/*
* 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.xmlstore;
import java.util.ArrayList;
import java.util.BitSet;
import java.util.Collection;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import org.apache.openjpa.abstractstore.AbstractStoreManager;
import org.apache.openjpa.conf.OpenJPAConfiguration;
import org.apache.openjpa.kernel.FetchConfiguration;
import org.apache.openjpa.kernel.OpenJPAStateManager;
import org.apache.openjpa.kernel.PCState;
import org.apache.openjpa.lib.rop.ListResultObjectProvider;
import org.apache.openjpa.lib.rop.ResultObjectProvider;
import org.apache.openjpa.meta.ClassMetaData;
import org.apache.openjpa.util.OptimisticException;
import org.apache.openjpa.util.StoreException;
/**
* Store manager to a back-end consisting of XML files. This
* implementation accesses data through the {@link XMLStore} associated with
* its {@link XMLConfiguration}. Configuration instances are shared by all
* store managers owned by all brokers created with the same factory.
*
* @see AbstractStoreManager
*/
public class XMLStoreManager
extends AbstractStoreManager {
private XMLConfiguration _conf;
private XMLStore _store;
// changed data within the current transaction
private Collection _updates;
private Collection _deletes;
protected Collection getUnsupportedOptions() {
Collection c = super.getUnsupportedOptions();
// remove options we do support but the abstract store doesn't
c.remove(OpenJPAConfiguration.OPTION_ID_DATASTORE);
c.remove(OpenJPAConfiguration.OPTION_OPTIMISTIC);
// and add some that we don't support but the abstract store does
c.add(OpenJPAConfiguration.OPTION_EMBEDDED_RELATION);
c.add(OpenJPAConfiguration.OPTION_EMBEDDED_COLLECTION_RELATION);
c.add(OpenJPAConfiguration.OPTION_EMBEDDED_MAP_RELATION);
return c;
}
protected OpenJPAConfiguration newConfiguration() {
// override to use our configuration type
return new XMLConfiguration();
}
protected void open() {
// cache operational state
_conf = (XMLConfiguration) ctx.getConfiguration();
_store = _conf.getStore();
}
public boolean exists(OpenJPAStateManager sm, Object context) {
// see if the given object exists in the store
return _store.getData(sm.getMetaData(), sm.getObjectId()) != null;
}
/**
* Increment the version indicator in the given state manager.
*/
private static void incrementVersion(OpenJPAStateManager sm) {
long version = 0;
if (sm.getVersion() != null)
version = ((Long) sm.getVersion()).longValue() + 1;
sm.setNextVersion(version);
}
public boolean initialize(OpenJPAStateManager sm, PCState state,
FetchConfiguration fetch, Object context) {
// we may already have looked up the backing ObjectData (see our extent
// implementation below), and passed it through as the context; if
// not, then look it up in the store
ObjectData data;
if (context != null)
data = (ObjectData) context;
else
data = _store.getData(sm.getMetaData(), sm.getObjectId());
// no matching record?
if (data == null)
return false;
// initialize the state manager with a new instance of the right
// type and lifecycle state
sm.initialize(data.getMetaData().getDescribedType(), state);
// load the data from the ObjectData into the state mgr; note that
// this store manager doesn't do any locking -- it relies on the
// system's lock manager to lock after the load is complete
data.load(sm, fetch);
return true;
}
public boolean load(OpenJPAStateManager sm, BitSet fields,
FetchConfiguration fetch, int lockLevel, Object context) {
// we may already have looked up the backing ObjectData (see our extent
// implementation below), and passed it through as the context; if
// not, then look it up in the store
ObjectData data;
if (context != null)
data = (ObjectData) context;
else
data = _store.getData(sm.getMetaData(), sm.getObjectId());
// no matching record?
if (data == null)
return false;
// load the data from the ObjectData into the state mgr; note that
// this store manager doesn't do any locking -- it relies on the
// system's lock manager to lock after the load is complete
data.load(sm, fields, fetch);
return true;
}
public boolean syncVersion(OpenJPAStateManager sm, Object context) {
if (sm.getVersion() == null)
return false;
// we may already have looked up the backing ObjectData (see our extent
// implementation below), and passed it through as the context; if
// not, then look it up in the store
ObjectData data;
if (context != null)
data = (ObjectData) context;
else
data = _store.getData(sm.getMetaData(), sm.getObjectId());
// no record?
if (data == null)
return false;
// if the version of data held by the state mgr is the same as the
// version in the datastore, return true, letting the broker know that
// it doesn't need to load any more data
if (sm.getVersion().equals(data.getVersion()))
return true;
// set the version to be up-to-date, and return false letting
// the broker know that it needs to load up-to-date data
sm.setVersion(data.getVersion());
return false;
}
public void begin() {
_store.beginTransaction();
}
public void commit() {
try {
_store.endTransaction(_updates, _deletes);
} finally {
_updates = null;
_deletes = null;
}
}
public void rollback() {
_updates = null;
_deletes = null;
_store.endTransaction(null, null);
}
protected Collection flush(Collection pNew, Collection pNewUpdated,
Collection pNewFlushedDeleted, Collection pDirty, Collection pDeleted) {
// we don't support incremental flushing, so pNewUpdated and
// pNewFlushedDeleted should be empty; we ignore them here
// track optimistic violations
Collection exceps = new LinkedList();
// convert instances to ObjectDatas
_updates = new ArrayList(pNew.size() + pDirty.size());
_deletes = new ArrayList(pDeleted.size());
// convert additions
for (Iterator itr = pNew.iterator(); itr.hasNext();) {
// create new object data for instance
OpenJPAStateManager sm = (OpenJPAStateManager) itr.next();
Object oid = sm.getObjectId();
ObjectData data = _store.getData(sm.getMetaData(), oid);
if (data != null)
throw new StoreException("Attempt to insert "
+ "new object " + sm.getManagedInstance()
+ "with the same oid as an existing instance: " + oid).
setFatal(true);
data = new ObjectData(oid, sm.getMetaData());
incrementVersion(sm);
data.store(sm);
_updates.add(data);
}
// convert updates
for (Iterator itr = pDirty.iterator(); itr.hasNext();) {
OpenJPAStateManager sm = (OpenJPAStateManager) itr.next();
ObjectData data = _store.getData(sm.getMetaData(),
sm.getObjectId());
// if data has been deleted or has the wrong version, record
// opt lock violation
if (data == null || !data.getVersion().equals(sm.getVersion())) {
exceps.add(new OptimisticException
(sm.getManagedInstance()));
continue;
}
// store changes
incrementVersion(sm);
data = (ObjectData) data.clone();
data.store(sm);
_updates.add(data);
}
// convert deletes
for (Iterator itr = pDeleted.iterator(); itr.hasNext();) {
OpenJPAStateManager sm = (OpenJPAStateManager) itr.next();
ObjectData data = _store.getData(sm.getMetaData(),
sm.getObjectId());
// record delete
if (data != null)
_deletes.add(data);
}
return exceps;
}
public ResultObjectProvider executeExtent(ClassMetaData meta,
boolean subclasses, FetchConfiguration fetch) {
// ask the store for all ObjectDatas for the given type; this
// actually gives us all instances of the base class of the type
ObjectData[] datas = _store.getData(meta);
Class candidate = meta.getDescribedType();
// create a list of the corresponding persistent objects that
// match the type and subclasses criteria
List pcs = new ArrayList(datas.length);
for (int i = 0; i < datas.length; i++) {
// does this instance belong in the extent?
Class c = datas[i].getMetaData().getDescribedType();
if (c != candidate && (!subclasses
|| !candidate.isAssignableFrom(c)))
continue;
// look up the pc instance for the data, passing in the data
// as well so that we can take advantage of the fact that we've
// already looked it up. note that in the store manager's
// initialize(), load(), etc methods we check for this data
// being passed through and save ourselves a trip to the store
// if it is present; this is particularly important in systems
// where a trip to the store can be expensive.
pcs.add(ctx.find(datas[i].getId(), fetch, null, datas[i], 0));
}
return new ListResultObjectProvider(pcs);
}
public boolean isCached(List<Object> oids, BitSet edata) {
// XMLStoreManager does not cache oids.
return false;
}
}