org.apache.openjpa.kernel.OpenJPASavepoint Maven / Gradle / Ivy
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* 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.kernel;
import java.io.Serializable;
import java.util.Collection;
import java.util.HashMap;
import java.util.Map;
/**
* Represents a savepoint where operations afterwards can be rolled
* back and restored to this point
*
* @author Steve Kim
* @since 0.3.4
*/
@SuppressWarnings("serial")
public class OpenJPASavepoint implements Serializable {
private final Broker _broker;
private final String _name;
private final boolean _copy;
private Map _saved;
/**
* Constructor. Indicate whether to copy field data into memory.
*/
public OpenJPASavepoint(Broker broker, String name, boolean copy) {
_broker = broker;
_name = name;
_copy = copy;
}
/**
* Return the Broker associated with this savepoint.
*/
public Broker getBroker() {
return _broker;
}
/**
* Return the name for this savepoint.
*/
public String getName() {
return _name;
}
/**
* Whether this savepoint copies the field values of retained instances.
*/
public boolean getCopyFieldState() {
return _copy;
}
/**
* Return the map of states to savepoint data.
*/
protected Map getStates() {
return _saved;
}
/**
* Set this savepoint, saving any state for the passed-in
* {@link OpenJPAStateManager}s as necessary.
*/
public void save(Collection states) {
if (_saved != null)
throw new IllegalStateException();
_saved = new HashMap((int) (states.size() * 1.33 + 1));
for (StateManagerImpl sm : states) {
_saved.put(sm, new SavepointFieldManager(sm, _copy));
}
}
/**
* Release this savepoint and any associated resources. Releases
* will happen in reverse order of creation.
*
* @param user if true, user initiated, otherwise a side effect of
* another savepoint's release/rollback
*/
public void release(boolean user) {
_saved = null;
}
/**
* Handle the rolled back state, returning saved data.
* Subclasses should return the collection returned from this method.
*
* @param previous previous savepoints set in the transaction
*/
public Collection rollback(Collection previous) {
Map saved;
if (previous.isEmpty())
saved = _saved;
else {
// merge all changes into one collection, allowing for later
// SavepointFieldManagers to replace previous ones.
saved = new HashMap();
for (OpenJPASavepoint savepoint : previous)
saved.putAll(savepoint.getStates());
saved.putAll(_saved);
}
_saved = null;
return saved.values ();
}
}