org.apache.openjpa.jdbc.meta.DelegatingJoinable Maven / Gradle / Ivy
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* 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
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* 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.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.kernel.OpenJPAStateManager;
import org.apache.openjpa.lib.util.Localizer;
import org.apache.openjpa.util.MetaDataException;
/**
* Delegates to another {@link Joinable} after doing column
* translation. Useful for joins that are not managed by any fields on
* the joined-from side. For example, a vertical class mapping manages
* foreign key columns linking to the superclass table. It needs to use
* the joinables of the superclass to actually extract the column values
* from field values and so forth, but in order for other mappings to join
* to its foreign key columns it needs joinables of its own. So it creates
* delegating joinables.
*
* @author Abe White
*/
@SuppressWarnings("serial")
public class DelegatingJoinable
implements Joinable {
private static final Localizer _loc = Localizer.forPackage
(DelegatingJoinable.class);
private final Joinable _join;
private final ForeignKey _fk;
private final Column[] _cols;
/**
* Constructor.
*
* @param join the mapping to delegate to
* @param fk the foreign key to use to translate any given columns
* to the given delegate's columns
*/
public DelegatingJoinable(Joinable join, ForeignKey fk) {
_join = join;
_fk = fk;
Column[] pks = join.getColumns();
_cols = new Column[pks.length];
for (int i = 0; i < pks.length; i++) {
_cols[i] = fk.getColumn(pks[i]);
if (_cols[i] == null)
throw new MetaDataException(_loc.get("incomplete-join",
pks[i].getFullDBIdentifier()));
}
}
/**
* Constructor.
*
* @param join the mapping to delegate to
* @param cols translated columns
*/
public DelegatingJoinable(Joinable join, Column[] cols) {
_join = join;
_fk = null;
_cols = cols;
if (cols.length != join.getColumns().length)
throw new MetaDataException(_loc.get("bad-remap",
join.getColumns()[0].getFullDBIdentifier()));
}
public int getFieldIndex() {
return _join.getFieldIndex();
}
public Object getPrimaryKeyValue(Result res, Column[] cols, ForeignKey fk,
JDBCStore store, Joins joins)
throws SQLException {
return _join.getPrimaryKeyValue(res, cols, fk, store, joins);
}
public Column[] getColumns() {
return _cols;
}
public Object getJoinValue(Object val, Column col, JDBCStore store) {
return _join.getJoinValue(val, translate(col), store);
}
public Object getJoinValue(OpenJPAStateManager sm, Column col,
JDBCStore store) {
return _join.getJoinValue(sm, translate(col), store);
}
public void setAutoAssignedValue(OpenJPAStateManager sm, JDBCStore store,
Column col, Object autogen) {
_join.setAutoAssignedValue(sm, store, translate(col), autogen);
}
private Column translate(Column col) {
if (_fk != null)
return _fk.getPrimaryKeyColumn(col);
Column[] cols = _join.getColumns();
for (int i = 0; i < cols.length; i++)
if (col == cols[i])
return _cols[i];
return null;
}
}