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Add BufferedStreamHandle
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‎src/main/java/org/scijava/io/handle/BufferedStreamHandle.java

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/*
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* #%L
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* SciJava Common shared library for SciJava software.
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* %%
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* Copyright (C) 2009 - 2017 Board of Regents of the University of
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* Wisconsin-Madison, Broad Institute of MIT and Harvard, and Max Planck
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* Institute of Molecular Cell Biology and Genetics.
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* %%
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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* #L%
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*/
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package org.scijava.io.handle;
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import org.scijava.io.location.Location;
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/**
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* A buffered {@link StreamHandle}.
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*
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* @author Gabriel Einsdorf
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*/
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public interface BufferedStreamHandle<L extends Location> extends
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SeekableStreamHandle<L>
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{
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}

‎src/main/java/org/scijava/io/handle/DefaultBufferedStreamHandle.java

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/*
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* #%L
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* SciJava Common shared library for SciJava software.
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* %%
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* Copyright (C) 2009 - 2017 Board of Regents of the University of
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* Wisconsin-Madison, Broad Institute of MIT and Harvard, and Max Planck
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* Institute of Molecular Cell Biology and Genetics.
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* %%
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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* #L%
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*/
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package org.scijava.io.handle;
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import java.io.IOException;
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import java.io.InputStream;
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import java.io.OutputStream;
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import org.scijava.io.ByteArrayByteBank;
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import org.scijava.io.ByteBank;
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import org.scijava.io.location.Location;
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/**
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* A {@link BufferedStreamHandle} backed by a {@link ByteBank}.
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*
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* @author Gabriel Einsdorf
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*/
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public class DefaultBufferedStreamHandle<L extends Location> extends
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AbstractStreamHandle<L> implements BufferedStreamHandle<L>
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{
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private static final int CHUNK_SIZE = 8192;
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private final StreamHandle<L> handle;
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private ByteBank buffer;
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private InputStream inStreamProxy;
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private OutputStream outStreamProxy;
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private boolean closed;
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/**
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* Wraps around StreamHandle in a buffer
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*
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* @param handle
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*/
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public DefaultBufferedStreamHandle(final StreamHandle<L> handle) {
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this.handle = handle;
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}
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@Override
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public int read() throws IOException {
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return offset() < length() ? readByte() & 0xff : -1;
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}
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@Override
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public byte readByte() throws IOException {
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// reached end of the buffer
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if (offset() == handle.length()) {
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return -1;
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}
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// check if we need to refill the buffer
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if (offset() > maxBuf() || maxBuf() == -1) {
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// buffer more bytes
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final int filled = fill();
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if (filled <= 0) {
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// no more bytes in input handle
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return -1;
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}
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}
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final byte b = getBufferIfOpen().getByte(offset());
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advance(1);
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return b;
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}
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@Override
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public void seek(final long pos) throws IOException {
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final long off = offset();
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if (off == pos) return;
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if (pos > off) {
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// ensure target is buffered
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while (pos > maxBuf()) {
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fill();
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}
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}
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// values in the range (pos < off) are already buffered
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setOffset(pos);
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}
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private long maxBuf() throws IOException {
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return getBufferIfOpen().size() - 1;
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}
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@Override
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public long skip(final long n) throws IOException {
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seek(offset() + n);
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return handle().skip(n);
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}
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@Override
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public int read(final byte[] b, final int off, final int len)
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throws IOException
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{
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while (maxBuf() < offset() + len) {
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final int filled = fill();
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if (filled <= 0) {
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// no more bytes available
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break;
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}
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}
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// read all available bytes
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final int available = (int) available(len);
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getBufferIfOpen().getBytes(offset(), b, off, available);
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setOffset(offset() + available);
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return available;
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}
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/**
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* Fills the buffer with XX more bytes
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*
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* @throws IOException
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*/
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private int fill() throws IOException {
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final byte[] buf = new byte[CHUNK_SIZE];
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final int read = handle().read(buf);
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if (read <= 0) {
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return -1;
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}
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getBufferIfOpen().appendBytes(buf, read);
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return read;
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}
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@Override
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public InputStream in() {
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if (inStreamProxy == null) {
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inStreamProxy = new DataHandleInputStream<>(this);
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}
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return inStreamProxy;
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}
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@Override
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public OutputStream out() {
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if (outStreamProxy == null) {
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outStreamProxy = new DataHandleOutputStream<>(this);
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}
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return outStreamProxy;
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}
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@Override
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public long length() throws IOException {
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return handle().length();
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}
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private StreamHandle<L> handle() throws IOException {
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if (closed) {
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throw new IOException("Handle is closed!");
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}
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return handle;
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}
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@Override
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public void setLength(final long length) throws IOException {
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handle().setLength(length);
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}
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@Override
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public boolean isReadable() {
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return !closed && handle.isReadable();
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}
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@Override
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public boolean isWritable() {
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return !closed && handle.isWritable();
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}
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@Override
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public boolean exists() throws IOException {
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return handle.exists();
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}
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@Override
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public Class<L> getType() {
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return handle.getType();
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}
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@Override
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public void resetStream() throws IOException {
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getBufferIfOpen();
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if (handle() instanceof ResettableStreamHandle) {
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((ResettableStreamHandle<L>) handle()).resetStream();
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}
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else {
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throw new IOException("Handle can not be reset!");
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}
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}
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@Override
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public void close() throws IOException {
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if (!closed) {
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closed = true;
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handle().close();
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getBufferIfOpen().clear();
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buffer = null;
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}
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}
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/**
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* @return the buffer used in this handle
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* @throws IOException if this handle has been closed
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*/
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private ByteBank getBufferIfOpen() throws IOException {
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if (closed) {
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throw new IOException("Handle is closed");
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}
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if (buffer == null) {
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buffer = new ByteArrayByteBank();
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}
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return buffer;
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}
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}

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