/**
* Returns a new consistent hash of the same type with the given address removed.
*
* @param ch consistent hash to start with
* @param toRemove address to remove
* @param c configuration
* @return a new consistent hash instance of the same type
*/
public static ConsistentHash removeAddress(ConsistentHash ch, Address toRemove, Configuration c) {
if (ch instanceof UnionConsistentHash)
return removeAddressFromUnionConsistentHash((UnionConsistentHash) ch, toRemove, c);
else {
ConsistentHash newCH = constructConsistentHashInstance(c);
Set<Address> caches = new HashSet<Address>(ch.getCaches());
caches.remove(toRemove);
newCH.setCaches(caches);
return newCH;
}
}
/**
* Creates a new consistent hash instance based on the type specified, and populates the
* consistent hash with the collection of addresses passed in.
*
* @param template An older consistent hash instance to clone
* @param addresses with which to populate the consistent hash
* @return a new consistent hash instance
*/
public static ConsistentHash createConsistentHash(
ConsistentHash template, Collection<Address> addresses) {
Hash hf = null;
HashSeed hs = null;
int numVirtualNodes = 1;
GroupManager groupManager = null;
if (template instanceof AbstractWheelConsistentHash) {
AbstractWheelConsistentHash wTemplate = (AbstractWheelConsistentHash) template;
hf = wTemplate.hashFunction;
hs = wTemplate.hashSeed;
numVirtualNodes = wTemplate.numVirtualNodes;
groupManager = wTemplate.groupManager;
}
ConsistentHash ch =
constructConsistentHashInstance(template.getClass(), hf, hs, numVirtualNodes, groupManager);
if (addresses != null && !addresses.isEmpty()) ch.setCaches(toSet(addresses));
return ch;
}
/**
* Creates a new consistent hash instance based on the user's configuration, and populates the
* consistent hash with the collection of addresses passed in.
*
* @param c configuration
* @param addresses with which to populate the consistent hash
* @return a new consistent hash instance
*/
public static ConsistentHash createConsistentHash(
Configuration c, Collection<Address> addresses) {
ConsistentHash ch = constructConsistentHashInstance(c);
ch.setCaches(toSet(addresses));
return ch;
}
