/*
* 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.meta;
import java.util.Comparator;
import org.apache.openjpa.enhance.PersistenceCapable;
import org.apache.openjpa.kernel.OpenJPAStateManager;
import org.apache.openjpa.util.ApplicationIds;
import org.apache.openjpa.util.ImplHelper;
import org.apache.openjpa.conf.OpenJPAConfiguration;
/**
* Order by the field value in memory. If the field contains
* {@link PersistenceCapable} objects, order on their primary key values.
* Relies on primary key values, including datastore oid objects, being
* {@link Comparable}.
*
* @author Abe White
*/
class InMemoryValueOrder
implements Order, Comparator {
private final boolean _asc;
private final OpenJPAConfiguration _conf;
public InMemoryValueOrder(boolean asc, OpenJPAConfiguration conf) {
_asc = asc;
_conf = conf;
}
public String getName() {
return Order.ELEMENT;
}
public boolean isAscending() {
return _asc;
}
public Comparator getComparator() {
return this;
}
public int compare(Object o1, Object o2) {
if (o1 == o2)
return 0;
if (o1 == null)
return (_asc) ? -1 : 1;
if (o2 == null)
return (_asc) ? 1 : -1;
// non-pc values must be comparable
int cmp;
if (!(ImplHelper.isManageable(o1))
|| !(ImplHelper.isManageable(o2))) {
cmp = ((Comparable) o1).compareTo(o2);
return (_asc) ? cmp : -cmp;
}
// order on primary key values
PersistenceCapable pc1 = ImplHelper.toPersistenceCapable(o1, _conf);
PersistenceCapable pc2 = ImplHelper.toPersistenceCapable(o2, _conf);
OpenJPAStateManager sm1 = (OpenJPAStateManager) pc1.pcGetStateManager();
OpenJPAStateManager sm2 = (OpenJPAStateManager) pc2.pcGetStateManager();
if (sm1 == null || sm2 == null)
return 0;
Object[] pk1 = toPKValues(sm1);
Object[] pk2 = toPKValues(sm2);
int len = Math.min(pk1.length, pk2.length);
for (int i = 0; i < len; i++) {
if (pk1[i] == pk2[i])
return 0;
if (pk1[i] == null)
return (_asc) ? -1 : 1;
if (pk2[i] == null)
return (_asc) ? 1 : -1;
cmp = ((Comparable) pk1[i]).compareTo(pk2[i]);
if (cmp != 0)
return (_asc) ? cmp : -cmp;
}
cmp = pk1.length - pk2.length;
return (_asc) ? cmp : -cmp;
}
/**
* Convert the given state manager's oid to an array of (possibly null)
* primary key values.
*/
private static Object[] toPKValues(OpenJPAStateManager sm) {
if (sm.getMetaData().getIdentityType() != ClassMetaData.ID_APPLICATION)
return new Object[]{ sm.getObjectId() };
Object[] pks = ApplicationIds.toPKValues(sm.getObjectId(),
sm.getMetaData());
if (pks == null)
pks = new Object[]{ null };
return pks;
}
}