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The MongoDB Java Driver uber-artifact, containing mongodb-driver, mongodb-driver-core, and bson
/*
* Copyright (c) 2008-2014 MongoDB, Inc.
*
* 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.mongodb.gridfs;
import com.mongodb.BasicDBObjectBuilder;
import com.mongodb.DBObject;
import com.mongodb.MongoException;
import com.mongodb.util.Util;
import org.bson.types.ObjectId;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Date;
/**
* This class represents a GridFS file to be written to the database. Operations include:
*
*
* - Writing data obtained from an InputStream
* - Getting an OutputStream to stream the data out to
*
*
* @mongodb.driver.manual core/gridfs/ GridFS
*/
public class GridFSInputFile extends GridFSFile {
/**
* Default constructor setting the GridFS file name and providing an input stream containing data to be written to the file.
*
* @param fs The GridFS connection handle.
* @param in Stream used for reading data from.
* @param filename Name of the file to be created.
* @param closeStreamOnPersist indicate the passed in input stream should be closed once the data chunk persisted
*/
protected GridFSInputFile( GridFS fs , InputStream in , String filename, boolean closeStreamOnPersist ) {
_fs = fs;
_in = in;
_filename = filename;
_closeStreamOnPersist = closeStreamOnPersist;
_id = new ObjectId();
_chunkSize = GridFS.DEFAULT_CHUNKSIZE;
_uploadDate = new Date();
try {
_messageDigester = MessageDigest.getInstance("MD5");
} catch (NoSuchAlgorithmException e) {
throw new RuntimeException("No MD5!");
}
_messageDigester.reset();
_buffer = new byte[(int) _chunkSize];
}
/**
* Default constructor setting the GridFS file name and providing an input stream containing data to be written to the file.
*
* @param fs The GridFS connection handle.
* @param in Stream used for reading data from.
* @param filename Name of the file to be created.
*/
protected GridFSInputFile( GridFS fs , InputStream in , String filename ) {
this( fs, in, filename, false);
}
/**
* Constructor that only provides a file name, but does not rely on the presence of an {@link java.io.InputStream}. An {@link
* java.io.OutputStream} can later be obtained for writing using the {@link #getOutputStream()} method.
*
* @param fs The GridFS connection handle.
* @param filename Name of the file to be created.
*/
protected GridFSInputFile( GridFS fs , String filename ) {
this( fs , null , filename );
}
/**
* Minimal constructor that does not rely on the presence of an {@link java.io.InputStream}. An {@link java.io.OutputStream} can later
* be obtained for writing using the {@link #getOutputStream()} method.
*
* @param fs The GridFS connection handle.
*/
protected GridFSInputFile( GridFS fs ) {
this( fs , null , null );
}
/**
* Sets the ID of this GridFS file.
*
* @param id the file's ID.
*/
public void setId(final Object id) {
_id = id;
}
/**
* Sets the file name on the GridFS entry.
*
* @param fn
* File name.
*/
public void setFilename( String fn ) {
_filename = fn;
}
/**
* Sets the content type (MIME type) on the GridFS entry.
*
* @param ct
* Content type.
*/
public void setContentType( String ct ) {
_contentType = ct;
}
/**
* Set the chunk size. This must be called before saving any data.
*
* @param chunkSize The size in bytes.
*/
public void setChunkSize(long chunkSize) {
if (_outputStream != null || _savedChunks)
return;
_chunkSize = chunkSize;
_buffer = new byte[(int) _chunkSize];
}
/**
* Calls {@link GridFSInputFile#save(long)} with the existing chunk size.
*
* @throws MongoException if there's a problem saving the file.
*/
@Override
public void save() {
save( _chunkSize );
}
/**
* This method first calls saveChunks(long) if the file data has not been saved yet. Then it persists the file entry to GridFS.
*
* @param chunkSize Size of chunks for file in bytes.
* @throws MongoException if there's a problem saving the file.
*/
public void save( long chunkSize ) {
if (_outputStream != null)
throw new MongoException( "cannot mix OutputStream and regular save()" );
// note that chunkSize only changes _chunkSize in case we actually save chunks
// otherwise there is a risk file and chunks are not compatible
if ( ! _savedChunks ) {
try {
saveChunks( chunkSize );
} catch ( IOException ioe ) {
throw new MongoException( "couldn't save chunks" , ioe );
}
}
super.save();
}
/**
* Saves all data into chunks from configured {@link java.io.InputStream} input stream to GridFS.
*
* @return Number of the next chunk.
* @throws IOException on problems reading the new entry's {@link java.io.InputStream}.
* @throws MongoException
* @see com.mongodb.gridfs.GridFSInputFile#saveChunks(long)
*/
public int saveChunks() throws IOException {
return saveChunks( _chunkSize );
}
/**
* Saves all data into chunks from configured {@link java.io.InputStream} input stream to GridFS. A non-default chunk size can be
* specified. This method does NOT save the file object itself, one must call save() to do so.
*
* @param chunkSize Size of chunks for file in bytes.
* @return Number of the next chunk.
* @throws IOException on problems reading the new entry's {@link java.io.InputStream}.
* @throws MongoException
*/
public int saveChunks( long chunkSize ) throws IOException {
if (_outputStream != null)
throw new MongoException( "cannot mix OutputStream and regular save()" );
if ( _savedChunks )
throw new MongoException( "chunks already saved!" );
if ( chunkSize <= 0) {
throw new MongoException("chunkSize must be greater than zero");
}
if ( _chunkSize != chunkSize ) {
_chunkSize = chunkSize;
_buffer = new byte[(int) _chunkSize];
}
int bytesRead = 0;
while ( bytesRead >= 0 ) {
_currentBufferPosition = 0;
bytesRead = _readStream2Buffer();
_dumpBuffer( true );
}
// only finish data, do not write file, in case one wants to change metadata
_finishData();
return _currentChunkNumber;
}
/**
* After retrieving this {@link java.io.OutputStream}, this object will be capable of accepting successively written data to the output
* stream. To completely persist this GridFS object, you must finally call the {@link java.io.OutputStream#close()} method on the output
* stream. Note that calling the save() and saveChunks() methods will throw Exceptions once you obtained the OutputStream.
*
* @return Writable stream object.
*/
public OutputStream getOutputStream() {
if ( _outputStream == null ) {
_outputStream = new MyOutputStream();
}
return _outputStream;
}
/**
* Dumps a new chunk into the chunks collection. Depending on the flag, also partial buffers (at the end) are going to be written
* immediately.
*
* @param writePartial Write also partial buffers full.
* @throws MongoException
*/
private void _dumpBuffer( boolean writePartial ) {
if ( ( _currentBufferPosition < _chunkSize ) && !writePartial ) {
// Bail out, chunk not complete yet
return;
}
if (_currentBufferPosition == 0) {
// chunk is empty, may be last chunk
return;
}
byte[] writeBuffer = _buffer;
if ( _currentBufferPosition != _chunkSize ) {
writeBuffer = new byte[_currentBufferPosition];
System.arraycopy( _buffer, 0, writeBuffer, 0, _currentBufferPosition );
}
DBObject chunk = createChunk(_id, _currentChunkNumber, writeBuffer);
_fs._chunkCollection.save( chunk );
_currentChunkNumber++;
_totalBytes += writeBuffer.length;
_messageDigester.update( writeBuffer );
_currentBufferPosition = 0;
}
/**
* Creates a new chunk of this file. Can be over-ridden, if input files need to be split into chunks using a different mechanism.
*
* @param id the file ID
* @param currentChunkNumber the unique id for this chunk
* @param writeBuffer the byte array containing the data for this chunk
* @return a DBObject representing this chunk.
*/
protected DBObject createChunk(final Object id, final int currentChunkNumber, final byte[] writeBuffer) {
return BasicDBObjectBuilder.start()
.add("files_id", id)
.add("n", currentChunkNumber)
.add("data", writeBuffer).get();
}
/**
* Reads a buffer full from the {@link java.io.InputStream}.
*
* @return Number of bytes read from stream.
* @throws IOException if the reading from the stream fails.
*/
private int _readStream2Buffer() throws IOException {
int bytesRead = 0;
while ( _currentBufferPosition < _chunkSize && bytesRead >= 0 ) {
bytesRead = _in.read( _buffer, _currentBufferPosition,
(int) _chunkSize - _currentBufferPosition );
if ( bytesRead > 0 ) {
_currentBufferPosition += bytesRead;
} else if ( bytesRead == 0 ) {
throw new RuntimeException( "i'm doing something wrong" );
}
}
return bytesRead;
}
/**
* Marks the data as fully written. This needs to be called before super.save()
*/
private void _finishData() {
if (!_savedChunks) {
_md5 = Util.toHex( _messageDigester.digest() );
_messageDigester = null;
_length = _totalBytes;
_savedChunks = true;
try {
if ( _in != null && _closeStreamOnPersist )
_in.close();
} catch (IOException e) {
//ignore
}
}
}
private final InputStream _in;
private boolean _closeStreamOnPersist;
private boolean _savedChunks = false;
private byte[] _buffer = null;
private int _currentChunkNumber = 0;
private int _currentBufferPosition = 0;
private long _totalBytes = 0;
private MessageDigest _messageDigester = null;
private OutputStream _outputStream = null;
/**
* An output stream implementation that can be used to successively write to a GridFS file.
*/
class MyOutputStream extends OutputStream {
@Override
public void write( int b ) throws IOException {
byte[] byteArray = new byte[1];
byteArray[0] = (byte) (b & 0xff);
write( byteArray, 0, 1 );
}
@Override
public void write( byte[] b , int off , int len ) throws IOException {
int offset = off;
int length = len;
int toCopy = 0;
while ( length > 0 ) {
toCopy = length;
if ( toCopy > _chunkSize - _currentBufferPosition ) {
toCopy = (int) _chunkSize - _currentBufferPosition;
}
System.arraycopy( b, offset, _buffer, _currentBufferPosition, toCopy );
_currentBufferPosition += toCopy;
offset += toCopy;
length -= toCopy;
if ( _currentBufferPosition == _chunkSize ) {
_dumpBuffer( false );
}
}
}
/**
* Processes/saves all data from {@link java.io.InputStream} and closes the potentially present {@link java.io.OutputStream}. The
* GridFS file will be persisted afterwards.
*/
@Override
public void close() {
// write last buffer if needed
_dumpBuffer( true );
// finish stream
_finishData();
// save file obj
GridFSInputFile.super.save();
}
}
}
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