/*
* 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.service.pager;
import java.io.DataInputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import org.apache.cassandra.io.util.DataOutputBuffer;
import org.apache.cassandra.transport.ProtocolException;
import org.apache.cassandra.utils.ByteBufferUtil;
public class PagingState
{
public final ByteBuffer partitionKey;
public final ByteBuffer cellName;
public final int remaining;
public PagingState(ByteBuffer partitionKey, ByteBuffer cellName, int remaining)
{
this.partitionKey = partitionKey == null ? ByteBufferUtil.EMPTY_BYTE_BUFFER : partitionKey;
this.cellName = cellName == null ? ByteBufferUtil.EMPTY_BYTE_BUFFER : cellName;
this.remaining = remaining;
}
public static PagingState deserialize(ByteBuffer bytes)
{
if (bytes == null)
return null;
try
{
DataInputStream in = new DataInputStream(ByteBufferUtil.inputStream(bytes));
ByteBuffer pk = ByteBufferUtil.readWithShortLength(in);
ByteBuffer cn = ByteBufferUtil.readWithShortLength(in);
int remaining = in.readInt();
return new PagingState(pk, cn, remaining);
}
catch (IOException e)
{
throw new ProtocolException("Invalid value for the paging state");
}
}
public ByteBuffer serialize()
{
try
{
DataOutputBuffer out = new DataOutputBuffer(serializedSize());
ByteBufferUtil.writeWithShortLength(partitionKey, out);
ByteBufferUtil.writeWithShortLength(cellName, out);
out.writeInt(remaining);
return out.asByteBuffer();
}
catch (IOException e)
{
throw new RuntimeException(e);
}
}
private int serializedSize()
{
return 2 + partitionKey.remaining()
+ 2 + cellName.remaining()
+ 4;
}
@Override
public String toString()
{
return String.format("PagingState(key=%s, cellname=%s, remaining=%d", ByteBufferUtil.bytesToHex(partitionKey), ByteBufferUtil.bytesToHex(cellName), remaining);
}
}