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Oracle Coherence Community Edition
/*
* Copyright (c) 2000, 2020, Oracle and/or its affiliates.
*
* Licensed under the Universal Permissive License v 1.0 as shown at
* http://oss.oracle.com/licenses/upl.
*/
package com.tangosol.net;
import com.tangosol.util.Base;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.SortedMap;
import java.util.TreeMap;
/**
* A simple ServiceLoadBalancer implementation.
*
* @author jh 2010.12.07
*/
public class SimpleServiceLoadBalancer
extends AbstractServiceLoadBalancer
{
/**
* Default constructor.
*/
public SimpleServiceLoadBalancer()
{
this(null);
}
/**
* Create a new SimpleServiceLoadBalancer that will order
* ServiceLoad objects using the specified Comparator. If null, the
* natural ordering of the ServiceLoad objects will be used.
*
* @param comparator the Comparator used to order ServiceLoad
* objects
*/
public SimpleServiceLoadBalancer(Comparator comparator)
{
m_mapLoad = new HashMap<>();
m_mapMember = new TreeMap<>(comparator);
}
// ----- ServiceLoadBalancer interface ---------------------------------
/**
* {@inheritDoc}
*/
@Override
public synchronized void update(Member member, T load)
{
if (load == null && isLocalMember(member))
{
// we have left the cluster
m_mapLoad.clear();
m_mapMember.clear();
return;
}
Map mapLoad = m_mapLoad;
Map> mapMember = m_mapMember;
T loadOld = mapLoad.remove(member);
if (loadOld != null)
{
List listMembersOld = mapMember.get(loadOld);
if (listMembersOld != null && listMembersOld.remove(member) &&
listMembersOld.isEmpty())
{
mapMember.remove(loadOld);
}
}
if (load != null)
{
mapLoad.put(member, load);
List listMembers = mapMember.get(load);
if (listMembers == null)
{
mapMember.put(load, listMembers = new ArrayList<>());
}
listMembers.add(member);
}
}
/**
* {@inheritDoc}
*/
@Override
public synchronized List getMemberList(Member client)
{
SortedMap> mapMember = m_mapMember;
if (mapMember.isEmpty())
{
return null;
}
List list = new ArrayList<>();
for (List listMember : mapMember.values())
{
list.addAll(Base.randomize(listMember));
}
return list;
}
@Override
public int compare(T load1, T load2)
{
Comparator comparator = m_mapMember.comparator();
return comparator == null
? load1.compareTo(load2)
: comparator.compare(load1, load2);
}
// ----- data members ---------------------------------------------------
/**
* A Map of ServiceLoad objects keyed by their associated Member.
*/
protected final Map m_mapLoad;
/**
* A SortedMap of List of Member objects keyed by their associated
* ServiceLoad.
*/
protected final SortedMap> m_mapMember;
}