io.questdb.mp.SPSequence Maven / Gradle / Ivy
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* / _ \ _ _ ___ ___| |_| _ \| __ )
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* | |_| | |_| | __/\__ \ |_| |_| | |_) |
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*
* Copyright (c) 2014-2019 Appsicle
* Copyright (c) 2019-2020 QuestDB
*
* 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 io.questdb.mp;
public class SPSequence extends AbstractSSequence {
private final int cycle;
private SPSequence(int cycle, WaitStrategy waitStrategy) {
super(waitStrategy);
this.cycle = cycle;
}
public SPSequence(int cycle) {
this(cycle, NullWaitStrategy.INSTANCE);
}
public long available() {
return cache + cycle + 1;
}
@Override
public long availableIndex(long lo) {
return value;
}
@Override
public long current() {
return value;
}
@Override
public void done(long cursor) {
value = cursor;
barrier.getWaitStrategy().signal();
}
@Override
public long next() {
long next = getValue() + 1;
long lo = next - cycle;
return lo > cache && lo > (cache = barrier.availableIndex(lo)) ? -1 : next;
}
}