/*
* 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.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.NoSuchElementException;
import org.apache.commons.collections.Predicate;
import org.apache.commons.collections.iterators.FilterIterator;
import org.apache.commons.collections.iterators.IteratorChain;
import org.apache.openjpa.lib.rop.ResultObjectProvider;
import org.apache.openjpa.lib.rop.ResultObjectProviderIterator;
import org.apache.openjpa.lib.util.Closeable;
import org.apache.openjpa.lib.util.ReferenceHashSet;
import java.util.concurrent.locks.ReentrantLock;
import org.apache.openjpa.meta.ClassMetaData;
import org.apache.openjpa.meta.MetaDataRepository;
import org.apache.openjpa.util.GeneralException;
import org.apache.openjpa.util.ImplHelper;
import org.apache.openjpa.util.OpenJPAException;
/**
* Representation of all members of a persistent class.
*
* @author Abe White
* @author Patrick Linskey
*/
public class ExtentImpl<T>
implements Extent<T> {
private static final ClassMetaData[] EMPTY_METAS = new ClassMetaData[0];
private final Broker _broker;
private final Class<T> _type;
private final boolean _subs;
private final FetchConfiguration _fc;
private final ReentrantLock _lock;
private boolean _ignore = false;
// set of open iterators
private ReferenceHashSet _openItrs = null;
/**
* Constructor.
*
* @param broker the owning broker
* @param type the candidate class
* @param subs whether subclasses are included in the extent
*/
ExtentImpl(Broker broker, Class<T> type, boolean subs,
FetchConfiguration fetch) {
_broker = broker;
_type = type;
_subs = subs;
if (fetch != null)
_fc = fetch;
else
_fc = (FetchConfiguration) broker.getFetchConfiguration().clone();
_ignore = broker.getIgnoreChanges();
if (broker.getMultithreaded())
_lock = new ReentrantLock();
else
_lock = null;
}
public FetchConfiguration getFetchConfiguration() {
return _fc;
}
public boolean getIgnoreChanges() {
return _ignore;
}
public void setIgnoreChanges(boolean ignoreChanges) {
_broker.assertOpen();
_ignore = ignoreChanges;
}
public List<T> list() {
List<T> list = new ArrayList<T>();
Iterator<T> itr = iterator();
try {
while (itr.hasNext())
list.add(itr.next());
return list;
} finally {
ImplHelper.close(itr);
}
}
public Iterator<T> iterator() {
_broker.assertNontransactionalRead();
CloseableIterator citr = null;
try {
// create an iterator chain; add pnew objects if transactional
CloseableIteratorChain chain = new CloseableIteratorChain();
boolean trans = !_ignore && _broker.isActive();
if (trans)
chain.addIterator(new FilterNewIterator());
// add database iterators for each implementing class
MetaDataRepository repos = _broker.getConfiguration().
getMetaDataRepositoryInstance();
ClassMetaData meta = repos.getMetaData(_type,
_broker.getClassLoader(), false);
ClassMetaData[] metas;
if (meta != null && (!_subs || !meta.isManagedInterface())
&& (meta.isMapped() || (_subs
&& meta.getMappedPCSubclassMetaDatas().length > 0)))
metas = new ClassMetaData[]{ meta };
else if (_subs && (meta == null || meta.isManagedInterface()))
metas = repos.getImplementorMetaDatas(_type,
_broker.getClassLoader(), false);
else
metas = EMPTY_METAS;
ResultObjectProvider rop;
for (int i = 0; i < metas.length; i++) {
rop = _broker.getStoreManager().executeExtent(metas[i],
_subs, _fc);
if (rop != null)
chain.addIterator(new ResultObjectProviderIterator(rop));
}
// filter deleted objects if transactional
if (trans)
citr = new FilterDeletedIterator(chain);
else
citr = chain;
citr.setRemoveOnClose(this);
} catch (OpenJPAException ke) {
throw ke;
} catch (RuntimeException re) {
throw new GeneralException(re);
}
lock();
try {
if (_openItrs == null)
_openItrs = new ReferenceHashSet(ReferenceHashSet.WEAK);
_openItrs.add(citr);
} finally {
unlock();
}
return citr;
}
public Broker getBroker() {
return _broker;
}
public Class<T> getElementType() {
return _type;
}
public boolean hasSubclasses() {
return _subs;
}
public void closeAll() {
if (_openItrs == null)
return;
lock();
try {
CloseableIterator citr;
for (Iterator itr = _openItrs.iterator(); itr.hasNext();) {
citr = (CloseableIterator) itr.next();
citr.setRemoveOnClose(null);
try {
citr.close();
} catch (Exception e) {
}
}
_openItrs.clear();
} catch (OpenJPAException ke) {
throw ke;
} catch (RuntimeException re) {
throw new GeneralException(re);
} finally {
unlock();
}
}
public void lock() {
if (_lock != null)
_lock.lock();
}
public void unlock() {
if (_lock != null)
_lock.unlock();
}
/**
* Closeable iterator.
*/
private static interface CloseableIterator<T>
extends Closeable, Iterator<T> {
/**
* Set the extent to remove self from on close.
*/
public void setRemoveOnClose(ExtentImpl<T> extent);
}
/**
* Closeable {@link IteratorChain}.
*/
private static class CloseableIteratorChain
extends IteratorChain
implements CloseableIterator {
private ExtentImpl<?> _extent = null;
private boolean _closed = false;
public boolean hasNext() {
return (_closed) ? false : super.hasNext();
}
public Object next() {
if (_closed)
throw new NoSuchElementException();
return super.next();
}
public void remove() {
throw new UnsupportedOperationException();
}
public void setRemoveOnClose(ExtentImpl extent) {
_extent = extent;
}
public void close()
throws Exception {
if (_extent != null && _extent._openItrs != null) {
_extent.lock();
try {
_extent._openItrs.remove(this);
} finally {
_extent.unlock();
}
}
_closed = true;
for (Iterator itr = getIterators().iterator(); itr.hasNext();)
((Closeable) itr.next()).close();
}
}
/**
* {@link FilterIterator} that skips deleted objects.
*/
private static class FilterDeletedIterator
extends FilterIterator
implements CloseableIterator, Predicate {
private ExtentImpl _extent = null;
private boolean _closed = false;
public FilterDeletedIterator(Iterator itr) {
super(itr);
setPredicate(this);
}
public boolean hasNext() {
return (_closed) ? false : super.hasNext();
}
public Object next() {
if (_closed)
throw new NoSuchElementException();
return super.next();
}
public void remove() {
throw new UnsupportedOperationException();
}
public void setRemoveOnClose(ExtentImpl extent) {
_extent = extent;
}
public void close()
throws Exception {
if (_extent != null && _extent._openItrs != null) {
_extent.lock();
try {
_extent._openItrs.remove(this);
} finally {
_extent.unlock();
}
}
_closed = true;
((Closeable) getIterator()).close();
}
public boolean evaluate(Object o) {
return !_extent._broker.isDeleted(o);
}
}
/**
* Iterator over all new objects in this extent. This iterator is always
* wrapped, so it doesn't need to keep track of whether it's closed.
*/
private class FilterNewIterator
extends FilterIterator
implements Closeable, Predicate {
public FilterNewIterator() {
super(_broker.getTransactionalObjects().iterator());
setPredicate(this);
}
public void close() {
}
public boolean evaluate(Object o) {
if (!_broker.isNew(o))
return false;
Class<?> type = o.getClass();
if (!_subs && type != _type)
return false;
if (_subs && !_type.isAssignableFrom(type))
return false;
return true;
}
}
}