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/*
* Copyright (c) OSGi Alliance (2015, 2017). All Rights Reserved.
*
* Licensed 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.osgi.util.pushstream;
import static java.util.Optional.ofNullable;
import static org.osgi.util.pushstream.AbstractPushStreamImpl.State.*;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.atomic.AtomicReference;
import java.util.function.Function;
class UnbufferedPushStreamImpl<T, U extends BlockingQueue<PushEvent< ? extends T>>>
extends AbstractPushStreamImpl<T> implements PushStream<T> {
protected final Function<PushEventConsumer<T>,AutoCloseable> connector;
protected final AtomicReference<AutoCloseable> upstream = new AtomicReference<AutoCloseable>();
UnbufferedPushStreamImpl(PushStreamProvider psp,
PushStreamExecutors executors,
Function<PushEventConsumer<T>,AutoCloseable> connector) {
super(psp, executors);
this.connector = connector;
}
@Override
protected boolean close(PushEvent<T> event, boolean sendDownStreamEvent) {
if (super.close(event, sendDownStreamEvent)) {
upstreamClose(event);
return true;
}
return false;
}
@Override
protected void upstreamClose(PushEvent< ? > close) {
ofNullable(upstream.getAndSet(() -> {
// This block doesn't need to do anything, but the presence
// of the Closable is needed to prevent duplicate begins
})).ifPresent(c -> {
try {
c.close();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
});
}
@Override
protected boolean begin() {
if(closed.compareAndSet(BUILDING, STARTED)) {
AutoCloseable toClose = connector.apply(this::handleEvent);
if(!upstream.compareAndSet(null,toClose)) {
//TODO log that we tried to connect twice...
try {
toClose.close();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (closed.get() == CLOSED
&& upstream.compareAndSet(toClose, null)) {
// We closed before setting the upstream - close it now
try {
toClose.close();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
return true;
}
return false;
}
}
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