/*
*
* * 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
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package org.apache.usergrid.persistence.graph.serialization.impl.shard.impl.comparators;
import java.util.Comparator;
import java.util.UUID;
import org.apache.usergrid.persistence.graph.MarkedEdge;
import org.apache.usergrid.persistence.model.entity.Id;
import com.fasterxml.uuid.UUIDComparator;
import com.fasterxml.uuid.impl.UUIDUtil;
/**
* Comparator for comparing edges in descending order. The first comparison is the timestamp,
* highest value should be first, so is considered "less". If those are equal, the UUIId is compared.
* this will return the UUID to compare. It will first be descending UUID, then ascending name
*
*/
public abstract class DirectedEdgeDescendingComparator implements Comparator<MarkedEdge> {
@Override
public int compare( final MarkedEdge first, final MarkedEdge second ) {
int compare = Long.compare( first.getTimestamp(), second.getTimestamp() ) * -1;
if(compare == 0){
final Id firstId = getId( first );
final Id secondId = getId( second );
compare = UUIDComparator.staticCompare( firstId.getUuid(), secondId.getUuid() ) * -1;
if(compare == 0){
compare = firstId.getType().compareTo( secondId.getType() );
}
}
return compare;
}
/**
* Return the Id to be used in the comparison
* @param edge
* @return
*/
protected abstract Id getId(final MarkedEdge edge);
}