/**
* 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.camel.component.aws.ddbstream;
import java.math.BigInteger;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import com.amazonaws.services.dynamodbv2.model.Shard;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
class ShardList {
private final Logger log = LoggerFactory.getLogger(ShardList.class);
private final Map<String, Shard> shards = new HashMap<>();
void addAll(Collection<Shard> shards) {
for (Shard shard : shards) {
add(shard);
}
}
void add(Shard shard) {
shards.put(shard.getShardId(), shard);
}
Shard nextAfter(Shard previous) {
for (Shard shard : shards.values()) {
if (previous.getShardId().equals(shard.getParentShardId())) {
return shard;
}
}
throw new IllegalStateException("Unable to find the next shard for " + previous + " in " + shards);
}
Shard first() {
// Potential optimisation: if the two provided sequence numbers are the
// same then we can skip the shard entirely. Need to confirm this with AWS.
for (Shard shard : shards.values()) {
if (!shards.containsKey(shard.getParentShardId())) {
return shard;
}
}
throw new IllegalStateException("Unable to find an unparented shard in " + shards);
}
Shard last() {
Map<String, Shard> shardsByParent = new HashMap<>();
for (Shard shard : shards.values()) {
shardsByParent.put(shard.getParentShardId(), shard);
}
for (Shard shard : shards.values()) {
if (!shardsByParent.containsKey(shard.getShardId())) {
return shard;
}
}
throw new IllegalStateException("Unable to find a shard with no children " + shards);
}
Shard afterSeq(String sequenceNumber) {
return atAfterSeq(sequenceNumber, BigIntComparisons.Conditions.LT);
}
Shard atSeq(String sequenceNumber) {
return atAfterSeq(sequenceNumber, BigIntComparisons.Conditions.LTEQ);
}
Shard atAfterSeq(String sequenceNumber, BigIntComparisons condition) {
BigInteger atAfter = new BigInteger(sequenceNumber);
List<Shard> sorted = new ArrayList<>();
sorted.addAll(shards.values());
Collections.sort(sorted, StartingSequenceNumberComparator.INSTANCE);
for (Shard shard : sorted) {
if (shard.getSequenceNumberRange().getEndingSequenceNumber() != null) {
BigInteger end = new BigInteger(shard.getSequenceNumberRange().getEndingSequenceNumber());
// essentially: after < end or after <= end
if (condition.matches(atAfter, end)) {
return shard;
}
}
}
if (shards.size() > 0) {
return sorted.get(sorted.size() - 1);
}
throw new IllegalStateException("Unable to find a shard with appropriate sequence numbers for " + sequenceNumber + " in " + shards);
}
/**
* Removes shards that are older than the provided shard. Does not remove
* the provided shard.
*
* @param removeBefore
*/
void removeOlderThan(Shard removeBefore) {
String current = removeBefore.getParentShardId();
int removedShards = 0;
while (current != null) {
Shard s = shards.remove(current);
if (s == null) {
current = null;
} else {
removedShards++;
current = s.getParentShardId();
}
}
log.trace("removed {} shards from the store, new size is {}", removedShards, shards.size());
}
@Override
public String toString() {
return "ShardList{" + "shards=" + shards + '}';
}
private enum StartingSequenceNumberComparator implements Comparator<Shard> {
INSTANCE() {
@Override
public int compare(Shard o1, Shard o2) {
BigInteger i1 = new BigInteger(o1.getSequenceNumberRange().getStartingSequenceNumber());
BigInteger i2 = new BigInteger(o2.getSequenceNumberRange().getStartingSequenceNumber());
return i1.compareTo(i2);
}
}
}
}