/**
* 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.IOException;
import java.nio.ByteBuffer;
import java.security.MessageDigest;
import org.apache.cassandra.config.CFMetaData;
import org.apache.cassandra.db.marshal.AbstractType;
import org.apache.cassandra.db.marshal.MarshalException;
import org.apache.cassandra.io.IColumnSerializer;
import org.apache.cassandra.io.util.DataOutputBuffer;
import org.apache.cassandra.utils.Allocator;
import org.apache.cassandra.utils.ByteBufferUtil;
import org.apache.cassandra.utils.HeapAllocator;
/**
* Alternative to Column that have an expiring time.
* ExpiringColumn is immutable (as Column is).
*
* Note that ExpiringColumn does not override Column.getMarkedForDeleteAt,
* which means that it's in the somewhat unintuitive position of being deleted (after its expiration)
* without having a time-at-which-it-became-deleted. (Because ttl is a server-side measurement,
* we can't mix it with the timestamp field, which is client-supplied and whose resolution we
* can't assume anything about.)
*/
public class ExpiringColumn extends Column
{
private final int localExpirationTime;
private final int timeToLive;
public ExpiringColumn(ByteBuffer name, ByteBuffer value, long timestamp, int timeToLive)
{
this(name, value, timestamp, timeToLive, (int) (System.currentTimeMillis() / 1000) + timeToLive);
}
public ExpiringColumn(ByteBuffer name, ByteBuffer value, long timestamp, int timeToLive, int localExpirationTime)
{
super(name, value, timestamp);
assert timeToLive > 0 : timeToLive;
assert localExpirationTime > 0 : localExpirationTime;
this.timeToLive = timeToLive;
this.localExpirationTime = localExpirationTime;
}
/** @return Either a DeletedColumn, or an ExpiringColumn. */
public static Column create(ByteBuffer name, ByteBuffer value, long timestamp, int timeToLive, int localExpirationTime, int expireBefore, IColumnSerializer.Flag flag)
{
if (localExpirationTime >= expireBefore || flag == IColumnSerializer.Flag.PRESERVE_SIZE)
return new ExpiringColumn(name, value, timestamp, timeToLive, localExpirationTime);
// the column is now expired, we can safely return a simple tombstone
return new DeletedColumn(name, localExpirationTime, timestamp);
}
public int getTimeToLive()
{
return timeToLive;
}
@Override
public boolean isMarkedForDelete()
{
return (int) (System.currentTimeMillis() / 1000 ) > localExpirationTime;
}
@Override
public int size()
{
/*
* An expired column adds to a Column :
* 4 bytes for the localExpirationTime
* + 4 bytes for the timeToLive
*/
return super.size() + DBConstants.intSize + DBConstants.intSize;
}
@Override
public void updateDigest(MessageDigest digest)
{
digest.update(name.duplicate());
digest.update(value.duplicate());
DataOutputBuffer buffer = new DataOutputBuffer();
try
{
buffer.writeLong(timestamp);
buffer.writeByte(serializationFlags());
buffer.writeInt(timeToLive);
}
catch (IOException e)
{
throw new RuntimeException(e);
}
digest.update(buffer.getData(), 0, buffer.getLength());
}
@Override
public int getLocalDeletionTime()
{
return localExpirationTime;
}
@Override
public IColumn localCopy(ColumnFamilyStore cfs)
{
return new ExpiringColumn(cfs.internOrCopy(name, HeapAllocator.instance), ByteBufferUtil.clone(value), timestamp, timeToLive, localExpirationTime);
}
@Override
public IColumn localCopy(ColumnFamilyStore cfs, Allocator allocator)
{
ByteBuffer clonedName = cfs.maybeIntern(name);
if (clonedName == null)
clonedName = allocator.clone(name);
return new ExpiringColumn(clonedName, allocator.clone(value), timestamp, timeToLive, localExpirationTime);
}
@Override
public String getString(AbstractType comparator)
{
StringBuilder sb = new StringBuilder();
sb.append(super.getString(comparator));
sb.append("!");
sb.append(timeToLive);
return sb.toString();
}
@Override
public long getMarkedForDeleteAt()
{
if (isMarkedForDelete())
{
return timestamp;
}
else
{
throw new IllegalStateException("column is not marked for delete");
}
}
@Override
public int serializationFlags()
{
return ColumnSerializer.EXPIRATION_MASK;
}
@Override
public void validateFields(CFMetaData metadata) throws MarshalException
{
super.validateFields(metadata);
if (timeToLive <= 0)
throw new MarshalException("A column TTL should be > 0");
if (localExpirationTime < 0)
throw new MarshalException("The local expiration time should not be negative");
}
}