/*
* Copyright (C) 2013 The Async HBase Authors. All rights reserved.
* This file is part of Async HBase.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* - Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* - Neither the name of the StumbleUpon nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
package org.hbase.async;
import org.jboss.netty.buffer.ChannelBuffer;
/**
* Abstract base class for {@link org.hbase.async.Scanner} filters.
* <p>
* These filters are executed on the server side, inside the
* {@code RegionServer}, while scanning. They are useful to
* prune uninteresting data before it gets to the network,
* but remember that the {@code RegionServer} still has to
* load the data before it can know whether the filter passes
* or not, so it's generally not efficient to filter out large
* amounts of data.
* <p>
* Subclasses are guaranteed to be immutable and are thus
* thread-safe as well as usable concurrently on multiple
* {@link org.hbase.async.Scanner} instances.
* @since 1.5
*/
public abstract class ScanFilter {
/** Package-private constructor to avoid sub-classing outside this package. */
ScanFilter() {
}
/**
* Returns the name of this scanner on the wire.
* <p>
* This method is only used with HBase 0.95 and newer.
* The contents of the array returned MUST NOT be modified.
*/
abstract byte[] name();
/**
* Serializes the byte representation to a protobuf in a byte array.
* <p>
* This method is only used with HBase 0.95 and newer.
*/
abstract byte[] serialize();
/**
* Serializes the byte representation to the RPC channel buffer.
* <p>
* This method is only used with HBase 0.94 and before.
* @param buf The RPC channel buffer to which the byte array is serialized
*/
abstract void serializeOld(ChannelBuffer buf);
/**
* returns the number of bytes that it will write to the RPC channel buffer when {@code serialize}
* is called. This method helps predict the initial size of the byte array
* <p>
* This method is only used with HBase 0.94 and before.
* @return A strictly positive integer
*/
abstract int predictSerializedSize();
}