com.speedment.runtime.config.identifier.ColumnIdentifier Maven / Gradle / Ivy
/**
*
* 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.config.identifier;
import com.speedment.runtime.config.identifier.trait.HasColumnName;
import com.speedment.runtime.config.identifier.trait.HasDbmsName;
import com.speedment.runtime.config.identifier.trait.HasSchemaName;
import com.speedment.runtime.config.identifier.trait.HasTableName;
import com.speedment.runtime.config.internal.identifier.ColumnIdentifierImpl;
import com.speedment.runtime.config.util.DocumentDbUtil;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
/**
* Identifies a particular Column. The identifier is an immutable non-complex
* object that only contains the names of the nodes required to uniquely
* identify it in the database.
*
* To find the actual documents referred to by the identifier, the following
* utility methods can be used:
*
* - DocumentDbUtil#referencedColumn(Project, ColumnIdentifier)
*
- DocumentDbUtil#referencedTable(Project, Project, ColumnIdentifier)
*
- DocumentDbUtil#referencedSchema(Project, Project, ColumnIdentifier)
*
- DocumentDbUtil#referencedDbms(Project, ColumnIdentifier)
*
*
* @param the entity type
*
* @author Emil Forslund
* @since 2.3
*
* @see DocumentDbUtil
*/
public interface ColumnIdentifier
extends HasDbmsName,
HasSchemaName,
HasTableName,
HasColumnName {
/**
* Internal class only used to hide a map of interned instances.
*/
class Hidden {
private static final Map, ColumnIdentifier>
INTERNED = new ConcurrentHashMap<>();
}
/**
* Returns a dynamic {@link ColumnIdentifier} based on the default
* implementation of the interface. Note that the
* {@link ColumnIdentifier}-interface is usually implemented using a
* generated {@code enum}. This method should therefore only be used if a
* generated instance is not possible to use.
*
* The returned instance has a well defined {@link Object#hashCode()} and
* {@link Object#equals(Object)} method so it is safe to use as the key of a
* map.
*
* @param dbmsName the dbms database name
* @param schemaName the schema database name
* @param tableName the table database name
* @param columnName the column database name
* @param the entity type
* @return the identifier instance
*
* @since 3.0.15
*/
static ColumnIdentifier of(
final String dbmsName,
final String schemaName,
final String tableName,
final String columnName) {
final ColumnIdentifier newId = new ColumnIdentifierImpl<>(
dbmsName, schemaName, tableName, columnName);
ColumnIdentifier.Hidden.INTERNED.putIfAbsent(newId, newId);
@SuppressWarnings("unchecked")
final ColumnIdentifier result = (ColumnIdentifier)
ColumnIdentifier.Hidden.INTERNED.get(newId);
return result;
}
/**
* Returns a {@link TableIdentifier} that has the same {@code dbmsName},
* {@code schemaName} and {@code tableName} as this
* {@link ColumnIdentifier}.
*
* @return the table identifier
*/
default TableIdentifier asTableIdentifier() {
return TableIdentifier.of(getDbmsName(), getSchemaName(), getTableName());
}
/**
* Returns a label that can be used as key in a map. Using the ColumnIdentifier itself
* does not work since there are generated enums as well as runtime created ColumnIdentifierImpls
* that are considered to be equal but have different hashCode.
*
* All implementations of this interface will, however, have equal
* {@code label()} iff they refer to the same column.
*
* @return a ColumnLabel that is unique for this particular ColumnIdentifier
*/
default ColumnLabel label() {
return ColumnLabel.of(this);
}
}