org.apache.cassandra.locator.AbstractEndpointSnitch Maven / Gradle / Ivy
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* to you under the Apache License, Version 2.0 (the
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* 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
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*/
package org.apache.cassandra.locator;
import java.net.InetAddress;
import java.util.*;
import org.apache.cassandra.config.DatabaseDescriptor;
public abstract class AbstractEndpointSnitch implements IEndpointSnitch
{
public abstract int compareEndpoints(InetAddress target, InetAddress a1, InetAddress a2);
/**
* Sorts the Collection of node addresses by proximity to the given address
* @param address the address to sort by proximity to
* @param unsortedAddress the nodes to sort
* @return a new sorted List
*/
public List getSortedListByProximity(InetAddress address, Collection unsortedAddress)
{
List preferred = new ArrayList(unsortedAddress);
sortByProximity(address, preferred);
return preferred;
}
/**
* Sorts the List of node addresses, in-place, by proximity to the given address
* @param address the address to sort the proximity by
* @param addresses the nodes to sort
*/
public void sortByProximity(final InetAddress address, List addresses)
{
Collections.sort(addresses, new Comparator()
{
public int compare(InetAddress a1, InetAddress a2)
{
return compareEndpoints(address, a1, a2);
}
});
}
public void gossiperStarting()
{
// noop by default
}
public boolean isWorthMergingForRangeQuery(List merged, List l1, List l2)
{
// Querying remote DC is likely to be an order of magnitude slower than
// querying locally, so 2 queries to local nodes is likely to still be
// faster than 1 query involving remote ones
boolean mergedHasRemote = hasRemoteNode(merged);
return mergedHasRemote
? hasRemoteNode(l1) || hasRemoteNode(l2)
: true;
}
private boolean hasRemoteNode(List l)
{
String localDc = DatabaseDescriptor.getLocalDataCenter();
for (InetAddress ep : l)
{
if (!localDc.equals(getDatacenter(ep)))
return true;
}
return false;
}
}