for
* @return the type associated with it or {@code null}
*/
Class<?> get(String key);
/**
* Creates a new {@link JavaTypeMap} using the default
* implementation.
*
* @return the created {@link JavaTypeMap}
*/
static JavaTypeMap create() {
return new JavaTypeMapImpl();
}
}