/*
* 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.marshal;
import java.nio.ByteBuffer;
import org.apache.cassandra.serializers.TypeSerializer;
import org.apache.cassandra.serializers.EmptySerializer;
import org.apache.cassandra.serializers.MarshalException;
import org.apache.cassandra.utils.ByteBufferUtil;
/**
* A type that only accept empty data.
* It is only useful as a value validation type, not as a comparator since column names can't be empty.
*/
public class EmptyType extends AbstractType<Void>
{
public static final EmptyType instance = new EmptyType();
private EmptyType() {} // singleton
public int compare(ByteBuffer o1, ByteBuffer o2)
{
return 0;
}
public String getString(ByteBuffer bytes)
{
return "";
}
public ByteBuffer fromString(String source) throws MarshalException
{
if (!source.isEmpty())
throw new MarshalException(String.format("'%s' is not empty", source));
return ByteBufferUtil.EMPTY_BYTE_BUFFER;
}
public TypeSerializer<Void> getSerializer()
{
return EmptySerializer.instance;
}
}