org.apache.openjpa.jdbc.meta.DiscriminatorStrategy Maven / Gradle / Ivy
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* 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.meta;
import java.sql.SQLException;
import org.apache.openjpa.jdbc.kernel.JDBCStore;
import org.apache.openjpa.jdbc.sql.Joins;
import org.apache.openjpa.jdbc.sql.Result;
import org.apache.openjpa.jdbc.sql.SQLBuffer;
import org.apache.openjpa.jdbc.sql.Select;
/**
* Handles determining the object class of database records.
*
* @author Abe White
*/
public interface DiscriminatorStrategy
extends Strategy {
/**
* Set the Discriminator that uses this strategy. This will be called
* before use.
*/
public void setDiscriminator(Discriminator owner);
/**
* Select the data for this Discriminator.
*
* @param mapping the known base class being selected; this may
* not be the base class in the inheritance hierarchy
* @return true if anything was selected; false otherwise
*/
public boolean select(Select sel, ClassMapping mapping);
/**
* Load all subclasses of the owning class mapping into the JVM.
*/
public void loadSubclasses(JDBCStore store)
throws SQLException, ClassNotFoundException;
/**
* Return the class for the current result row.
*/
public Class getClass(JDBCStore store, ClassMapping base, Result result)
throws SQLException, ClassNotFoundException;
/**
* Whether any class conditions are necessary.
*
* @see #getClassConditions
*/
public boolean hasClassConditions(ClassMapping base, boolean subs);
/**
* Return SQL to limit the classes selected as much as possible to the
* given base class, and optionally its subclasses. The select and joins
* instances are supplied in order to get column aliases.
*/
public SQLBuffer getClassConditions(Select sel, Joins joins,
ClassMapping base, boolean subs);
}