/**
* 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.cassandra.db;
import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.util.Comparator;
import org.apache.cassandra.dht.IPartitioner;
import org.apache.cassandra.dht.Token;
import org.apache.cassandra.io.ICompactSerializer2;
import org.apache.cassandra.service.StorageService;
import org.apache.cassandra.utils.FBUtilities;
/**
* Represents a decorated key, handy for certain operations
* where just working with strings gets slow.
*
* We do a lot of sorting of DecoratedKeys, so for speed, we assume that tokens correspond one-to-one with keys.
* This is not quite correct in the case of RandomPartitioner (which uses MD5 to hash keys to tokens);
* if this matters, you can subclass RP to use a stronger hash, or use a non-lossy tokenization scheme (as in the
* OrderPreservingPartitioner classes).
*/
public class DecoratedKey<T extends Token> implements Comparable<DecoratedKey>
{
private static DecoratedKeySerializer serializer = new DecoratedKeySerializer();
private static IPartitioner partitioner = StorageService.getPartitioner();
public static DecoratedKeySerializer serializer()
{
return serializer;
}
public static final Comparator<DecoratedKey> comparator = new Comparator<DecoratedKey>()
{
public int compare(DecoratedKey o1, DecoratedKey o2)
{
return o1.compareTo(o2);
}
};
public final T token;
public final String key;
public DecoratedKey(T token, String key)
{
super();
assert token != null;
this.token = token;
this.key = key;
}
@Override
public int hashCode()
{
return token.hashCode();
}
@Override
public boolean equals(Object obj)
{
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
DecoratedKey other = (DecoratedKey) obj;
return token.equals(other.token);
}
public int compareTo(DecoratedKey other)
{
return token.compareTo(other.token);
}
public boolean isEmpty()
{
return token.equals(partitioner.getMinimumToken());
}
@Override
public String toString()
{
return "DecoratedKey(" + token + ", " + key + ")";
}
}
class DecoratedKeySerializer implements ICompactSerializer2<DecoratedKey>
{
public void serialize(DecoratedKey dk, DataOutput dos) throws IOException
{
Token.serializer().serialize(dk.token, dos);
FBUtilities.writeNullableString(dk.key, dos);
}
public DecoratedKey deserialize(DataInput dis) throws IOException
{
return new DecoratedKey(Token.serializer().deserialize(dis), FBUtilities.readNullableString(dis));
}
}