private NPOIFSFileSystem(FileChannel channel, boolean closeChannelOnError) throws IOException {
this(false);
try {
// Get the header
ByteBuffer headerBuffer = ByteBuffer.allocate(POIFSConstants.SMALLER_BIG_BLOCK_SIZE);
IOUtils.readFully(channel, headerBuffer);
// Have the header processed
_header = new HeaderBlock(headerBuffer);
// Now process the various entries
_data = new FileBackedDataSource(channel);
readCoreContents();
} catch (IOException e) {
if (closeChannelOnError) {
channel.close();
}
throw e;
} catch (RuntimeException e) {
// Comes from Iterators etc.
// TODO Decide if we can handle these better whilst
// still sticking to the iterator contract
if (closeChannelOnError) {
channel.close();
}
throw e;
}
}
/**
* Create a POIFSFileSystem from an <tt>InputStream</tt>. Normally the stream is read until EOF.
* The stream is always closed.
*
* <p>Some streams are usable after reaching EOF (typically those that return <code>true</code>
* for <tt>markSupported()</tt>). In the unlikely case that the caller has such a stream
* <i>and</i> needs to use it after this constructor completes, a work around is to wrap the
* stream in order to trap the <tt>close()</tt> call. A convenience method (
* <tt>createNonClosingInputStream()</tt>) has been provided for this purpose:
*
* <pre>
* InputStream wrappedStream = POIFSFileSystem.createNonClosingInputStream(is);
* HSSFWorkbook wb = new HSSFWorkbook(wrappedStream);
* is.reset();
* doSomethingElse(is);
* </pre>
*
* Note also the special case of <tt>ByteArrayInputStream</tt> for which the <tt>close()</tt>
* method does nothing.
*
* <pre>
* ByteArrayInputStream bais = ...
* HSSFWorkbook wb = new HSSFWorkbook(bais); // calls bais.close() !
* bais.reset(); // no problem
* doSomethingElse(bais);
* </pre>
*
* @param stream the InputStream from which to read the data
* @exception IOException on errors reading, or on invalid data
*/
public NPOIFSFileSystem(InputStream stream) throws IOException {
this(false);
ReadableByteChannel channel = null;
boolean success = false;
try {
// Turn our InputStream into something NIO based
channel = Channels.newChannel(stream);
// Get the header
ByteBuffer headerBuffer = ByteBuffer.allocate(POIFSConstants.SMALLER_BIG_BLOCK_SIZE);
IOUtils.readFully(channel, headerBuffer);
// Have the header processed
_header = new HeaderBlock(headerBuffer);
// Sanity check the block count
BlockAllocationTableReader.sanityCheckBlockCount(_header.getBATCount());
// We need to buffer the whole file into memory when
// working with an InputStream.
// The max possible size is when each BAT block entry is used
int maxSize = BATBlock.calculateMaximumSize(_header);
ByteBuffer data = ByteBuffer.allocate(maxSize);
// Copy in the header
headerBuffer.position(0);
data.put(headerBuffer);
data.position(headerBuffer.capacity());
// Now read the rest of the stream
IOUtils.readFully(channel, data);
success = true;
// Turn it into a DataSource
_data = new ByteArrayBackedDataSource(data.array(), data.position());
} finally {
// As per the constructor contract, always close the stream
if (channel != null) channel.close();
closeInputStream(stream, success);
}
// Now process the various entries
readCoreContents();
}
