org.apache.openjpa.jdbc.meta.strats.LRSCollectionFieldStrategy Maven / Gradle / Ivy
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* to you under the Apache License, Version 2.0 (the
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* http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.openjpa.jdbc.meta.strats;
import java.sql.SQLException;
import org.apache.openjpa.jdbc.kernel.JDBCFetchConfiguration;
import org.apache.openjpa.jdbc.kernel.JDBCStore;
import org.apache.openjpa.jdbc.meta.ClassMapping;
import org.apache.openjpa.jdbc.meta.FieldMapping;
import org.apache.openjpa.jdbc.meta.FieldStrategy;
import org.apache.openjpa.jdbc.meta.ValueMapping;
import org.apache.openjpa.jdbc.schema.Column;
import org.apache.openjpa.jdbc.schema.ForeignKey;
import org.apache.openjpa.jdbc.sql.Joins;
import org.apache.openjpa.jdbc.sql.Result;
import org.apache.openjpa.jdbc.sql.Select;
import org.apache.openjpa.kernel.OpenJPAStateManager;
/**
* Interface implemented by collection strategies so that they can
* support large result set collections.
*
* @author Abe White
*/
public interface LRSCollectionFieldStrategy
extends FieldStrategy {
/**
* The owning field mapping.
*/
public FieldMapping getFieldMapping();
/**
* Return all independent mappings to which this strategy must join in
* order to access collection elements, or empty array if none.
*
* @param traverse whether we're traversing through to the related type
* @see ValueMapping#getIndependentTypeMappings
* @see ClassMapping#EMPTY_MAPPINGS
*/
public ClassMapping[] getIndependentElementMappings(boolean traverse);
/**
* Return the foreign key used to join to the owning field for the given
* element mapping from {@link #getIndependentElementMappings} (or null).
*/
public ForeignKey getJoinForeignKey(ClassMapping elem);
/**
* Return the columns holding the data for a collection element for the
* given element mapping from {@link #getIndependentElementMappings}
* (or null).
*/
public Column[] getElementColumns(ClassMapping elem);
/**
* Implement this method to select the elements of this field for the
* given element mapping from {@link #getIndependentElementMappings}
* (or null). Elements of the result will be loaded with
* {@link #loadElement}.
*/
public void selectElement(Select sel, ClassMapping elem,
JDBCStore store, JDBCFetchConfiguration fetch, int eagerMode,
Joins joins);
/**
* Load an element of the collection. The given state manager might be
* null if the load is for a projection or for processing eager parallel
* results.
*/
public Object loadElement(OpenJPAStateManager sm, JDBCStore store,
JDBCFetchConfiguration fetch, Result res, Joins joins)
throws SQLException;
/**
* Join this value's table to the table for the given element mapping
* from {@link #getIndependentElementMappings} (or null).
*
* @see FieldMapping#joinRelation
*/
public Joins joinElementRelation(Joins joins, ClassMapping elem);
}