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- /*
- Copyright (c) 2016 James Ahlborn
-
- Licensed 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 com.healthmarketscience.jackcess.util;
-
- import java.io.IOException;
- import java.nio.ByteBuffer;
- import java.nio.MappedByteBuffer;
- import java.nio.channels.FileChannel;
- import java.nio.channels.FileLock;
- import java.nio.channels.NonWritableChannelException;
- import java.nio.channels.ReadableByteChannel;
- import java.nio.channels.WritableByteChannel;
- import com.healthmarketscience.jackcess.Database;
-
- /**
- * Wrapper for existing FileChannel which is read-only.
- * <p>
- * Implementation note: this class is optimized for use with {@link Database}.
- * Therefore not all methods may be implemented.
- *
- * @author James Ahlborn
- * @usage _advanced_class_
- */
- public class ReadOnlyFileChannel extends FileChannel
- {
- private final FileChannel _delegate;
-
- public ReadOnlyFileChannel(FileChannel delegate) {
- _delegate = delegate;
- }
-
- @Override
- public int read(ByteBuffer dst) throws IOException {
- return _delegate.read(dst);
- }
-
- @Override
- public long read(ByteBuffer[] dsts, int offset, int length) throws IOException {
- return _delegate.read(dsts, offset, length);
- }
-
- @Override
- public int read(ByteBuffer dst, long position) throws IOException {
- return _delegate.read(dst, position);
- }
-
- @Override
- public long position() throws IOException {
- return _delegate.position();
- }
-
- @Override
- public FileChannel position(long newPosition) throws IOException {
- _delegate.position(newPosition);
- return this;
- }
-
- @Override
- public long size() throws IOException {
- return _delegate.size();
- }
-
- @Override
- public FileChannel truncate(long size) throws IOException {
- throw new NonWritableChannelException();
- }
-
- @Override
- public void force(boolean metaData) throws IOException {
- // do nothing
- }
-
- @Override
- public long transferTo(long position, long count, WritableByteChannel target)
- throws IOException
- {
- return _delegate.transferTo(position, count, target);
- }
-
- @Override
- public long transferFrom(ReadableByteChannel src, long position, long count)
- throws IOException
- {
- throw new NonWritableChannelException();
- }
-
- @Override
- public int write(ByteBuffer src, long position) throws IOException {
- throw new NonWritableChannelException();
- }
-
-
- @Override
- public int write(ByteBuffer src) throws IOException {
- throw new NonWritableChannelException();
- }
-
- @Override
- public long write(ByteBuffer[] srcs, int offset, int length)
- throws IOException
- {
- throw new NonWritableChannelException();
- }
-
- @Override
- public MappedByteBuffer map(MapMode mode, long position, long size)
- throws IOException
- {
- throw new UnsupportedOperationException();
- }
-
- @Override
- public FileLock lock(long position, long size, boolean shared)
- throws IOException
- {
- throw new UnsupportedOperationException();
- }
-
- @Override
- public FileLock tryLock(long position, long size, boolean shared)
- throws IOException
- {
- throw new UnsupportedOperationException();
- }
-
- @Override
- protected void implCloseChannel() throws IOException {
- _delegate.close();
- }
- }
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