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/*
Copyright (c) 2010 James Ahlborn
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
USA
*/
package com.healthmarketscience.jackcess.impl;
import java.io.IOException;
import java.nio.ByteBuffer;
/**
* Interface for a handler which can encode/decode a specific access page
* encoding.
*
* @author James Ahlborn
*/
public interface CodecHandler
{
/**
* Returns {@code true} if this handler can encode partial pages,
* {@code false} otherwise. If this method returns {@code false}, the
* {@link #encodePage} method will never be called with a non-zero
* pageOffset.
*/
public boolean canEncodePartialPage();
/**
* Returns {@code true} if this handler can decode a page inline,
* {@code false} otherwise. If this method returns {@code false}, the
* {@link #decodePage} method will always be called with separate buffers.
*/
public boolean canDecodeInline();
/**
* Decodes the given page buffer.
*
* @param inPage the page to be decoded
* @param outPage the decoded page. if {@link #canDecodeInline} is {@code
* true}, this will be the same buffer as inPage.
* @param pageNumber the page number of the given page
*
* @throws IOException if an exception occurs during decoding
*/
public void decodePage(ByteBuffer inPage, ByteBuffer outPage, int pageNumber)
throws IOException;
/**
* Encodes the given page buffer into a new page buffer and returns it. The
* returned page buffer will be used immediately and discarded so that it
* may be re-used for subsequent page encodings.
*
* @param page the page to be encoded, should not be modified
* @param pageNumber the page number of the given page
* @param pageOffset offset within the page at which to start writing the
* page data
*
* @throws IOException if an exception occurs during decoding
*
* @return the properly encoded page buffer for the given page buffer
*/
public ByteBuffer encodePage(ByteBuffer page, int pageNumber,
int pageOffset)
throws IOException;
}
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