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Easy Redis Java client and Real-Time Data Platform. Valkey compatible. Sync/Async/RxJava3/Reactive API. Client side caching. Over 50 Redis based Java objects and services: JCache API, Apache Tomcat, Hibernate, Spring, Set, Multimap, SortedSet, Map, List, Queue, Deque, Semaphore, Lock, AtomicLong, Map Reduce, Bloom filter, Scheduler, RPC
/**
* Copyright (c) 2013-2024 Nikita Koksharov
*
* 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.redisson.iterator;
import java.util.Iterator;
import java.util.NoSuchElementException;
import org.redisson.ScanResult;
import org.redisson.client.RedisClient;
import org.redisson.client.RedisNodeNotFoundException;
/**
*
* @author Nikita Koksharov
*
* @param entry type
* @param value type
*/
public abstract class BaseIterator implements Iterator {
private Iterator lastIter;
protected String nextIterPos = "0";
protected RedisClient client;
private boolean finished;
private boolean currentElementRemoved;
protected E value;
protected void reset() {
}
@Override
public boolean hasNext() {
if (lastIter == null || !lastIter.hasNext()) {
if (finished) {
currentElementRemoved = false;
client = null;
nextIterPos = "0";
if (!tryAgain()) {
return false;
}
finished = false;
}
do {
ScanResult res;
try {
res = iterator(client, nextIterPos);
} catch (RedisNodeNotFoundException e) {
if (client != null) {
client = null;
nextIterPos = "0";
}
reset();
res = iterator(client, nextIterPos);
}
client = res.getRedisClient();
lastIter = res.getValues().iterator();
nextIterPos = res.getPos();
if ("0".equals(res.getPos())) {
finished = true;
if (res.getValues().isEmpty()) {
currentElementRemoved = false;
client = null;
nextIterPos = "0";
if (tryAgain()) {
continue;
}
return false;
}
}
} while (!lastIter.hasNext());
}
return lastIter.hasNext();
}
protected boolean tryAgain() {
return false;
}
protected abstract ScanResult iterator(RedisClient client, String nextIterPos);
@Override
public V next() {
if (!hasNext()) {
throw new NoSuchElementException("No such element");
}
value = lastIter.next();
currentElementRemoved = false;
return getValue(value);
}
protected abstract V getValue(E entry);
@Override
public void remove() {
if (currentElementRemoved) {
throw new IllegalStateException("Element been already deleted");
}
if (lastIter == null || value == null) {
throw new IllegalStateException();
}
lastIter.remove();
remove(value);
currentElementRemoved = true;
}
protected abstract void remove(E value);
}
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