Returns an estimate of the number of remaining bytes that can be read (or skipped over) from this input stream without blocking by the next invocation of a method for this input stream. Returns 0 when the file position is beyond EOF. The next invocation might be the same thread or another thread. A single read or skip of this many bytes will not block, but may read or skip fewer bytes.
In some cases, a non-blocking read (or skip) may appear to be blocked when it is merely slow, for example when reading large files over slow networks.
IOException | if this file input stream has been closed by calling
close or an I/O error occurs. |
Closes this file input stream and releases any system resources associated with the stream.
If this stream has an associated channel then the channel is closed as well.
IOException | if an I/O error occurs. |
@apiNote
Overriding close to perform cleanup actions is reliable
only when called directly or when called by try-with-resources.
Do not depend on finalization to invoke close;
finalization is not reliable and is deprecated.
If cleanup of native resources is needed, other mechanisms such as
java.lang.ref.Cleaner should be used.
@revised 1.4
@spec JSR-51
Reads a byte of data from this input stream. This method blocks if no input is yet available.
-1 if the end of the
file is reached.
IOException | if an I/O error occurs. |
Reads up to b.length bytes of data from this input
stream into an array of bytes. This method blocks until some input
is available.
b | the buffer into which the data is read. |
-1 if there is no more data because the end of
the file has been reached.
IOException | if an I/O error occurs. |
Reads up to len bytes of data from this input stream
into an array of bytes. If len is not zero, the method
blocks until some input is available; otherwise, no
bytes are read and 0 is returned.
b | the buffer into which the data is read. | |
off | the start offset in the destination array b | |
len | the maximum number of bytes read. |
-1 if there is no more data because the end of
the file has been reached.
IOException | if an I/O error occurs. |
Skips over and discards n bytes of data from the
input stream.
The skip method may, for a variety of
reasons, end up skipping over some smaller number of bytes,
possibly 0. If n is negative, the method
will try to skip backwards. In case the backing file does not support
backward skip at its current position, an IOException is
thrown. The actual number of bytes skipped is returned. If it skips
forwards, it returns a positive value. If it skips backwards, it
returns a negative value.
This method may skip more bytes than what are remaining in the backing file. This produces no exception and the number of bytes skipped may include some number of bytes that were beyond the EOF of the backing file. Attempting to read from the stream after skipping past the end will result in -1 indicating the end of the file.
n | the number of bytes to be skipped. |
IOException | if n is negative, if the stream does not support seek, or if an I/O error occurs. |
Diagram: InputStream