| /* |
| * 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.io.util; |
| |
| import java.nio.ByteBuffer; |
| |
| import org.apache.cassandra.io.compress.BufferType; |
| |
| /** |
| * RandomFileReader component that reads data from a file into a provided buffer and may have requirements over the |
| * size and alignment of reads. |
| * A caching or buffer-managing rebufferer will reference one of these to do the actual reading. |
| * Note: Implementations of this interface must be thread-safe! |
| */ |
| public interface ChunkReader extends RebuffererFactory |
| { |
| /** |
| * Read the chunk at the given position, attempting to fill the capacity of the given buffer. |
| * The filled buffer must be positioned at 0, with limit set at the size of the available data. |
| * The source may have requirements for the positioning and/or size of the buffer (e.g. chunk-aligned and |
| * chunk-sized). These must be satisfied by the caller. |
| */ |
| void readChunk(long position, ByteBuffer buffer); |
| |
| /** |
| * Buffer size required for this rebufferer. Must be power of 2 if alignment is required. |
| */ |
| int chunkSize(); |
| |
| /** |
| * If true, positions passed to this rebufferer must be aligned to chunkSize. |
| */ |
| boolean alignmentRequired(); |
| |
| /** |
| * Specifies type of buffer the caller should attempt to give. |
| * This is not guaranteed to be fulfilled. |
| */ |
| BufferType preferredBufferType(); |
| } |