org.apache.openjpa.jdbc.meta.Embeddable Maven / Gradle / Ivy
/*
* 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.JDBCFetchConfiguration;
import org.apache.openjpa.jdbc.kernel.JDBCStore;
import org.apache.openjpa.jdbc.schema.Column;
import org.apache.openjpa.jdbc.schema.ColumnIO;
import org.apache.openjpa.jdbc.sql.Result;
import org.apache.openjpa.kernel.OpenJPAStateManager;
/**
* Interface for field strategies that can managed fields of
* embedded-element, embedded-key, and embedded-value objects. Fields of
* directly embedded objects do not have to implement this interface.
*
* @author Abe White
* @since 0.4.0
*/
public interface Embeddable {
Object UNSUPPORTED = new Object();
/**
* Return the columns used by this strategy.
*/
Column[] getColumns();
/**
* Return column I/O information for this mapping.
*/
ColumnIO getColumnIO();
/**
* Return the arguments needed to extract datastore values via
* {@link Result#getObject} for each column.
*/
Object[] getResultArguments();
/**
* Convert the given Java value to its datastore equivalent. If this
* mapping occupies multiple columns, return an object array with one
* element per column. For relation id columns, return the state manager
* the column depends on.
*/
Object toEmbeddedDataStoreValue(Object val, JDBCStore store);
/**
* Convert the given datastore value to its Java equivalent.
* If {@link #getColumns} returns multiple columns, the given datastore
* value will be an object array of the corresponding length. This method
* must only be supported by mappings of embedded id objects. In other
* cases {@link #loadEmbedded} will be used instead. Return
* {@link #UNSUPPORTED} if this mapping cannot support this method.
*/
Object toEmbeddedObjectValue(Object val);
/**
* Load this strategy's field by transforming the given datastore value.
* If {@link #getColumns} returns multiple columns, the given datastore
* value will be an object array of the corresponding length. The value
* does not have to be loaded immediately; it may be stored as impl data.
*/
void loadEmbedded(OpenJPAStateManager sm, JDBCStore store,
JDBCFetchConfiguration fetch, Object val)
throws SQLException;
}