com.liulishuo.filedownloader.stream

Interface FileDownloadOutputStream

public interface FileDownloadOutputStream

The output stream used to write the file for download.

Method Summary

Modifier and Type	Method and Description
void	close() Closes this output stream and releases any system resources associated with this stream.
void	flushAndSync() Flush all buffer to system and force all system buffers to synchronize with the underlying device.
void	seek(long offset) Sets the file-pointer offset, measured from the beginning of this file, at which the next read or write occurs.
void	setLength(long newLength) Sets the length of this file.
void	write(byte[] b, int off, int len) Writes len bytes from the specified byte array starting at offset off to this file.

Method Detail

write

void write(byte[] b,
           int off,
           int len)
    throws java.io.IOException

Writes len bytes from the specified byte array starting at offset off to this file.

Parameters:

b - the data.

off - the start offset in the data.

len - the number of bytes to write.

Throws:

java.io.IOException - if an I/O error occurs.

flushAndSync

void flushAndSync()
           throws java.io.IOException

Flush all buffer to system and force all system buffers to synchronize with the underlying device.

This method must ensure all data whatever on buffers of VM or buffers of system for this output stream must persist on the physical media, otherwise the breakpoint will not be integrity.

Throws:

java.io.SyncFailedException - Thrown when the buffers cannot be flushed, or because the system cannot guarantee that all the buffers have been synchronized with physical media.

java.io.IOException

See Also:

OutputStream.flush(), FileDescriptor.sync()

close

void close()
    throws java.io.IOException

Closes this output stream and releases any system resources associated with this stream. The general contract of close is that it closes the output stream. A closed stream cannot perform output operations and cannot be reopened.

The close method of OutputStream does nothing.

Throws:

java.io.IOException - if an I/O error occurs.

seek

void seek(long offset)
   throws java.io.IOException,
          java.lang.IllegalAccessException

Sets the file-pointer offset, measured from the beginning of this file, at which the next read or write occurs. The offset may be set beyond the end of the file. Setting the offset beyond the end of the file does not change the file length. The file length will change only by writing after the offset has been set beyond the end of the file.

Parameters:

offset - the offset position, measured in bytes from the beginning of the file, at which to set the file pointer.

Throws:

java.io.IOException - if offset is less than 0 or if an I/O error occurs.

java.lang.IllegalAccessException - if in this output stream doesn't support this function. You can return false in FileDownloadHelper.OutputStreamCreator#supportSeek() let the internal mechanism can predict this situation, and handle it smoothly.

See Also:

RandomAccessFile.seek(long), FileChannel.position(long)

setLength

void setLength(long newLength)
        throws java.io.IOException,
               java.lang.IllegalAccessException

Sets the length of this file.

If the present length of the file as returned by the length method is greater than the newLength argument then the file will be truncated. In this case, if the file offset as returned by the getFilePointer method is greater than newLength then after this method returns the offset will be equal to newLength.

If the present length of the file as returned by the length method is smaller than the newLength argument then the file will be extended. In this case, the contents of the extended portion of the file are not defined.

Parameters:

newLength - The desired length of the file

Throws:

java.io.IOException - If an I/O error occurs

java.lang.IllegalAccessException - If in this output stream doesn't support this function.

See Also:

RandomAccessFile.setLength(long)